The HBV Serological patterns, Treatment eligibility, Genotypes and the TNF-α-863C/A & 1031 T/C Promoter gene polymorphisms in a high and low endemic region of Uganda.

Abstract

ABSTRACT Introduction: There is a disparity in HBV endemicity in Uganda. This can be influenced by the HBsAg seronegative persons who continue to shade the virus, chronically infected HBV not initiated on therapy, the circulating HBV genotypes and some host gene mutations. To bridge this gap, several strategies have been adopted elsewhere. These include among others: - first, screening for all the HBV serological markers eliminating the potential of the apparently HBsAg seronegative persons shading the virus which increases the risk of infection. Second, establishing the number of treatment naïve chronically infected people for enrollment on therapy reducing the transmission of the virus. Third, routine surveillance of the circulating HBV genotypes since they influence the choice of treatment, response to therapy, route of transmission and severity of the disease. Fourth, establishing the single nucleotide polymorphisms (SNPs) in the promoter region of the immune modulatory cytokines since they influence the risk of infection, chronicity of the infection and resolution of the infection. In Uganda, these strategies have not been fully studied. Thus, this doctoral work aimed to establish the HBV serological makers among the HBsAg seronegative persons, establish the number of treatment naïve chronically HBV infected people who need to be enrolled on therapy and determine the HBV genotypes as well as the polymorphisms at the TNF-α-863 and -1031 sites in a low and a high endemic region of Uganda. This will guide in scaling up HBV diagnosis and informing treatment decisions. Methods: From March 2019 to May 2022, a hospital and laboratory based cross-sectional study screened a total of 1154 participants attending Kitgum general hospital (n=555) and Kibuku Health Center IV (n=599) using the HBsAg rapid diagnostic tests. The HBeAg among the HBsAg seropositive and the HBV serological markers among the HBsAg seronegative samples were determined by using the 5-panel HBV One Step Hepatitis B Virus Combo Test Device. The plasma levels of the liver enzymes and other chemistry parameters were determined using the Chemistry analyzer B120. The HBV DNA was quantified in HBsAg positive samples by using the Roche Molecular Systems. The HBV, TNF-α-863 and -1031 genotypes were characterized through sequencing on 3130 Genetic Analyzer followed by sequencing using the NCBI genotyping tool. Demographic characteristics and predictors of HBV infection were collected by using a close-ended questionnaire. Results: There were more trio (HBsAb/HBeAb/HBcAb) and duo (HBsAb/HBeAb) seropositivity from the high endemic region (HER) than the low endemic region (LER). Age of 18-19 years, being married, the male gender, family contact with an HBV infected person, ≥30 years and blood transfusion (p<0.05) were associated with HBsAb+, HBeAb+ and HBeAb+ seropositivity. In contrast, more participants from the LER were more eligible for treatment using the TREAT-B algorithm (p<0.000). Alcohol use, albuminemia, elevated AST, total bilirubin and GGT were significantly associated with treatment eligibility (p<0.05). Genotype D was more prevalent in the HER (p=0.009), A in the LER (AOR=1.697, 95%CI= [0.72 to 4.0]) whereas mixed infection with D/E was associated with elevated viral load (p=0.013). Finally, the TNF-α-863C>A, TNF-α-1031T>C SNPs did not differ significantly among the study groups and by endemicity (p>0.05) although they were significantly low for all the study groups (p<0.05). Conclusions: The prevalence of HBV serological markers among the HBsAg seronegative persons and the large number of HBV chronically infected treatment naïve eligible for treatment indicates an increased risk of transmission of the virus in the communities. The disproportionate distribution of HBV genotypes by endemicity can explain the difference in HBV burden. The nucleotides in the TNF-α gene at the positions 863C/A and 1031T/C are conserved. Thus, the host genetic factors are less important in the differential burden of HBV. Finally, the TREAT-B algorithm can be a plausible alternative to specify treatment candidature with the potential to scale up interventions targeting HBV management and elimination.