Abstract
COVID‐19 and ME/CFS present with some similar symptoms, especially physical and mental fatigue. In order to understand the basis of these similarities and the possibility of underlying common genetic components, we performed a systematic review of all published genetic association and cohort studies regarding COVID‐19 and ME/CFS and extracted the genes along with the genetic variants investigated. We then performed gene ontology and pathway analysis of those genes that gave significant results in the individual studies to yield functional annotations of the studied genes using protein analysis through evolutionary relationships (PANTHER) VERSION 17.0 software. Finally, we identified the common genetic components of these two conditions. Seventy‐one studies for COVID‐19 and 26 studies for ME/CFS were included in the systematic review in which the expression of 97 genes for COVID‐19 and 429 genes for ME/CFS were significantly affected. We found that ACE, HLA‐A, HLA‐C, HLA‐DQA1, HLA‐DRB1, and TYK2 are the common genes that gave significant results. The findings of the pathway analysis highlight the contribution of inflammation mediated by chemokine and cytokine signaling pathways, and the T cell activation and Toll receptor signaling pathways. Protein class analysis revealed the contribution of defense/immunity proteins, as well as protein‐modifying enzymes. Our results suggest that the pathogenesis of both syndromes could involve some immune dysfunction.
Introduction
The last few years, the world has been devastated by Corona virus disease‐2019 (COVID‐19) 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 and its postinfection sequelae that are reminiscent of another chronic condition, Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). 10 , 11 Both these diseases are characterized by physical and mental fatigue, especially brain fog. 12 , 13 , 14 Understanding the basis of these similarities and the possibility of an underlying immune dysfunction could help with diagnosis, prognosis, and possible treatment of these debilitating conditions.
Infection with the recent Coronavirus (severe acute respiratory syndrome (SARS)‐CoV‐2) leads to COVID‐19, a multiorgan syndrome, the severity of which appears to derive from the host's immune response, 8 especially the release primarily in the lungs of a storm of pro‐inflammatory chemokines and cytokines, 1 , 2 , 3 , 4 , 5 , 6 , 7 , 15 such as IL‐6. 16 , 17 , 18 , 19 , 20 In addition to the well‐known severe respiratory and inflammatory problems, infection with SARS‐CoV‐2 can also contribute to persistent fatigue 21 , 22 that is apparently independent of the initial severity of the infection 23 , 24 in 30%–50% of COVID patients. 25 , 26 , 27 , 28 , 29 , 30 This condition has been termed “long‐COVID syndrome” 26 , 28 , 31 , 32 and is particularly associated with neurological, 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 neurodegenerative, 36 , 42 , 43 psychiatric, 44 , 45 , 46 , 47 , 48 , 49 , 50 and cognitive 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 problems, especially brain fog. 24 , 26 , 28 , 32 , 44 , 56 , 57 , 58 , 59 Long‐COVID has been considered the “next health disaster” in the USA. 60
Host genetic factors have been investigated 61 , 62 for the possibility they may determine COVID‐19 susceptibility and severity. 63 In particular, Genome‐wide association studies (GWAS) have uncovered the importance of the ABO locus and possible protective variants in patients with COVID‐19. 64
ME/CFS is a chronic, debilitating disease 65 , 66 , 67 , 68 with a prevalence of about 1% in the USA. 69 It is characterized by disabling fatigue of 6 months in the absence of any systemic disease, along with sleep disturbances, malaise, muscle aches, gastrointestinal symptoms, dizziness, and cognitive problems. 67 , 70 , 71 , 72 , 73 , 74 Approximately 50% of ME/CFS patients developed symptoms following a sudden, influenza‐like illness 75 implying the possible involvement of some clinical or subclinical infection. In such cases, immune cells could be activated by pathogen‐associated molecular patterns (PAMPs), including nucleic acid variants associated with viruses. ME/CFS may, therefore, involve some autoimmune 76 , 77 or neuroinflammatory components. 78 , 79 , 80 Even though serum pro‐inflammatory cytokine levels have been reported to be increased in ME/CFS patients, 81 , 82 other studies have not supported such findings, 71 , 83 except for elevated serum IL‐6. 81 , 84 As a result, it was suggested that ME/CFS may involve some dysfunction in the brain. 85 We proposed that inflammation in the hypothalamus could affect brain function, 76 , 82 and dysregulate homeostasis, 86 but the mediators involved and their interactions are still unknown. 87
Because both COVID‐19 and ME/CFS are characterized by physical and mental fatigue, it has been speculated as to whether these two conditions may have common underlying pathogenetic mechanisms 12 , 88 , 89 or whether COVID‐19 could lead to ME/CFS. 90 , 91
We reviewed genetic association and cohort studies involving COVID‐19 and/or ME/CFS and we specifically investigated whether there may be any overlap, especially in any genes associated with immune processes.
Methods
Identification and eligibility of relevant studies
In order to clarify any genetic contribution in the pathogenesis of COVID‐19 and ME/CFS, we conducted a systematic review of genetic association studies either in candidate genes or in genome‐wide scale and cohort studies. We searched in PubMed using the search terms (“myalgic encephalomyelitis” or “chronic fatigue syndrome” OR COVID‐19 OR SARS‐CoV‐2) AND (“genetic association” OR genes, Filter: Humans) until January 2022. We also retrieved articles from the GWAS Catalog (https://www.ebi.ac.uk/gwas/). In addition, any meta‐analyses and references of the eligible articles were also screened. Case reports, editorials, reviews, and non‐English articles were excluded, as well as studies with other study designs. We did not request unpublished data from any author. The eligibility of the records was assessed independently by two investigators (M.T. and C.C.), the results were compared, and any disagreements were resolved by reaching a consensus.
The inclusion criteria for studies to be considered were (i) genetic association studies or cohort studies and (ii) cases either with COVID‐19 or with ME/CFS. In the case of COVID‐19, controls could be either healthy or asymptomatic subjects.
Data extraction
The following information was extracted from each article: first author, year of publication, ethnicity, phenotype, the studied gene and genetic variant, the number of cases and controls, and their clinical characteristics.
GO analysis
In order to understand the functional role of the genes that gave significant results in the individual studies, we performed a gene ontology (GO) analysis using the PANTHER version 17.0 software (http://www.pantherdb.org/). 92 , 93 GO analysis consists of molecular function (MF), biological process (BP), and cellular component (CC). PANTHER also performs protein class and pathway analysis.
Results
Study characteristics
The literature search retrieved 2069 records. When an article provided data for different populations, each population was regarded as a different study. Figure 1 presents a flowchart of retrieved articles. Finally, 71 studies for COVID‐19 and 26 studies for ME/CFS were included in the systematic review. The characteristics of each study either of COVID‐19 or ME/CFS are shown in Tables S1 and S2, respectively. Overall, 97 genes for COVID‐19 and 429 genes for ME/CFS gave significant results. The most studied genes for both COVID‐19 and ME/CFS are presented in Tables S3 and S4.
Figure 1.

Flowchart showing how studies were selected for the review.
Findings from genetic association and cohort studies of COVID‐19
These findings are listed in Table S1. A recent GWAS of severe COVID‐19 patients with respiratory failure in Caucasians of European descent highlighted the significance of two genetic loci located in 3p21.31 (rs11385942) and 9q34.2 (rs657152). 94 The association signal at locus 3p21.31 spans six genes, namely SLC6A20, LZTFL1, CCR9, FYCO1, CXCR6, and XCR1, whereas the signal at locus 9q34.2 contains the ABO blood group locus. Individuals with blood group A encountered the highest risk, whereas individuals with blood group O had the highest protection. 94 However, the results regarding the ABO implication in COVID‐19 are conflicting. 95 , 96
Another whole‐exome sequencing study (WESS) in two pairs of brothers with severe COVID‐19 from the Netherlands tried to detect monogenic elements of the disease. Indeed, loss‐of‐function variants of X‐chromosomal TLR7 were detected and were correlated with impaired type I and II interferon (IFN) responses. 97 Loss‐of‐function variants harbored in TLR3, TICAM1, TBK1, IRF3, UNC93B1, IRF7, IFNAR1, and IFNAR2 were also found significantly associated with life‐threatening COVID‐19 pneumonia in another GWAS. 98
Two loci, 11q23.3 and 11q14.2, were significantly associated with COVID‐19 severity in the context of a GWAS in Chinese patients. 99 Wang et al. 100 also identified the most significant association signal (rs6020298) located in the TMEM189‐UBE2V1 at 20q13.13 region, which has been associated with the interleukin‐1 (IL‐1) signaling pathway promoting innate immune responses. 101 The missense variant rs12329760 in TMPRSS2 was less frequent in critically ill patients. 101 This variant decreases the stability of TMPRSS2 and therefore angiotensin‐converting enzyme 2 (ACE2) binding of the coronavirus. In addition, HLA‐A*11:01, B*51:01, and C*14:02 alleles constitute the most significant risk alleles predisposing for severity. 101 Other immune molecules, like cytokines and chemokines, were also significantly associated with the majority of the studies. 102 , 103 , 104 , 105
The most significant association signals of another GWAS in UK patients were reported to be harbored in the gene cluster of OAS1, OAS2, and OAS3 (rs10735079), in DPP9 (rs2109069), in IFNAR2 (rs2236757) near the gene TYK2 (rs74956615). 106 DNAH7, CLUAP1, DES, SPEG, STXBP5, TOMM7, and WSB1 have been also associated with COVID‐19 mortality in another GWAS. 107 COVID‐19 severity was apparently associated with ABO and SLC6A20, as mentioned previously by Roberts et al. (2021), especially the variant rs657152. 108 , 109 A locus near IVNS1ABP was associated only in males, whereas two other loci, SRRM1 and the immunoglobulin lambda locus, were associated with COVID‐19 (Roberts et al., 2021). The IFITM3 variants, rs12252 and rs6598045, were associated with COVID‐19 severity/mortality. 110 , 111 , 112 , 113 However, in the context of another study, IFITM3 rs12252 was not associated significantly with the severity of COVID‐19. 114 The TMPRSS2/MX1 locus was associated with the severe COVID‐19, 115 whereas MX1 could constitute a potential therapeutic target. TLR7 loss‐of‐function variants were associated with severe COVID‐19 in young males. 116 HLA‐A*11:01:01:01 and HLA‐C*12:02:02:01‐HLA‐B*52:01:01:02 were significantly associated with severity of COVID‐19 based on the findings of a study in Japanese patients. 117 HLA‐DRB1*15:01 and *09:01, ‐DQB1*06:02 and ‐B*27:07 were also significantly associated with susceptibility to COVID‐19. 118 , 119 Major histocompatibility complex variants have been examined in many other studies with inconclusive results. 120 , 121 , 122 , 123 , 124 ApoE e4e4 genotype apparently increased the risk of severe COVID‐19 compared with the e3e3 genotype. 125 , 126 , 127 , 128 It is noteworthy that APOE is co‐expressed in type II alveolar cells in the lungs. 125
Variants of TMPRSS2 and PCSK3 protease genes could also affect the entry of the virus into the cells. 129 , 130 The DPP4 rs3788979 polymorphism, as well as the low levels of DPP4, were associated with COVID‐19 severity. 131 Rare loss‐of‐function variants in 13 genes involved in TLR3‐ and IRF7‐dependent type I IFN pathways were not found to be associated with severe COVID‐19. 132 The p.His159Tyr variant in TNFRSF13C gene was reported to be associated with severe COVID‐19. 133 The variant rs383510 in TMPRSS2 increased the risk of getting infected with SARS‐CoV‐2. 134 A polymorphism in the promoter of MUCB5 gene was also associated with the severity of COVID‐19. 135 The KLRC2del and HLA‐E*0101 alleles increased significantly the risk for severe COVID‐19. 136 HLA‐C*07:29 and B*15:27 were also associated with the risk for COVID‐19. 137 XCR1, CCR2, SACM1L, OAS3, NSF, WNT3, NAPSA, and IFNAR2 were also associated with COVID‐19 severity. 138 Over 10 units of C9orf72 HREs could constitute a risk factor for severe COVID‐19. 139 IFNλ polymorphisms could also be found to affect the SARS‐CoV‐2 viral load. 140 The DBP polymorphisms of rs7041 and rs4588 were significantly correlated with the prevalence and mortality rates of COVID‐19. 141
Regarding the implication of ACE2 in COVID‐19 pathogenesis, the data are conflicting. A study of whole‐exome sequencing data in Italians revealed greater genetic variability of the ACE2 gene in controls than in‐patient cases implying the significance of variants harbored in this gene for the differential outcomes in COVID‐19 patients. 142 Nevertheless, the association of ACE2 variants with COVID‐19 severity was not significant in other studies. 143 , 144 , 145 , 146 In contrast, the minor allele of rs2285666 located in ACE2 which increases the expression of the gene up to 50% affects the infection and case fatality rate of COVID‐19. 135 However, Asselta et al. did not detect any significant association between ACE2 and COVID‐19 severity, whereas TMPRSS2 levels and genetic variants were associated with the severity of the disease. 147 , 148 , 149 The outcome of COVID‐19 also depends on ACE I/D variant status which could influence both the risk and the severity of the disease. 150 , 151 Other host genetic variants that affect the outcome of COVID‐19 include ACE2 (p.Arg514Gly) or TMPRSS2 (p.Val160Met) variants. 152 ACE I/I genotype was significantly more common in COVID‐19 patients than in the controls suggesting a potential predictive genetic factor for symptomatic COVID‐19. 153 Two other studies regarding the implication of ACE in the course of COVID‐19 produced inconclusive results. 95 , 105 In addition, vitamin D receptor (VDR) variants were found to be implicated in COVID‐19 susceptibility. 154
Many other studies examined the association between COVID‐19 susceptibility and genetic loci implicated in distinct functions. 155 , 156 , 157 , 158 , 159 , 160 , 161 , 162 More specifically, the mannose‐binding lectin 2 (MBL) deficiency‐causing B allele (rs1800450) constitutes a risk factor for severe COVID‐19, 160 the pentraxin 3 (PTX3) gene polymorphism rs1840680 (1449A/G) predisposes for macrophage activation syndrome in COVID‐19 patients, and the sigma‐1 receptor (S1R) genetic variant rs17775810 affects the survival rate of COVID‐19 course, as homozygotes for T allele had the lowest death rate. 154 The GC (rs2282679), which encodes the vitamin D‐binding protein, was related statistically to the severity of infection. 159 The KIR gene polymorphisms were also associated with severe COVID‐19 disease, 158 while certain variants across IFNL4, TLL1, and DDR1 affected the course and outcome of COVID‐19. 162 Last but not least, polymorphisms in genes encoding proteases (FURIN, PLG, and PRSS1) and in genes related with innate immunity (MBL2 and OAS1) were also associated with host response to SARS‐CoV‐2 infection. 163
GO analysis
Due to the large number of SNPs that are located in many different genes, we performed a GO analysis for the functional annotation of the genes that gave significant results in the individual studies. We chose the top five results based on their percentages. The results of the GO analysis regarding the molecular function, biological process, and cellular component are shown in Table 1. More specifically, the majority of genes encode defense/immunity proteins, protein‐modifying enzymes, transmembrane signal receptors, metabolite interconversion enzymes, and gene‐specific transcriptional regulators. Regarding the pathway analysis, most of the genes are involved in inflammation mediated by chemokine and cytokine signaling pathways, Toll receptor signaling pathways, interleukin signaling pathways, Alzheimer disease‐presenilin pathways, as well as in vitamin D metabolism (Table 1).
