title: Association of interleukin-18 gene variants with susceptibility to visceral leishmaniasis in Iranian population.
abstract: Host resistance to Leishmania infection is mediated by cellular immune responses leading to macrophage activation and parasite killing. Interleukin-18 (IL-18) known as interferon-γ (IFN-γ) inducing factor, stimulates IFN-γ production by T cells. Taking into account the important role of IL-18 in the defense against visceral leishmaniasis (VL) and the known effect of IL-18 gene polymorphisms on its production, the aim of this study was to investigate the probable relationship between IL-18 gene polymorphisms and the susceptibility to VL. The study groups included 118 pediatric patients who suffered from VL and 156 non-relative healthy people as the controls from the same endemic area. IL-18 gene polymorphisms at the positions -656 G/T, -137 G/C and +105A/C (codon 35/3) were analyzed by polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP). The results showed that the frequency of T allele at the position -656 was significantly higher in the controls, compared with that in the patients (P = 0.047), but it couldn't tolerate Bonferroni correction. Regarding the IL-18 genotypes, there was no significant difference between the patients and controls. Although the frequencies of ATG single haplotype and AGG/ATG double haplotype were significantly higher in the controls (P = 0.043) and the patients (P = 0.044), respectively, the two P values couldn't tolerate Bonferroni correction. Furthermore, a strong linkage disequilibrium was observed among the -656, -137 and +105 single nucleotide polymorphisms of IL-18 gene (all Ps < 0.001). In conclusion, this study suggests that the inheritance of T allele at the position -656 may be considered as a genetic factor for resistance to VL.
authors.affiliation: Department of Immunology, Fasa University of Medical Sciences, Fasa, Fars, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Moravej
authors.forename: Manoochehr
authors.initials: M
authors.lastname: Rasouli
authors.forename: Sadaf
authors.initials: S
authors.lastname: Asaei
authors.forename: Mehdi
authors.initials: M
authors.lastname: Kalani
authors.forename: Yaser
authors.initials: Y
authors.lastname: Mansoori
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D007223:Infant; D020382:Interleukin-18 / Q000235:genetics*; D007492:Iran; D007898:Leishmaniasis, Visceral / Q000235:genetics*; D015810:Linkage Disequilibrium / Q000235:genetics; D008297:Male; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*
chemical_list: D020382:Interleukin-18