Interferon-gamma low producer genotype +5644 over presented in patients with focal brucellosis.

Genetic polymorphisms that affect production levels of certain cytokines may determine the risk, severity or protection in some infectious diseases like brucellosis. IFN-gamma plays a key role in the defense mechanism against brucella infection. This study aimed to determine the influence of the polymorphism within the +5644 position of IFN-gamma gene on the susceptibility to brucellosis. We investigated the allelic and genotypes distribution of A5644G polymorphism in IFN-gamma gene in an Iranian population comprising 259 patients with brucellosis and 238 healthy controls. The single nucleotide polymorphism was determined using the polymerase chain reaction in association with sequence-specific primers (PCR-SSP) incorporating mismatches at the 3'-end. Allelic and genotype frequencies of G5644A polymorphism of IFN-gamma gene were not significantly differed between patients with brucellosis and controls (p > 0.05). Stratification of patients to focal and non focal diseases revealed a significant increased of 5644A allele in patients with focal brucellosis (79.31% vs. 61.94%, p = 0.0005). Moreover, multivariate logistic regression models showed patients harboring the INF-y G5644A genotype were significantly more likely to develop focal infectious complications (OR = 3.45, p = 0.0004, 95% CI = 1.26-7.94). The present study suggests that the variant genotypes of G6544A of IFN-gamma might be associated with focal form of brucellosis and play as a genetic risk factor in brucellosis.