Table 1.
Cell-free DNA research in Systemic lupus erythematosus and Rheumatoid arthritis.
| References | Year of publication | Patients (n) | Healthy controls, HC (n) | Method | cfDNA source | Observation |
|---|---|---|---|---|---|---|
| Tan and Kunkel (2) | 1966 | SLE (95) | 30 | Gel diffusion precipitin test | Serum | Frequency of positive test for cfDNA: SLE 11.5%, liver disease 15%, lymphosarcoma 3%, and none were observed in HC |
| Leukemia, lymphosarcoma, and lymphoma (29) | cfDNA positivity fluctuate with disease activity | |||||
| Multiple myeloma (15) | ||||||
| Acute rheumatic fever (9) | ||||||
| RA (17) | ||||||
| Liver disease (40) | ||||||
| Miscellaneous (myocardial infarction, renal disease, lung disease, infection, carcinoma) (72) | ||||||
| Barnett (3) | 1968 | Serum tested | 14 | Quantitative complement-fixation test | SF and Serum | ↑ cfDNA in the sera of patients with SLE, RA, systemic mastocytosis, uremia with chronic glomerulonephritis compared to HC |
| RA (6) | ↑ cfDNA in SFs of patients with SLE, RA, Gout | |||||
| SLE+Nephritis (6) | ||||||
| SLE-Nephritis (7) | ||||||
| Systemic Mastocytosis (1) | ||||||
| Uremia with Chronic Glomerulonephritis (1) | ||||||
| Vasculitis, Local (1) | ||||||
| Rheumatic Heart (1) | ||||||
| Psoriasis+RA (2) | ||||||
| Gout (1) | ||||||
| Scleroderma (1) | ||||||
| SF tested | ||||||
| SLE (1) | ||||||
| RA (3) | ||||||
| Gout (2) | ||||||
| Reiter's (1) | ||||||
| Infection (1) | ||||||
| Koffler et al. (4) | 1973 | SLE (60) | 56 | Hemagglutination inhibition test | Serum | ↑ cfDNA in sera of patients with SLE and RA compared to HC and other diseases |
| RA (54) | Association with disease severity | |||||
| Chronic glomerulonephritis (40) | ||||||
| Leukemia (19) | ||||||
| Malignant tumors (20) | ||||||
| Hospital diseases (99) | ||||||
| Davis and Davis (147) | 1973 | SLE (44) | 83 | Counterimmuno-electrophoresis | Plasma | Frequency of positive test for cfDNA: 1.2% in HC, 3.2% in RA, 4.2% in SLE, 1.4% preoperative, 44.0% post-operative |
| RA (28) | ||||||
| Newborn cord bloods (36) | ||||||
| Surgery | ||||||
| Preoperative (71) | ||||||
| Post-operative (50) | ||||||
| Nonsurgical (278) | ||||||
| Miscellaneous (60) | ||||||
| Leon et al. (148) | 1977 | RA (70) | 61 | Radioimmunoassay | Serum | ↑ cfDNA in RA patients compared to HC |
| ↑ cfDNA levels in RA patients with active disease for <10 years, seronegative for rheumatoid factor | ||||||
| Steinman (149) | 1979 | SLE (43) | None | Modified counterimmuno-electrophoresis | Plasma | Frequency of positive test for cfDNA: 80% in SLE with CNS involvement and vasculitis, 20% in SLE with dermal vasculitis |
| SLE+CNS involvement (12) | 5.5% in active SLE, none in other rheumatological disorders and SLE patients on treatment | |||||
| SLE+Systemic Vasculitis (8) | ||||||
| SLE+Dermal Vasculitis (5) | ||||||
| Other rheumatological disorders and SLE on treatment (53) | ||||||
| Raptis and Menard (150) | 1980 | inactive SLE (5) | 3 | Nick translation on purified cfDNA | Plasma | ↑ cfDNA levels in active SLE patients compared to steroid-inactive SLE and HC |
| active SLE (2) | cfDNA positivity fluctuate with disease activity | |||||
| RA (2) | ||||||
| DM (1) | ||||||
| Leon et al. (151) | 1981 | Seropositive RA (26) | 95 | Radioimmunoassay | Serum and SF | ↑ cfDNA in SF and serum of RA, gout and pseudogout |