Table 1.
The top five genetic ontology (GO) terms per category and pathway analysis regarding COVID‐19.
| GO term | Percent of genes hit against the total # genes | ||
|---|---|---|---|
| Molecular function | |||
| 1 | Binding (GO:0005488) | 35 | 42.70% |
| 2 | Catalytic activity (GO:0003824) | 27 | 32.90% |
| 3 | Molecular transducer activity (GO:0060089) | 8 | 9.80% |
| 4 | Transcription regulator activity (GO:0140110) | 5 | 6.10% |
| 5 | Molecular function regulator (GO:0098772) | 3 | 3.70% |
| Biological process | |||
| 1 | Cellular process (GO:0009987) | 49 | 22.70% |
| 2 | Biological regulation (GO:0065007) | 37 | 17.10% |
| 3 | Metabolic process (GO:0008152) | 31 | 14.40% |
| 4 | Response to stimulus (GO:0050896) | 30 | 13.90% |
| 5 | Immune system process (GO:0002376) | 20 | 9.30% |
| Cellular component | |||
| 1 | Cellular anatomical entity (GO:0110165) | 57 | 82.6% |
| 2 | Protein‐containing complex (GO:0032991) | 12 | 17.4% |
| Protein class | |||
| 1 | Defense/immunity protein (PC00090) | 20 | 25.00% |
| 2 | Protein‐modifying enzyme (PC00260) | 14 | 17.50% |
| 3 | Transmembrane signal receptor (PC00197) | 8 | 10.00% |
| 4 | Metabolite interconversion enzyme (PC00262) | 8 | 10.00% |
| 5 | Gene‐specific transcriptional regulator (PC00264) | 6 | 7.50% |
| Pathway | |||
| 1 | Inflammation mediated by chemokine and cytokine signaling pathway (P00031) | 8 | 17.40% |
| 2 | Toll receptor signaling pathway (P00054) | 8 | 17.40% |
| 3 | Interleukin signaling pathway (P00036) | 2 | 4.30% |
| 4 | Alzheimer disease‐presenilin pathway (P00004) | 2 | 4.30% |
| 5 | Vitamin D metabolism and pathway (P04396) | 2 | 4.30% |
Findings from genetic association and cohort studies of ME/CFS
These findings are listed in Table S2. Thirty‐three unique genes were associated with ME/CFS based on the results of an association study. 164 The two major findings that are also supported from the findings of gene expression analysis include the G allele of rs2247215 in GRIK2 and the T allele of rs356653 in NPAS2, both of which increased the risk of ME/CFS. The aforementioned genes are involved in glutaminergic transmission and circadian rhythm regulation, respectively. 164 In a GWAS, the functional annotation of the 50 most detrimental SNPs highlighted the importance of immune, hormone, and metabolic dysfunction in ME/CFS. 165 Slauch et al. also performed a GWAS which identified 23 SNPs (significant at p < 1*10−10) among which the variant rs12235235 revealed the most significant result located in RECK gene. 166 Two other SNPs are harbored in the T‐cell receptor alpha locus, with T‐cell receptor alpha locus (TRA) and one variant in T‐cell receptor alpha/delta locus. This study 166 confirmed the results of Smith et al. 164 regarding the significance of GRIK3, an ortholog of GRIK2 gene. Another study that genotyped 11 K SNPs located in genes involved in immune and inflammatory pathways identified 32 variants associated with ME/CFS and highlighted the importance of pathways involved in complement activation, chemokines, cytokines, and toll‐like receptor signaling. 167 SNPs in TRP ion channel genes, as well as SNPs in nicotinic and muscarinic acetylcholine receptor (AChR) genes from both isolated natural killer (NK) cells and isolated B cells, were also associated with ME/CFS. 168 , 169 The TNF 857 TT and CT genotypes were significantly increased, whereas IFN gamma low producers (A/A) were significantly decreased in patients with ME/CFS. 170 The significance of TNF rs1799724 was also highlighted. 171 SLC25A15, P4HA1, EBF3, and COX7B2 were significantly associated with ME/CFS in the UK Biobank ME/CFS Cohort. 172 HLA‐C*07:04 and HLA‐DQB1*03:03 were associated with ME/CFS suggesting the involvement of the immune system in the pathogenesis of the disease. 173 However, the contribution of the immune system was not confirmed in all studies. 174 TCOF1 and THUMPD2 were found to have more copy number variants (CNV)s in the UK Biobank ME/CFS cases than in controls. 175 The variants rs1866388, rs2918419, rs860458, and rs6188 in NR3C1 were also associated with ME/CFS. 173
Although Fukuda et al. (2013) did not detect an association between monoamine‐synthesizing genes, tyrosine hydroxylase (TH), and GTP cyclohydrolase I (GCH) with ME/CFS, the C + 243 T polymorphism in GCH gene and the C‐824T polymorphism in TH gene affected personality traits (like harm avoidance and persistence) observed in ME/CFS. 176 In another study, a significant association between 5‐HTTLPR and ME/CFS was also found; more specifically, longer (L and XL) allelic variants were detected in patients with ME/CFS strengthening the 5‐hydroxytryptamine (5‐HT) system dysfunction hypothesis in which patients with longer alleles have dysfunction due to the lower extracellular 5‐HT. 177 Three variants in HTR2A were also associated with ME/CFS. 178 The involvement of genetic variation of HTR2A in the pathogenesis of ME/CFS was also reported by Meyer et al. (2015). 179 In addition, in the context of an integrated approach, seven variants in the NR3C1 gene, a major effector of the hypothalamic–pituitary–adrenal (HPA) axis, were detected as significant biomarkers of ME/CFS. 180 One more study highlighted the significance of the NR3C1 gene in ME/CFS pathogenesis. 181 , 182 HLA‐DQA1*01 was also associated with ME/CFS. 183 Polymorphisms of COMT (rs4680) and the β₂‐adrenergic receptor (rs1042714) were also associated with ME/CFS. 184 The CCTTT8 allele in the NOS2A gene apparently reduced by 10‐fold the risk for ME/CFS, whereas the CCTTT11 allele increased the risk of developing the disease. 185 Carlo‐Stella et al. (2009) proposed that HLA haplotypes could contribute to a greater extent to ME/CFS pathogenesis than single alleles of RAGE or HLA‐DRB1. 186 The DD genotype of the ACE gene increased eight times the risk of developing ME/CFS as compared with the II genotype. 187 Many other studies found a significant association between ME/CFS and polymorphisms in the disrupted‐in‐schizophrenia 1 gene (DISC1), with copy number variants in genes associated with the function of the central nervous system, as well as with polymorphisms in ion channels and acetylcholine receptors, as well as with previously mentioned polymorphisms in HLA class I and class II loci. 188 , 189 , 190 , 191 One more study examined the contribution of AMPD1, CPT2, and PGYM genes, but no significant association was detected with CFS. 192 In addition, polymorphisms in neuroendocrine effector and receptor genes like TPH2, COMT, and NR3C1 were found to predict the development of CFS. 193 Twenty‐one variants harbored in 13 different genes (FAM126B, TCF3, EIF3A, UBTF, METTL3, SORL1, IL6ST, PNPLA6, BMP2K, ARSD, GSN, HIF1A, and PEX16) were also associated with ME/CFS in the context of one more study. 194
GO analysis
The results of GO analysis regarding ME/CFS are shown in Table 2. The pathways in which the most genes are involved are the nicotinic acetylcholine receptor signaling pathway, the heterotrimeric G‐protein signaling pathway, the gonadotropin‐releasing hormone receptor pathway, and the inflammation pathway mediated by chemokine and cytokine signaling (Table 2). The pathway of inflammation was the common pathway of COVID‐19 and ME/CFS analyses.
Table 2.
