Class I associations and frequencies of class II HLA-DRB alleles by RFLP analysis in children with rheumatoid-factor-negative juvenile chronic arthritis.

A total of 94 patients with juvenile chronic arthritis (JCA) was tested for HLA class I by serology and for class II by RFLP typing. Early onset JCA (EOPA) is associated with HLA-A2, DR5 and DR8 in both males and females. The combination (joint occurrence) of these JCA associated alleles (A2, DR5, DR8) is frequently seen in patients with chronic iridocyclitis. Late onset pauciarticular disease has an increased frequency of HLA-B27, especially in males. Our data confirm that polyarticular JCA with early childhood onset (< or = 4 years) is associated with DR5 and DR8 and has a different immunogenetic background from polyarticular JCA with later childhood (> 4 years) onset (associated with DR4).