[Analysis of HLA antigen in Japanese patients with sarcoidosis]

Current clinical investigation of sarcoidosis should be directed toward not only identification of causative agents but also elucidation of the mechanism of the disease susceptibility. For the latter purpose, allotypes of human leucocyte antigen (HLA) are determined under the hypothesis that immune response to antigen peptides is efficiently triggered if the peptides well fit the unique pocket of a given HLA molecule. We have serologically determined HLA allotype in 57 normal controls and 53 patients with sarcoidosis. When assessed by corrected p value, the frequency of DRw52 was significantly increased in the sarcoid patients (79.2% in the patient group vs 50.9% in the control group). This finding has been confirmed by several other studies in Japan. However, as DRw52 and DRw3, DRw5, DRw6, and DRw8 are in strong linkage disequilibrium when determined by a serological method, it has not been elucidated which antigen is most responsible for the disease susceptibility in sarcoidosis. DNA typing of HLA antigens will potentially solve this issue.