The top five genetic ontology (GO) terms per category and pathway analysis regarding ME/CFS.
| GO term | Percent of gene hit against total number of genes | ||
|---|---|---|---|
| Molecular function | |||
| 1 | Binding (GO:0005488) | 127 | 38.40% |
| 2 | Catalytic activity (GO:0003824) | 83 | 25.10% |
| 3 | Molecular transducer activity (GO:0060089) | 39 | 11.80% |
| 4 | Transporter activity (GO:0005215) | 32 | 9.70% |
| 5 | Transcription regulator activity (GO:0140110) | 20 | 6.00% |
| Biological process | |||
| 1 | Cellular process (GO:0009987) | 213 | 27.70% |
| 2 | Biological regulation (GO:0065007) | 134 | 17.40% |
| 3 | Metabolic process (GO:0008152) | 103 | 13.40% |
| 4 | Response to stimulus (GO:0050896) | 82 | 10.70% |
| 5 | Signaling (GO:0023052) | 69 | 9.00% |
| Cellular component | |||
| 1 | Cellular anatomical entity (GO:0110165) | 218 | 79.0% |
| 2 | Protein‐containing complex (GO:0032991) | 58 | 21.0% |
| Protein class | |||
| 1 | Metabolite interconversion enzyme (PC00262) | 40 | 15.30% |
| 2 | Transporter (PC00227) | 39 | 14.90% |
| 3 | Protein‐modifying enzyme (PC00260) | 34 | 13.00% |
| 4 | Transmembrane signal receptor (PC00197) | 29 | 11.10% |
| 5 | Gene‐specific transcriptional regulator (PC00264) | 22 | 8.40% |
| Pathway | |||
| 1 | Nicotinic acetylcholine receptor signaling pathway (P00044) | 12 | 4.80% |
| 2 | Heterotrimeric G‐protein signaling pathway‐Gi alpha and Gs alpha‐mediated pathway (P00026) | 12 | 4.80% |
| 3 | Gonadotropin‐releasing hormone receptor pathway (P06664) | 10 | 4.00% |
| 4 | Inflammation mediated by chemokine and cytokine signaling pathway (P00031) | 10 | 4.00% |
| 5 | Heterotrimeric G‐protein signaling pathway‐Gq alpha and Go alpha‐mediated pathway (P00027) | 10 | 4.00% |
Evidence of gene overlap between COVID‐19 and ME/CFS
Our review indicates that there is some gene overlap between COVID‐19 and ME/CFS. These genes include ACE, HLA‐A, HLA‐C, HLA‐DQA1, HLA‐DQB1, HLA‐DRB1, TIRAP, and TYK2 (Table 3). A Venn diagram depicts the common significant genes between COVID‐19 and ME/CFS (Figure 2), whereas Figure 3 presents the common genes and the cytogenetic locations in which they are located. The significance of this overlap is not apparent at the present. However, according to GO analysis, the overlapping genes appear to be associated with the regulation of immune processes. More specifically, the common genes are involved in inflammation mediated by chemokine and cytokine signaling pathways, in T cell activation and Toll receptor signaling pathways (Figure 4), and encode defense/immunity proteins and protein‐modifying enzymes (Figure 5).
Table 3.
Common genes between COVID‐19 and ME/CFS.
| Gene official symbol | Official full name | Cytogenetic location |
|---|---|---|
| ACE | Angiotensin I‐converting enzyme | 17q23.3 |
| HLA‐A | Major histocompatibility complex, class I, A | 6p22.1 |
| HLA‐C | Major histocompatibility complex, class I, C | 6p21.33 |
| HLA‐DQA1 | Major histocompatibility complex, class II, DQ alpha 1 | 6p21.32 |
| HLA‐DQB1 | Major histocompatibility complex, class II, DQ beta 1 | 6p21.32 |
| HLA‐DRB1 | Major histocompatibility complex, class II, DR beta 1 | 6p21.32 |
| TIRAP | TIR domain‐containing adaptor protein | 11q24.2 |
| TYK2 | Tyrosine kinase 2 | 19p13.2 |
Figure 2.

Venn diagram regarding the significant genes of COVID‐19 and ME/CFS.
Figure 3.

Common genetic loci from COVID‐19 and ME/CFS studies in peer‐reviewed publications to date.
Figure 4.

Results of the “pathway” category regarding the common genes between COVID‐19 and ME/CFS. Inflammation mediated by chemokine and cytokine signaling pathway is depicted in green, T cell activation in pink and Toll receptor signaling pathway in blue.
Figure 5.

Results of “protein class” category regarding the common genes between COVID‐19 and ME/CFS. Defense/immunity protein is depicted in blue and protein‐modifying enzyme in purple.
It has been found that the D allele increases the serum or local levels of ACE resulting in damage to the vascular endothelium and lung epithelium. 195 More specifically, the serum levels of ACE are almost twice in people with the DD genotype than in people with the II genotype. 196 Furthermore, the frequency of the D allele has been reported to be higher in SARS patients than in healthy controls. 197 Acute respiratory distress syndrome (ARDS) is also more frequent in the presence of the D allele. 198 It is noteworthy that the I/D polymorphism in the ACE gene is correlated with both the frequency of SARS‐CoV‐2 infection and mortality. 199 As a result, this I/D polymorphism could constitute a predictive biomarker of the severity of COVID‐19. However, it should be pointed out that these data are derived from studies on Caucasians. In the Chinese population, the I/D polymorphism was not associated with SARS‐CoV‐2 infection maybe due to the difference in allele frequencies in different ethnicities. 200 It has also been reported that high ACE:ACE2 ratio is responsible for severe outcomes in COVID‐19, whereas the SARS‐CoV‐2 infection per se increases this ratio. 201 Last, but not least, ACE levels are also elevated in about 80% of patients with ME/CFS. 202
In this context, it is interesting to note that the unique tissue immune cells, the mast cells, express an active renin‐angiotensin generating system in the lungs 203 , 204 and can convert angiotensin I to angiotensin II. 205 , 206 iMast cells also store and can release preformed renin 207 , 208 and angiotensin II. 209 , 210 The mast cell‐derived ACE is chymase and recent papers reported increased amounts of chymase in the serum of COVID‐19 patients. 211 , 212 Increased mast cell density was also correlated with increased tissue expression of ACE2, as well as the bradykinin receptors B1 and B2. 203 In fact, mast cells have been recently implicated in both COVID‐19 211 , 212 , 213 , 214 , 215 , 216 , 217 , 218 , 219 , 220 and ME/CFS. 221 , 222
TIRAP has been implicated in the activation of both mast cells 223 and microglia. 224 Mast cells interact with microglia 225 leading to their activation 226 and neuroinflammation. 227 Microglia have been implicated in COVID‐19 228 and were also associated with neuroinflammation. 229 Microglia have important functions both in health and disease of the central nervous system (CNS), especially with respect to neuroinflammation 230 , 231 , 232 and neurodegenerative 230 , 233 , 234 , 235 diseases. Microglia were recently implicated in COVID‐19 228 , 236 and express toll‐like receptors (TLRs) 237 activated by damage‐associated molecular patterns (DAMPs). It is interesting that SARS‐CoV‐2 was recently reported to stimulate TLRs. 238
TYK2 239 and HLA 240 polymorphisms have been associated with autoimmune diseases. In particular, human leukocyte antigen DR isotype (HLA‐DRhigh) CD11chigh‐positive inflammatory monocytes accumulate in mild COVID‐19 but are depleted in severe disease 241 ; in contrast, HLA‐DRlow and S100A (calprotectin)high monocytes are plentiful and drive severe disease. 241 Coordinated profiling of gene expression and cell lineage protein markers showed that S100Ahigh/HLA‐DRlow classical monocytes and activated LAG‐3hi T cells are critical drivers of progressive COVID‐19. 242 We and others recently showed that S100A8/A9 (calprotectin) is increased in the serum of COVID‐19 patients and is significantly associated with symptom severity. 243 , 244 , 245 , 246 Calprotectin has not been so far measured in ME/CFS samples. However, it is interesting that calprotectin was recently shown to be elevated in the serum of patients with inflammatory demyelinating polyneuropathy. 247
The precise pathogenic mechanisms of long‐COVID in the brain are not well understood 248 but could involve activation of mast cells 249 and microglia 229 , 250 leading to neuroinflammation. 42 , 251 This process could, in turn, damage brain blood vessels 252 and other brain cells. 253 , 254 Similarly, ME/CFS may also involve inflammation in the hypothalamus 86 and dysregulate homeostasis. 255
Limitations
Our review did not include gene expression or epigenetic studies. It would be important to investigate the protein expression of suspected genes, especially in the brain, but such studies would require access to brain tissue that is not feasible at the present. In addition, evidence about genetic components of either COVID‐19 or ME/CFS comes from a small number of studies. Moreover, a source of heterogeneity is the inclusion of either healthy or asymptomatic subjects as controls in COVID‐19 studies. Finally, the clinical criteria applied for ME/CFS by the different studies may have led to possible population heterogeneity.
Potential interventions
In view of the involvement of immune activation genes, one could consider using certain natural flavonoids that could regulate the immune response, 248 especially luteolin, which inhibits both microglia 256 , 257 , 258 , 259 and the unique tissue immune cells, mast cells. 260 , 261 Moreover, luteolin has been reported to prevent neuroinflammation 262 , 263 , 264 , 265 is neuroprotective 262 , 264 , 266 , 267 and reduces cognitive dysfunction, 268 , 269 , 270 , 271 , 272 especially brain fog. 56 , 58 , 59 The novel luteolin structural analog tetramethoxyluteolin (methoxyluteolin) is even more potent than luteolin. 259 , 260 , 261 , 273 Use of these flavonoids, formulated in olive pomace oil to increase oral absorption, 274 have been used successfully in COVID‐19 56 , 275 and Long‐COVID. 56 , 248 At the end of the day, treatment of the affected patients will have to be personalized based on the particular patient subgroup, any comorbidities, and the presence of any metabolizing enzyme gene polymorphisms.
Conclusion
In spite of the fact that COVID‐19 and ME/CFS present with some similar symptoms, especially physical and mental fatigue, genetic association, and cohort studies indicate that these two complex diseases share only a few common genes. These are associated with ACE, HLA‐A, HLA‐C, HLA‐DQA1, HLA‐DRB1, and TYK2, which appear to be involved in the regulation of immune processes. This finding supports the notion that the pathogenesis of both syndromes may derive from some aberrant and lasting immune response, possibly involving mast cells and microglia, which have been recently implicated in both diseases. Understanding the basis of this immune dysfunction could help with the diagnosis, prognosis, and treatment of these debilitating conditions.
Authors' Contributions
Design of the work: Theoharis C. Theoharides. Review of the literature: Maria Tziastoudi and Christos Cholevas. Analysis and interpretation of data: Maria Tziastoudi, Ioannis Stefanidis, and Theoharis C. Theoharides. Writing of the manuscript: Maria Tziastoudi and Theoharis C. Theoharides. The authors read and approved the final manuscript.
Conflict of Interest
Not applicable.
Consent to Participate
Not applicable.
Informed Consent
Not applicable.
Research involving Human Participants and/or Animals
Not applicable.
Supporting information
Table S1. The findings of genetic and cohort studies of COVID‐19
Table S2. The findings of genetic association and cohort studies of ME/CFS
Table S3. The most studied genes in COVID‐19 patients
Table S4. The most studied genes in ME/CFS patients
Figure S1. (A) Genetic loci from ME/CFS studies in peer‐reviewed publications to date. (B) Genetic loci from ME/CFS studies in peer‐reviewed publications to date. (C) Genetic loci from ME/CFS studies in peer‐reviewed publications to date.
Figure S2. (A) Genetic loci from COVID‐19 studies in peer‐reviewed publications to date and (B) Genetic loci from COVID‐19 studies in peer‐reviewed publications to date.
Acknowledgments
Not applicable.
Funding Information
No funding information provided.
Data Availability Statement
Not applicable.
