Dear Editor: We read with great interest the article “epidemiology of OCCULT HEPATITIS B infection among thalassemia, hemophilia and hemodialysis patients” by Arababadi et al. (1). because of our common field of interest in investigation of OCCULT HEPATITIS B infection (OBI) in high risk patients such as HIV infected cases and hemodialysis patients. OBI is defined as the presence of HBV-DNA in the liver tissue or serum without detectable HEPATITIS B surface antigen (HBsAg) (2). About 20% of OBI cases are negative for all HBV markers except HBV-DNA, 50 % are positive for HEPATITIS B core antibody (anti-HBc) and 35% are positive for HEPATITIS B surface antibody (anti-HBs) (3).

OCCULT HEPATITIS B virus (HBV) infection (OBI); the presence of HBV DNA in the absence of HBsAg, has been recognized as one of the possible phases in the natural history of chronic HBV infection. OBI is a known clinical entity in some clinical settings including blood transfusion, cryptogenic cirrhosis, dialysis patients, solid transplantation, etc. The molecular basis of OBI is closely related to the peculiar life cycle of the HBV, and in particular to the long-lasting persistence of HBV covalently closed circular DNA (cccDNA) organized as a minichromosome into the nucleus of the infected hepatocytes. This feature together with the long half-life of liver cells imply that HBV infection, once occurred may continue for life, even in condition of strong inhibition of viral transcription and replication. In addition to cccDNA stability, other factors such as immune responses, viral mutations, epigenetic mechanisms, and co-infection are associated with OCCULT infection. Importantly, all the conditions inducing host immunosuppression (i. e., hematological malignancies, chemo-or immunotherapies, etc. ) can cause the reactivation of OBI with the development of a typical overt HEPATITIS B infection.

Objectives: Diagnosis of the OCCULT HEPATITIS B virus (HBV) infection in patients co-infected with human immunodeficiency virus (HIV) and HEPATITIS C virus (HCV) is important due to the fact that the HBV infection may have a clinical impact on liver disease in coinfected HIV/HCV patients. Isolated HEPATITIS B core antibody (HBcAb) positive HBV infection has been reported in HIV patients.The aim of this study was to determine the OCCULT HEPATITIS B in patients co-infected with HCV-HIV.Methods: In a cross-sectional study, HEPATITIS B surface antigen (HBsAg) and HBcAb tests were performed for all HIV-HCV co-infected patients, referred to the HIV Clinic of Hamadan. HBsAb was requested for HBsAg negative-HBcAb positive individuals and in the case of negative HBsAb, HBV-DNA PCR was performed. Finally the collected data was analyzed with SPSS.Results: Of 103 HIV-HCV coinfected patients, both HBsAg and HBcAb were positive in 7 patients (6.8%), negative in 44 (42.7%) patients and 52 (50.5%) of all patients were HBsAg negative and HBcAb positive, which positivity of HBsAg had statistical correlation with positivity of HBcAb. In the last group HBsAb and HBV-DNA PCR were done, which resulted in the titer of antibody to be positive in 4 patients (7.7%) and the PCR to be negative in all (100%) patients.Conclusions: The significant number of coinfected HIV-HCV patients only had HBcAb positive test without detectable HBV-DNA.Further studies for detection of HBV-DNA in both serum and liver biopsy specimens may help clarify the impact of HBV infection in coinfected HIV/HCV patients.

We read with great interest the article, “efficacy of HEPATITIS B vaccine in those who lost HEPATITIS B surface antigen during follow-up” by Taheriet al. published in HEPATITIS Monthly (1). In this article, the authors assessed the efficacy of HBV vaccine in those who lost their HBsAg without seroconverssion to anti-HBs antibody with no detectable anti-HBs antibody and HBV DNA in their sera.They reported that nearly 24% of chronic HBsAg-positive subjects who lost their HBsAg responded to HBV vaccine and the remaining cases need to be followed for OCCULT HBV infection (OBI).