The relationship between IFN-γ and TNF-α gene polymorphisms and brucellosis: A meta-analysis

BACKGROUND: Brucellosis is an infectious disease and one of the major public health problems worldwide. Several current studies have provided data that polymorphisms in the interferon-gamma gene (IFN-γ) and tumor necrosis factor-alpha gene (TNF-α) are related to brucellosis. OBJECTIVES: The aim of this study was to investigate the relationship between IFN-γ +874 A/T, IFN-γ UTR5644 A/T, TNF-α -308 G/A, and TNF-α -238 G/A single nucleotide polymorphisms (SNPs) and brucellosis risk by meta-analysis. MATERIAL AND METHODS: We performed a comprehensive search of the PubMed, MEDLINE, EMBASE, Web of Science, and Elsevier Science Direct databases. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to measure the strength of association between IFN-γ and TNF-α polymorphisms and brucellosis risk. RESULTS: A total of 17 studies including 1,904 cases and 2,233 controls fulfilled the inclusion criteria. Our pooled analysis demonstrated that the IFN-γ +874 AT vs AA genotype in a codominant model may confer an increased risk of brucellosis in the overall population (p = 0.001; OR = 0.51). Regarding TNF-α -308 G/A, our pooled analysis revealed that the AA vs GG + GA (recessive) genotype increased the risk of brucellosis (p = 0.02; OR = 2.00). CONCLUSIONS: In summary, our pooled analysis suggested that the IFN-γ +874 AT vs AA as well as the TNF-α -308 AA vs GG + GA genotypes demonstrated a trend for the association with a higher risk of brucellosis.