PRECORE AND X-REGION MUTANTS IN HEPATITIS-B VIRUS-INFECTIONS AMONG RENAL DIALYSIS PATIENTS

Hepatitis B virus (HBV) variants containing mutations within the X and the precore regions of the viral genome were demonstrated by polymera se chain reaction (PCR) amplification and DNA sequencing in renal dial ysis patients with different serological patterns of HBV infection. Am ong carriers, X region deletion mutants predominated in patients who l ost hepatitis B e antigen (HBeAg), or developed anti-HBe, but not in p ersistently HBeAg-positive patients. The precore region remained wild type in all carriers whether or not they seroconverted from HBeAg to a nti-HBe. The frequency of precore and X region mutants was greatest am ong cion-carrier patients with viral antibodies as the only indication of infection and among patients with non-A, non-B hepatitis (NANBH), suggesting an inverse relationship between the presence of wild type H BV markers and the presence of HBV mutants. Furthermore, the detection of one but not the other mutation in many serum samples suggests that these mutations are independently selected for during infection. Fina lly, the absence of HBV DNA in 21 'uninfected' dialysis patients with normal transaminases and no viral serology, suggests that replication of these mutants is associated with hepatitis. These results have impo rtant implications for HBV screening and treatment, as well as for the pathogenesis of chronic infection.