Occult hepatitis B virus infection: A hidden menace?

Abstract

SEE ARTICLE ON PAGE 194 Recovery from an acute hepatitis B virus (HBV) infection is associated with loss of HBV DNA from serum, hepatitis B e antigen seroconversion, hepatitis B surface antigen (HBsAg) seroconversion, and normalization of serum aminotransferases. These changes generally imply clearance of virus, but clinical observations have shown that reactivation of HBV infection can occur either spontaneously or after immunosuppression. 1-3 Recent studies showed that immune response to HBV remains vigorous long after an acute infection. In addition, HBV DNA can be detected by polymerase chain reaction (PCR) assays in serum, liver, and peripheral blood mononuclear cells more than a decade after an apparent recovery from HBV infection.4-6 These findings suggest that recovery from acute hepatitis B may not result in complete virus elimination, but rather the immune system keeps the virus at very low levels. There is, however, no clear evidence that patients who have persistently low levels of HBV after recovery from acute hepatitis B develop progressive liver disease. The availability of PCR assays for HBV DNA allows the detection of 10 2 copies/mL compared with 10 6 copies/mL using hybridization assays. Using PCR assays, HBV DNA has been detected in some subjects who are HBsAg negative including those with no serologic markers of HBV infection. In