Prevalence and clinical correlates of anti-phospholipid antibodies in South Africans with systemic lupus erythematosus.

OBJECTIVE To determine the prevalence and clinical correlates of anti-phospholipid antibodies (aPL), including anti-cardiolipin antibodies (aCL), lupus anti-coagulant (LA), anti-beta2-glycoprotein 1 (abeta2GP1), and anti-prothrombin (aPT) antibodies, in Black South African patients with systemic lupus erythematosus (SLE). METHODS A cross-sectional study of 100 SLE patients in whom clinical characteristics, including features of the anti-phospholipid syndrome (APS), disease activity, and damage were documented, and sera tested for aCL, abeta2GP, and aPT of all isotypes, and LA. RESULTS Positive aCL, abeta2GPI, aPT, and LA were found in 53, 84, 20, and 2 patients, respectively. Immunoglobulin (Ig)A aCL and IgG abeta2GPI were the commonest aCL (49.1%) and abeta2GPI (47%) isotypes, respectively. IgA abeta2GPI were associated with both a history of thrombosis alone (p<0.05) and a history of any clinical feature, thrombosis, and/or spontaneous abortion of the APS (p<0.05); IgA aCL were associated with a history of any clinical APS event (p<0.05); and abeta2GPI of any isotype were associated with a history of arthritis (p<0.001). CONCLUSION Our findings provide further evidence that screening for abeta2GPI and IgA aCL isotypes may improve the risk assessment for APS in SLE patients of African extraction. Further prospective studies are warranted to determine the clinical utility of these tests and to elucidate the genetic basis for the increased IgA aPL response in SLE patients of African extraction.