Objective: To study the prevalence of Human Leukocyte Antigen (HLA) DR alleles in children with juvenile rheumatoid arthritis (JRA).
Methods: DNA samples from 64 children with oligoarticular and seronegative polyarticular JRA and 64 controls of the same ethnic background were analyzed using PCR-sequence specific primers (PCR-SSP) method. Analysis took into account the onset subtype, the presence of antinuclear antibodies (ANA) and the presence of chronic anterior uveitis, a recognised serious complication of JRA.
Results: A high prevalence of DR3 alleles were detected in children with oligoarticular JRA compared to controls (p < 0.05). DR3 alleles were the commonest also in patients with positive ANA as well as those with chronic anterior uveitis. The interesting finding in this study is the absence of two DR3 alleles, namely DRB1*0307 and DRB1 *0308 in the control group while present in significant proportion in children with JRA. DRB1*0307 was present in 16% of children with oligoarticular subtype and 15% of those with polyarticular JRA. DRB1*0308 was only detected in children with oligoarticular JRA, none of the children with polyarticular JRA or the controls had this allele.
Conclusion: These findings support earlier observations linking these two DR3 alleles, namely 0307 and 0308, to the genetic susceptibility to JRA.