The DRB1 alleles of these two haplotypes share the epitope (70)DRRAA(74)and were associated with both the pauciarticular and the systemic subset of JRA.
Analysis of MHC region genetics in Finnish patients with juvenile idiopathic arthritis: evidence for different locus-specific effects in polyarticular vs pauciarticular subsets and a shared DRB1 epitope.
The frequency of DRB1*03 was found to be much higher in the polyarticular subtype of Kuwaiti JRA cases compared to the oligoarticular subgroup and the controls.
Comparisons among patients with RA, patients with RF positive polyarticular JRA, and controls showed increased frequencies of the RA shared epitope in patients with RA and of DRB1*0901 in patients with seropositive polyarticular JRA, while the frequency of DRB1*08 alleles was decreased in patients with RF positive polyarticular JRA.
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 DQB1*0603 (OR 11.5, 95% CI 2.5-53.4).
Certain HLA associations (DRB1*0801, DPB1*0201) appear to be present in patients with JA in most studies; others (DRB1*1301, DPB1*0301) are more variable.
However, when the JRA patients were classified into four clinical types, i.e., a rheumatoid factor-positive [RF(+)] polyarticular type, a rheumatoid factor-negative [RF(-)] polyarticular type, a pauciarticular type, and a systemic onset type, DRB1*0405 was found to be significantly higher in the RF(+) polyarticular JRA patients than in the controls (P < 0.05).
Eighty-six percent of our patients present either HLA-DR5 or the beta DR-2.9-kb-EcoRI allogenotope or lack the C4-14.3-kb-EcoRI allogenotope compared to 48% in controls; however, these particular DR and C4 RFLPs may not represent the corresponding DRB1 or C4 genes but rather neighboring ones which may be relevant to confer JRA susceptibility.