| Seronegative RA and variants (21) | Temporal correlation between serum and SF cfDNA during active disease in RA patients | |||||
| Non-classified and mono- and oligoarticular RA (6) | ||||||
| Gout and pseudogout (6) | ||||||
| OA (29) | ||||||
| OA+chonrocalcinosis (4) | ||||||
| Post-traumatic arthropathy (14) | ||||||
| Klemp et al. (152) | 1981 | Clinically active SLE (43) with specific organ or system involved | 58 | PAGE and fluorimetric scan on purified cfDNA | Plasma | Frequency of subjects with cfDNA <10 ng/ml: Clinically active SLE: 88%; Clinically inactive SLE: 82%; HC: 81% |
| Skin (8) | Frequency of subjects with cfDNA >10 ng/ml: Clinically active SLE: 11.6%; Clinically inactive SLE: 17% | |||||
| Musculoskeletal system (20) | ||||||
| Kidney (5) | ||||||
| Nervous system (3) | ||||||
| Cardiovascular system (1) | ||||||
| Nonspecific (constitutional symptoms) (6) | ||||||
| Clinically inactive (53) | ||||||
| Morimoto et al. (153) | 1982 | SLE (28) | 5 | 32P-phosphate incorporation into 5′ ends of DNA | Serum | ↑ concentrations of DNA in DNA/anti-DNA immune complexes of SLE patients |
| RA (4) | DNA in DNA/anti-DNA immune complexes of SLE patients correlate with disease activity | |||||
| McCoubrey-Hoyer et al. (154) | 1984 | SLE+Nephritis at the time of blood sampling (10) | 20 | Counterimmuno-electrophoresis on purified cfDNA | Plasma | ↑ concentrations of cfDNA in SLE patients compared to HC |
| SLE+Nephritis in the past that was inactive at the time of blood sampling (9) | cfDNA levels in the plasma of SLE patients did not correlate with nephritis. | |||||
| SLE-Nephritis (12) | ||||||
| Hajizadeh et al. (155) | 2003 | RA (54) | 30 and 22 | PCR and SDS–polyacrylamide-gel electrophoresis | SF and Plasma | PCR-amplifiable mtDNA fragments detected in SF of RA patients but not in HCs |
| ↑ of cfDNA in plasma of RA patients compared to HCs | ||||||
| mtDNA presence in SF correlated significantly with rheumatoid factor positivity | ||||||
| Collins et al. (129) | 2004 | RA (54) | 17 | PCR and SDS–polyacrylamide-gel electrophoresis | SF | PCR-amplifiable mtDNA fragments detected in SF of RA patients but not in HCs |
| Zhong et al. (156) | 2007 | RA (54) | 44 | qPCR on purified cfDNA | Serum and plasma | ↑ concentrations of cfDNA in RA patients compared to HC |
| ↑ serum-to-plasma cfDNA ratio in RA patients compared to HC | ||||||
| ↑ antibody-bound plasma cfDNA in RA patients compared to HC | ||||||
| Chen et al. (5) | 2007 | SLE (12) | 8 | PicoGreen assay (fluorescence detection) on purified cfDNA | Serum and Plasma | ↑ concentrations of cfDNA in SLE patients compared to HC |
| ↑ concentrations of cfDNA in the serum compared to plasma | ||||||
| Bartoloni et al. (157) | 2011 | SLE (44) | 66 | qPCR on purified cfDNA | Plasma | ↑ cfDNA in SLE, RA and SS |
| RA (20) | Correlation of cfDNA with disease activity in SS | |||||
| SS (48) | ||||||
| Cepika et al. (158) | 2012 | SLE (15) | 11 | qPCR on purified cfDNA | Serum | ↑ concentrations of cfDNA in SLE patients compared to HC |
| ↑ concentrations of cfDNA in SLE patients compared to HC following treatment. | ||||||
| ↓ cfDNA levels in chloroquine treated patients compared to untreated patients | ||||||
| Tug et al. (159) | 2014 | SLE (59) | 59 | qPCR on unpurified cfDNA | Plasma | ↑ concentrations of cfDNA in SLE patients compared to HC |
| No difference in the DNA integrity between SLE and HC | ||||||
| cfDNA levels fluctuate with disease activity | ||||||
