HLA-DR7 IN ASSOCIATION WITH CHLORPROMAZINE-INDUCED LUPUS ANTICOAGULANT (LA)

The presence of anti-phospholipid antibodies (aPL) has been associated with the major histocompatibility complex (MHC) genes. These autoanti bodies occur in individuals with infections such as that produced by t he human immunodeficiency virus 1 (HIV-1) or with syphilis, but they c an also occur in drug-induced lupus-like syndromes. In the present stu dy, we analysed the presence of aPL (detected as lupus anti-coagulant) and its relationship with the MHC markers in 93 Caucasian psychiatric patients chronically treated with chlorpromazine. Forty-one out of 93 patients were positive for LA, and the HLA-DR7 antigen was significan tly increased in LA-positive patients as compared to normal controls o r LA-negative patients (PC=0.024, RR=2.12 and P=0.05, RR=1.57, respect ively). Likewise, we noted a significantly increased frequency of HLA- B44 in LA-positive patients as compared to normal controls (PC=0.024, RR=2.12), but not when compared to aPL-negative patients. No significa nt differences were found among any other class I, II or III MHC antig ens. Haplotype analysis showed that DR7 was mostly part of the HLA-B44 -DR7-FC31 and B7-DR7-SC31 haplotypes. These results suggest that the H LA-DR7 antigen might be playing a role in the production of aPL in chl orpromazine-treated patients. (C) 1997 Academic Press Limited.