[Differentiation of juvenile chronic arthritis--diagnostic significance of HLA associations].

From January 1980 to June 1982, 150 children with primary onset of a joint disease during the previous 6 months were entered into a prospective non-randomized observation study. 106 of the 150 children were diagnosed as juvenile chronic arthritis cases according to the EULAR-criteria. Nine children of this group belonged to the systemic subgroup (7 girls, 2 boys). HLA-typing was performed in 100 of the 106 children: HLA-B27 was evident in the total patient group with significantly increased 41% versus 8.9% of the control group. This antigen is significantly evident in all subgroups with variously increased frequency, except in the systemic and early-onset (pauciarticular) subgroups; the frequency in the rheumatoid-factor-negative polyarticular type of juvenile chronic arthritis (JCA) was 37.9%, in the rheumatoid-factor-positive polyarticular form 33.3%, and in the oligoarthritis/sacroiliitis-group 72.2%. DR5 was significantly present in the total patient group with 32% (control group 13.4%) and in the early-onset oligoarthritis group (43.7%). The rheumatoid-factor-positive (50%) and negative polyarticular group (31%) showed a pronounced slightly significant increase.