Occult Hepatitis B Virus Infection: Diagnosis, Clinical and Biological Profiles.

Roger Nana Tchwenko (rntchwenko@hotmail.com)
Internal Medicine, The University of Yaounde 1
June, 2013
 

Abstract

BACKGROUND:
The presence of hepatitis B virus-DNA in the sera or in the liver of hepatitis B surface antigen (HBsAg)-negative patients defines the entity called occult hepatitis B infection (OBI). This represents a diagnostic problem for hepatitis b virus (HBV) since HBsAg remains the main and usually the only marker used in HBV screening. Even if OBI is suspected, the detection and quantification of HBV-DNA remains difficult in resource limited settings. The aim of our study was to describe the clinical profiles in OBI in order to identify signs, symptoms, biological characteristics, and serological patterns which could be suggestive of OBI.

METHODS
This longitudinal study included 6 individuals diagnosed with OBI 2 years ago. Clinical data dating from the time of diagnosis was collected from patient files in the retrospective phase. 5 patients participated in a 6-month prospective phase involving monthly clinical examination coupled with monthly blood work for liver transaminases and HBsAg.

RESULTS
All (6) subjects were HIV positive, including 1 Anti-retroviral therapy (ART) –naïve patient, and 2 hepatitis C virus (HCV) infected patients. No signs and no symptoms of chronic liver disease were observed throughout the study. 3 patients had received transfusions of blood/derivatives and none had been vaccinated against HBV. ART was begun at least 3 years before the diagnosis of OBI and included Nucleosidic analogues (NUCs) active on HBV; first Lamivudine, then subsequently associated with Tenofovir. Patients were not screened for HBV before initiation of ART and drug regimens were not adjusted to take OBI into account. Mean CD4 values stayed above 350c/mm3. The mean values for liver transaminases stayed below the upper limit of normal throughout the study. The HCV infected patients were not treated for hepatitis C. Anti-HBc was the only positive serological marker of HBV infection in all patients. HBsAg remained negative and there were no cases of seroconversion even in the ART naïve patient.

CONCLUSIONS

OBI is a real clinical entity especially in HIV infected persons and blood transfusion is major risk factor for OBI. The use of NUCs in ART and immune competence may be responsible for the absence of clinical signs of chronic liver disease. Liver transaminases alone may not be sufficient to evaluate liver function in OBI. Anti-HBc could be a surrogate marker for HBV-DNA, for the diagnosis of OBI.


********************************************************************************************