HBsAg seroconversion in a HIV co-infected patient during combination therapy with adefovir dipivoxil and pegylated interferon alfa 2b followed by HBsAg seroreversion and viral reoccurrence after stopping HBV directed antiviral treatment

Co-infection of HBV and HIV is common due to overlapping routes of transmission accompanied by an increased risk for liver-related mortality. We report the case of a chronically infected HBeAg positive patient, co-infected with HIV (CD4 >500/ul), with histological evidence of advanced liver disease. The patient developed anti-HBs seroconversion, strong reduction of intrahepatic cccDNA and remarkable improvement of liver histology after 24 weeks of HBV targeted combination therapy with adefovir dipivoxil and pegylated interferon alfa2b followed by another 12 weeks of adefovir dipivoxil monotherapy. Antiviral therapy was stopped after evolution of stable anti-HBs titres and anti-HBs titres remained stable for additional 9 months post treatment. A continuous decline of anti-HBs was observed during the next 6 months until anti-HBs disappeared despite a stable HIV infection. A triple course of therapeutic vaccination failed to re-establish anti-HBs antibodies but reappearance of HBV DNA and HBs antigen was detected. By elispot analyses, HBV directed T-cell responses clearly increased during antiviral combination therapy followed by a reduction to pre-treatment levels in association with disappearance of anti-HBs antibodies despite therapeutic vaccination. The presented case highlights the volatile nature of chronic hepatitis B virus infection even after a prolonged disease-free period in the setting of an underlying HIV co-infection in a patient with a stable and relatively high CD4 count but nevertheless impaired immune system and calls for further investigation of probably temporary immunomodulatory effects of interferon alfa or nucleos(t)ide analogs in immunocompromised patients.