Purpose: To investigate the difference, if any, in the immunogenetic backgrounds between two clinical subtypes of Vogt-Koyanagi-Harada disease (VKH).
Methods: HLA-DR4 gene variations were investigated in 46 Japanese patients, 28 with the prolonged type and 18 with the nonprolonged type of VKH. HLA-DR4 genes were amplified with polymerase chain reaction (PCR) and then analyzed for its variation with single-strand conformation polymorphism (SSCP) and restriction fragment length polymorphism (RFLP) methods.
Results: Significant differences were found in the DR4 gene variation in the two clinical subtypes. All the patients with the prolonged type had either the DRB1*0405 or DRB1*0410 variant, whereas 39% of the patients with the nonprolonged type had neither of them. This difference in frequency was statistically highly significant (P = 0.00059, Pc = 0.0041). DRB1*0405 was also more frequent in the prolonged type (93%) than in the nonprolonged type (56%) (P = 0.0044, Pc " 0.030). In the prolonged type, relative risk was highest for DRB1*0405/0410 (128), whereas in the nonprolonged type it was highest for DR4 (8.6).
Conclusion: This preliminary study showed that DR4 gene variants differed significantly between the two subtypes of VKH, suggesting that the clinical course of VKH is determined partly by the patient's HLA-DR gene variation.