A Functional Polymorphism of the Granulocyte Macrophage Colony Stimulating Factor is not Associated with the Outcome of HTLV-I Infection

Abstract

Introduction Genetic background has known to be associated with the outcome of human T cell lymphotropic virus (HTLV) type I infection. In The present study we investigate the association between GM-CSF gene polymorphisms with the outcome of HTLV-I infection. Materials and Methods We analyzed 3 single-nucleotide polymorphisms in the promter region of granulocyte macrophage colony stimulating factor (GM-CSF) at positions -677*A/C, -1440*A/G and -1916*T/C in 68 patients with HTLV- I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and 77 HTLV-I-seropositive asymptomatic carriers and 175 healthy controls from an area in Iran, Mashhad, where HTLV-I is endemic. Results No significant differences were observed in the distribution of GM-CSF polymorphisms between HAM/TSP patients, HTLV-I carriers and healthy controls (P> 0.05). The -677*A/C polymorphism fall within the transcriptional enhancer factor-2 (TEF-2) binding site, so an electrophoretic mobility shift assay (EMSA) was performed to determine the effects of polymorphisms on protein binding to the GM-CSF promoter. The result showed a significantly higher binding efficiency of nuclear protein to the A allele compared with the C allele. Conclusion Our study suggests that polymorphisms in the GM-CSF promoter is not associated with the outcome of HTLV-I infection, however, GM-CSF polymorphism at position -677 could indeed influence gene expression.