ABSTRACT
A peculiar finding in hemodialysis patients, reported by several investigators (17,18), is the isolated presence of HBsAg in the absence of anti-HBc or any other marker of HBV infection of immunity. This phenomenon turned out to be due to the appearance in the circulation of HBsAg of vaccine origin. It is transient and rarely persists for more than 20 days. Therefore, it is recommended that dialysis patients are not screened for HBV markers within one month following an HBsAg vaccine administration. The reappearance of HBsAg in hemodialysis or kidney transplant patients who had seemingly eliminated the virus has been reported (19). This rather unexpected situation is not the result of a laboratory error but the consequence of a relapse of the HBV infection that is due to a drastic reduction of the patient’s immune function. Recent observations in patients with normal renal function suggest that it may take years before the HBV is completely eliminated from the body; it may even be that complete clearance never occurs (20). As long as the immune system functions normally, the virus persists
in the body at extremely low levels (only detectable with nested PCR) without causing any harm. Severe immunosuppression may lead to the reappearance of the virus and the clinical picture of chronic HBV infection.
