Abstract
Introduction
The rapid spread of COVID-19 has been a global public health problem and it is yet to be put under control. Active COVID-19 is associated with unrestrained secretion of pro-inflammatory cytokines and imbalances in haematological profile including anaemia, leukocytosis and thrombocytopaenia. However, the haematological profile and immune status following recovery from COVID-19 has not been recognized. We evaluated the immunohaematological profile among COVID-19 patients with active infection, recovered cases and unexposed healthy individuals in the Ashanti region of Ghana.
Methodology
A total of 95 adult participants, consisting of 35 positive, 30 recovered and 30 unexposed COVID-19 negative individuals confirmed by RT-PCR were recruited for the study. All the patients had the complete blood count performed using the haematological analyzer Sysmex XN-1500. Their plasma cytokine levels of interleukin (IL)-1β, IL-6, IL-10, IL-17, tumour necrosis factor-alpha (TNF-α) and interferon gamma (IFN-γ) were analysed using ELISA. Statistical analyses were performed on R statistical software.
Result
The Patients with COVID-19 active infection had significantly higher levels of IL10 (181±6.14 pg/mL vs 155.00±14.32 pg/mL vs 158.80±11.70 pg/mL, p = 0.038), WBC count (5.5±0.4 x109 /L vs 4.5±0.6 x109 /L vs 3.8±0.5, p < 0.0001) and percentage basophil (1.8±0.1% vs 0.8±0.3% vs 0.7±0.2%, p = 0.0040) but significantly lower levels of IFN-γ (110.10±9.52 pg/mL vs 142.80±5.46 pg/mL vs 140.80±6.39 pg/mL, p = 0.021), haematocrit (24.1±3.7% vs 38.3± 3.0% vs 38.5±2.2%, p < 0.0001), haemoglobin concentration (9.4±0.1g/dl vs 12.5± 5.0g/dl vs 12.7±0.8, p < 0.0001) and MPV (9.8±0.2fL vs 11.1±0.5fL vs 11.6±0.3fL, p < 0.0001) compared to recovered and unexposed controls respectively. There were significant association between IL-1β & neutrophils (r = 0.42, p<0.05), IL-10 & WBC (r = 0.39, p<0.05), IL-10 & Basophils (r = -0.51, p<0.01), IL-17 & Neutrophil (r = 0.39, p<0.05) in the active COVID-19 cases.
Conclusion
COVID-19 active infection is associated with increased IL-10 and WBC with a concomitant decrease in IFN-γ and haemoglobin concentration. However, recovery from the disease is associated with immune recovery with appareantly normal haematological profile.
Introduction
The infection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19 is a pandemic that has battled the world for more than a year now with no indication of backing down [1, 2]. COVID-19 exhibits a range of symptoms from asymptomatic to acute respiratory distress syndrome (ARDS) [3]. Currently, there are effective vaccines to protect the people from COVID-19 and there have been a significant reduction in the global COVID-19 cases, emergency department visits, hospital admissions and mortality following the introduction of vaccines [4]. This has resulted in the reduction of COVID-19 restrictions such as mandatory wearing facemasks and social distancing.
The deadly form of COVID-19 have been associated with the development of cytokine storms, especially in comorbidities [5]. The unrestrained secretion of TNF-ɑ, IL-1, IL-6, and IFN-γ are some of the pro-inflammatory cytokines underlying the pathogenesis of the severe and life-threatening disease conditions in COVID-19 [6, 7]. The high elevated levels of IL-6, IL-1 and TNF-ɑ have been associated with the increased monocytes and macrophages in the COVID-19 patients experiencing cytokine storm [5, 8].
The immune system underlying COVID-19 and its complications are not fully elucidated. The peripheral blood circulation of natural killer (NK) cells, macrophages, monocytes, granulocytes, eosinophils, dendritic cells, Basophils and neutrophils which are major components of the innate immune system that expresses several varieties of pattern recognition receptors (PRRs) responsible for identifying pathogen-associated molecular patterns (PAMPs) during infections have been reported in COVID-19 cases [9, 10]. The recognition of PRRs such as toll-like receptors by PAMPs on the infecting pathogens triggers the expression of NF-kB, a pro-inflammatory cytokine transcription factor responsible for activating type 1 interferons against viral infection [11, 12]. The type 1 interferons stimulate the NK cells and CD8 cytotoxic T cells. NK cells recognize infected cells that downregulate MHC class 1 on their surface and upregulate stress ligands, and secrete perforin and granzyme to induce apoptosis. On the other hand, CD8+ T cells recognize viral peptides on MHC class 1 on infected cells and along with co-stimulation also secrete perforin-mediated granulysin to their cellular targets [13, 14].
However, in severe COVID-19 cases, the NK and the cytolytic CD8 T cells are not able to kill the SARS-CoV-2 resulting in the over activation of the antigen-presenting cells and exaggerated interactions leading to cytokine storms, thrombotic tendency, multiple organ failure and death [15, 16]. The monocytes and macrophages inflammatory cells infiltrate the lungs and cause alveolar injury [17, 18]. The hyperstimulation and infiltration of monocytes and macrophages into the organs in SARS-CoV-2 infections result in a condition called macrophage activation syndrome (MAS) [19]. The MAS is characterised by fever, pancytopenia, elevated serum ferritin, liver dysfunction, and splenomegaly which impairs viral clearance [15, 19]. Also, the increase in neutrophil infiltration in the organs in COVID-19 has been suggested to play a role in COVID-19 pathogenesis by forming neutrophil extracellular traps (NETs) and NETosis, through a programmed cell death in apoptosis and necrosis [15, 20–23].
Haematological parameters have been reported in active COVID-19 [24]. Anaemia, decrease in the erythropoiesis and mean platelet volume (MPV) have been associated with mild to severe COVID-19 cases. Multiple unknown factors may be contributing to anaemia in critically ill patients suffering from COVID-19 [25, 26]. Monitoring the haematological abnormalities in COVID-19 is critical for clinical prognosis and prompt management of affected patients [27, 28]. Moreover, thrombocytopenia is commonly reported in active COVID-19 and is significantly associated with death [29]. Again, high white blood cell (WBC) and thrombocytopenia has been described among patients with severe and fatal COVID-19 [30]. Monitoring these parameters following recovery from COVID-19 may be required to make decisions such as the need to continue treatment following discharge from the hospital [31].
The immunohaematological profile has been well studied in active COVID-19. However, there is paucity of data on the haematological profile and immune status following COVID-19 recovery. We evaluated the immunohaematological profile among COVID-19 patients with active infection, recovered cases and unexposed healthy individuals in the Ashanti region of Ghana.
