Occult Hepatitis B Virus infection in ART-Naive HIV-Infected Patients seen at a Tertiary Care Centre in North India

BACKGROUND Co-infections of hepatitis B and C viruses are frequent with HIV due to shared routes of transmission. In most of the tertiary care health settings, HIV reactive patients are routinely tested for HBsAg and anti-HCV antibodies to rule out these co-infections. However, using the routine serological markers one can only detect active HBV infection while the occult HBV infection may be missed. There is insufficient data from India on HIV-HBV co-infection and even scarce on occult HBV infection in this group. METHODS We estimated the burden of HBV infection in patients who were tested positive for HIV at a tertiary care centre in north India. We also attempted to determine the prevalence and clinical characteristics of occult HBV infection among these treatment-naïve patients and compare their demographic features with other HIV patients. During a period of 6 years between January 2002 to December 2007, 837 HIV positive patients (631 males and 206 females (M: F :: 3.06:1) were tested for serological markers of HBV (HBsAg) and HCV (anti-HCV antibodies) infections in our laboratory. For comparison 1000 apparently healthy, HIV-negative organ donors were also included in the study. Data on demographics, sexual behaviour, medical history, laboratory tests including the serum ALT and CD4 count of these patients were recorded. A sub-group of 53 HBsAg negative samples from HIV positive patients were assessed for anti-HBs, anti-HBc total (IgG+IgM) and HBV-DNA using a highly sensitive qualitative PCR and analysed retrospectively. RESULTS Overall, 7.28% of HIV positive patients showed presence of HBsAg as compared to 1.4% in the HIV negative control group. The prevalence of HBsAg was higher (8.55%) in males than females (3.39%). The study revealed that occult HBV infection with detectable HBV-DNA was prevalent in 24.5% of patients positive for anti-HBc antibodies; being 45.5% in HBsAg negative patients. Most importantly the occult infection was seen in 20.7% patients who were positive for anti-HBs antibodies. However, in none of the seronegative patient HBV-DNA was detected. Five of the nine HBV-DNA positive (55.6%) patients showed raised alanine aminotransferase levels and 66.7% had CD4+ T cell counts below 200 cells/cumm. CONCLUSIONS High prevalence of HIV-HBV co-infection was found in our patients. A sizeable number of co-infected patients remain undiagnosed, if only conventional serological markers are used. Presence of anti-HBs antibodies was not a reliable surrogate marker to rule out occult HBV infection. The most reliable method to diagnose occult HBV co-infection in HIV seropositive patients is the detection of HBV-DNA.