Background: Brucellosis is the major bacterial zoonoses of global importance caused by Brucella spps. FCγRIIA receptor plays a central role in phagocytosis of IgG2-opsonized bacteria. FCγRIIA exhibits allelic polymorphisms with different capacities for binding IgG2 and phagocytosis. Cells expressing Fc γ RIIa-H131, bind more efficiently to complexes of IgG2 than those expressing the Fc γ RII A -R131 variant. The purpose of this study was to evaluate the association of FCγRIIA polymorphisms with susceptibility to or severity of brucellosis.

Materials and Methods: In this study, we evaluated FCγRIIA polymorphisms (R/R131, R/H131, H/H131) in 67 patients with brucellosis and 67 age, sex and geographical matched healthy volunteers. FCγRIIA genotyping was performed by using a sequence-specific primer polymerase chain reaction (SSP-PCR).

Results: The comparison of the FCγRIIA genotypes distribution in patients with brucellosis and controls showed a higher frequency in FCγRIIA-R/R131 homozygosity in patients than controls (47.8% vs. 28.4%). Logistic regression analysis showed that there is a significant correlation between R/R131 genotype and brucellosis (OR=2.3, 95%CI=1.3-4.2, P=0.04). Although the frequency of the FCγRIIA-R/R131 was higher in patients with chronic brucellosis compared with acute brucellosis, we did not find any statistically significant differences (53.8% vs. 46.3%, P=0.65).

Conclusion: The result of this study showed that the homozygous genotype of FCγRIIA-R/R131 in patients with brucellosis may be associated with susceptibility to brucellosis as a genetic risk factor.