Background: It seems that polymorphism in the regulatory areas of cytokine genes affects the cytokine production capacity and may play a role in the development of infectious diseases. Interleukin-10 (IL-10) and Interleukin-6 (IL-6), which are cytokines of Th2, cause the macrophage become inactive and patient conditions get worse.
Methods: In this case-control study, 60 patients with brucellosis and 60 healthy participants were recruited. IL-10 genotyping at positions -1082 (G/A), -819 (C/T), and -592 (C/A) and IL-6 genotyping at position -174 (G/C) were analyzed by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) and restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) methods. The levels of IL-10 and IL-6 were determined by a sandwich enzyme-linked immunosorbent assay in sera of study population.
Results: The AA and CC genotypes of the IL-10 gene at positions -1082 G/A and -819 C/T were significantly more frequent in patients in comparison to controls, respectively. The AG genotype of the IL-10 gene at positions -1082 G/A was significantly more frequent in control groups than the patients. Serum levels of IL-10 and IL-6 were significantly more frequent in the patients than in the control groups.
Conclusions: Our study showed that the AA and CC genotypes at positions -1082 and -819 are very important, respectively. These results suggest that IL-10 (-1082 G/A) GG genotype may be considered as a risk factor for brucellosis, while the AG genotype might be a protective factor against the disease.
Keywords: Brucellosis; IL-10; IL-6; case control; polymorphism.