Mutations in the "a" determinant region of HBV as often found in OBI remarkably impair the detection of HBsAg from serum and infected cells, emphasizing the relevance of alternative methods such as HBV-DNA quantification for high-risk groups like HIV-infected individuals. J. Med. Virol. 89:246-256, 2017. © 2016 Wiley Periodicals, Inc.

Aim: The aims of this study were to find out the prevalence of occult hepatitis B infection (OBI) in HIV-1 patients, as well as to analyze the mutational patterns of OBI-positive individuals. Materials & methods: 172 HBsAg-negative, HIV-1-positive patients were selected according to data extracted from questionnaires. HBV serologic and molecular assays were performed. An extensive mutational analysis was applied using direct sequencing on HBsAg. Results: Thirty-one samples (18%) were OBI positive. Among 24 available OBI-positive samples, 17 (71%) contained at least one mutation only within ‘a’ determinant region of HBsAg. A stretch of mutations was found between amino acid positions 121 and 136. The physicochemical properties of individual amino acid substitutions and their potential impacts on 3D structure of ‘a’ determinant mutants were also determined. Conclusion: HBV serologic assays are not reliable markers to exclude occult HBV infection in HIV-positive patients.

Finding the predominant circulating subtype of human immunodeficiency virus type 1 (HIV-1) and surveying co-infection with other infectious viruses are crucial to making preventive decisions. To this end, 50 Iranian HIV-positive patients made up of 37 men and 13 women were selected. Most of the HIV-positive patients (70%) were intravenous drug users (IDUs), and 48 and 32% of patients were co-infected with HCV and HBV, respectively. The rate of simultaneous infection with HIV, HCV, and HBV was found to be 6%. The p17 region of the gag and the c2-v5 region of the env genes were sequenced and then clustered by phylogenetic analyses. CRF35-AD was specified as the predominant circulating subtype among different high-risk groups. In our survey, most of the patients in the IDU group had co-infections with HCV and HBV. Some possible reasons for the increased transmission risk of HIV in IDUs could be low levels of education, poor hygiene and housing conditions, and limited access to health services.