Interleukin-8 but Not Interleukin-6 Variant May Affect Susceptibility to Brucellosis

Background: Increased levels of interleukin-8 (IL-8) and interleukin-6 (IL-6) in acute human brucellosis have been reported. Previous studies have shown that the production and level of IL-6 and IL-8 cytokines are associated with the polymorphism of the encoding genes. Objective: To investigate the probable association between IL-6 (-174 C/G) and IL-8 (-251 A/T) gene polymorphisms and susceptibility/resistance to brucellosis. Methods: The patient group included 196 patients suffering from Brucella infection and the control group consisted of 82 healthy animal husbandmen from the same geographical area. IL-8 (-251 A/C) and IL-6 (-174 C/G) gene polymorphisms were analyzed by PCR-RFLP and Allele Specific PCR (AS-PCR) respectively. Results: The frequency of -251 IL-8 AA genotype was significantly lower in the controls compared with that of the patients (p=0.0051), while the frequencies of other genotypes (AT and TT) and alleles (A and T) were not significantly different among the participants. No association was found between IL-6 (-174 C/G) polymorphism and brucellosis. Conclusion: This study indicates that the IL-8 -251 AA genotype may be considered as a genetic susceptibility factor for brucellosis.