References
- 1. Ye Q, Wang B, Mao J. The pathogenesis and treatment of the ‘Cytokine Storm’ in COVID‐19. J Infect. 2020;80:607‐613. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2. Chen G, Wu D, Guo W, et al. Clinical and immunological features of severe and moderate coronavirus disease 2019. J Clin Invest. 2020;130:2620‐2629. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3. Conti P, Ronconi G, Caraffa A, et al. Induction of pro‐inflammatory cytokines (IL‐1 and IL‐6) and lung inflammation by Coronavirus‐19 (COVI‐19 or SARS‐CoV‐2): anti‐inflammatory strategies. J Biol Regul Homeost Agents. 2020;34:327‐331. [DOI] [PubMed] [Google Scholar]
- 4. Giamarellos‐Bourboulis EJ, Netea MG, Rovina N, et al. Complex immune dysregulation in COVID‐19 patients with severe respiratory failure. Cell Host Microbe. 2020;27:992‐1000. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5. Tang Y, Liu J, Zhang D, Xu Z, Ji J, Wen C. Cytokine storm in COVID‐19: the current evidence and treatment strategies. Front Immunol. 2020;11:1708. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6. Paces J, Strizova Z, Smrz D, et al. COVID‐19 and the immune system. Physiol Res. 2020;69:379‐388. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7. Ragab D, Salah EH, Taeimah M, Khattab R, Salem R. The COVID‐19 cytokine storm; what we know so far. Front Immunol. 2020;11:1446. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8. Brodin P. Immune determinants of COVID‐19 disease presentation and severity. Nat Med. 2021;27:28‐33. [DOI] [PubMed] [Google Scholar]
- 9. Canna SW, Cron RQ. Highways to hell: mechanism‐based management of cytokine storm syndromes. J Allergy Clin Immunol. 2020;146:949‐959. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10. Deumer US, Varesi A, Floris V, et al. Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): an overview. J Clin Med. 2021;10(20):4786. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11. Bateman L, Bested AC, Bonilla HF, et al. Myalgic encephalomyelitis/chronic fatigue syndrome: essentials of diagnosis and management. Mayo Clin Proc. 2021;96:2861‐2878. [DOI] [PubMed] [Google Scholar]
- 12. Poenaru S, Abdallah SJ, Corrales‐Medina V, Cowan J. COVID‐19 and post‐infectious myalgic encephalomyelitis/chronic fatigue syndrome: a narrative review. Ther Adv Infect Dis. 2021;8:20499361211009385. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13. Komaroff AL, Lipkin WI. Insights from myalgic encephalomyelitis/chronic fatigue syndrome may help unravel the pathogenesis of postacute COVID‐19 syndrome. Trends Mol Med. 2021;27:895‐906. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14. Wong TL, Weitzer DJ. Long COVID and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)‐a systemic review and comparison of clinical presentation and symptomatology. Medicina (Kaunas). 2021;57(5):418. doi: 10.3390/medicina57050418. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15. Zhang C, Baumer A, Mackay IR, Linnane AW, Nagley P. Unusual pattern of mitochondrial DNA deletions in skeletal muscle of an adult human with chronic fatigue syndrome. Hum Mol Genet. 1995;4:751‐754. [DOI] [PubMed] [Google Scholar]
- 16. Herold T, Jurinovic V, Arnreich C, et al. Elevated levels of IL‐6 and CRP predict the need for mechanical ventilation in COVID‐19. J Allergy Clin Immunol. 2020;146:128‐136. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17. Copaescu A, Smibert O, Gibson A, Phillips EJ, Trubiano JA. The role of IL‐6 and other mediators in the cytokine storm associated with SARS‐CoV‐2 infection. J Allergy Clin Immunol. 2020;146:518‐534. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18. Han H, Ma Q, Li C, et al. Profiling serum cytokines in COVID‐19 patients reveals IL‐6 and IL‐10 are disease severity predictors. Emerg Microbes Infect. 2020;9:1123‐1130. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19. Mazzoni A, Salvati L, Maggi L, et al. Impaired immune cell cytotoxicity in severe COVID‐19 is IL‐6 dependent. J Clin Invest. 2020;130:4694‐4703. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20. Liu F, Li L, Xu M, et al. Prognostic value of interleukin‐6, C‐reactive protein, and procalcitonin in patients with COVID‐19. J Clin Virol. 2020;127:104370. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21. Ceban F, Ling S, Lui LMW, et al. Fatigue and cognitive impairment in Post‐COVID‐19 Syndrome: a systematic review and meta‐analysis. Brain Behav Immun. 2022;101:93‐135. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22. Chen C, Haupert SR, Zimmermann L, Shi X, Fritsche LG, Mukherjee B. Global prevalence of post COVID‐19 condition or long COVID: a meta‐analysis and systematic review. J Infect Dis. 2022:jiac136. doi: 10.1093/infdis/jiac136. Epub ahead of print. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23. Townsend L, Dyer AH, Jones K, et al. Persistent fatigue following SARS‐CoV‐2 infection is common and independent of severity of initial infection. PLoS One. 2020;15:e0240784. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24. Bell ML, Catalfamo CJ, Farland LV, et al. Post‐acute sequelae of COVID‐19 in a non‐hospitalized cohort: results from the Arizona CoVHORT. PLoS One. 2021;16:e0254347. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25. Moreno‐Perez O, Merino E, Leon‐Ramirez JM, et al. Post‐acute COVID‐19 Syndrome. Incidence and risk factors: a Mediterranean cohort study. J Infect. 2021;82:378‐383. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26. Nalbandian A, Sehgal K, Gupta A, et al. Post‐acute COVID‐19 syndrome. Nat Med. 2021;27:601‐615. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27. Montagne A, Nation DA, Sagare AP, et al. APOE4 leads to blood‐brain barrier dysfunction predicting cognitive decline. Nature. 2020;581:71‐76. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 28. Huang C, Huang L, Wang Y, et al. 6‐month consequences of COVID‐19 in patients discharged from hospital: a cohort study. Lancet. 2021;397:220‐232. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 29. Sudre CH, Murray B, Varsavsky T, et al. Attributes and predictors of long COVID. Nat Med. 2021;27:626‐631. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30. Dennis A, Wamil M, Alberts J, et al. Multiorgan impairment in low‐risk individuals with post‐COVID‐19 syndrome: a prospective, community‐based study. BMJ Open. 2021;11:e048391. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 31. Baig AM. Chronic COVID syndrome: need for an appropriate medical terminology for long‐COVID and COVID long‐haulers. J Med Virol. 2021;93(5):2555–2556. doi: 10.1002/jmv.26624. [DOI] [PubMed] [Google Scholar]
- 32. Higgins V, Sohaei D, Diamandis EP, Prassas I. COVID‐19: from an acute to chronic disease? Potential long‐term health consequences. Crit Rev Clin Lab Sci. 2021;58(5):297–310. doi: 10.1080/10408363.2020.1860895. [DOI] [PubMed] [Google Scholar]
- 33. Helms J, Kremer S, Merdji H, et al. Neurologic features in severe SARS‐CoV‐2 infection. N Engl J Med. 2020;382:2268‐2270. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 34. Fotuhi M, Mian A, Meysami S, Raji CA. Neurobiology of COVID‐19. J Alzheimers Dis. 2020;76:3‐19. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 35. Najjar S, Najjar A, Chong DJ, et al. Central nervous system complications associated with SARS‐CoV‐2 infection: integrative concepts of pathophysiology and case reports. J Neuroinflammation. 2020;17:231. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 36. Singh AK, Bhushan B, Maurya A, Mishra G, Singh SK, Awasthi R. Novel coronavirus disease 2019 (COVID‐19) and neurodegenerative disorders. Dermatol Ther. 2020;33:e13591. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 37. Liotta EM, Batra A, Clark JR, et al. Frequent neurologic manifestations and encephalopathy‐associated morbidity in Covid‐19 patients. Ann Clin Transl Neurol. 2020;7:2221‐2230. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 38. Koralnik IJ, Tyler KL. COVID‐19: a global threat to the nervous system. Ann Neurol. 2020;88:1‐11. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 39. Nepal G, Rehrig JH, Shrestha GS, et al. Neurological manifestations of COVID‐19: a systematic review. Crit Care. 2020;24:421. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 40. Favas TT, Dev P, Chaurasia RN, et al. Neurological manifestations of COVID‐19: a systematic review and meta‐analysis of proportions. Neurol Sci. 2020;41:3437‐3470. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 41. Nazari S, Azari Jafari A, Mirmoeeni S, et al. Central nervous system manifestations in COVID‐19 patients: a systematic review and meta‐analysis. Brain Behav. 2021;11(5):e02025. doi: 10.1002/brb3.2025. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 42. Kempuraj D, Selvakumar GP, Ahmed ME, et al. COVID‐19, mast cells, cytokine storm, psychological stress, and neuroinflammation. Neuroscientist. 2020;26:402‐414. [DOI] [PubMed] [Google Scholar]
- 43. Levin SN, Venkatesh S, Nelson KE, et al. Manifestations and impact of the COVID‐19 pandemic in neuroinflammatory diseases. Ann Clin Transl Neurol. 2021;8:918‐928. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 44. Baig AM. Deleterious outcomes in long‐hauler COVID‐19: the effects of SARS‐CoV‐2 on the CNS in chronic COVID syndrome. ACS Chem Nerosci. 2020;11:4017‐4020. [DOI] [PubMed] [Google Scholar]
- 45. Ongur D, Perlis R, Goff D. Psychiatry and COVID‐19. JAMA. 2020;324:1149‐1150. [DOI] [PubMed] [Google Scholar]
- 46. Vindegaard N, Benros ME. COVID‐19 pandemic and mental health consequences: systematic review of the current evidence. Brain Behav Immun. 2020;89:531‐542. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 47. Pfefferbaum B, North CS. Mental health and the Covid‐19 pandemic. N Engl J Med. 2020;383:510‐512. [DOI] [PubMed] [Google Scholar]
- 48. Xiang YT, Yang Y, Li W, et al. Timely mental health care for the 2019 novel coronavirus outbreak is urgently needed. Lancet Psychiatry. 2020;7:228‐229. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 49. Gordon JA, Borja SE. The COVID‐19 pandemic: setting the mental health research agenda. Biol Psychiatry. 2020;88:130‐131. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 50. Taquet M, Luciano S, Geddes JR, Harrison PJ. Bidirectional associations between COVID‐19 and psychiatric disorder: retrospective cohort studies of 62 354 COVID‐19 cases in the USA. Lancet Psychiatry. 2021;8:130‐140. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 51. Schirinzi T, Landi D, Liguori C. COVID‐19: dealing with a potential risk factor for chronic neurological disorders. J Neurol. 2021;268(4):1171‐1178. doi: 10.1007/s00415-020-10131-y. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 52. Steardo L Jr, Steardo L, Verkhratsky A. Psychiatric face of COVID‐19. Transl Psychiatry. 2020;10:261. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 53. Shader RI. COVID‐19 and depression. Clin Ther. 2020;42:962‐963. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 54. Smith CM, Komisar JR, Mourad A, Kincaid BR. COVID‐19‐associated brief psychotic disorder. BMJ Case Rep. 2020;13(8):e236940. doi: 10.1136/bcr-2020-236940. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 55. Druss BG. Addressing the COVID‐19 pandemic in populations with serious mental illness. JAMA Psychiat. 2020;77:891‐892. [DOI] [PubMed] [Google Scholar]
- 56. Theoharides TC, Cholevas C, Polyzoidis K, Politis A. Long‐COVID syndrome‐associated brain fog and chemofog: luteolin to the rescue. Biofactors. 2021;47:232‐241. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 57. Graham EL, Clark JR, Orban ZS, et al. Persistent neurologic symptoms and cognitive dysfunction in non‐hospitalized Covid‐19 "long haulers". Ann Clin Transl Neurol. 2021;8:1073‐1085. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 58. Stefano GB, Buttiker P, Weissenberger S, Martin A, Ptacek R, Kream RM. Editorial: the pathogenesis of long‐term neuropsychiatric COVID‐19 and the role of microglia, mitochondria, and persistent neuroinflammation: a hypothesis. Med Sci Monit. 2021;27:e933015. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 59. Hugon J, Msika EF, Queneau M, Farid K, Paquet C. Long COVID: cognitive complaints (brain fog) and dysfunction of the cingulate cortex. J Neurol. 2021;269:44‐46. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 60. Phillips S, Williams MA. Confronting our next national health disaster ‐ long‐haul Covid. N Engl J Med. 2021;385:577‐579. [DOI] [PubMed] [Google Scholar]
