Liver enzyme flares and occult hepatitis B in persons with chronic hepatitis C infection

Background: Occult hepatitis B (HBV) has been reported in numerous clinical settings, but it remains unclear whether occult HBV contributes to liver damage. Given that typical chronic HBV infections often have periodic flairs in viral replication and liver damage, we hypothesized that occult HBV may also have flares in viral replication that are associated with increased liver enzymes. Study design: We screened hepatitis B surface antigen negative injection drug users with untreated chronic hepatitis C viral (HCV) infection for unexplained ALT/AST flares. To further enrich for individuals with possible occult HBV flares, we studied those individuals whose flares were associated with IgM antibodies to hepatitis B core antigen. Serum samples were assayed for HBV DNA and serologies were performed in serum collected 6 months before, at the time, and 6 months after the flare. HCV RNA levels were also determined. Controls consisted of individuals who also had ALT/AST flares but who were negative for IgM antibodies to hepatitis B core antigen. Results: Seven study cases and eight control cases were identified. HBV DNA was detectable during the enzyme flares in 7/7 study cases versus 3/8 controls, p = 0.026. HBV DNA levels during the flare were low, averaging 1943 ± 2341 copies/ml, but were higher in study cases versus controls, p = 0.002. No change in HCV levels was associated with the flares. Conclusions: In this population at high risk for occult HBV, AST/ALT flares can be associated with detection of HBV DNA. These findings may link occult hepatitis B to liver injury.