HLA class II alleles associations of anticardiolipin and anti-beta2GPI antibodies in a large series of European patients with systemic lupus erythematosus.

The objective of this study was to determine the HLA class II associations of the anticardiolipin (aCL) and anti-beta2GPI (abeta2GPI) antibodies in a large series of European patients with systemic lupus erythematosus (SLE). A cohort of 577 European SLE patients was enrolled. aCL and abeta2GPI were measured by ELISA methods. Molecular typing of HLA-DRB1, DRB3, DRB4, DRB5, DQA1 and DQB1 loci was performed by the polymerase chain reaction-sequence specific oligonucleotide probes (PCR-SSOP) method. aCL of IgG, IgM and IgA isotypes were detected in 22.8%, 14% and 13.9% of patients, respectively. IgG and IgM abeta2GPI were detected in 20% of patients. aCL showed positive association with HLA DRB1*04, DRB1*0402, DRB1*0403, DRB1*07, DRB3*0301, DQA1*0201, DQA1*0301, DQB1*0302, and negative association with DQA1*0501, DRB3*0202. abeta2GPI showed positive association with DRB1*0402, DRB1*0403, DQB1*0302. DRB1*0402 carried the highest relative risk for the presence of both aCL (RR=8. 1) and abeta2GPI (RR=4.6). Our results confirm the already described associations of aCL with HLA DR4 and DR7, but also demonstrate that, among the alleles at the DRB1*04 locus, the *0402 was most represented both in aCL and in abeta2GPI positive patients. In addition, HLA class II associations of abeta2GPI are for the first time extensively examined in a large cohort of European SLE patients.