Materials and methods
Participants, study design, and data collection, ethics & consents
This case-control study was conducted in the Kumasi Metropolis in the Ashanti Region of Ghana from January 2021 to June 2021. A total of 95 unvaccinated adult participants, consisting of 35 COVID-19 positive participants with active infection, 30 recovered patients and 30 unexposed COVID-19 negative controls were recruited for the study. Positive group consisted of patients who had been diagnosed and confirmed to be positive for COVID-19 by Reverse Transcription-quantitative Real Time-Polymerase Chain Reaction (RT-qPCR) [32]. The recovered group consisted of individuals who had been previously confirmed to be positive for SARS-CoV-2 nucleic acid by RT-qPCR, undergone treatment in hospital and had been discharged according to standard protocols. After two weeks of isolation, these patients were regarded as completely recovered, with no SARS-CoV-2 remaining in the body and a negative nucleic acid detection test. The unexposed negative controls consisted of individuals who had tested negative for SARS-CoV-2 by RT-qPCR. Non exposure among the controls was confirmed by periodical RT-qPCR testing for a period of three months. Participants in each of the study groups were excluded if they had known chronic or inflammatory condition such as HIV, tuberculusis, Asthma, diabetes and hypertension. This study was submitted to and approved by Committee on Human Research Publication Ethics (CHRPE), KNUST (CHRPE/AP/238/20). Written informed consent was sought from all participants who opted to particiapte after the aims and objectives of the study had been explained to them. All study participants were 18 years or older and did not require consent from parent/guardian to participate. Participation was voluntary and respondents were assured of data confidentiality. All methods were carried out in accordance with relevant guidelines and regulations.
Laboratory examination of blood samples
Approximately 3 to 5 mL of peripheral blood was obtained with EDTA collection tubes from the subjects in each study group. Testing for hematological parameters (White blood cell, Basophil, Eosinophil, Monocyte, Lymphocyte, Neutrophil, Platelet, MCHC, MCH, MCV, MPV, Hematocrit, Hemoglobin and Red blood cell) was performed using a hematological analyzer Sysmex XN-1500 (Sysmex Corp., Kobe, Japan).
Enzyme Linked Immunosorbent Assay (ELISA)
Enzyme Linked Immunosorbent Assay (ELISA) was used to detect the cytokine concentration [pg/mL] in the plasma samples including: IL-1β, IL-6, IL-10, IL-17, IFN-γ and TNF-α according to the manufacturer’s instruction. ELISA kit used was by shanghai Group Company limited.
Statistical analyses
All statistical analyses were performed using the R language for statistical computing [33]. Continous data were expressed as mean±standard deviation whilst categorical variables were expressed as frequencis and percentages. The One-way Analysis of Variance (ANOVA) and Tukey multiple comparism test was used to compared haematologcal parameters and cytokine levels among the three study groups. Pearson’s correlation test was performed to test association between white cell parameters and cytokine levels. Statistical significance was determined as p < 0.05.
Results
Demographic characteristics of the study subjects
A total of 95 participants,18–69 years, consisting of 35 COVID-19 active cases, 30 COVID-19 recovered patents and 30 unexposed healthy controls were included in the statistical analysis. There was no significant difference in the mean age between the COVID-19 active cases, unexposed and the recovered (35.8±12.0 years vs 39.7±13.3 years vs 44.6±13.3 years, p = 0.145). The distribution of males and females were similar among the three study groups (p = 0.820) (Table 1).
Table 1. Demographic characteristics among the study participants.
| COVID-19 STATUS | |||||
|---|---|---|---|---|---|
| Variable | N | Active (35) | Unexposed (30) | Recovered (30) | p-value |
| Age (years) | 95 | 35.8±12.0 | 39.7±13.3 | 44.6±13.3 | 0.145b |
| Gender | 0.820a | ||||
| Male | 55 | 20 (57.4%) | 17 (56.7%) | 18 (60.0%) | |
| Female | 40 | 15 (42.6%) | 13 (43.3%) | 12 (40.0%) | |
N = number of participants. a p-values are chi-square test of association, b p-values were obtained by One-way Analysis of variance (ANOVA).COVID-19 Active cases are patients who had ongoing COVID-19; COVID-19 Recovered cases are patients who were previous diagnosed with COVID-19 but the subsequent test was negative by RT-PCR testing; COVID-19 Unexposed cases are subjects who have not been exposed to COVID-19, thus they have never been diagnosed with COVID-19.
Haematological parameters among study groups
The white blood cell count (5.5±0.4 x109 /L vs 4.5±0.6 x109 /L vs 3.8±0.5, p < 0.0001) and percentage basophil (1.8±0.1% vs 0.8±0.3% vs 0.7±0.2%, p = 0.0040) were significantly higher among COVID-19 active cases, followed by the recovered cases and the unexposed controls. However, there was not significant difference in Eosinophil (%), Monocyte (%), Lymphocyte (%) and Neutrophil (%) between the three study groups (p > 0.05). With respect to red cell and platelet parameters, the COVID-19 active infection group had significantly lower levels of haematocrit (24.1±3.7% vs 38.3± 3.0% vs 38.5±2.2%, p < 0.0001), haemoglobin concentration (9.4±0.1g/dl vs 12.5± 5.0g/dl vs 12.7±0.8, p < 0.0001) and MPV (9.8±0.2fL vs 11.1±0.5fL vs 11.6±0.3fL, p < 0.0001) compared to recovered and unexposed controls respectively. In multiple comparison, the percentage basophil, HB, HCT and MPV were similar between the recovered patients and the unexposed healthy controls (p > 0.05).
Moreover, the unexposed controls had significantly higher levels of MCH and MCHC compared to the recovered and active infection groups respectively (p< 0.0001). There was no significant difference in red blood cell count, platelets count and MPV between the three study groups (p > 0.05). Table 2 displays the haematological parameters among the three study groups.
Table 2. Haematological parameters among the study participants.
| COVID-19 STATUS | ||||
|---|---|---|---|---|
| Parameter | Active cases | Unexposed cases | Recovered cases | p-value |
| White blood cell (x109/L) | 5.5±0.4 | 3.8±0.5 | 4.5±0.6 | 0.0290 a b c |
| Basophil (%) | 1.8±0.1 | 0.7±0.2 | 0.8±0.3 | 0.0040 a c |
| Eosinophil (%) | 3.6±0.4 | 2.5±0.5 | 3.2±0.8 | 0.3580 |
| Monocyte (%) | 7.4±0.9 | 11.5±2.2 | 12.2±2.2 | 0.0590 |
| Lymphocyte (%) | 45.8±2.2 | 49.3±3.4 | 40.5±2.2 | 0.1830 |
| Neutrophil (%) | 46.1±2.5 | 44.8±4.1 | 45.3±3.3 | 0.2810 |
| Haematocrit (%) | 24.1±3.7 | 38.5±2.2 | 38.3± 3.0 | <0.0001 a c |
| Haemoglobin (g/dL) | 9.4±0.1 | 12.7±0.8 | 12.5± 5.0 | <0.0001 a c |
| Red blood cell (x1012/L) | 4.1±0.2 | 4.6±0.3 | 4.4±0.4 | 0.2800 |
| MCHC (g/L) | 32.1±0.2 | 33.7±0.6 | 32.8±0.5 | <0.0001 a b |
| MCH (pg) | 28.6±0.5 | 31.0±0.6 | 28.9±0.8 | <0.0001 a b |
| MCV (fL) | 83.9±2.6 | 81.4±2.8 | 88.2±3.4 | 0.4410 |
| Platelet (x109/L) | 227.8±84.0 | 276.9±55.8 | 280.6±49.4 | 0.6940 |
| MPV (fL) | 9.8±0.2 | 11.6±0.3 | 11.1±0.5 | <0.0001 a c |
P-values obtained by One-way Analysis of Variance (ANOVA) was used to compare the mean differences of haematological parameters within groups.