| Zhang et al. (42) | 2014 | SLE (54) | 43 | PicoGreen assay (fluorescence detection) on unpurified cfDNA | Plasma | ↑ concentrations of cfDNA in SLE patients compared to HC |
| ↑ concentrations of cfDNA in SLE patients with LN compared to patients without LN | ||||||
| ↑ concentrations of cfDNA in SLE patients with active LN compared to patients with inactive LN | ||||||
| Chan et al. (19) | 2014 | SLE (24) | 11 | qPCR on purified plasma DNA | Plasma | ↑ aberrant genomic representation, size shortening and hypomethylation of plasma DNA |
| Plasma DNA sequencing and methylation analysis | Correlation with SLEDAI and anti-dsDNA antibodies | |||||
| Hendy et al. (160) | 2015 | SLE (52) | 25 | qPCR on purified cfDNA | Serum | ↑ concentrations of cfDNA in SLE patients compared to HC |
| cfDNA levels fluctuate with treatment | ||||||
| Dunaeva et al. (6) | 2015 | RA | 29 | qPCR on purified cfDNA | Serum | ↓ cfDNA levels in esRA compared to eRA, RRMS and HC |
| eRA (39) | cfDNA levels in eRA, RRMS comparable to HC | |||||
| esRA (26) | ||||||
| RRMS | ||||||
| Abdelal et al. (161) | 2016 | SLE (35) | 25 | qPCR on purified cfDNA | Plasma | ↑ concentrations of cfDNA in SLE patients compared to HC |
| RA (30) | Correlation with ESR, anti-dsDNA, C3, C4 and SLEDAI-2000 | |||||
| Rykova et al. (162) | 2017 | RA (74) | 63 | qPCR on purified cfDNA | Plasma and cell-surface bound | ↑ concentrations of plasma nuclear DNA in RA patients compared to HC. |
| No differences in plasma mtDNA levels between RA patients and HC | ||||||
| ↑ concentrations of cell-surface bound mtDNA and ↓ levels of cell-surface bound nuclear DNA in RA compared to HC | ||||||
| Hashimoto et al. (163) | 2017 | RA on bDMARD (30) | 21 | qPCR on purified cfDNA | Plasma and SF | ↑ concentrations of plasma cfDNA in RA patients compared to HC |
| OA (12) | Compared to baseline ↑ concentrations of plasma cfDNA in RA patients with the introduction of biological DMARDs until 8 weeks | |||||
| and is associated with improvement in disease activity | ||||||
| ↑ concentrations of SF cfDNA in RA patients compared to OA patients. | ||||||
| Laukova et al. (164) | 2018 | RA on bDMARD (37) | none | qPCR on purified cfDNA | Plasma | ↓ in total cfDNA, nuclear and mt DNA 6 months post-bDMARD treatment and association with clinical and laboratory parameters |
| Eldosoky. et al. (165) | 2018 | RA (35) | 22 | qPCR on purified cfDNA | Plasma | |
| Xu et al. (166) | 2018 | Pregnant women with SLE (36) | 199 | Fluorometric Qubit® dsDNA BR Assay Kit Qubit assay | Plasma | ↑ levels of cfDNA in non-pregnant and pregnant women with SLE compared to HC |
| Non-pregnant women with SLE (22) | 60 | ↑ levels of cfDNA in patients with active SLE compared to patients with inactive disease | ||||
| Correlation of SLEDAI scores with higher cfDNA levels in entire patient cohort, non-pregnant and pregnant patients |
Anti-dsDNA, Anti-double stranded DNA; bDMARD, Biological disease-modifying antirheumatic drugs; C3, Complement factor C3; C4, Complement factor C4; DM, Dermatomyositis; eRA, Early RA; ESR, Erythrocyte sedimentation rate; esRA, Established RA; HC, Healthy control; MtDNA, Mitochondrial DNA; OA, Osteoarthritis; qPCR, Quantitative real-time PCR; RA, Rheumatoid arthritis; RRMS, Relapsing-remitting multiple sclerosis; SF, Synovial fluid; SLE, Systemic lupus erythematosus; and SLEDAI, SLE disease activity index.