Occult hepatitis B virus infection in a Cohort of HIV-positive patients: correlation with hepatitis C virus coinfection, virological and immunological features

Background: : An evaluation of the prevalence of occult hepatitis B virus (HBV) infection in HIV-positive individuals is important as HBV infection may have an impact on the outcome of the liver disease in these patients. Materials and Methods: : Of the 1,593 HIV-positive subjects enrolled in the Italian Cohort Naïve Antiretroviral (ICONA) program, 175 (10.9%) were selected for inclusion in the study on the basis of hepatitis B surface antigen (HBsAg) negativity and antibody to hepatitis B core antigen (anti- HBc) positivity; 101/175 (58%) were also anti-hepatitis C virus (HCV) positive. HBV-DNA was detected in plasma using a highly sensitive PCR assay (detection limit: 2.6 copies/ml). Two different genomic regions were assayed. Quantification was performed by real-time PCR. The HBV genotype was determined in 20 cases with occult HBV infection. Data on the antiretroviral therapy (ART) regimen was obtained in 169 individuals: 53 (31.4%) patients were ART-naive, 46 (27.2%) were under ART without lamivudine or tenofovir, and the remaining 70 (41.4%) were under ART including lamivudine or tenofovir. Results: : 27/175 (15%) patients had detectable HBV-DNA in their plasma: 21/101 (21%) were anti-HCV positive and 6/74 (8%) were anti-HCV negative. Genotype D was invariably found in the 20 cases analyzed. Occult HBV infection was significantly higher in HCV-coinfected subjects: adjusted OR 5.02, 95% CI 1.31-19.26, p = 0.02. The value was not associated with immune status, HIV load, or ART regimen. Conclusions: : In relation to the high prevalence of occult HBV infection, particularly in HIV/HCV-coinfected individuals, it is necessary to clarify the clinical impact of this cryptic infection by monitoring HBV-DNA in plasma using the correct approach. Similarly to HBsAg-positive individuals of the Mediterranean area, HBV genotype D is invariably detected in this cohort of HIV-infected patients with occult HBV infection.