association between cytokine gene polymorphisms and human susceptibility to brucellosis

Background: allelic single nucleotide polymorphisms (snps) in cytokine-encoding genes can affect the degree of cytokine produc- tion, and may be related to the tendency to infectious illnesses as well as various clinical consequences. objectives: the aim of this work was to evaluate the possible role of snps in the regions of the il-10 (-592), il-15 (-367), il-18 (-656), il-12 (+1188), ifn-γ (+874), tnf-α (-308), and tnf-β (+252) genes in susceptibility or resistance to brucellosis and its crucial complications. methods: in a period of one year, 125 patients with acute brucellosis referring to 3 large public teaching hospitals were enrolled in this study. we studied the snps of il-10, il-15, il-18, il-12, ifn-γ, and tnf-α/β genes using the allele specific polymerase chain reaction (as-pcr) with sequence-specific primers. results: frequency of gg genotype in the tnf-α and tnf-β-encoding genes increased significantly by 52% and 31.2% in patient and control groups, respectively. for ifn-γ, ta genotype was found highly enhanced in patients (60%), while the frequency of aa and tt genotypes were higher in controls (23.2% and 26.4%, respectively). the aa and cc snps in il-12 were dominant in both patient (78.4%) and control (14.4%) groups. in the patient group, the gg and tt genotypes had a higher frequency for genes encoding il-15 (33.6%) and il-18 (89.6%). conclusions: based on the present study, some snps within the several cytokine genes, including tnf-α/β (-308/+252), ifn-γ (+874), il-15 (-367), il-18 (-656), and il-12 (+1188) are related to the susceptibility or resistance to brucellosis. in order to approve the biological consequence of our results, additional investigations should be carried out in larger population groups.