a significant difference between active and unexposed, b significant difference between recovered and unexposed, c significant difference between active and recovered. MCV: Mean Corpuscular Volume, MCH: Mean Corpuscular Haemoglobin, MCHC: Mean Corpuscular Haemoglobin Concentration, MPV: Mean Platelet Volume.
Plasma cytokine levels among the study participants
Serum IL-10 was significantly higher among COVID-19 active patients compared to unexposed controls and the recovered patients respectively (181±6.14 pg/mL vs 158.80±11.70 pg/mL vs 155.00±14.32 pg/mL, p = 0.038). However, IFN-γ was significantly lower among COVID-19 active patients compared to unexposed controls and the recovered patients respectively (110.10±9.52 pg/mL vs 142.80±5.46 pg/mL vs 140.80±6.39 pg/mL, p = 0.021). The serum levels of IL-10 and IFN-γ was similar between the unexposed controls and the recovered participants (p > 0.05).
Moreover, there was no significant difference in IL-1β (p = 0.937), IL-6 (p = 0.582), IL-17 (p = 0.993) and TNF-α (p = 0.542) between the three study groups. Fig 1 displays the cytokine levels among the three groups.
Fig 1. Comparison of plasma cytokine levels among the study participants.
Relationship between plasma cytokines and circulating leucocytic cell types in COVID-19
The plasma IL-1β levels in COVID-19 active cases were significantly associated with circulating neutrophils concentration (r = 0.42, p<0.05) whiles IL-1β levels in COVID-19 unexposed cases was positively associated with Lymphocytes (r = 0.57, p<0.05). The plasma IL-6 level in COVID-19 was associated with total WBC (r = 0.39, p<0.05); IL-10 levels were positive associated with WBC (r = 0.39, p<0.05) and negatively associated with Basophils (r = -0.51, p<0.01) in COVID-19 active cases; IL-17 levels in COVID-19 active cases was positively associated with Neutrophil (r = 0.39, P<0.05). Interestingly, the plasma levels of IFN-γ and TNF-ɑ among COVID-19 active cases did not show any association with circulating leucocytes. There was no association between all the plasma cytokines and circulating leucocytes among COVID-19 recovered cases. However, IL-6 was associated with Lymphocytes (r = 0.59, p<0.05); IL-10 was associated with Eosinophils (r = 0.60, p<0.05); and TNF-ɑ was associated with Basophils (r = 0.56, p<0.05), all in COVID-19 unexposed cases (Table 3).
Table 3. Association between cytokine levels and leucocyte parameters among the COVID-19 active cases, recovered patients and unexposed healthy controls.
| IL-1β | IL-6 | IL-10 | IL-17 | IFN-γ | TNF-α | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Parameter | AaAct | Rec | Une | Act | Rec | Une | Act | Rec | Une | Act | Rec | Une | Act | Rec | Une | Act | Rec | Une |
| White blood cell | 0.35 | 0.16 | -0.02 | 0.39* | 0.18 | -0.10 | 0.39 * | 0.14 | 0.02 | 0.30 | 0.15 | -0.04 | 0.05 | 0.44 | -0.24 | 0.1 | -0.43 | -0.19 |
| Basophil | -0.21 | 0.25 | 0.03 | -0.21 | 0.18 | -0.02 | -0.51 ** | -0.00 | 0.19 | -0.20 | 0.20 | 0.03 | 0.1 | -0.61 | 0.00 | -0.02 | 0.3 | 0.56 * |
| Eosinophil | -0.16 | -0.19 | 0.08 | -0.15 | -0.17 | 0.21 | 0.08 | -0.12 | 0.60* | -0.13 | -0.26 | 0.13 | -0.25 | 0.2 | 0.07 | 0.05 | 0.16 | 0.42 |
| Monocyte | -0.22 | -0.2 | -0.05 | -0.29 | -0.23 | -0.06 | -0.38 | 0.11 | 0.10 | -0.21 | -0.2 | -0.07 | 0. 06 | 0.42 | -0.22 | -0.1 | -0.1 | -0.01 |
| Lymphocyte | -0.33 | 0.09 | 0.57 * | -0.27 | 0.12 | 0.59* | 0.04 | -0.41 | 0.22 | -0.3 | 0.01 | 0.60 * | -0.09 | -0.4 | -0.12 | 0.05 | 0.35 | 0.26 |
| Neutrophil | 0.42 * | 0.07 | -0.46 | 0.35 | 0.06 | -0.49 | 0.11 | 0.18 | -0.32 | 0.39* | 0.12 | -0.49 | 0.18 | -0.04 | 0.2 | 0.01 | -0.24 | -0.3 |
Pearson correlation coefficients between cytokines and the five main types of leucocytes cells among Covid-19 active cases, recovered cases, Negative (unexposed) cases
(*p ≤ 0.05
** p ≤ 0.01), Act: Covid-19 active cases; Rec, Covid-19 recovered cases; Une, Covid-19 unexposed cases.
Discussion
COVID-19 has been reported to induced total leucocyte and neutrophil counts with severe lymphopenia as an early sign of disease complication [8, 26]. The lymphopenia, neutrophil/lymphocyte ratio (NLR) are considered as potential diagnostic criteria for severe COVID-19 cases [34]. This indicates that peripheral blood counts may play an essential role in the progressing of the COVID-19 infectious disease [35, 36]. The striking morphologic changes and intensity of peripheral WBCs, neutrophilia and lymphopenia between mild and severe COVID-19 diseases have been demonstrated [24]. However, the immunohaematological profile following recovery from COVID-19 has not gained much interest. We assessed the evaluated the haematological profile and the plasma cytokine levels among COVID-19 active patients, recovered cases and unexposed healthy controls.