- 61. Magalhaes AC, Pedro N, Pereira L. Genomic insights into the human susceptibility to SARS‐CoV‐2 infection. Acta Med Port. 2021;34:407‐409. [DOI] [PubMed] [Google Scholar]
- 62. Rodriguez‐Morales AJ, Balbin‐Ramon GJ, Rabaan AA, et al. Genomic Epidemiology and its importance in the study of the COVID‐19 pandemic. Infez Med. 2020;28:139‐142. [PubMed] [Google Scholar]
- 63. Velavan TP, Pallerla SR, Ruter J, et al. Host genetic factors determining COVID‐19 susceptibility and severity. EBioMedicine. 2021;72:103629. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 64. Karlsen TH. Understanding COVID‐19 through genome‐wide association studies. Nat Genet. 2022;54:368‐369. [DOI] [PubMed] [Google Scholar]
- 65. Cortes Rivera M, Mastronardi C, Silva‐Aldana CT, Arcos‐Burgos M, Lidbury BA. Myalgic encephalomyelitis/chronic fatigue syndrome: a comprehensive review. Diagnostics (Basel). 2019;9(3):91. doi: 10.3390/diagnostics9030091. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 66. Yancey JR, Thomas SM. Chronic fatigue syndrome: diagnosis and treatment. Am Fam Physician. 2012;86:741‐746. [PubMed] [Google Scholar]
- 67. Griffith JP, Zarrouf FA. A systematic review of chronic fatigue syndrome: don't assume it's depression. Prim Care Companion J Clin Psychiatry. 2008;10:120‐128. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 68. Nacul L, O'Boyle S, Palla L, et al. How myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) progresses: the natural history of ME/CFS. Front Neurol. 2020;11:826. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 69. Jason LA, Richman JA, Rademaker AW, et al. A community‐based study of chronic fatigue syndrome. Arch Intern Med. 1999;159:2129‐2137. [DOI] [PubMed] [Google Scholar]
- 70. Van't LM, Zielhuis GA, van der Meer JW, Verbeek AL, Bleijenberg G. Fatigue and chronic fatigue syndrome‐like complaints in the general population. Eur J Public Health. 2010;20:251‐257. [DOI] [PubMed] [Google Scholar]
- 71. Natelson BH. Myalgic encephalomyelitis/chronic fatigue syndrome and fibromyalgia: definitions, similarities, and differences. Clin Ther. 2019;41:612‐618. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 72. Jason LA, Corradi K, Torres‐Harding S, Taylor RR, King C. Chronic fatigue syndrome: the need for subtypes. Neuropsychol Rev. 2005;15:29‐58. [DOI] [PubMed] [Google Scholar]
- 73. Holgate ST, Komaroff AL, Mangan D, Wessely S. Chronic fatigue syndrome: understanding a complex illness 1. Nat Rev Neurosci. 2011;12:539‐544. [DOI] [PubMed] [Google Scholar]
- 74. Anderson VR, Jason LA, Hlavaty LE, Porter N, Cudia J. A review and meta‐synthesis of qualitative studies on myalgic encephalomyelitis/chronic fatigue syndrome. Patient Educ Couns. 2012;86:147‐155. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 75. Ciccone DS, Natelson BH. Comorbid illness in women with chronic fatigue syndrome: a test of the single syndrome hypothesis. Psychosom Med. 2003;65:268‐275. [DOI] [PubMed] [Google Scholar]
- 76. Theoharides TC, Weinkauf C, Conti P. Brain cytokines and neuropsychiatric disorders. J Clin Psychopharmacol. 2004;24:577‐581. [DOI] [PubMed] [Google Scholar]
- 77. Sotzny F, Blanco J, Capelli E, et al. Myalgic encephalomyelitis/chronic fatigue syndrome ‐ evidence for an autoimmune disease. Autoimmun Rev. 2018;17:601‐609. [DOI] [PubMed] [Google Scholar]
- 78. Dietert RR, Dietert JM. Possible role for early‐life immune insult including developmental immunotoxicity in chronic fatigue syndrome (CFS) or myalgic encephalomyelitis (ME). Toxicology. 2008;247:61‐72. [DOI] [PubMed] [Google Scholar]
- 79. Bower JE. Fatigue, brain, behavior, and immunity: summary of the 2012 Named Series on fatigue. Brain Behav Immun. 2012;26:1220‐1223. [DOI] [PubMed] [Google Scholar]
- 80. Nakatomi Y, Mizuno K, Ishii A, et al. Neuroinflammation in patients with chronic fatigue syndrome/myalgic encephalomyelitis: an 11C‐(R)‐PK11195 PET study. J Nucl Med. 2014;55:945‐950. [DOI] [PubMed] [Google Scholar]
- 81. Fletcher MA, Zeng XR, Barnes Z, Levis S, Klimas NG. Plasma cytokines in women with chronic fatigue syndrome. J Transl Med. 2009;7:96. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 82. Maes M, Twisk FN, Ringel K. Inflammatory and cell‐mediated immune biomarkers in myalgic encephalomyelitis/chronic fatigue syndrome and depression: inflammatory markers are higher in myalgic encephalomyelitis/chronic fatigue syndrome than in depression. Psychother Psychosom. 2012;81:286‐295. [DOI] [PubMed] [Google Scholar]
- 83. Nakamura T, Schwander S, Donnelly R, et al. Exercise and sleep deprivation do not change cytokine expression levels in patients with chronic fatigue syndrome. Clin Vaccine Immunol. 2013;20:1736‐1742. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 84. Milrad SF, Hall DL, Jutagir DR, et al. Depression, evening salivary cortisol and inflammation in chronic fatigue syndrome: a psychoneuroendocrinological structural regression model. Int J Psychophysiol. 2018;131:124‐130. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 85. Natelson BH. Brain dysfunction as one cause of CFS symptoms including difficulty with attention and concentration. Front Physiol. 2013;4:109. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 86. Hatziagelaki E, Adamaki M, Tsilioni I, Dimitriadis G, Theoharides TC. Myalgic encephalomyelitis/chronic fatigue syndrome‐metabolic disease or disturbed homeostasis due to focal inflammation in the hypothalamus? J Pharmacol Exp Ther. 2018;367:155‐167. [DOI] [PubMed] [Google Scholar]
- 87. Klimas NG, Broderick G, Fletcher MA. Biomarkers for chronic fatigue. Brain Behav Immun. 2012;26:1202‐1210. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 88. Long COVID: let patients help define long‐lasting COVID symptoms. Nature. 2020;586(7828):170. doi: 10.1038/d41586-020-02796-2. [DOI] [PubMed] [Google Scholar]
- 89. White P. Long COVID: don't consign ME/CFS to history. Nature. 2020;587:197. [DOI] [PubMed] [Google Scholar]
- 90. Komaroff AL, Bateman L. Will COVID‐19 lead to myalgic encephalomyelitis/chronic fatigue syndrome? Front Med (Lausanne). 2020;7:606824. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 91. Shlatz L, Marinetti GV. Hormone‐calcium interactins with the plasma membrane of rat liver cells. Science. 1972;176:175‐177. [DOI] [PubMed] [Google Scholar]
- 92. Thomas PD, Campbell MJ, Kejariwal A, et al. PANTHER: a library of protein families and subfamilies indexed by function. Genome Res. 2003;13:2129‐2141. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 93. Mi H, Ebert D, Muruganujan A, et al. PANTHER version 16: a revised family classification, tree‐based classification tool, enhancer regions and extensive API. Nucleic Acids Res. 2021;49:D394‐D403. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 94. Ellinghaus D, Degenhardt F, Bujanda L, et al. Genomewide association study of severe Covid‐19 with respiratory failure. N Engl J Med. 2020;383:1522‐1534. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 95. Gomez J, Albaiceta GM, Garcia‐Clemente M, Coto E. DNA genotyping of the ABO gene showed a significant association of the A‐group (A1/A2 variants) with severe COVID‐19. Eur J Intern Med. 2021;88:129‐132. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 96. Wu P, Ding L, Li X, et al. Trans‐ethnic genome‐wide association study of severe COVID‐19. Commun Biol. 2021;4:1034. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 97. van der Made CI, Simons A, Schuurs‐Hoeijmakers J, et al. Presence of genetic variants among young men with severe COVID‐19. JAMA. 2020;324:663‐673. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 98. Zhang Q, Bastard P, Liu Z, et al. Inborn errors of type I IFN immunity in patients with life‐threatening COVID‐19. Science. 2020;370(6515):eabd4570. doi: 10.1126/science.abd4570. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 99. Li Y, Ke Y, Xia X, et al. Genome‐wide association study of COVID‐19 severity among the Chinese population. Cell Discov. 2021;7:76. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 100. Collaborators . Mapping the human genetic architecture of COVID‐19. Nature. 2021;600:472‐477. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 101. Wang F, Huang S, Gao R, et al. Initial whole‐genome sequencing and analysis of the host genetic contribution to COVID‐19 severity and susceptibility. Cell Discov. 2020;6:83. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 102. Hubacek JA, Dusek L, Majek O, et al. CCR5Delta32 deletion as a protective factor in Czech first‐wave COVID‐19 subjects. Physiol Res. 2021;70:111‐115. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 103. Cantalupo S, Lasorsa VA, Russo R, et al. Regulatory noncoding and predicted pathogenic coding variants of CCR5 predispose to severe COVID‐19. Int J Mol Sci. 2021;22(10):5372. doi: 10.3390/ijms22105372. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 104. Avendano‐Felix M, Ochoa‐Ramirez LA, Ramos‐Payan R, et al. Lack of effects of the genetic polymorphisms of interleukin‐10 in clinical outcomes of COVID‐19. Viral Immunol. 2021;34:567‐572. [DOI] [PubMed] [Google Scholar]
- 105. Smieszek SP, Przychodzen BP, Polymeropoulos VM, Polymeropoulos CM, Polymeropoulos MH. Assessing the potential correlation of polymorphisms in the IL6R with relative IL6 elevation in severely ill COVID‐19 patients. Cytokine. 2021;148:155662. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 106. Pairo‐Castineira E, Clohisey S, Klaric L, et al. Genetic mechanisms of critical illness in COVID‐19. Nature. 2021;591:92‐98. [DOI] [PubMed] [Google Scholar]
- 107. Hu J, Li C, Wang S, Li T, Zhang H. Genetic variants are identified to increase risk of COVID‐19 related mortality from UKBiobank data. Hum Genomics. 2021;15:10. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 108. Steffen BT, Pankow JS, Lutsey PL, et al. Proteomic profiling identifies novel proteins for genetic risk of severe COVID‐19: the Atherosclerosis Risk in Communities Study. Hum Mol Genet. 2022;31(14):2452‐2461. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 109. Roberts GHL, Partha R, Rhead B, et al. Expanded COVID‐19 phenotype definitions reveal distinct patterns of genetic association and protective effects. Nat Genet. 2022;54:374‐381. [DOI] [PubMed] [Google Scholar]
- 110. Alghamdi J, Alaamery M, Barhoumi T, et al. Interferon‐induced transmembrane protein‐3 genetic variant rs12252 is associated with COVID‐19 mortality. Genomics. 2021;113:1733‐1741. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 111. Kim YC, Jeong BH. Strong correlation between the case fatality rate of COVID‐19 and the rs6598045 single nucleotide polymorphism (SNP) of the interferon‐induced transmembrane protein 3 (IFITM3) gene at the population‐level. Genes (Basel). 2020;12(1):42. doi: 10.3390/genes12010042. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 112. Gomez J, Albaiceta GM, Cuesta‐Llavona E, et al. The Interferon‐induced transmembrane protein 3 gene (IFITM3) rs12252 C variant is associated with COVID‐19. Cytokine. 2021;137:155354. [DOI] [PubMed] [Google Scholar]
