Association of Interleukin-27 Gene Variants with Susceptibility to Brucellosis Among Iranian Population: A Case–Control Study

Objectives: Brucellosis is recognized as one of the most widespread zoonotic diseases, caused by facultative intracellular coccobacilli of the genus Brucella . Interleukin-27 (IL-27) is a pleiotropic cytokine that serves a critical role in the development of immunity against Brucella . IL-27 single nucleotide polymorphisms (SNPs) may influence susceptibility to brucellosis by altering the expression and/or function of this cytokine. This study sought to examine the potential association between IL-27 genetic polymorphisms and brucellosis susceptibility among Iranian individuals. Methods: The study comprised 207 patients diagnosed with brucellosis and 82 healthy livestock workers as controls matched geographically to the patients’ population. IL-27 SNPs at positions −964 A/G, 2905 T/G, and 4730 T/C were genotyped and then evaluated through case–control comparisons. Results: Genotype analysis revealed a significantly higher frequency of the TG genotype at rs17855750 in controls compared to patients ( p = 0.0002). Conversely, the TT genotype at rs17855750 and the CC genotype at rs181206 were more frequent in patients ( p = 0.012 and p = 0.026, respectively). Furthermore, specific haplotypes (AGT and GGT) and haplogenotypes (ATT/AGT, GTC/GGT, and ATT/GTT) showed a significantly different distribution between the groups, being more prevalent in controls. Conclusion: This study provides evidence for an association between IL-27 gene variants and brucellosis susceptibility, reinforcing the role of host genetics in Brucella infection. These findings not only enhance our understanding of brucellosis pathogenesis but also pave the way for genetic-based risk assessment and the development of novel therapeutic strategies.