The result showed that total circulating WBC and basophils were significantly higher among COVID-19 active cases and the recovered patients compared to the unexposed healthy controls. The macrophage proliferation and increased macrophages are the predominant inflammatory cells that have been observed in alveolar injuries in the severe COVID-19 cases [37, 38]. Antibodies produced against COVID-19 spike glycoprotein has been reported to induced infiltration and accumulation of proinflammatory monocytes and macrophages in the lungs where virus-mediated lung injury causes [15, 39]. The circulating basophils number has been reported to correlate with IgG response in COVID-19, suggesting the potentiation and enhancement effects of basophil to humoral response to COVID-19 [40, 41]. Increased basophils circulation has been associated with a lower risk of developing severe COVID-19 [40, 42]. Basophil regulates innate immune response to COVID-19 and repairs damaged tissues caused by inflammation [43, 44]. All the COVID-19 active cases enrolled on the study were experiencing a mild form of infection. This explains the high number of circulating basophils among the active infection cases compare to the recovered cases and the unexposed COVID-19 cases [37, 41]. Moreover, the levels of circulating basophils was similar between the recovered patients and the unexposed healthy controls suggesting that patients have innate immune recovery with apparently normal white production of the WBC subsets.
The COVID-19 active infection group had significantly lower levels of haematocrit, HB, and MPV compared to the recovered patients and unexposed controls. This results is similar to the finding of Djakpo et al. [45]. Several previous studies have reported low haemoglobin and HCT and difference in the red cell indices (MCV, MCH and MCHC) between mild and severe COVID-19 cases, suggesting changes in these observed parameters are critical monitoring and administration of appropriate management when the need arises [24, 46–48]. Although there are significant difference in the red cell indices among the study groups, all the values were within the normal standard reference ranges suggesting that the low HB and HCT observed in our COVID-19 patients may be due to haemolysis associated with the complex disseminated intravasxular couagulation (DIC) in the pathophysiology of COVID-19 where there is normocytic normochromic anaemia [49, 50]. Again, it has been established that COVID-19 non-structural spike proteins exert inhibitory effects on the haemoglobin by binding to heme and cause an imbalance in iron metabolism [51–53]. Hence, COVID-19 effects on the erythrocyte parameters have not been observed in the pathological cases of the COVID-19. However, the COVID-19 patients had mild form of the disease explaining why we found normal red cell indices.
The antiinflammatory cytokine, IL-10 has been identified with protective roles in COVID-19. In the current study, IL-10 was significantly higher among patients with active COVID-19 conpared to the recovered patients and the unexposed controls. The increased IL-10 concentration in the plasma sample of active COVID-19 cases indicates providing some form of protection to the infected individuals [53, 54]. IL-10 is a nonspecific cell-type cytokine, widely expressed by several immune cells with many layers of regulating its production [55]. IL-10 is mainly produced by macrophages, dendritic cells and CD4+ T cells [56, 57]. IL-10 production is triggered by pathogen activation of DCs and macrophages that are involved in the recognition of pathogen-derived products by pattern recognition receptors. Aside these cells, CD8+ T cells also produce IL-10 following TCR activation [58]. Neutrophils have been reported to express IL-10 [59]. Agonists to Toll-like receptor 2 (TLR2) are specialized in inducing IL-10 expression by APCs [59]. Example; TLR2 influence IL-10 production by macrophages following pneumoccocal cell wall stimulation [60]. Again, higher amounts of IL-10 are also produced by macrophages and myeloid DCs following stimulation with TLR4 and TLR9 ligands [61]. The higher levels of IL-10 among patients with active COVID-19 suggests activated cellular non-specific cellular production by IL-10 producing cells or high ligand action of TLRs. The apprantly normal levels of IL-10 in recovered patients and healthly controls could be due to less activation by IL-10 producing cells as well as TLR ligans. IL-10 inhibit TNF-ɑ and neutrophil activation in an acute lung injury [2, 62]. Although dramatic elevation of IL-10 and IL-6 with inflammatory markers such as C-reactive protein have been reported in severe or critical COVID-19 cases [63–65]. All the COVID-19 active cases had the mild disease with no evidence of increased IL-6 levels compared among the recovered and health groups. This suggests that the increased levels of IL-10 may be suppressing inflammation through a negative feedback mechanism. Moreover, IL-10 was similar among the recovered patients and the unexposed healthy controls. This suggests that recovered patients have achieved imune recovery with less production of antiinflammatory cytokines.
Decrease IFN-γ expression in CD4+ T cells has been associated with severe COVID-19 cases in severe reports [66, 67]. However, an increase in IFN-γ levels in the peripheral blood had also been reported in severe cases compared to mild cases [34]. In our study, plasma IFN-γ levels were low among patients with active infection compared to the recovered patients and the unexposed control groups. The low IFN-γ was detected in mild active cases suggesting that the increased IL-10 may be suppressing pro-inflammatory cytokines through a negative feedback mechanism [68]. This probably prevents the overactivation of inflammatory cells such as macrophages as observed in cytokine storm syndrome [9].
Basophil-mediated IL10 induction has been reported to diminish without IL-6 or IL-4, however, culturing antigen-presenting cells (APCs) or CD8 with either IL-6 or IL-4 could not sufficiently secrete IL-10 production [69, 70]. But in the presence of IL-6 and IL-4 without basophils significantly induced IL-10 production [70, 71]. This suggested that basophils only present antigens to CD8+ T cells to induce IL-10 production [70]. This explains the negative correlations observed between IL-10 and basophils in COVID-19 active cases. Also, the study observed a positive association between neutrophils and each of plasma IL-1β and IL-17 in the active COVID-19 cases. Both IL1-β and IL-17 stimulation from the Th1/Th17 response increases the vascular permeability which results in the recruitment and infiltration of neutrophils in the affected sites and forms NETs and NETosis to clear the virus infections.
Finally, the observed increased levels of IL-10, neutrophils and basophils with a conconmittant decrease in IFN-γ may had confers some level of protections to the Ghanaians by preventing the development of severe or critical disease cases in mild COVID-19 resulting higher prevelance of mild active cases of COVID-19 among Ghanaian population.
Our study had few limitations. First, all the COVID-19 patients were diagnosed with the mild form of the disease and could not explore into how the variable differe in severe disease compared prior to recovery. Again, the study was conducted with a relatively small sample size which may have some impact on the statistical comparisons. Confirming our findings in larger prospective cohort studies may contribute to better understanding of COVID-19 following reovery.
Conclusison
COVID-19 active infection is associated with increased IL-10 and WBC with a conconmittant decrease in IFN-γ and haemoglobin concentation. However, recovery from the disease is associated with immune recovery with appreantly normal haematological profile.
Supporting information
(XLSX)
Acknowledgments
The authors are grateful to all the study participants for willingly donating samples used for this study. We acknowledge Christian Sewor of Department of Biomedical Science for his support during the Data analysis.
