Prevalence of human leukocyte antigen (HLA) DRB1 alleles in Kuwaiti children with juvenile rheumatoid arthritis

The prevalence of human leukocyte antigen (HLA) DR alleles has been determined in 69 Kuwaiti Arab children with juvenile rheumatoid arthritis (JRA) and compared to that in 212 ethnically matched normal healthy controls using a PCR-sequence specific primers (PCR-SSP) method. A very high incidence of DR3 was detected in JRA patients compared to the controls (P < 0.0001, RR = 2.235). The high incidence of HLA-DR3 in JRA patients was accounted for mainly by an excess of DRB1*0307 (P < 0.05, RR = 3.072) and DRB1*0308 (P < 0.009, RR = 2.663) compared to the controls. Moreover, DR3 was more prevalent when patients with ANA-positive JRA were analysed separately; 73% compared to 58% for the whole JRA patient group. The frequency of DR1 was also higher in the JRA group compared to controls (P = 0.019, RR = 3.585). Although the incidence of some alleles was higher in the control group (DR13 and DR7), none reached a statistically significant level. All the patients with iridocyclitis had either a DR1 or DR3 allele, except for one child. 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. Also, a non-significant increase in the frequency of the DRB1*04, *11 and *15 alleles was detected in the polyarticular subtype of the Kuwaiti JRA cases compared to the controls.