HLA-B27 in juvenile chronic arthritis

The prevalence of HLA-B27 in 88 patients with juvenile chronic arthritis was 22/88 (25%) with little variation among the 3 commonly recognized onset types. This was significantly more frequent than the prevalence of 9.4% in a Danish reference population. A strong association was found between the HLA-B27 antigen and 3 subgroups of patients: (1) boys with pauciarticular and late onset disease; (2) girls with apophyseal joint fusion; (3) a group of patients in whom the clinical picture was compatible with reactive arthritis or incomplete Reiter's syndrome. When these 3 subgroups were excluded from the total patient population, only 8 of the remaining 63 patients carried the B27 antigen, i.e., 13%, which was not significantly different from the prevalence in the reference population. Thus, the 3 subgroups account completely for the increase of B27 in the entire group of patients.