[Human leukocyte antigens and episcleritis in leprosy (Hansen's disease)]

Human leukocyte antigens (HLA) were analyzed in Japanese leprosy patients to ascertain whether immunogenetic differences exist between leprosy patients with episcleritis (ES) and those without it. The subjects were 79 Japanese leprosy patients, including 33 patients with a past history of ES, and 49 patients without ES. Controls were 114 healthy subjects. A standard microcytotoxicity test was used for typing HLA-A, -B, -C, -DR and -DQ antigens. HLA-DRB1 and DQB1 genotypings were performed by using the polymerase chain reaction (PCR)-single strand conformation polymorphism and PCR-restriction fragment length polymorphism methods. The occurrence of HLA-Cw3 was significantly greater in the patients with ES (66.7%) than in those without ES (43.5%; odds ratio = 2.6, p < 0.05). The occurrence of HLA-DR4 was significantly lesser in the patients with ES (15.2%) than in those without ES (39.1%; odds ratio = 0.28, p < 0.05) and the controls (46.5%; odds ratio = 0.21, p < 0.005). At the genomic level, the occurrence of HLA-DRB1*0405, DQB1*0401, and DQB1*0302 was significantly lesser in the patients with ES (0%, 0% and 6.1%, respectively) than in those without ES (15.2%, 13.0%, and 26.1%, respectively; odds ratio = 0.07, 0.09 and 0.18, p < 0.05). HLA-DRB1*0405 and DQB1*0401 were also significantly lesser in the patients with ES than in the controls (29.8% and 29.8%; odds ratio = 0.04, p < 0.0001). Our results suggest that HLA-Cw3 causes susceptibility to episcleritis in Japanese patients with leprosy, whereas DR4 (DRB1*0405), DQB1*0401, and DQB1*0302 provide some protection against leprous episcleritis.