HLA and self-limiting, unclassified rheumatism. A role for HLA-B35?

Objective. To test the hypothesis of increased frequency of HLA-B35 in self -limiting, unclassified rheumatism (SUR). Methods. Patients (n = 50) were included if they had swelling of one or mor e joints far more than 24 h and/or pain without trauma of 2 or more joints for one month or longer, and at least one of (1) history of joint swelling, (2) morning stiffness, (3) elevated erythrocyte sedimentation rate and/or C-reactive protein. Patients fulfilling diagnostic criteria sets of any rhe umatic disease and patients with other identified diseases were excluded. C ontrols were 50 patients with rheumatoid arthritis (RA) and 199 healthy blo od donors. Results. HLA-B35 frequency (0.32) was significantly greater in SUR than in RA (0.14) and controls (0.17). HLA-DR4 frequency was significantly increase d in HLA-B35 positive SUR, while that of HLA-DR1 was decreased (NS). Clinic al characteristics of SUR were: history of atopy; transient, mono or oligoa rticular synovitis and widespread, longlasting pain. HLA-B35 positive patie nts with SUR more often had hip, knee, or hack pain than HLA-B35 negative p atients. Conclusion. HLA-B35 frequency is increased in SUR, while HLA-DRI frequency is not. A likely hypothesis of attenuated immune inflammation in SUR is fur ther supported by results in juvenile RA, adult Still's disease, and a seri es of mild inflammatory arthritides, and by indirect evidence of decreased Th1 response and increased Th2 response in HLA-B35 positive patients with v arious conditions.