Data Availability
All data generated or analyzed during this study are included in this article and its Supporting Information files data.
Funding Statement
The author(s) received no specific funding for this work.
References
- 1.Pandey SK, Sharma V. A tribute to frontline corona warriors––Doctors who sacrificed their life while saving patients during the ongoing COVID-19 pandemic. Indian Journal of Ophthalmology. 2020;68(5):939. doi: 10.4103/ijo.IJO_754_20 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Pressman E, Noureldine MHA, Kumar JI, Krafft PR, Mantei B, Greenberg MS, et al. The return back to typical practice from the “battle plan” of the coronavirus disease 2019 (COVID-19) pandemic: a comparative study. World Neurosurgery. 2020;142:e481–e6. doi: 10.1016/j.wneu.2020.07.083 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Mohanty SK, Satapathy A, Naidu MM, Mukhopadhyay S, Sharma S, Barton LM, et al. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and coronavirus disease 19 (COVID-19)—anatomic pathology perspective on current knowledge. Diagn Pathol. 2020;15(1):103. Epub 2020/08/18. doi: 10.1186/s13000-020-01017-8 ; PubMed Central PMCID: PMC7427697. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Christie A, Henley SJ, Mattocks L, Fernando R, Lansky A, Ahmad FB, et al. Decreases in COVID-19 cases, emergency department visits, hospital admissions, and deaths among older adults following the introduction of COVID-19 vaccine—United States, September 6, 2020–May 1, 2021. Morbidity and Mortality Weekly Report. 2021;70(23):858. doi: 10.15585/mmwr.mm7023e2 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Alcock J, Masters A. Cytokine storms, evolution and COVID-19. Evol Med Public Health. 2021;9(1):83–92. Epub 2021/09/24. doi: 10.1093/emph/eoab005 ; PubMed Central PMCID: PMC7928963. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Fara A, Mitrev Z, Rosalia RA, Assas BM. Cytokine storm and COVID-19: a chronicle of pro-inflammatory cytokines. Open Biol. 2020;10(9):200160. Epub 2020/09/23. doi: 10.1098/rsob.200160 ; PubMed Central PMCID: PMC7536084. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Thwaites RS, Sanchez Sevilla Uruchurtu A, Siggins MK, Liew F, Russell CD, Moore SC, et al. Inflammatory profiles across the spectrum of disease reveal a distinct role for GM-CSF in severe COVID-19. Sci Immunol. 2021;6(57). Epub 2021/03/12. doi: 10.1126/sciimmunol.abg9873 ; PubMed Central PMCID: PMC8128298. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Vabret N, Britton GJ, Gruber C, Hegde S, Kim J, Kuksin M, et al. Immunology of COVID-19: Current State of the Science. Immunity. 2020;52(6):910–41. Epub 2020/06/09. doi: 10.1016/j.immuni.2020.05.002 ; PubMed Central PMCID: PMC7200337 Checkpoint Sciences, Primevax, Novartis, Array BioPharma, Roche, Avidea, Boeringer Ingelheim, Rome Therapeutics, Roswell Park, and the Parker Institute for Cancer Immunotherapy. N.B. receives research support from the Parker Insitute, Novocure, Celldex, Genentech, Oncovir, and Regeneron. M.M. serves as an advisor/board member for Celsius, Pionyr, Compugen, Myeloids and Innate pharma and ad hoc for Takeda. M.M. receives research support from Regeneron, Takeda, and Genentech. A.M. has equity in Gilead Sciences and Regeneron Pharmaceuticals. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Wang J, Jiang M, Chen X, Montaner LJ. Cytokine storm and leukocyte changes in mild versus severe SARS-CoV-2 infection: Review of 3939 COVID-19 patients in China and emerging pathogenesis and therapy concepts. J Leukoc Biol. 2020;108(1):17–41. Epub 2020/06/14. doi: 10.1002/JLB.3COVR0520-272R ; PubMed Central PMCID: PMC7323250. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Rodrigues PRS, Alrubayyi A, Pring E, Bart VMT, Jones R, Coveney C, et al. Innate immunology in COVID-19-a living review. Part II: dysregulated inflammation drives immunopathology. Oxf Open Immunol. 2020;1(1):iqaa005. Epub 2021/07/01. doi: 10.1093/oxfimm/iqaa005 ; PubMed Central PMCID: PMC7798612. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Mirzaei R, Karampoor S, Sholeh M, Moradi P, Ranjbar R, Ghasemi F. A contemporary review on pathogenesis and immunity of COVID-19 infection. Mol Biol Rep. 2020;47(7):5365–76. Epub 2020/07/01. doi: 10.1007/s11033-020-05621-1 ; PubMed Central PMCID: PMC7323602. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Sallenave JM, Guillot L. Innate Immune Signaling and Proteolytic Pathways in the Resolution or Exacerbation of SARS-CoV-2 in Covid-19: Key Therapeutic Targets? Front Immunol. 2020;11:1229. Epub 2020/06/24. doi: 10.3389/fimmu.2020.01229 ; PubMed Central PMCID: PMC7270404. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Mishra KP, Singh AK, Singh SB. Hyperinflammation and Immune Response Generation in COVID-19. Neuroimmunomodulation. 2020;27(2):80–6. Epub 2020/12/21. doi: 10.1159/000513198 ; PubMed Central PMCID: PMC7801965. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Song JW, Zhang C, Fan X, Meng FP, Xu Z, Xia P, et al. Immunological and inflammatory profiles in mild and severe cases of COVID-19. Nat Commun. 2020;11(1):3410. Epub 2020/07/10. doi: 10.1038/s41467-020-17240-2 ; PubMed Central PMCID: PMC7343781. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Soy M, Keser G, Atagündüz P, Tabak F, Atagündüz I, Kayhan S. Cytokine storm in COVID-19: pathogenesis and overview of anti-inflammatory agents used in treatment. Clin Rheumatol. 2020;39(7):2085–94. Epub 2020/06/01. doi: 10.1007/s10067-020-05190-5 ; PubMed Central PMCID: PMC7260446. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Quan C, Li C, Ma H, Li Y, Zhang H. Immunopathogenesis of Coronavirus-Induced Acute Respiratory Distress Syndrome (ARDS): Potential Infection-Associated Hemophagocytic Lymphohistiocytosis. Clin Microbiol Rev. 2020;34(1). Epub 2020/10/16. doi: 10.1128/CMR.00074-20 ; PubMed Central PMCID: PMC7566897. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Niesler U, Palmer A, Radermacher P, Huber-Lang MS. Role of alveolar macrophages in the inflammatory response after trauma. Shock. 2014;42(1):3–10. Epub 2014/03/29. doi: 10.1097/SHK.0000000000000167 . [DOI] [PubMed] [Google Scholar]
