Table 5.
Autoantibodies in systemic sclerosis
| Autoantibody | Methods of testing | Prevalence in SSc | Clinical and serologic associations | Prognosis |
| Anti-centromere | IIF | 20–30% | CREST | Better prognosis than anti-Scl-70 |
| IB | lcSSc | ↑ Survival compared with anti-Scl-70 or anti-nucleolar antibodies | ||
| ELISA | ↓ Pulmonary fibrosis | No benefit in following levels over time | ||
| Pulmonary hypertension | ||||
| Anti-Scl-70 | ID | ~15–20% | Mutually exclusive with ACA | Worse prognosis |
| CIE | dcSSc | ? Levels by ELISA fluctuate with extent of disease involvment | ||
| IB | Pulmonary fibrosis and secondary cor pulmonale | |||
| ELISA | ||||
| Anti-PM-Scl | ID | ~3% | lcSSc | Benign/chronic course with better response to steroids |
| IP | (Rare in Japanese) | PM/SSc overlap | ||
| Anti-Th/To | IP | ~2–5% | Mutually exclusive with ACA | Worse prognosis with reduced 10-year survival |
| (More common in Japanese) | lcSSc | |||
| ↓ Joint involvement | ||||
| ↑ puffy fingers, small bowel involvement, hypothyroidism | ||||
| AFA | IP | ~4% | Mutually exclusive with ACA, anti-Scl-70, anti-RNAP | Seen in younger patients with greater internal organ involvement |
| 16–22% in patients of African descent | dcSSc | |||
| 4% in Caucasians | Myositis, pulmonary hypertension, renal disease | |||
| Anti-RNAP | IP | ~20% | dcSSc | Increased mortality |
| Anti-RNAP II with ↓ lung function | ||||
| Cor pulmonale unrelated to pulmonary fibrosis | ||||
| Anti-Ku | IB | Infrequent | Overlap syndrome with scleroderma features | |
| IP | ||||
| ELISA | ||||
| Anti-Ro | ID | Infrequent | Seen in one-third to one-half of SSc patients with sicca complex | |
| ELISA | ||||
| Anti-Sm | IIF | Rare | SLE overlap | Poor prognosis |
| IP/CIE/ID | Lupus nephritis, renal crisis | |||
| ELISA | Pulmonary hypertension | |||
| HA | ||||
| Anti-ribonucleoprotein | IIF | ~8% | MCTD | |
| IP/CIE/ID | Less CNS and renal diseases | |||
| ELISA | Raynaud's, puffy hands, sicca, myositis, esophageal disease | |||
| HA | lcSSc | |||
| Septal hypertrophy | ||||
| Cor pulmonale secondary to pulmonary hypertension | ||||
| Negatively correlates with dsDNA and low complement glomerulonephritis in those with SLE overlap | More benign prognosis with favorable response to steroids | |||
| Anti-phospholipid antibodies | ELISA | ~20–25% with <1% SSc with APS | Mutually exclusive with anti-centromere antibodies | Associations inconsistent – needs further study |
| aCL with ↑ disease severity and ↓ proximal skin involvement, scarring, esophageal hypomotility in one study | ||||
| β2gp/aCL with pulmonary hypertension | ||||
| Associations inconsistent – needs further study |
ACA, anti-centromere antibodies; aCL, anticardiolipin antibodies; AFA, antifibrillarin/anti-U3-ribonucleoprotein; β2gp, β2 glycoprotein antibodies; CIE, counterimmunoelectrophoresis; CNS, central nervous system; dcSSc, diffuse cutaneous systemic sclerosis; dsDNA, double-stranded DNA; ELISA, enzyme-linked immunosorbent assay; HA, hemagglutination; IB, immunoblotting; ID, immunodiffusion; IIF, indirect immunofluorescence; IP, immunoprecipitation; lcSSc, limited cutaneous systemic sclerosis; MCTD, mixed connective tissue disease; PM/SSc, myositis/scleroderma overlap; SLE, systemic lupus erythematosus.