- 113. Zhang Y, Qin L, Zhao Y, et al. Interferon‐induced transmembrane protein 3 genetic variant rs12252‐C associated with disease severity in coronavirus disease 2019. J Infect Dis. 2020;222:34‐37. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 114. Schonfelder K, Breuckmann K, Elsner C, et al. The influence of IFITM3 polymorphisms on susceptibility to SARS‐CoV‐2 infection and severity of COVID‐19. Cytokine. 2021;142:155492. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 115. Andolfo I, Russo R, Lasorsa VA, et al. Common variants at 21q22.3 locus influence MX1 and TMPRSS2 gene expression and susceptibility to severe COVID‐19. iScience. 2021;24:102322. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 116. Fallerini C, Daga S, Mantovani S, et al. Association of Toll‐like receptor 7 variants with life‐threatening COVID‐19 disease in males: findings from a nested case‐control study. Elife. 2021;2(10):e67569. doi: 10.7554/eLife.67569. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 117. Khor SS, Omae Y, Nishida N, et al. HLA‐A*11:01:01:01, HLA‐C*12:02:02:01‐HLA‐B*52:01:02:02, age and sex are associated with severity of Japanese COVID‐19 with respiratory failure. Front Immunol. 2021;12:658570. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 118. Novelli A, Andreani M, Biancolella M, et al. HLA allele frequencies and susceptibility to COVID‐19 in a group of 99 Italian patients. Hla. 2020;96:610‐614. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 119. Anzurez A, Naka I, Miki S, et al. Association of HLA‐DRB1*09:01 with severe COVID‐19. Hla. 2021;98:37‐42. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 120. Naemi FMA, Al‐Adwani S, Al‐Khatabi H, et al. Association between the HLA genotype and the severity of COVID‐19 infection among South Asians. J Med Virol. 2021;93:4430‐4437. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 121. Naemi FMA, Al‐Adwani S, Al‐Khatabi H, et al. Frequency of HLA alleles among COVID‐19 infected patients: preliminary data from Saudi Arabia. Virology. 2021;560:1‐7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 122. De MR, Faria TC, Mine KL, et al. HLA‐A homozygosis is associated with susceptibility to COVID‐19. HLA. 2021;98:122‐131. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 123. Vishnubhotla R, Sasikala M, Ketavarapu V, et al. High‐resolution HLA genotyping identifies alleles associated with severe COVID‐19: a preliminary study from India. Immun Inflamm Dis. 2021;9:1781‐1785. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 124. Ebrahimi S, Ghasemi‐Basir HR, Majzoobi MM, et al. HLA‐DRB1*04 may predict the severity of disease in a group of Iranian COVID‐19 patients. Hum Immunol. 2021;82:719‐725. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 125. Kuo CL, Pilling LC, Atkins JL, et al. APOE e4 genotype predicts severe COVID‐19 in the UKBiobank Community Cohort. J Gerontol A Biol Sci Med Sci. 2020;75:2231‐2232. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 126. Hubacek JA, Dlouha L, Dusek L, et al. Apolipoprotein E4 Allele in subjects with COVID‐19. Gerontology. 2021;67:320‐322. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 127. Kurki SN, Kantonen J, Kaivola K, et al. APOE epsilon4 associates with increased risk of severe COVID‐19, cerebral microhaemorrhages and post‐COVID mental fatigue: a Finnish biobank, autopsy and clinical study. Acta Neuropathol Commun. 2021;9:199. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 128. Al‐Jaf SMA, Niranji SS, Ali HN, et al. Association of Apolipoprotein e polymorphism with SARS‐CoV‐2 infection. Infect Genet Evol. 2021;95:105043. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 129. Latini A, Agolini E, Novelli A, et al. COVID‐19 and genetic variants of protein involved in the SARS‐CoV‐2 entry into the host cells. Genes (Basel). 2020;11(9):1010. doi: 10.3390/genes11091010. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 130. Torre‐Fuentes L, Matias‐Guiu J, Hernandez‐Lorenzo L, et al. ACE2, TMPRSS2, and Furin variants and SARS‐CoV‐2 infection in Madrid. Spain J Med Virol. 2021;93:863‐869. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 131. Posadas‐Sánchez R, Sánchez‐Muñoz F, Guzmán‐Martín CA, et al. Dipeptidylpeptidase‐4 levels and DPP4 gene polymorphisms in patients with COVID‐19. Association with disease and with severity. Life Sci. 2021;276:119410. doi: 10.1016/j.lfs.2021.119410. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 132. Povysil G, Butler‐Laporte G, Shang N, et al. Rare loss‐of‐function variants in type I IFN immunity genes are not associated with severe COVID‐19. J Clin Invest. 2021;131(14):e147834. doi: 10.1172/JCI147834. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 133. Russo R, Andolfo I, Lasorsa VA, et al. The TNFRSF13C H159Y variant is associated with severe COVID‐19: a retrospective study of 500 patients from Southern Italy. Genes (Basel). 2021;12(6):881. doi: 10.3390/genes12060881. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 134. Schonfelder K, Breuckmann K, Elsner C, et al. Transmembrane serine protease 2 polymorphisms and susceptibility to severe acute respiratory syndrome coronavirus type 2 infection: a German Case‐Control Study. Front Genet. 2021;12:667231. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 135. Srivastava A, Bandopadhyay A, Das D, et al. Genetic association of ACE2 rs2285666 polymorphism with COVID‐19 spatial distribution in India. Front Genet. 2020;11:564741. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 136. Vietzen H, Zoufaly A, Traugott M, et al. Deletion of the NKG2C receptor encoding KLRC2 gene and HLA‐E variants are risk factors for severe COVID‐19. Genet Med. 2021;23:963‐967. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 137. Wang W, Zhang W, Zhang J, et al. Distribution of HLA allele frequencies in 82 Chinese individuals with coronavirus disease‐2019 (COVID‐19). HLA. 2020;96:194‐196. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 138. Wu L, Zhu J, Liu D, et al. An integrative multiomics analysis identifies putative causal genes for COVID‐19 severity. Genet Med. 2021;23:2076‐2086. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 139. Zanella I, Zacchi E, Piva S, et al. C9orf72 intermediate repeats confer genetic risk for severe COVID‐19 pneumonia independently of age. Int J Mol Sci. 2021;22(13):6991. doi: 10.3390/ijms22136991. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 140. Amodio E, Pipitone RM, Grimaudo S, et al. SARS‐CoV‐2 viral load, IFNλ polymorphisms and the course of COVID‐19: an observational study. J Clin Med. 2020;9(10):3315. doi: 10.3390/jcm9103315. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 141. Karcioglu BL, Hekim N. The role of DBP gene polymorphisms in the prevalence of new coronavirus disease 2019 infection and mortality rate. J Med Virol. 2021;93:1409‐1413. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 142. Benetti E, Tita R, Spiga O, et al. ACE2 gene variants may underlie interindividual variability and susceptibility to COVID‐19 in the Italian population. Eur J Hum Genet. 2020;28:1602‐1614. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 143. Novelli A, Biancolella M, Borgiani P, et al. Analysis of ACE2 genetic variants in 131 Italian SARS‐CoV‐2‐positive patients. Hum Genomics. 2020;14:29. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 144. Strafella C, Caputo V, Termine A, et al. Analysis of ACE2 genetic variability among populations highlights a possible link with COVID‐19‐related neurological complications. Genes (Basel). 2020;11(7):741. doi: 10.3390/genes11070741. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 145. Karakas CS, Cakmak GG, Piskin N, et al. Polymorphisms of ACE (I/D) and ACE2 receptor gene (Rs2106809, Rs2285666) are not related to the clinical course of COVID‐19: a case study. J Med Virol. 2021;93:5947‐5952. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 146. Traets MJM, Nijhuis RHT, Morre SA, et al. Association of genetic variations in ACE2, TIRAP and factor X with outcomes in COVID‐19. PLoS ONE. 2022;17:e0260897. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 147. Asselta R, Paraboschi EM, Mantovani A, et al. ACE2 and TMPRSS2 variants and expression as candidates to sex and country differences in COVID‐19 severity in Italy. Aging (Albany NY). 2020;12:10087‐10098. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 148. Debruyne D, Moulin MA, Bricard H, et al. Liquid chromatographic determination of noxytiolin and 1‐methyl‐2‐thiourea in serum: application to pharmacokinetic studies in rabbits and humans. J Pharm Sci. 1985;74:224‐226. [DOI] [PubMed] [Google Scholar]
- 149. Wulandari L, Hamidah B, Pakpahan C, et al. Initial study on TMPRSS2 p.Val160Met genetic variant in COVID‐19 patients. Hum Genomics. 2021;15(1):29. doi: 10.1186/s40246-021-00330-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 150. Gomez J, Albaiceta GM, Garcia‐Clemente M, et al. Angiotensin‐converting enzymes (ACE, ACE2) gene variants and COVID‐19 outcome. Gene. 2020;762:145102. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 151. Verma S, Abbas M, Verma S, et al. Impact of I/D polymorphism of angiotensin‐converting enzyme 1 (ACE1) gene on the severity of COVID‐19 patients. Infect Genet Evol. 2021;91:104801. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 152. Hou Y, Zhao J, Martin W, et al. New insights into genetic susceptibility of COVID‐19: an ACE2 and TMPRSS2 polymorphism analysis. BMC Med. 2020;18:216. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 153. Hubacek JA, Dusek L, Majek O, et al. ACE I/D polymorphism in Czech first‐wave SARS‐CoV‐2‐positive survivors. Clin Chim Acta. 2021;519:206‐209. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 154. Al‐Anouti F, Mousa M, Karras SN, et al. Associations between genetic variants in the vitamin D metabolism pathway and severity of COVID‐19 among UAE residents. Nutrients. 2021;13(11):3680. doi: 10.3390/nu13113680. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 155. Lehrer S, Rheinstein PH. Homozygosity for rs17775810 minor allele associated with reduced mortality of COVID‐19 in the UKBiobank Cohort. In Vivo. 2021;35:965‐968. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 156. Hornig M, Gottschalk G, Peterson DL, et al. Cytokine network analysis of cerebrospinal fluid in myalgic encephalomyelitis/chronic fatigue syndrome. Mol Psychiatry. 2016;21:261‐269. [DOI] [PubMed] [Google Scholar]
- 157. Kosmicki JA, Horowitz JE, Banerjee N, et al. Pan‐ancestry exome‐wide association analyses of COVID‐19 outcomes in 586,157 individuals. Am J Hum Genet. 2021;108:1350‐1355. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 158. Hajeer A, Jawdat D, Massadeh S, et al. Association of KIR gene polymorphisms with COVID‐19 disease. Clin Immunol. 2022;234:108911. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 159. Freitas AT, Calhau C, Antunes G, et al. Vitamin D‐related polymorphisms and vitamin D levels as risk biomarkers of COVID‐19 disease severity. Sci Rep. 2021;11:20837. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 160. Speletas M, Dadouli K, Syrakouli A, et al. MBL deficiency‐causing B allele (rs1800450) as a risk factor for severe COVID‐19. Immunobiology. 2021;226:152136. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 161. Kerget F, Kerget B, Kahraman CY, et al. Evaluation of the relationship between pentraxin 3 (PTX3) rs2305619 (281A/G) and rs1840680 (1449A/G) polymorphisms and the clinical course of COVID‐19. J Med Virol. 2021;93:6653‐6659. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 162. Agwa SHA, Kamel MM, Elghazaly H, et al. Association between interferon‐lambda‐3 rs12979860, TLL1 rs17047200 and DDR1 rs4618569 variant polymorphisms with the course and outcome of SARS‐CoV‐2 patients. Genes (Basel). 2021;12(6):830. doi: 10.3390/genes12060830. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 163. Klaassen K, Stankovic B, Zukic B, et al. Functional prediction and comparative population analysis of variants in genes for proteases and innate immunity related to SARS‐CoV‐2 infection. Infect Genet Evol. 2020;84:104498. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 164. Smith AK, Fang H, Whistler T, et al. Convergent genomic studies identify association of GRIK2 and NPAS2 with chronic fatigue syndrome. Neuropsychobiology. 2011;64:183‐194. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 165. Perez M, Jaundoo R, Hilton K, et al. Genetic predisposition for immune system, hormone, and metabolic dysfunction in myalgic encephalomyelitis/chronic fatigue syndrome: a pilot study. Front Pediatr. 2019;7:206. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 166. Schlauch KA, Khaiboullina SF, Meirleir DE KL et al. Genome‐wide association analysis identifies genetic variations in subjects with myalgic encephalomyelitis/chronic fatigue syndrome. Transl Psychiatry 2016; 6:e730. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 167. Rajeevan MS, Dimulescu I, Murray J, et al. Pathway‐focused genetic evaluation of immune and inflammation related genes with chronic fatigue syndrome. Hum Immunol. 2015;76:553‐560. [DOI] [PubMed] [Google Scholar]
