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

Abstract

Objective: To determine the prevalence and clinical correlates of anti‐phospholipid antibodies (aPL), including anti‐cardiolipin antibodies (aCL), lupus anti‐coagulant (LA), anti‐β₂‐glycoprotein 1 (aβ₂GP1), 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, aβ₂GP, and aPT of all isotypes, and LA.

Results: Positive aCL, aβ₂GPI, aPT, and LA were found in 53, 84, 20, and 2 patients, respectively. Immunoglobulin (Ig)A aCL and IgG aβ₂GPI were the commonest aCL (49.1%) and aβ₂GPI (47%) isotypes, respectively. IgA aβ₂GPI 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 aβ₂GPI of any isotype were associated with a history of arthritis (p<0.001).

Conclusion: Our findings provide further evidence that screening for aβ₂GPI 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.