Association between HLA Class I Alleles and Proviral Load in HTLV-I Associated Myelopathy/Tropical Spastic Paraperesis (HAM/TSP) Patients in Iranian Population

OBJECTIVE(S) The aim of this study was to investigate the association between HLA class I alleles (HLA-A*02, HLA-A*24, HLA-Cw*08, HLA-B5401) and proviral load in HTLV-I associated myelopathy/tropical spastic paraperesis (HAM/TSP) patients in Iranian population. MATERIALS AND METHODS 20 new cases of HAM/TSP patients and 30 HTLV-I infected healthy carriers were recruited. Peripheral blood samples were collected. Peripheral blood mononuclear cells (PBMCs) were isolated. DNA was extracted from PBMC.HTLV-I proviral load was calculated by Taqman quantitative real time polymerase chain reaction (qRT-PCR). PCR sequence-specific primer (PCR-SSP) reactions were performed to detect HLA-A, HLA-B and, HLA-Cw alleles. RESULTS There was no significant difference in sex and age between asymptomatic and HAM/TSP group. The Mann-Whitney U test was used to compare proviral load between HAM/TSP patients and healthy carrier. Provirus load of HAM/TSP patients was significantly higher than that of HCs (P=0.003, Mann-Whitney U test).Odd ratio was calculated to determine association between class I alleles including (HLA-A*02, HLA-A*24, HLA-Cw*08) and risk of HAM/TSP development. We couldn't find any association between these class I alleles and risk of HAM/TSP development in our study. In our survey HLA-A*02, HLA-A24, HLA-Cw*08 didn't have protective effect on proviral load (P=0.075, P=0.060 and 0.650 Mann-Whitney U test respectively). CONCLUSION In conclusion, certain HLA alleles with protective effect in one population may have not similar effect in other population. This may be because of pathogen polymorphism or host genetic heterogeneity and allele frequency in desired population.