Table 2.
Clinical characteristics and prevalence of patients with early complement component deficiencies (8, 19–21).
| C deficiency | Global prevalence | SLE/SLE-like and complement deficiency | Clinical characteristics | Autoantibody positivity |
|---|---|---|---|---|
| Clq | Few cases | 90–93% | Rash 95% | ANA 75% |
| Glomerulonephritis 42% | ENA (Sm, RNP, Ro, and/or La) 70% | |||
| Central nervous system 18% | DNAds antibody 20% | |||
| Clr/Cls | Few cases | 50–57% | Cutaneous 90% | ANA 75% |
| Glomerulonephritis 50% | ENA (Sm, RNP, Ro, and/or La) 70% | |||
| C4 | Few cases | 75% | Glomerulonephritis 50% | ANA 75% |
| Anti-Ro 70% (with anti-La negative) | ||||
| DNAds antibody 18% | ||||
| C2 | 1:10,000–20,000 (homozygous) 1–2% (heterozygous) | 10% (homozygous) 2.4–5.8% (heterozygous) | Arthritis 83% Malar rash 92% Discoid rash 67% Photosensitivity 67% Serositis 42% |
ANA low titer 25–55% DNAds antibody 33% Anti-Ro 25–50%, 77% (pickering) Anti-histone antibody 20% |
| Anti-Clq | 2–8% | 30–60% |