Anticardiolipin antibodies, haemolytic anaemia and thrombocytopenia in systemic lupus erythematosus.

Anticardiolipin antibody (ACA) levels were determined in 17 Asian female SLE patients with autoimmune haemolytic anaemia (AIHA) and 29 Asian female SLE inpatients without AIHA (control patients). Both IgG and IgM isotypes were measured by ELISA. Elevated IgM APA titres (greater than 5 SD of normal health controls) were seen in 11 (64.7%) of 17 AIHA patients and six (20.7%) of 29 control patients (P less than 0.01). There was no significant difference in IgG ACA titres between the two groups. Thrombocytopenia was present in 11 (64.7%) of the AIHA patients and nine (31%) of the control patients (P less than 0.05). None of the control SLE patients with thrombocytopenia had raised IgM ACA levels and only one had an elevated IgG ACA titre. Autoimmune haemolytic anaemia occurring in the context of SLE frequently associated with the concomitant presence of thrombocytopenia (Evan's syndrome) and with the presence of ACA.