Analysis of the immunogenetic background of Japanese leprosy patients by the HLA system.

295 lepromatous and 74 tuberculoid leprosy patients were typed for HLA-A, -B and -C and compared to 110 healthy controls. It was found that frequency of HLA-B7 was significantly high and that of Bw54 was significantly low in lepromatous leprosy. HLA-DR and MT types were investigated in 84 lepromatous and 28 tuberculoid patients and compared to 55 controls. Both lepromatous and tuberculoid patients showed a marked increase in DR2 frequency. The relative risk is 8.7 and 5.9. Lepromatous leprosy showed an increase in frequency of MT1 and decreases in those of DRw9 and MT3 too.