Idiopathic Thrombocytopenic Purpura환자에서 HLA class II와 연관성

Abstract

Background/Aims: HLA(Human Leukocyte Antigen) molecules regulate immune responses to antigens by presenting antigenic peptides to CD4 helper T cells and control production of antibodies. The presence of various autoantibodies was shown to be associated with specific HLA class II alleles. Idiopathic thrombocytopenic purpura is a well defined autoimmune disease since excessive platelet destruction is caused by circulating autoantibodies directed to platelets. Therefore, specific HLA class II alleles may be associated with the occurrence of Idiopathic thrombocytopenic purpura and the response of treatment. However, this association was not studied in Korean. I investigated the frequencies of HLA class II alleles in Korean patients with Idiopathic thrombocytopenic purpura. Methods and Results: HLA class II alleles were determined in 20 Korean patients with Idiopathic thrombocytopenic purpura and 200 race-matched healthy controls. The median age of patients was 32 years(range, 16~62) and male to female ratio 3:17. A twenty patients received an initial treatment with prednisone(1mg/kg/day) and then initial complete or partial response to prednisone was observed in 12 patients(60%). Ten patients(refractory:8, relapse:2) underwent splenectomy, H.Pylori irradication, or immunosuppressive therapy(vincristine). HLA DQB1*0501 and 0601 were the most prevalent alleles in patients with idiopathic thrombocytopenic purpura. However, none of these alleles showed a significant difference in frequency when compared with controls. When factors influencing therapeutic responses to prednisone were examined, good response was correlated with the presence of HLA DQB1*0302(p=0.05). Conclusions: The majority of patients who received prednisone treatment can have a complete or partial response. The present study showed that idiopathic thrombocytopenic purpura in Korean was not associated with specific HLA class II phenotypes. However, HLA class II phenotypes could be useful in predicting therapeutic responses to prednisone in patients with idiopathic thrombocytopenic purpura.