Prevalence of occult hepatitis B amongst Indian human immunodeficiency virus type 1 infected individuals-a pilot...

The diagnosis of hepatitis B is routinely based on the detection of hepatitis B surface antigen (HBsAg) only. However, occult hepatitis B virus (HBV) infection (OBI), which is defined as infection with positive hepatitis B core antibody (anti-HBc) antibodies, positive DNA (deoxyribonucleic acid) PCR (polymerase chain reaction), and undetectable HBsAg, as well as anti-HBs antibodies in serum or plasma of HBV infected individuals, will remain undetected using this screening diagnostic approach of detecting HBsAg. The current study aims in studying the prevalence of the OBI amongst human immunodeficiency virus type 1 (HIV-1) infected individuals who have not been exposed to anti-retroviral therapy.

Estimation of HBsAg, anti-HBs, and anti-HBc total antibody status amongst 100 HIV-1 infected study participants was carried out using enzyme-linked immunosorbent assay (ELISA) kits. Detection of HBV-DNA was carried out by in-house qualitative PCR. CD4 + T lymphocyte counts were analysed using Becton Dickinson's (BD) FACSCount™ system.

The median age of the HIV-1 infected study population was 35 years (range: 22-67), with the gender distribution being 53 males and 47 females. The mean CD4 T lymphocyte count of the study participants was 210/mm(3). Overall, serological evidence of HBV infection was observed in 28% of the HIV-1 infected study participants. There was 5% seropositivity for HBsAg, of which 2% were additionally positive for HBV-DNA-PCR. "Anti-HBc alone" status was seen in 18% of study participants, this being statistically higher in those with CD4 T lymphocyte counts < 200/mm(3). While there was a single specimen with co-positivity for anti-HBc total antibodies and HBV-DNA, 5% of the in the study population exhibited anti-HBs antibodies positivity, with one sample exhibiting dual positivity for HBsAg and anti-HBs antibodies.

Occult HBV infections may contribute to chronic liver damage, and associ-ated reactivation amongst immunocompromised individuals, HIV-1 in-fected being a subset of them. "Anti-HBc" testing followed by HBV-DNA detection by PCR can be utilised for such populations to detect OBIs. Early detection of hepatitis B viraemia will be important for deciding the antiviral therapeutic protocol so as to avoid evolution of antiviral resistance in the circulating HBV strains in HIV-1 infected individuals harbouring OBIs.