HLA antigens in Reiter's syndrome in Israeli patients.

Major histocompatibility antigens (HLA loci A, B and C) were determined in 28 Israeli patients with Reiter's syndrome. The HLA-B27 antigen was found in only 8 (29%). Seven of the 20 B27 negative patients (35%) demonstrated crossreactive group antigens (CREG) B7, or Bw 22. HLA-B40 or Bw42 were not found. Only 3 of the 13 (22%) patients with the classical triad were B27 or Bw22 positive. In contrast, 12 of 15 patients with incomplete RS carried the B7 CREG antigens. These data suggest that in the Israeli population Reiter's syndrome is infrequently associated with HLA-B27 and that the B7 CREG antigens may be additional markers for this form of reactive arthritis.