Genetic Polymorphisms of Tumor Necrosis Factor Alpha and Susceptibility to Dengue Virus Infection in a Mexican Population

To evaluate the association of the -308 and -238 tumor necrosis factor alpha (TNF-) gene polymorphisms with clinical manifestations of dengue and TNF- serum levels in a northwestern Mexican population. The study populations included dengue fever (DF) and dengue hemorrhagic fever (DHF) patients, and a group of healthy controls (HCs) without history of dengue. Polymerase chain reaction-restriction fragment length polymorphism and Enzyme-Linked Immunosorbent Assay were performed to determine genotypes and serum concentration of TNF-, respectively. There were no significant differences in alleles, genotypes, and haplotype frequencies between patients and HCs. However, when patients were separated into DF and DHF, there was an increased prevalence of the -308 GA genotype in HCs compared to DHF (odds ratio [OR]=0.129, 95% confidence interval [CI]=0.018-0.945, p=0.025), as well as the GG haplotype (OR=0.49, 95% CI=0.273-0.880, p=0.01757) in DF. The genotypes of both polymorphisms were not associated with hematologic manifestations. Serum TNF- levels were significantly higher in patients than in HCs (p=0.004). Our results suggest a minimal effect of the -308 and -238 TNF- gene polymorphisms in dengue patients and that their increased serum levels of TNF- are independent of genotypes.