VARIABILITY OF ANTICARDIOLIPIN ANTIBODY ISOTYPE DISTRIBUTION IN 3 GEOGRAPHIC POPULATIONS OF PATIENTS WITH SYSTEMIC LUPUS-ERYTHEMATOSUS

Objective, To investigate the prevalence of anticardiolipin antibodies (aCL) and isotype distribution and their clinical associations with t he features of the antiphospholipid syndrome (APS) in 3 different ethn ic groups of patients with systemic lupus erythematosus (SLE). Methods , The study population consisted of 152 African-American, 136 Afro-Car ibbean (Jamaican), and 163 Hispanic (Colombian) unselected patients wi th SLE. Serum samples were studied for the prevalence of aCL and isoty pe distribution. All aCL measurements were performed in the same labor atory by ELISA. Results, Positive results for 1 of the 3 aCL isotypes were found in 42 African-Americans (28%), 28 Afro-Caribbeans (21%), an d 43 Hispanics (26%). IgG aCL was the dominant isotype in Hispanic and African-American patients, while IgA was the dominant isotype in Afro -Caribbeans. Of note, IgA aCL was found in all Afro-Caribbean patients who were aCL positive, while only 3 patients in this group had IgG aC L and 2 had IgM aCL. Clinical features of the APS were found to correl ate better in Hispanics than in African-Americans and Afro-Caribbean p atients with aCL isotypes. Conclusion. Our data suggest the existence of ethnic differences in the prevalence and isotype distribution of aC L as well as in their clinical relevance in patients with SLE. Further studies of the role of genetic and/or environmental factors in the ob served differences are required.