- 168. Marshall‐Gradisnik S, Huth T, Chacko A, et al. Natural killer cells and single nucleotide polymorphisms of specific ion channels and receptor genes in myalgic encephalomyelitis/chronic fatigue syndrome. Appl Clin Genet. 2016;9:39‐47. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 169. Marshall‐Gradisnik S, Johnston S, Chacko A, et al. Single nucleotide polymorphisms and genotypes of transient receptor potential ion channel and acetylcholine receptor genes from isolated B lymphocytes in myalgic encephalomyelitis/chronic fatigue syndrome patients. J Int Med Res. 2016;44:1381‐1394. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 170. Carlo‐Stella N, Badulli C, De SA, et al. A first study of cytokine genomic polymorphisms in CFS: positive association of TNF‐857 and IFNgamma 874 rare alleles. Clin Exp Rheumatol. 2006;24:179‐182. [PubMed] [Google Scholar]
- 171. Steiner S, Becker SC, Hartwig J, et al. Autoimmunity‐related risk variants in PTPN22 and CTLA4 are associated with ME/CFS with infectious onset. Front Immunol. 2020;11:578. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 172. Dibble JJ, McGrath SJ, Ponting CP. Genetic risk factors of ME/CFS: a critical review. Hum Mol Genet. 2020;29:R117‐R124. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 173. Lande A, Fluge O, Strand EB, et al. Human leukocyte antigen alleles associated with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Sci Rep. 2020;10:5267. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 174. Underhill JA, Mahalingam M, Peakman M, et al. Lack of association between HLA genotype and chronic fatigue syndrome. Eur J Immunogenet. 2001;28:425‐428. [DOI] [PubMed] [Google Scholar]
- 175. Aguirre M, Rivas MA, Priest J. Phenome‐wide burden of copy‐number variation in the UKBiobank. Am J Hum Genet. 2019;105:373‐383. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 176. Fukuda S, Horiguchi M, Yamaguti K, et al. Association of monoamine‐synthesizing genes with the depression tendency and personality in chronic fatigue syndrome patients. Life Sci. 2013;92:183‐186. [DOI] [PubMed] [Google Scholar]
- 177. Narita M, Nishigami N, Narita N, et al. Association between serotonin transporter gene polymorphism and chronic fatigue syndrome. Biochem Biophys Res Commun. 2003;311:264‐266. [DOI] [PubMed] [Google Scholar]
- 178. Smith AK, Dimulescu I, Falkenberg VR, et al. Genetic evaluation of the serotonergic system in chronic fatigue syndrome. Psychoneuroendocrinology. 2008;33:188‐197. [DOI] [PubMed] [Google Scholar]
- 179. Meyer B, Nguyen CB, Moen A, et al. Maintenance of chronic fatigue syndrome (CFS) in young CFS patients is associated with the 5‐HTTLPR and SNP rs25531 A>G genotype. PLoS One. 2015;10:e0140883. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 180. Lee E, Cho S, Kim K, et al. An integrated approach to infer causal associations among gene expression, genotype variation, and disease. Genomics. 2009;94:269‐277. [DOI] [PubMed] [Google Scholar]
- 181. Rajeevan MS, Smith AK, Dimulescu I, et al. Glucocorticoid receptor polymorphisms and haplotypes associated with chronic fatigue syndrome. Genes Brain Behav. 2007;6:167‐176. [DOI] [PubMed] [Google Scholar]
- 182. Smith AK, White PD, Aslakson E, et al. Polymorphisms in genes regulating the HPA axis associated with empirically delineated classes of unexplained chronic fatigue. Pharmacogenomics. 2006;7:387‐394. [DOI] [PubMed] [Google Scholar]
- 183. Smith J, Fritz EL, Kerr JR, et al. Association of chronic fatigue syndrome with human leucocyte antigen class II alleles. J Clin Pathol. 2005;58:860‐863. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 184. Sommerfeldt L, Portilla H, Jacobsen L, et al. Polymorphisms of adrenergic cardiovascular control genes are associated with adolescent chronic fatigue syndrome. Acta Paediatr. 2011;100:293‐298. [DOI] [PubMed] [Google Scholar]
- 185. De Luca C, Gugliandolo A, Calabrò C, et al. Role of polymorphisms of inducible nitric oxide synthase and endothelial nitric oxide synthase in idiopathic environmental intolerances. Mediators Inflamm. 2015;2015:245308. doi: 10.1155/2015/245308. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 186. Carlo‐Stella N, Bozzini S, De SA, et al. Molecular study of receptor for advanced glycation endproduct gene promoter and identification of specific HLA haplotypes possibly involved in chronic fatigue syndrome. Int J Immunopathol Pharmacol. 2009;22:745‐754. [DOI] [PubMed] [Google Scholar]
- 187. Vladutiu GD, Natelson BH. Association of medically unexplained fatigue with ACE insertion/deletion polymorphism in Gulf War veterans. Muscle Nerve. 2004;30:38‐43. [DOI] [PubMed] [Google Scholar]
- 188. Fukuda S, Hashimoto R, Ohi K, et al. A functional polymorphism in the disrupted‐in schizophrenia 1 gene is associated with chronic fatigue syndrome. Life Sci. 2010;86:722‐725. [DOI] [PubMed] [Google Scholar]
- 189. Docampo E, Escaramis G, Gratacos M, et al. Genome‐wide analysis of single nucleotide polymorphisms and copy number variants in fibromyalgia suggest a role for the central nervous system. Pain. 2014;155:1102‐1109. [DOI] [PubMed] [Google Scholar]
- 190. Johnston S, Staines D, Klein A, et al. A targeted genome association study examining transient receptor potential ion channels, acetylcholine receptors, and adrenergic receptors in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis. BMC Med Genet. 2016;17:79. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 191. Hajdarevic R, Lande A, Rekeland I, et al. Fine mapping of the major histocompatibility complex (MHC) in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) suggests involvement of both HLA class I and class II loci. Brain Behav Immun. 2021;98:101‐109. [DOI] [PubMed] [Google Scholar]
- 192. Maltese PE, Venturini L, Poplavskaya E, et al. Genetic evaluation of AMPD1, CPT2, and PGYM metabolic enzymes in patients with chronic fatigue syndrome. Genet Mol Res. 2016;15(3). doi: 10.4238/gmr.15038717. [DOI] [PubMed] [Google Scholar]
- 193. Goertzel BN, Pennachin C, de Souza CL, et al. Combinations of single nucleotide polymorphisms in neuroendocrine effector and receptor genes predict chronic fatigue syndrome. Pharmacogenomics. 2006;7:475‐483. [DOI] [PubMed] [Google Scholar]
- 194. Shimosako N, Kerr JR. Use of single‐nucleotide polymorphisms (SNPs) to distinguish gene expression subtypes of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME). J Clin Pathol. 2014;67:1078‐1083. [DOI] [PubMed] [Google Scholar]
- 195. Imai Y, Kuba K, Ohto‐Nakanishi T, et al. Angiotensin‐converting enzyme 2 (ACE2) in disease pathogenesis. Circ J. 2010;74:405‐410. [DOI] [PubMed] [Google Scholar]
- 196. Rigat B, Hubert C, henc‐Gelas F et al. An insertion/deletion polymorphism in the angiotensin I‐converting enzyme gene accounting for half the variance of serum enzyme levels. J Clin Invest 1990; 86:1343–1346. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 197. Itoyama S, Keicho N, Quy T, et al. ACE1 polymorphism and progression of SARS. Biochem Biophys Res Commun. 2004;323:1124‐1129. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 198. Marshall RP, Webb S, Bellingan GJ, et al. Angiotensin converting enzyme insertion/deletion polymorphism is associated with susceptibility and outcome in acute respiratory distress syndrome. Am J Respir Crit Care Med. 2002;166:646‐650. [DOI] [PubMed] [Google Scholar]
- 199. Yamamoto N, Ariumi Y, Nishida N, et al. SARS‐CoV‐2 infections and COVID‐19 mortalities strongly correlate with ACE1 I/D genotype. Gene. 2020;758:144944. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 200. Chan KC, Tang NL, Hui DS, et al. Absence of association between angiotensin converting enzyme polymorphism and development of adult respiratory distress syndrome in patients with severe acute respiratory syndrome: a case control study. BMC Infect Dis. 2005;5:26. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 201. Pagliaro P, Penna C. ACE/ACE2 ratio: a key also in 2019 coronavirus disease (Covid‐19)? Front Med (Lausanne). 2020;7:335. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 202. Lieberman J, Bell DS. Serum angiotensin‐converting enzyme as a marker for the chronic fatigue‐immune dysfunction syndrome: a comparison to serum angiotensin‐converting enzyme in sarcoidosis. Am J Med. 1993;95:407‐412. [DOI] [PubMed] [Google Scholar]
- 203. Nagashima S, Dutra AA, Arantes MP, et al. COVID‐19 and lung mast cells: the Kallikrein‐Kinin activation pathway. Int J Mol Sci. 2022;23(3):1714. doi: 10.3390/ijms23031714. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 204. Veerappan A, Reid AC, Estephan R, et al. Mast cell renin and a local renin‐angiotensin system in the airway: role in bronchoconstriction. Proc Natl Acad Sci USA. 2008;105:1315‐1320. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 205. Company C, Piqueras L, Naim Abu NY, et al. Contributions of ACE and mast cell chymase to endogenous angiotensin II generation and leucocyte recruitment in vivo. Cardiovasc Res. 2011;92:48‐56. [DOI] [PubMed] [Google Scholar]
- 206. Caughey GH, Raymond WW, Wolters PJ. Angiotensin II generation by mast cell alpha‐ and beta‐chymases. Biochim Biophys Acta. 2000;1480:245‐257. [DOI] [PubMed] [Google Scholar]
- 207. Silver RB, Reid AC, Mackins CJ, et al. Mast cells: a unique source of renin. Proc Natl Acad Sci USA. 2004;101:13607‐13612. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 208. Aldi S, Robador PA, Tomita K, et al. IgE receptor‐mediated mast‐cell renin release. Am J Pathol. 2014;184:376‐381. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 209. Miyazaki M, Takai S, Jin D, et al. Pathological roles of angiotensin II produced by mast cell chymase and the effects of chymase inhibition in animal models. Pharmacol Ther. 2006;112:668‐676. [DOI] [PubMed] [Google Scholar]
- 210. Hara M, Ono K, Wada H, et al. Preformed angiotensin II is present in human mast cells. Cardiovasc Drugs Ther. 2004;18:415‐420. [DOI] [PubMed] [Google Scholar]
- 211. Tan J, Anderson DE, Rathore APS, et al. Signatures of mast cell activation are associated with severe COVID‐19. medRxiv. 2021;1‐18. [Google Scholar]
- 212. Gebremeskel S, Schanin J, Coyle KM, et al. Mast cell and eosinophil Activation are associated with COVID‐19 and TLR‐mediated viral inflammation: implications for an Anti‐Siglec‐8 antibody. Front Immunol. 2021;12:650331. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 213. Theoharides TC. COVID‐19, pulmonary mast cells, cytokine storms, and beneficial actions of luteolin. Biofactors. 2020;46:306‐308. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 214. Theoharides TC, Conti P. COVID‐19 and multisystem inflammatory syndrome, or is it mast cell activation syndrome? J Biol Regul Homeost Agents. 2020;34:1633‐1636. [DOI] [PubMed] [Google Scholar]
- 215. Theoharides TC. The impact of psychological stress on mast cells. Ann Allergy Asthma Immunol. 2020;125:388‐392. [DOI] [PubMed] [Google Scholar]
- 216. Motta Junior JDS, Miggiolaro AFRD, Nagashima S, et al. Mast cells in alveolar septa of COVID‐19 patients: a pathogenic pathway that may link interstitial edema to immunothrombosis. Front Immunol. 2020;11:574862. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 217. Weinstock LB, Brook JB, Walters AS, et al. Mast cell activation symptoms are prevalent in Long‐COVID. Int J Infect Dis. 2021;112:217‐226. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 218. Afrin LB, Weinstock LB, Molderings GJ. Covid‐19 hyperinflammation and post‐Covid‐19 illness may be rooted in mast cell activation syndrome. Int J Infect Dis. 2020;100:327‐332. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 219. Wu ML, Liu FL, Sun J, et al. SARS‐CoV‐2‐triggered mast cell rapid degranulation induces alveolar epithelial inflammation and lung injury. Signal Transduct Target Ther. 2021;6:428. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 220. Murdaca G, Di Gioacchino M, Greco M, et al. Basophils and mast cells in COVID‐19 pathogenesis. Cells. 2021;10(10):2754. doi: 10.3390/cells10102754. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 221. Omdal R, Skoie IM, Grimstad T. Fatigue is common and severe in patients with mastocytosis. Int J Immunopathol Pharmacol. 2018;32:2058738418803252. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 222. Nguyen T, Johnston S, Chacko A, et al. Novel characterisation of mast cell phenotypes from peripheral blood mononuclear cells in chronic fatigue syndrome/myalgic encephalomyelitis patients. Asian Pac J Allergy Immunol. 2017;35:75‐81. [DOI] [PubMed] [Google Scholar]
