Association of IL18 gene polymorphisms (positions -656 G/T, -137 G/C and +105A/C) with Kala-Azar

Background & Objective: Host resistance to Leishmania infection is mediated by cellular immune responses leading to macrophage activation and parasite killing. IL-18 known as interferon-γ inducing factor, stimulate IFN-γ production by T-cells. According to the important role of IL-18 in defense against VL and known effect of IL-18 gene polymorphisms on its production, the aim of this study was to investigate the probable relation between IL-18 gene polymorphisms and susceptibility to VL in Iranian patients. Materials & Methods: The study groups included 118 pediatric patients suffered from VL and 156 non-relative healthy persons from the same endemic area as the patients. In both study groups IL-18 gene polymorphisms at positions -656 G/T, -137 G/C and +105A/C (codon 35/3) were analyzed by PCR-RFLP (Polymerase Chain Reaction - Restriction Fregment Length Polymorphism). Results: The result showed that the frequency of T allele at position -656 was significantly higher in the controls compared to that in the patients (P=0.047). But in none of the genotypes of IL-18 there was significant difference between patients and controls. In addition, the distribution of ATG haplotype and AGG/ATG haplo-genotype were significantly higher in the controls compared to that in patients with VL (P=0.043and P=0.044, respectively). Furthermore a strong LDs (P