- 18.Zhao M, Fernandez LG, Doctor A, Sharma AK, Zarbock A, Tribble CG, et al. Alveolar macrophage activation is a key initiation signal for acute lung ischemia-reperfusion injury. Am J Physiol Lung Cell Mol Physiol. 2006;291(5):L1018–26. Epub 2006/07/25. doi: 10.1152/ajplung.00086.2006 . [DOI] [PubMed] [Google Scholar]
- 19.Lebeau G, Vagner D, Frumence É, Ah-Pine F, Guillot X, Nobécourt E, et al. Deciphering SARS-CoV-2 Virologic and Immunologic Features. Int J Mol Sci. 2020;21(16). Epub 2020/08/23. doi: 10.3390/ijms21165932 ; PubMed Central PMCID: PMC7460647. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Ackermann M, Anders HJ, Bilyy R, Bowlin GL, Daniel C, De Lorenzo R, et al. Patients with COVID-19: in the dark-NETs of neutrophils. Cell Death Differ. 2021;28(11):3125–39. Epub 2021/05/26. doi: 10.1038/s41418-021-00805-z ; PubMed Central PMCID: PMC8142290 CM, NM, IM, LEM, TN, EN, IN, LGN, MZR, KR, PR-Q, M Schapher, CS, GS, H-US, JS, PS, KS, M Stürzl, PV, JvV, LV, MvK-B, CY, SY, and AZ have nothing to disclose. H-JA reports personal fees from AstraZeneca, personal fees from Boehringer, personal fees from Previpharma, personal fees from Secarna, personal fees from Inositec, personal fees from Novartis, personal fees from Bayer, personal fees from GSK, outside the submitted work. ME reports personal fees from CytoxM, personal fees from MPM Capital, non-financial support from Santhera, outside the submitted work. M Herrmann reports non-financial support from Neutrolis outside the submitted work; YK reports personal fees from Surface oncology, personal fees from Acer Therapeutics, outside the submitted work. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Schönrich G, Raftery MJ, Samstag Y. Devilishly radical NETwork in COVID-19: Oxidative stress, neutrophil extracellular traps (NETs), and T cell suppression. Adv Biol Regul. 2020;77:100741. Epub 2020/08/11. doi: 10.1016/j.jbior.2020.100741 ; PubMed Central PMCID: PMC7334659. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Trivedi A, Khan MA, Bade G, Talwar A. Orchestration of Neutrophil Extracellular Traps (Nets), a Unique Innate Immune Function during Chronic Obstructive Pulmonary Disease (COPD) Development. Biomedicines. 2021;9(1). Epub 2021/01/14. doi: 10.3390/biomedicines9010053 ; PubMed Central PMCID: PMC7826777. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Apel F, Zychlinsky A, Kenny EF. The role of neutrophil extracellular traps in rheumatic diseases. Nat Rev Rheumatol. 2018;14(8):467–75. Epub 2018/06/23. doi: 10.1038/s41584-018-0039-z . [DOI] [PubMed] [Google Scholar]
- 24.Pozdnyakova O, Connell NT, Battinelli EM, Connors JM, Fell G, Kim AS. Clinical Significance of CBC and WBC Morphology in the Diagnosis and Clinical Course of COVID-19 Infection. Am J Clin Pathol. 2021;155(3):364–75. Epub 2020/12/04. doi: 10.1093/ajcp/aqaa231 ; PubMed Central PMCID: PMC7799218. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Khartabil TA, Russcher H, van der Ven A, de Rijke YB. A summary of the diagnostic and prognostic value of hemocytometry markers in COVID-19 patients. Crit Rev Clin Lab Sci. 2020;57(6):415–31. Epub 2020/06/23. doi: 10.1080/10408363.2020.1774736 . [DOI] [PubMed] [Google Scholar]
- 26.Bell R, Zini G, d’Onofrio G, Rogers HJ, Lee YS, Frater JL. The hematology laboratory’s response to the COVID-19 pandemic: A scoping review. Int J Lab Hematol. 2021;43(2):148–59. Epub 2020/11/13. doi: 10.1111/ijlh.13381 . [DOI] [PubMed] [Google Scholar]
- 27.Ponti G, Maccaferri M, Ruini C, Tomasi A, Ozben T. Biomarkers associated with COVID-19 disease progression. Crit Rev Clin Lab Sci. 2020;57(6):389–99. Epub 2020/06/07. doi: 10.1080/10408363.2020.1770685 ; PubMed Central PMCID: PMC7284147. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 28.Fox TA, Troy-Barnes E, Kirkwood AA, Chan WY, Day JW, Chavda SJ, et al. Clinical outcomes and risk factors for severe COVID-19 in patients with haematological disorders receiving chemo- or immunotherapy. Br J Haematol. 2020;191(2):194–206. Epub 2020/07/18. doi: 10.1111/bjh.17027 ; PubMed Central PMCID: PMC7405103. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 29.Yang X, Yang Q, Wang Y, Wu Y, Xu J, Yu Y, et al. Thrombocytopenia and its association with mortality in patients with COVID-19. J Thromb Haemost. 2020;18(6):1469–72. Epub 2020/04/18. doi: 10.1111/jth.14848 . [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Henry BM, de Oliveira MHS, Benoit S, Plebani M, Lippi G. Hematologic, biochemical and immune biomarker abnormalities associated with severe illness and mortality in coronavirus disease 2019 (COVID-19): a meta-analysis. Clin Chem Lab Med. 2020;58(7):1021–8. Epub 2020/04/15. doi: 10.1515/cclm-2020-0369 . [DOI] [PubMed] [Google Scholar]
- 31.Hasichaolu, Zhang X, Li X, Li X, Li D. Circulating Cytokines and Lymphocyte Subsets in Patients Who Have Recovered from COVID-19. Biomed Res Int. 2020;2020:7570981. Epub 2020/12/05. doi: 10.1155/2020/7570981 ; PubMed Central PMCID: PMC7695995 publication of this paper. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 32.Paradiso AV, De Summa S, Loconsole D, Procacci V, Sallustio A, Centrone F, et al. Rapid Serological Assays and SARS-CoV-2 Real-Time Polymerase Chain Reaction Assays for the Detection of SARS-CoV-2: Comparative Study. J Med Internet Res. 2020;22(10):e19152. Epub 2020/10/09. doi: 10.2196/19152 ; PubMed Central PMCID: PMC7641647. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 33.Cohen Y, Cohen JY. Statistics and Data with R: An applied approach through examples: John Wiley & Sons; 2008. [Google Scholar]