- 223. Sandig H, Jobbings CE, Roldan NG, et al. IL‐33 causes selective mast cell tolerance to bacterial cell wall products by inducing IRAK1 degradation. Eur J Immunol. 2013;43:979‐988. [DOI] [PubMed] [Google Scholar]
- 224. Nguyen TT, Kim YM, Kim TD, et al. Phosphatidylinositol 4‐phosphate 5‐kinase alpha facilitates Toll‐like receptor 4‐mediated microglial inflammation through regulation of the Toll/interleukin‐1 receptor domain‐containing adaptor protein (TIRAP) location. J Biol Chem. 2013;288:5645‐5659. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 225. Hendriksen E, van Bergeijk D, Oosting RS, Redegeld FA. Mast cells in neuroinflammation and brain disorders. Neurosci Biobehav Rev. 2017;79:119‐133. [DOI] [PubMed] [Google Scholar]
- 226. Zhang X, Wang Y, Dong H, et al. Induction of microglial activation by mediators released from mast cells. Cell Physiol Biochem. 2016;38:1520‐1531. [DOI] [PubMed] [Google Scholar]
- 227. Skaper SD, Facci L, Zusso M, et al. Neuroinflammation, mast cells, and glia: dangerous liaisons. Neuroscientist. 2017;23:478‐498. [DOI] [PubMed] [Google Scholar]
- 228. Vargas G, Medeiros Geraldo LH, Gedeao SN, et al. Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and glial cells: insights and perspectives. Brain Behav Immun Health. 2020;7:100127. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 229. Tremblay ME, Madore C, Bordeleau M, et al. Neuropathobiology of COVID‐19: the role for glia. Front Cell Neurosci. 2020;14:592214. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 230. Subhramanyam CS, Wang C, Hu Q, et al. Microglia‐mediated neuroinflammation in neurodegenerative diseases. Semin Cell Dev Biol. 2019;94:112‐120. [DOI] [PubMed] [Google Scholar]
- 231. Colonna M, Butovsky O. Microglia function in the central nervous system during health and neurodegeneration. Annu Rev Immunol. 2017;35:441‐468. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 232. Voet S, Prinz M, van Loo G. Microglia in central nervous system inflammation and multiple sclerosis pathology. Trends Mol Med. 2019;25:112‐123. [DOI] [PubMed] [Google Scholar]
- 233. Perry VH, Nicoll JA, Holmes C. Microglia in neurodegenerative disease. Nat Rev Neurol. 2010;6:193‐201. [DOI] [PubMed] [Google Scholar]
- 234. Ransohoff RM. How neuroinflammation contributes to neurodegeneration. Science. 2016;353:777‐783. [DOI] [PubMed] [Google Scholar]
- 235. Hickman S, Izzy S, Sen P, et al. Microglia in neurodegeneration. Nat Neurosci. 2018;21:1359‐1369. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 236. Murta V, Villarreal A, Ramos AJ. Severe acute respiratory syndrome coronavirus 2 impact on the central nervous system: are astrocytes and microglia main players or merely bystanders? ASN Neuro. 2020;12:1759091420954960. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 237. Jack CS, Arbour N, Manusow J, et al. TLR signaling tailors innate immune responses in human microglia and astrocytes. J Immunol. 2005;175:4320‐4330. [DOI] [PubMed] [Google Scholar]
- 238. Zheng M, Karki R, Williams EP, et al. TLR2 senses the SARS‐CoV‐2 envelope protein to produce inflammatory cytokines. Nat Immunol. 2021;22:829‐838. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 239. Pellenz FM, Dieter C, Lemos NE, et al. Association of TYK2 polymorphisms with autoimmune diseases: a comprehensive and updated systematic review with meta‐analysis. Genet Mol Biol. 2021;44:e20200425. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 240. Rajaei E, Jalali MT, Shahrabi S, et al. HLAs in autoimmune diseases: dependable diagnostic biomarkers? Curr Rheumatol Rev. 2019;15:269‐276. [DOI] [PubMed] [Google Scholar]
- 241. Paludan SR, Mogensen TH. Innate immunological pathways in COVID‐19 pathogenesis. Sci Immunol. 2022;7(67):eabm5505. doi: 10.1126/sciimmunol.abm5505. [DOI] [PubMed] [Google Scholar]
- 242. Unterman A, Sumida TS, Nouri N, et al. Single‐cell multi‐omics reveals dyssynchrony of the innate and adaptive immune system in progressive COVID‐19. Nat Commun. 2022;13:440. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 243. Mahler M, Meroni PL, Infantino M, et al. Circulating calprotectin as a biomarker of COVID‐19 severity. Expert Rev Clin Immunol. 2021;17:431‐443. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 244. Mao Q, Wang C, Wen W, et al. A meta‐analysis of the association between calprotectin and the severity of COVID‐19. J Infect. 2022;84:e31‐e33. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 245. Chen L, Long X, Xu Q, et al. Elevated serum levels of S100A8/A9 and HMGB1 at hospital admission are correlated with inferior clinical outcomes in COVID‐19 patients. Cell Mol Immunol. 2020;17:992‐994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 246. Bauer W, Diehl‐Wiesenecker E, Ulke J, et al. Outcome prediction by serum calprotectin in patients with COVID‐19 in the emergency department. J Infect. 2021;82:84‐123. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 247. Stascheit F, Hotter B, Klose S, et al. Calprotectin in chronic inflammatory demyelinating polyneuropathy and variants‐a potential novel biomarker of disease activity. Front Neurol. 2021;12:723009. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 248. Theoharides TC. Could SARS‐CoV‐2 spike protein be responsible for long‐COVID syndrome? Mol Neurobiol. 2022;13:1‐12. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 249. Theoharides TC. Mast cells: the immune gate to the brain. Life Sci. 1990;46:607‐617. [DOI] [PubMed] [Google Scholar]
- 250. McMahon CL, Staples H, Gazi M, et al. SARS‐CoV‐2 targets glial cells in human cortical organoids. Stem Cell Rep. 2021;16:1156‐1164. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 251. Karnik M, Beeraka NM, Uthaiah CA, et al. A review on SARS‐CoV‐2‐induced neuroinflammation, neurodevelopmental complications, and recent updates on the vaccine development. Mol Neurobiol. 2021;Jun 5:1‐29. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 252. Lee MH, Perl DP, Nair G, et al. Microvascular injury in the brains of patients with Covid‐19. N Engl J Med. 2021;384:481‐483. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 253. Bodnar B, Patel K, Ho W, et al. Cellular mechanisms underlying neurological/neuropsychiatric manifestations of COVID‐19. J Med Virol. 2021;93:1983‐1998. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 254. Ng JH, Sun A, Je HS, Tan EK. Unravelling pathophysiology of neurological and psychiatric complications of COVID‐19 using brain organoids. Neuroscientist. 2021:10738584211015136. doi: 10.1177/10738584211015136. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 255. Mackay A. A paradigm for post‐covid‐19 fatigue syndrome analogous to ME/CFS. Front Neurol. 2021;12:701419. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 256. Rezai‐Zadeh K, Ehrhart J, Bai Y, et al. Apigenin and luteolin modulate microglial activation via inhibition of STAT1‐induced CD40 expression 1. J Neuroinflammation. 2008;5:41. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 257. Jang S, Kelley KW, Johnson RW. Luteolin reduces IL‐6 production in microglia by inhibiting JNK phosphorylation and activation of AP‐1. Proc Natl Acad Sci USA. 2008;105:7534‐7539. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 258. Burton MD, Rytych JL, Amin R, et al. Dietary luteolin reduces proinflammatory microglia in the brain of senescent mice. Rejuvenation Res. 2016;19:286‐292. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 259. Patel AB, Tsilioni I, Leeman SE, et al. Neurotensin stimulates sortilin and mTOR in human microglia inhibitable by methoxyluteolin, a potential therapeutic target for autism. Proc Natl Acad Sci USA. 2016;113:E7049‐E7058. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 260. Weng Z, Patel AB, Panagiotidou S, et al. The novel flavone tetramethoxyluteolin is a potent inhibitor of human mast cells. J Allergy Clin Immunol. 2015;135:1044‐1052. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 261. Patel AB, Theoharides TC. Methoxyluteolin inhibits neuropeptide‐stimulated proinflammatory mediator release via mTOR activation from human mast cells. J Pharmacol Exp Ther. 2017;361:462‐471. [DOI] [PubMed] [Google Scholar]
- 262. Ashaari Z, Hadjzadeh MA, Hassanzadeh G, et al. The flavone luteolin improves central nervous system disorders by different mechanisms: a review. J Mol Neurosci. 2018;65:491‐506. [DOI] [PubMed] [Google Scholar]
- 263. Calis Z, Mogulkoc R, Baltaci AK. The roles of flavonols/flavonoids in neurodegeneration and neuroinflammation. Mini Rev Med Chem. 2020;20:1475‐1488. [DOI] [PubMed] [Google Scholar]
- 264. Kempuraj D, Thangavel R, Kempuraj DD, et al. Neuroprotective effects of flavone luteolin in neuroinflammation and neurotrauma. Biofactors. 2020;47:190‐197. [DOI] [PubMed] [Google Scholar]
- 265. Theoharides TC, Conti P, Economu M. Brain inflammation, neuropsychiatric disorders, and immunoendocrine effects of luteolin. J Clin Psychopharmacol. 2014;34:187‐189. [DOI] [PubMed] [Google Scholar]
- 266. Dajas F, Rivera‐Megret F, Blasina F, et al. Neuroprotection by flavonoids 1. Braz J Med Biol Res. 2003;36:1613‐1620. [DOI] [PubMed] [Google Scholar]
- 267. Lin TY, Lu CW, Wang SJ. Luteolin protects the hippocampus against neuron impairments induced by kainic acid in rats. NeuroToxicol. 2016;55:48‐57. [DOI] [PubMed] [Google Scholar]
- 268. Rezai‐Zadeh K, Douglas SR, Bai Y, et al. Flavonoid‐mediated presenilin‐1 phosphorylation reduces Alzheimer's disease beta‐amyloid production. J Cell Mol Med. 2009;13:574‐588. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 269. Theoharides TC, Stewart JM, Hatziagelaki E, et al. Brain "fog," inflammation and obesity: key aspects of 2 neuropsychiatric disorders improved by luteolin. Front Neurosci. 2015;9:225. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 270. Yao ZH, Yao XL, Zhang Y, et al. Luteolin could improve cognitive dysfunction by inhibiting neuroinflammation. Neurochem Res. 2018;43:806‐820. [DOI] [PubMed] [Google Scholar]
- 271. Gratton G, Weaver SR, Burley CV, et al. Dietary flavanols improve cerebral cortical oxygenation and cognition in healthy adults. Sci Rep. 2020;10:19409. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 272. Devi SA, Chamoli A. Polyphenols as an Effective Therapeutic Intervention Against Cognitive Decline During Normal and Pathological Brain Aging. Adv Exp Med Biol. 2020;1260:159‐174. [DOI] [PubMed] [Google Scholar]
- 273. Taracanova A, Tsilioni I, Conti P, et al. Substance P and IL‐33 administered together stimulate a marked secretion of IL‐1beta from human mast cells, inhibited by methoxyluteolin. Proc Natl Acad Sci USA. 2018;115:E9381‐E9390. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 274. Theoharides TC. Luteolin supplements: all that glitters is not gold. Biofactors. 2020;47:242‐244. [DOI] [PubMed] [Google Scholar]
- 275. Theoharides TC, Guerra L, Patel K. Successful treatment of a patient with severe COVID‐19 using an integrated approach addressing mast cells and their mediators. Int J Infect Dis. 2022;118:164‐166. [DOI] [PMC free article] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Table S1. The findings of genetic and cohort studies of COVID‐19
Table S2. The findings of genetic association and cohort studies of ME/CFS
Table S3. The most studied genes in COVID‐19 patients
Table S4. The most studied genes in ME/CFS patients
Figure S1. (A) Genetic loci from ME/CFS studies in peer‐reviewed publications to date. (B) Genetic loci from ME/CFS studies in peer‐reviewed publications to date. (C) Genetic loci from ME/CFS studies in peer‐reviewed publications to date.
Figure S2. (A) Genetic loci from COVID‐19 studies in peer‐reviewed publications to date and (B) Genetic loci from COVID‐19 studies in peer‐reviewed publications to date.
Data Availability Statement
Not applicable.
