A common HLA-DRB1* allele was not involved in the JCA groups and subgroups studied; on the other hand, the DQA1*0501 allele was found to be associated with different JCA groups/subgroups (O-JCA, P-JCA RF-negative ANA-positive, JCA with CAU), probably suggesting a closer relationship of this locus with the immunogenetic background of JCA.
The microsatellite locus DQ CAR, which is localized between DQA1 and DQB1, shows a significant positive association with JA for the allele DQ CAR 121 and a negative association for the allele DQ CAR 111.
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% CI 3.6-241) and DQB1*0603 (OR 7.3, 95% CI 3.0-17.6) were found in the EOPA-JCA group compared with Caucasoid controls.
A TCR V beta gene segment in the vicinity of V beta 6.1, possibly V beta 6.1, is apparently involved in the pathogenesis of pauciarticular-onset JRA in DQA1*0101-positive individuals.