HLA class II alleles and genetic predisposition to the antiphospholipid syndrome

The antiphospholipid syndrome (APS) is an autoinimune disease characterized by the presence of antiphospho- lipid antibodies (aPL). Its etiology is linked to genetic predisposition, which is accounted for, at least in part, by genes of major histocompatibility complex (HLA system). The association of APS with human leukocyte antigen (HLA) alleles is a consequence of the association of aPL with HLA alleles. Some HLA alleles carry the risks to produce aPL, and this is independent of the clinical, context. In fact, we find the same associations between HLA and aPL in primary APS and in APS secondary to systemic lupus erythematosus (SLE). The association of HLA-DR4, -DR7, -DRw53 and DQB1*0302 with aCL that has been demonstrated in primary APS can, also be found in SLE, a disease with a completely different pattern of HLA allele association (DR2, DR3, DRw52). In addition, the various aPL (anticardiolipin antibodies, lupus anticoagulant, anti-betaGPI antibobies,antiphosphatidylserine/prothrombin antibodies) show similar HLA association, again independent of the clinical context (primary APS or SLE), and across various ethnic groups. (C) 2003 Elsevier B.V. All rights reserved.