The wild type alleles at positions 857 and 1031 in the Tumor Necrosis Factor gene promoter are highly conserved among the low/high endemic HBV infected persons in Uganda and may not be attributable to disease burden.

Abstract

Genetic polymorphisms within the gene loci of the promoter region of tumor necrosis factor (TNF) alpha have been associated with the pathogenesis of hepatitis B virus (HBV) infection. Moreover, the prevalence of these polymorphisms varies from individual to individual and are population specific. Thus, we aimed at testing the hypothesis that, TNF-α-863C/A and − 1031T/C polymorphic sites may have an effect on the difference in the burden of HBV in our country. We used a sample of 140 participants from both the low (70, 50%) and high (70, 50%) endemic regions. For each region, 35(50%) were HBsAg seropositive and 35(50%) were HBsAg seronegative. The HBsAg serostatus was evaluated by using the HBsAg Rapid Test Strip (Healgen Scientific Limited Liability Company, Houston, TX77047- USA) and confirmed by using the 5-panel HBV One Step Hepatitis B Virus Combo Test Device (FastepR, HBV-P43 M). For evaluation of the liver function parameters, the chemistry analyzer B120 (Mindray, China) was used. For the total DNA extraction, the QIAamp® DNA extraction kit was used following the manufactures guidelines. The PCR amplification of the extracted DNA was performed using Platinum Taq DNA Polymerase (Invitrogen Corporation, USA) to obtain a 450bp portion of the human TNF alpha promoter gene spanning position 862 and 1031. This was cleaned and sequenced by chain termination cycle sequencing using BigDye Terminator v3.1 (Applied Biosystems) following manufacturer’s guide lines. The cycle sequencing products were then cleaned with Big Dye X Terminator kit following the manufacturers guide line (Applied Biosystems). The NCBI HBV genotyping tool available at http://www.ncbi.nlm.nih.gov/projects/genotyping was used to determine the TNF-α-863C/A and TNF-α-863T/C genotype for each sequence. Pearson’s Chi-square and multinomial logistic were used for the analysis. All the analyses were done using SPSS version 26.0 and MedCalc software version 20.010 at 95% CI. A p < 0.05 was considered statistically significant. The HBsAg seropositive participants from the low and endemic region were significantly associated with elevation of both ALT and AST (p < 0.05). In contrast, only alanine aminotransferase (ALT) was significantly elevated among the HBsAg seropositive participants from the high endemic region (p < 0.05). The prevalence of Both the TNF-α-863C/A TNF-α-1031T/C genotypes and their alleles did not differ significantly among the study groups and by endemicity (p > 0.05). However, the prevalence of the nucleotide substitution mutations for TNF-α-863C > A and TNF-α-1031T > C was significantly low for all the study groups (p < 0.05). The conclusion from this research is that the TNF-α gene promoter is highly conserved in our population. Henceforth, the TNF-α-857C/A and 1031T/C polymorphisms may have no significant effects on the endemicity of HBV infection. Future research should focus on the use nationwide samples in order to come up with concreate decisions on the role of the TNF-α-polymorphisms in the risk/resolution of the HBV infections in an African or Negroid population.