The relationship between IFN-gamma and TNF-alpha gene polymorphisms and brucellosis: A meta-analysis

Abstract

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-gamma) and tumor necrosis factor-alpha gene (TNF-alpha) are related to brucellosis. OBJECTIVES: The aim of this study was to investigate the relationship between IFN-gamma +874 A/T, IFN-gamma UTR5644 A/T, TNF-alpha -308 G/A, and TNF-alpha -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-gamma and TNF-alpha 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-gamma +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-alpha -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-gamma +874 AT vs AA as well as the TNF-alpha -308 AA vs GG + GA genotypes demonstrated a trend for the association with a higher risk of brucellosis.