PREVALENCE OF OCCULT HEPATITIS B INFECTION IN IRANIAN CANCER PATIENTS BEFORE CHEMOTHERAPY TREATMENT

Detection of occult hepatitis B virus in patients undergoing chemotherapy in Iran

Aim: Occult hepatitis B infection (OBI) is life threatening and has a high mortality rate despite applying antiviral treatments in cancer patients. This study aimed to investigate the prevalence of OBI in patients undergoing chemotherapy in Iran. Materials & methods: A total of 342 patients undergoing chemotherapy were enrolled. OBI detection in anti-HBc positive individuals was conducted using nested PCR. Results: Among 342 subjects, 103 (30.1%) were positive for anti-HBc. Fifteen (14.6%) cases of 103 anti-HBc positive samples were also positive for HBsAg. Overall, HBV DNA was positive in three (3.4%) of 88 anti-HBc subjects. Conclusion: Our results indicated that OBI might occur in almost one in 25 anti-HBc-positive patients undergoing chemotherapy.

Occult Hepatitis B virus (HBV) infection and challenges for hepatitis elimination: A literature review

Occult hepatitis B infection (OBI) is characterized by the detection of hepatitis B virus (HBV) DNA in serum or liver but negativity for hepatitis B surface antigen. OBI, which is thought to be maintained by host, immunological, viral and/or epigenetic factors, is one of the most challenging clinical features in the study of viral hepatitis. Currently, there is no validated detection test for OBI. It is believed that OBI is widely distributed throughout the world, with a higher prevalence in populations at high-risk HBV, but the detailed worldwide prevalence patterns are unknown. We conducted a survey of recently published studies on OBI rates across all continents. High prevalence rates of OBI are observed in some specific groups, including patients with hepatitis C virus, human immunodeficiency virus co-infection or hepatocellular carcinoma. In 2016, the World Health Organization adopted strategies to eliminate viral hepatitis by 2030, but the difficulties in detecting and treating OBI currently challenge this goal. Subjects with OBI can transmit HBV, and episodes of reactivation can occur. Further studies to understanding the mechanisms that drive the development of OBI are needed and can contribute to efforts at eliminating viral hepatitis.

Prevalence of occult HBV infection in Western countries

Due to a lack of standardized tests, it is difficult to obtain prevalence data and define the real impact of occult HBV infection (OBI) in Western countries. The present review article addresses the prevalence of OBI, defined as presence of hepatitis B virus (HBV) DNA in liver tissue or plasma in HBsAg-negative subjects, in Western countries. This varies in different studies according to the different methodologies used (based on serology vs virology), to the sample analyzed for the diagnosis (liver tissue vs plasma), to the different populations studied, to the different geographical variations in the HBV spread, to the host characteristics (age, gender, risk factors for acquiring HBV infection) and to the presence of other parenteral infections (hepatitis C virus and/or human immunodeficiency virus [HIV] infections). Considering the different liver diseases analyzed, that is in patients with cryptogenic cirrhosis or advanced liver fibrosis, the prevalence of OBI ranges 4% to 38%. Considering the different populations studied, in the case of parenteral blood exposure it is about 45%, in patients with chronic hepatitis C it is estimated at about 52%, in HIV-infected patients it ranges from 0% to 45%, in blood donors from 0% to 22.7% and in hemodialysis patients it ranges from 0% to 54%. In conclusion, OBI is a virological entity to be considered when performing the patient's evaluation for immunosuppressive diseases, liver pathologies, or for blood transfusions. Knowing the prevalence and clinical impact of OBI will allow better patient management.