Autoantibodies in black South Africans with systemic lupus erythematosus: spectrum and clinical associations.

The clinical features and autoantibody profile of 111 black South Africans (103 females and 8 males) with systemic lupus erythematosus were retrospectively analysed. The mean age of the patients was 35.1 years and mean duration of disease 3.5 years. The commonest clinical and laboratory features noted were arthritis (62.2%), hypocomplementaemia (61.2%), haematological abnormalities (60.5%) and malar rash (55%). The serological abnormalities included antinuclear antibodies (98.2%), anti-dsDNA (66.2%), anti-Sm (44.2%), anti-RNP (65.5%), anti-Ro (60.5%), anti-La (28.4%) and rheumatoid factor (10.1%). Positive clinicoserological associations observed included: combination of anti-dsDNA antibodies and low C4 levels with renal disease; anti-dsDNA antibodies with cutaneous vasculitis; anti-Sm antibodies with psychosis; anti-RNP antibodies with Raynaud's phenomenon; anti-Ro antibodies with renal disease, psychosis and malar rash. Anti-La antibodies showed a weak negative association with serositis and Raynaud's phenomenon. Most of these clinical correlates are consistent with past studies. The high frequency of anti-Sm and anti-RNP antibodies is similar to the observations in African-Americans and Afro-Caribbeans.