Prevalence of the -308 and -238 tumor necrosis factor alpha (TNF-α) promoter polymorphisms in Mexican chronic hepatitis C patients.

BACKGROUND Tumor necrosis factor alpha (TNF-α) has been involved in the pathogenesis of chronic hepatitis C virus (HCV) infection. Two polymorphisms at positions -308 and -238 in the TNF-α promoter region influence TNF-α expression and these have been linked to a number of infectious diseases. AIM To analyze the prevalence of the -308 and -238 TNF-α polymorphisms in a group of Mexican HCV-infected patients and in healthy control subjects not related to the patients. MATERIAL AND METHODS Both polymorphisms were determined in peripheral blood samples from 48 patients with positive anti-HCV antibodies and discernible HCV-RNA levels. Twenty five patients were women and 23 were men. The control group included 100 healthy subjects. Forty-four were women and 56 were men. The polymorphisms were evaluated by polymerase chain reaction amplification (PCR), followed by the Restriction Fragment Length Polymorphism (RFLP) method. RESULTS The prevalence of the -308 TNF-α polymorphism was found to be 12% in patients with chronic hepatitis C and 20% in control subjects, (P=0.2616); whereas that of the -238 TNF-α polymorphism was found to be 2% and 12% in patients and control subjects, respectively (P=0.061). The TNF-α genotypes were found to be in Hardy-Weinberg equilibrium. CONCLUSIONS No association was found between -308 and -238 TNF-α polymorphisms and chronic hepatitis C in the Mexican group studied. Our data suggest that additional studies increasing the sample size and a control group which has been exposed to an equal risk of infection are required to investigate whether these polymorphisms represent genetic susceptibility for chronic HCV infection.