1Immunology Research Center, BuAli Research Institute, Mashhad University of Medical Sciences, Iran
2Center for Integrated Genomic Medical Research, The University of Manchester, Manchester, UK
3Immunology Research Group, Faculty of Life sciences, The University of Manchester, UK
4Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
5Transplantation Laboratory, Central Manchester, Healthcare Trust, Manchester, UK
6ARC Epidemiology Unit, The University of Manchester, Manchester, UK
Background: Human T cell lymphotropic virus type I (HTLV-I)-associated myelopa-thy/tropical spastic paraparesis (HAM/TSP) is an inflammatory disease which occurs in less than 2% of HTLV-I -infected individuals. High proviral load, high HTLV-I-specific CD8+ cytotoxic T lymphocyte frequency (CTL) and host genetic factors such as HLA all appear to be associated with HTLV-I infection. Previous studies have shown that HLA-DRB1*01 increases the risk of HAM/TSP in Japanese HTLV-I infected individu-als. Objective: To investigate the association between HLA class II DRB1 alleles and HLA class I alleles (HLA-Cw*08, B54, A*02 and A-30) in HTLV-I infected individu-als in Mashhad. Methods: Here we determined the frequency of HLA class II DRB1, using INNO-LIPA reverse hybridization line probe assay, and HLA class I alleles (HLA-Cw*08,B54, A*02 and A-30) by PCR-SSCP method in healthy controls, HAM/TSP patients and HTLV-I infected individuals born and resident in Mashhad. Results: The frequency of HLA-DRB1*01 alleles in this population was different from other areas of Iran. The frequency of HLA-DRB1*01 was significantly increased in HAM/TSP patients compared with carriers (p 0.028; OR=9.4). The frequency of HLA-Cw*08 was also significantly increased in HAM/TSP patients compared with controls (p=0.03; OR=13.5). Conclusion: Our results may suggest that possession of HLA-DRB1*01 increases the risk of HAM/TSP in HTLV-I-infected individuals and HLA-Cw*08 correlates with low CTL immune response in HAM/TSP patients.