Antibodies to type II collagen and their association with HLA DR1 alleles in Japanese patients with rheumatoid arthritis

 To investigate whether immunological responses to type II collagen (CII) play an important role in the pathogenesis of rheumatoid arthritis (RA), the presence of anti-CII antibodies was examined by enzyme immunoassay in 130 Japanese patients with RA, 10 systemic lupus erythematosus (SLE) patients, and 30 healthy subjects. In addition, the HLA-DRB1 genes of 40 RA patients were determined, and their association with positive findings of anti-CII antibodies was examined. A significantly high frequency of positive findings of anti-CII antibodies was detected in sera from RA patients (19%, P < 0.05) in comparison with that in sera from healthy subjects (3%). High frequencies of DRB1^*0405 and 0101 alleles were observed in the 40 RA patients examined (40.0% and 30.0%, respectively). Patients with DRB1^*0101 had a significantly higher rate of positive findings of anti-CII antibodies than those without DRB1^*0101 (66.7% and 28.6%, respectively, P < 0.05). No such association was observed for DRB1^*0405. From these findings, we suggest that immunological responses to CII may play an important role in the development of arthritis in some RA patients. Received: April 9, 2002 / Accepted: June 13, 2002 Acknowledgment We thank Dr. T. Sakamaki, Division of Clinical Research, Sakura National Hospital, Japan, for technical assistance and useful advices on HLA typing. Correspondence to:T. Sumida