Paediatric rheumatology: Original article antinuclear antibodies in early onset pauciarticular juvenile chronic arthritis (JCA) are associated with HLA-DQB1(*)0603: A possible JCA-associated human leucocyte antigen haplotype

A panel of 43 early onset pauciarticular (EOPA) juvenile chronic arthritis (JCA) patients have been typed for human leucocyte antigens (HLA) DRB1, DPB1, DQA1 alleles,and DQB1(*)0603 status using molecular-based methods. Increased frequencies of DRB1(*)08 [odds ratio (OR) 7.7, 95% confidence interval (CI) 2.6-22.3], DRB1(*)11 (OR 3.1, 95% CI 1.2-8.1), DRB1(*)1301 (OR 7.7, 95% CI 2.6-22.3), DPB1(*)0201 (OR 3.5, 95% CI 1.6-8.0), DQA1(*)0103 (OR 4.4, 95% CI 1.5-13.3), DQA1(*)0501 (OR 2.9, 95% CI 1.3-6.6), DQA1(*)0601 (OR 30, 95% CI3.6-241) and DQB1(*)0603 (OR 7.3, 95% CI 3.0-17.6) were found in the EOPA-JCA group compared with Caucasoid controls. Stratification of the EOPA-JCA group into antinuclear antibody (ANA) positive (n = 18) and ANA negative (n = 25) individuals revealed that ANA positivity was only associated with DRB1(*)1301 (OR 4.2, 95% CI 1.0-17.3), DPB1(*)0201(*) (OR 4.0, 95% CI 1.0-15.7) and DQB 1(*)0603 (OR 11.5, 95% CI2.5-53.4). Further analysis of the relative contributions of HLA antigens to ANA status revealed that DQB 1(*)0603 determined the primary HLA effect. No apparent interaction between DQB1(*)0603 and DRB1(*)1301 or between DQB 1(*)0603 and DPB1(*)0201 was found to contribute to the association with ANA. We suggest that those ANA positive individuals with a restricted HLA background, (DQB1(*)0603 positive), defines a group of EOPA-JCA patients which will be especially valuable in the characterization of the ANA associated with EOPA-JCA.