The contribution of HLA‐DQB1 coding and QBP promoter alleles to anti‐Ro alone autoantibody response in systemic lupus erythematosus
AbstractAbstract Objective . To analyse the influence of HLA‐DR , DQ and corresponding DQA1 and DQB1 promoter alleles ( QAP and QBP ) on the anti‐Ro alone autoantibody response in systemic lupus erythematosus (SLE). Methods . Sixty‐five unrelated anti‐La antibody‐negative SLE patients, 37 of them with and 28 without anti‐Ro antibodies, were included. Anti‐Ro antibodies were determined by both counter‐immunoelectrophoresis and enzyme‐linked immunosorbent assay. Seventy‐four healthy individuals were selected as controls. The patients and controls were analysed for HLA‐DRB1 , QAP , DQA1 , QBP and DQB1 alleles by DNA typing. The allelic frequencies of anti‐Ro alone‐positive and anti‐Ro‐negative SLE patients and healthy controls were compared using the χ 2 test or Fisher's exact test as appropriate. Results . The DQB1*0202 allele showed a significant positive correlation with anti‐Ro alone antibodies odds ratio (OR)=16.949, P =0.0015, corrected P =0.018, while the QBP5.11 allele and the combination of DQB1*0301 and its promoter QBP3.1 were under‐represented in anti‐Ro‐alone‐positive SLE patients ( P =0.01, corrected P =0.048 and corrected P =0.048 respectively). Conclusions . The above‐mentioned alleles may contribute to the presence or absence of anti‐Ro alone autoantibodies in SLE patients.