- 34.Yang AP, Liu JP, Tao WQ, Li HM. The diagnostic and predictive role of NLR, d-NLR and PLR in COVID-19 patients. Int Immunopharmacol. 2020;84:106504. Epub 2020/04/19. doi: 10.1016/j.intimp.2020.106504 ; PubMed Central PMCID: PMC7152924. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 35.Zheng HY, Zhang M, Yang CX, Zhang N, Wang XC, Yang XP, et al. Elevated exhaustion levels and reduced functional diversity of T cells in peripheral blood may predict severe progression in COVID-19 patients. Cell Mol Immunol. 2020;17(5):541–3. Epub 2020/03/24. doi: 10.1038/s41423-020-0401-3 ; PubMed Central PMCID: PMC7091621. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 36.Sun S, Cai X, Wang H, He G, Lin Y, Lu B, et al. Abnormalities of peripheral blood system in patients with COVID-19 in Wenzhou, China. Clin Chim Acta. 2020;507:174–80. Epub 2020/04/28. doi: 10.1016/j.cca.2020.04.024 ; PubMed Central PMCID: PMC7194694. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 37.Gómez-Rial J, Martinón-Torres F. A strategy targeting monocyte-macrophage differentiation to avoid pulmonary complications in SARS-Cov2 infection. Clin Immunol. 2020;216:108442. Epub 2020/04/27. doi: 10.1016/j.clim.2020.108442 ; PubMed Central PMCID: PMC7194539. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 38.Bösmüller H, Traxler S, Bitzer M, Häberle H, Raiser W, Nann D, et al. The evolution of pulmonary pathology in fatal COVID-19 disease: an autopsy study with clinical correlation. Virchows Arch. 2020;477(3):349–57. Epub 2020/07/02. doi: 10.1007/s00428-020-02881-x ; PubMed Central PMCID: PMC7324489. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 39.Jafarzadeh A, Chauhan P, Saha B, Jafarzadeh S, Nemati M. Contribution of monocytes and macrophages to the local tissue inflammation and cytokine storm in COVID-19: Lessons from SARS and MERS, and potential therapeutic interventions. Life Sci. 2020;257:118102. Epub 2020/07/21. doi: 10.1016/j.lfs.2020.118102 ; PubMed Central PMCID: PMC7367812. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 40.Sun Y, Zhou J, Ye K. White Blood Cells and Severe COVID-19: A Mendelian Randomization Study. J Pers Med. 2021;11(3). Epub 2021/04/04. doi: 10.3390/jpm11030195 ; PubMed Central PMCID: PMC8002054. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 41.Sabroe I, Jones EC, Usher LR, Whyte MK, Dower SK. Toll-like receptor (TLR)2 and TLR4 in human peripheral blood granulocytes: a critical role for monocytes in leukocyte lipopolysaccharide responses. J Immunol. 2002;168(9):4701–10. Epub 2002/04/24. doi: 10.4049/jimmunol.168.9.4701 . [DOI] [PubMed] [Google Scholar]
- 42.Han H, Xu Z, Cheng X, Zhong Y, Yuan L, Wang F, et al. Descriptive, Retrospective Study of the Clinical Characteristics of Asymptomatic COVID-19 Patients. mSphere. 2020;5(5). Epub 2020/10/09. doi: 10.1128/mSphere.00922-20 ; PubMed Central PMCID: PMC7568656. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 43.Criado PR, Pagliari C, Criado RFJ, Marques GF, Belda W Jr., What the physicians should know about mast cells, dendritic cells, urticaria, and omalizumab during COVID-19 or asymptomatic infections due to SARS-CoV-2? Dermatol Ther. 2020;33(6):e14068. Epub 2020/07/28. doi: 10.1111/dth.14068 . [DOI] [PubMed] [Google Scholar]
- 44.Djakpo DK, Wang Z, Zhang R, Chen X, Chen P, Antoine M. Blood routine test in mild and common 2019 coronavirus (COVID-19) patients. Biosci Rep. 2020;40(8). Epub 2020/07/30. doi: 10.1042/BSR20200817 ; PubMed Central PMCID: PMC7414516. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 45.Wu Y, Huang X, Sun J, Xie T, Lei Y, Muhammad J, et al. Clinical Characteristics and Immune Injury Mechanisms in 71 Patients with COVID-19. mSphere. 2020;5(4). Epub 2020/07/17. doi: 10.1128/mSphere.00362-20 ; PubMed Central PMCID: PMC7364211. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 46.Pan Y, Ye G, Zeng X, Liu G, Zeng X, Jiang X, et al. Can routine laboratory tests discriminate SARS-CoV-2-infected pneumonia from other causes of community-acquired pneumonia? Clin Transl Med. 2020;10(1):161–8. Epub 2020/06/09. doi: 10.1002/ctm2.23 ; PubMed Central PMCID: PMC7274074. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 47.Lin S, Mao W, Zou Q, Lu S, Zheng S. Associations between hematological parameters and disease severity in patients with SARS-CoV-2 infection. J Clin Lab Anal. 2021;35(1):e23604. Epub 2020/11/14. doi: 10.1002/jcla.23604 ; PubMed Central PMCID: PMC7843261. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 48.Lechuga GC, Souza-Silva F, Sacramento CQ, Trugilho MRO, Valente RH, Napoleão-Pêgo P, et al. SARS-CoV-2 Proteins Bind to Hemoglobin and Its Metabolites. Int J Mol Sci. 2021;22(16). Epub 2021/08/28. doi: 10.3390/ijms22169035 ; PubMed Central PMCID: PMC8396565. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 49.Courrol LC, de Oliveira Silva FR, Masilamani V. SARS-CoV-2, hemoglobin and protoporphyrin IX: Interactions and perspectives. Photodiagnosis Photodyn Ther. 2021;34:102324. Epub 2021/05/10. doi: 10.1016/j.pdpdt.2021.102324 ; PubMed Central PMCID: PMC8123386. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 50.Neumann J, Prezzemolo T, Vanderbeke L, Roca CP, Gerbaux M, Janssens S, et al. Increased IL-10-producing regulatory T cells are characteristic of severe cases of COVID-19. Clin Transl Immunology. 2020;9(11):e1204. Epub 2020/11/20. doi: 10.1002/cti2.1204 ; PubMed Central PMCID: PMC7662088. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 51.Lindner HA, Velásquez SY, Thiel M, Kirschning T. Lung Protection vs. Infection Resolution: Interleukin 10 Suspected of Double-Dealing in COVID-19. Front Immunol. 2021;12:602130. Epub 2021/03/23. doi: 10.3389/fimmu.2021.602130 ; PubMed Central PMCID: PMC7966717. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 52.Robinson PC, Liew DFL, Liew JW, Monaco C, Richards D, Shivakumar S, et al. The Potential for Repurposing Anti-TNF as a Therapy for the Treatment of COVID-19. Med (N Y). 2020;1(1):90–102. Epub 2020/12/10. doi: 10.1016/j.medj.2020.11.005 ; PubMed Central PMCID: PMC7713589. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 53.Akbari H, Tabrizi R, Lankarani KB, Aria H, Vakili S, Asadian F, et al. The role of cytokine profile and lymphocyte subsets in the severity of coronavirus disease 2019 (COVID-19): A systematic review and meta-analysis. Life Sci. 2020;258:118167. Epub 2020/08/01. doi: 10.1016/j.lfs.2020.118167 ; PubMed Central PMCID: PMC7387997. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 54.Velavan TP, Meyer CG. Mild versus severe COVID-19: Laboratory markers. Int J Infect Dis. 2020;95:304–7. Epub 2020/04/29. doi: 10.1016/j.ijid.2020.04.061 ; PubMed Central PMCID: PMC7194601. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 55.Saraiva M O ’garra A. The regulation of IL-10 production by immune cells. Nature reviews immunology. 2010;10(3):170–81. doi: 10.1038/nri2711 [DOI] [PubMed] [Google Scholar]
- 56.Li D, Romain G, Flamar A-L, Duluc D, Dullaers M, Li X-H, et al. Targeting self-and foreign antigens to dendritic cells via DC-ASGPR generates IL-10–producing suppressive CD4+ T cells. Journal of Experimental Medicine. 2012;209(1):109–21. doi: 10.1084/jem.20110399 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 57.Ma X, Yan W, Zheng H, Du Q, Zhang L, Ban Y, et al. Regulation of IL-10 and IL-12 production and function in macrophages and dendritic cells. F1000Research. 2015;4. doi: 10.12688/f1000research.7010.1 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 58.Liu Z, Liu JQ, Talebian F, Wu LC, Li S, Bai XF. IL‐27 enhances the survival of tumor antigen‐specific CD8+ T cells and programs them into IL‐10‐producing, memory precursor‐like effector cells. European journal of immunology. 2013;43(2):468–79. doi: 10.1002/eji.201242930 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 59.Andrade EB, Alves J, Madureira P, Oliveira L, Ribeiro A, Cordeiro-da-Silva A, et al. TLR2-induced IL-10 production impairs neutrophil recruitment to infected tissues during neonatal bacterial sepsis. The Journal of Immunology. 2013;191(9):4759–68. doi: 10.4049/jimmunol.1301752 [DOI] [PubMed] [Google Scholar]
- 60.Moreira LO, El Kasmi KC, Smith AM, Finkelstein D, Fillon S, Kim YG, et al. The TLR2‐MyD88‐NOD2‐RIPK2 signalling axis regulates a balanced pro‐inflammatory and IL‐10‐mediated anti‐inflammatory cytokine response to Gram‐positive cell walls. Cellular microbiology. 2008;10(10):2067–77. doi: 10.1111/j.1462-5822.2008.01189.x [DOI] [PMC free article] [PubMed] [Google Scholar]
- 61.Boonstra A, Rajsbaum R, Holman M, Marques R, Asselin-Paturel C, Pereira JP, et al. Macrophages and myeloid dendritic cells, but not plasmacytoid dendritic cells, produce IL-10 in response to MyD88-and TRIF-dependent TLR signals, and TLR-independent signals. The Journal of Immunology. 2006;177(11):7551–8. doi: 10.4049/jimmunol.177.11.7551 [DOI] [PubMed] [Google Scholar]
- 62.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(3):518–34.e1. Epub 2020/09/09. doi: 10.1016/j.jaci.2020.07.001 ; PubMed Central PMCID: PMC7471766. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 63.Pedersen SF, Ho YC. SARS-CoV-2: a storm is raging. J Clin Invest. 2020;130(5):2202–5. Epub 2020/03/29. doi: 10.1172/JCI137647 ; PubMed Central PMCID: PMC7190904. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 64.Thevarajan I, Nguyen THO, Koutsakos M, Druce J, Caly L, van de Sandt CE, et al. Breadth of concomitant immune responses prior to patient recovery: a case report of non-severe COVID-19. Nat Med. 2020;26(4):453–5. Epub 2020/04/15. doi: 10.1038/s41591-020-0819-2 ; PubMed Central PMCID: PMC7095036 Gilead Sciences, Merck, Viiv Healthcare and Leidos; and honoraria for advisory boards and educational activities (Gilead Sciences, Merck, Viiv Healthcare and Abbvie). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 65.Gao YM, Xu G, Wang B, Liu BC. Cytokine storm syndrome in coronavirus disease 2019: A narrative review. J Intern Med. 2021;289(2):147–61. Epub 2020/07/23. doi: 10.1111/joim.13144 ; PubMed Central PMCID: PMC7404514. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 66.Sokol CL, Chu NQ, Yu S, Nish SA, Laufer TM, Medzhitov R. Basophils function as antigen-presenting cells for an allergen-induced T helper type 2 response. Nat Immunol. 2009;10(7):713–20. Epub 2009/05/26. doi: 10.1038/ni.1738 ; PubMed Central PMCID: PMC3252751. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 67.Kim S, Shen T, Min B. Basophils can directly present or cross-present antigen to CD8 lymphocytes and alter CD8 T cell differentiation into IL-10-producing phenotypes. J Immunol. 2009;183(5):3033–9. Epub 2009/08/12. doi: 10.4049/jimmunol.0900332 . [DOI] [PubMed] [Google Scholar]
- 68.Chen CC, Manning AM. TGF-beta 1, IL-10 and IL-4 differentially modulate the cytokine-induced expression of IL-6 and IL-8 in human endothelial cells. Cytokine. 1996;8(1):58–65. Epub 1996/01/01. doi: 10.1006/cyto.1995.0008 . [DOI] [PubMed] [Google Scholar]
- 69.Maddur MS, Kaveri SV, Bayry J. Basophils as antigen presenting cells. Trends Immunol. 2010;31(2):45–8. Epub 2010/01/12. doi: 10.1016/j.it.2009.12.004 . [DOI] [PubMed] [Google Scholar]
- 70.Jovanovic DV, Di Battista JA, Martel-Pelletier J, Jolicoeur FC, He Y, Zhang M, et al. IL-17 stimulates the production and expression of proinflammatory cytokines, IL-beta and TNF-alpha, by human macrophages. J Immunol. 1998;160(7):3513–21. Epub 1998/04/08. . [PubMed] [Google Scholar]
- 71.Li L, Kim J, Boussiotis VA. IL-1β-mediated signals preferentially drive conversion of regulatory T cells but not conventional T cells into IL-17-producing cells. J Immunol. 2010;185(7):4148–53. Epub 2010/09/08. doi: 10.4049/jimmunol.1001536 ; PubMed Central PMCID: PMC2956066. [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
(XLSX)
Data Availability Statement
All data generated or analyzed during this study are included in this article and its Supporting Information files data.

