Molecular characterization of occult hepatitis B virus infection in patients with end-stage liver disease in Colombia

Abstract

BackgroundHepatitis B virus (HBV) occult infection (OBI) is a risk factor to be taken into account in transfusion, hemodialysis and organ transplantation. The aim of this study was to identify and characterize at the molecular level OBI cases in patients with end-stage liver disease.MethodsSixty-six liver samples were obtained from patients with diagnosis of end-stage liver disease submitted to liver transplantation in Medellin (North West, Colombia). Samples obtained from patients who were negative for the surface antigen of HBV (n = 50) were tested for viral DNA detection by nested PCR for ORFs S, C, and X and confirmed by Southern-Blot. OBI cases were analyzed by sequencing the viral genome to determine the genotype and mutations; additionally, viral genome integration events were examined by the Alu-PCR technique.ResultsIn five cases out of 50 patients (10%) the criteria for OBI was confirmed. HBV genotype F (subgenotypes F1 and F3), genotype A and genotype D were characterized in liver samples. Three integration events in chromosomes 5q14.1, 16p13 and 20q12 affecting Receptor-type tyrosine-protein phosphatase T, Ras Protein Specific Guanine Nucleotide Releasing Factor 2, and the zinc finger 263 genes were identified in two OBI cases. Sequence analysis of the viral genome of the 5 OBI cases showed several punctual missense and nonsense mutations affecting ORFs S, P, Core and X.ConclusionsThis is the first characterization of OBI in patients with end-stage liver disease in Colombia. The OBI cases were identified in patients with HCV infection or cryptogenic cirrhosis. The integration events (5q14.1, 16p13 and 20q12) described in this study have not been previously reported. Further studies are required to validate the role of mutations and integration events in OBI pathogenesis.

Molecular and serological characterization of occult hepatitis B virus infection among patients with hemophilia

“…Thus, any mutation disturbing this conformational space between the alpha‐helixes may impair the interaction between Ab and Ag . The exact Function of R73H and I110L is yet to be fully understood, however, these codons lie within the region that specifies epitopes of surface protein . Therefore, these mutations may reduce the specificity of the epitopes that prevent Ab from binding to the Ag.…”

Cellular Genomic Sites of Hepatitis B Virus DNA Integration

“…Alu PCR assays that use primers specific for HBV and Alu repetitive elements to amplify virus-cell DNA junctions have been used to detect HBV DNA integration in both HCC and non-tumour tissue of patients with HBV infection [ 48 , 49 , 50 ]. Alu sequences accounts for more than 10% of the human genome and are the most abundant repetitive elements [ 56 ].…”

Risk factors of de novo hepatitis B virus infection in pediatric hepatitis B core antibody positive liver graft recipients under prophylactic therapy

“…In China, 10% of the population are positive for HBsAg, and the positive rate of HBcAb is as high as 50% . The HBcAb positive donors are at high risk of occult HBV infection, which is defined as detectable intrahepatic HBV DNA in HBsAg negative population . A previous study showed that the occult HBV infection rate in HBsAg negative/HBcAb positive liver donors was 60% .…”