Immunogenetics of polymyalgia rheumatica.

Evidence suggests that polymyalgia rheumatica (PMR) may be an immune-mediated disease. Therefore, the role of HLA class II genes, the switch region of immunoglobin mu and alpha 1 heavy chain as the T-cell receptor (TcR) genes were investigated by Southern blot analysis. The frequency of DR4 specificity was increased in PMR (67.4% versus 30.3%; P = 0.00017). No association was found with the DQA and DQB genes, the switch region of immunoglobulin mu and alpha 1 heavy chain genes, and the TcR alpha, beta and gamma genes. This study suggests that HLA-DR4 is an important susceptibility factor for PMR. Further studies are needed to elucidate the role of Ig and TcR genes.