Indoleamine-2,3-dioxygenase gene expression levels in response to chronic hepatitis B virus infection in Zaria, Nigeria

Abstract

Background: Hepatitis B virus (HBV) is one of the aetiological factors for hepatocellular carcinoma. HBV is hyper-endemic in Nigeria with different viral genotypes. In the chronic phase of infection, T-cells respond weakly thereby promoting viral persistence. This response could be attributable to either the infecting HBV genotype or immune tolerance induction by indoleamine-2,3-dioxygenase (IDO). This study therefore, aimed at assessing IDO gene expression by mononuclear cells in individuals infected by different genotypes of HBV in Zaria, Nigeria.

Materials and Methods: A total of 20 chronic hepatitis B (CHB) patients with identified HBV genotypes and 20 healthy controls were enrolled into this study. Venous blood was collected in EDTA-container from each of the participants and IDO gene expression was determined by RT-qPCR. Data were analysed using GraphPad prism 6. Mann-Whitney U and Kruskal-Wallis were used to determine differences between two or more groups, respectively. Statistical significance was set at p≤0.05.

Results: This study showed significant up-regulation of IDO-1 and IDO-2 gene expressions by the mononuclear cells of those with CHB. There was a significant up-regulation of IDO-1 gene in patients with HBV/A as compared with healthy control group and in those with single HBV genotype infection as against the healthy control group.

Conclusion: Chronic hepatitis B infection is associated with up-regulation of IDO expression which could be responsible for stalling lymphocytes proliferation.