Isolated hepatitis B core antibody in HIV infected patients--can response to hepatitis B vaccine help to elucidate the cause?

Background: Concomitant hepatitis B and HIV infections are common. In some of these patients, HBcAb is the only serologic marker of hepatitis B. This study was conducted to elucidate the cause of isolated HBcAb in HIV-infected patients via hepatitis B vaccination. Methods: In this interventional study during 2014-15 in the HIV Clinic in Hamadan, thirty four patients with HIV infection and isolated HBcAb positive isolate, received hepatitis B vaccine and their responses to vaccination were investigated. Demographic data, stage of disease, and status of CD4 and HCV Ab were extracted from the patients' medical records and were entered in a checklist. Results: Of the 103 HIV positive patients, the prevalence of HBs Ag, and HBc Ab isolates were 6.79% (n=7) and 46.6% (n=48), respectively. All of the patients with isolated HBcAb were positive for HCV Ab. Among the 48 patients with isolated HBc Ab, 34 (70.8%) were available and examined for HBV DNA in serum samples. The result of PCR was negative in all. After the first round of hepatitis B vaccination, HBs Ab titer exceeded 10 International Units Per Liter (IU/L) in 58.8% of patients with isolated HBc Ab. With the completion of the three-dose of vaccine, this titer was observed in 97% of patients. Significant correlation was observed between titer of antibodies and values of CD4 cells. Conclusions: Due to favorable response to hepatitis B vaccination in HIV positive patients with isolated HBc Ab, false positive HBc Ab and recovery from previous infection were more probable than hidden hepatitis B.