QUANTIFICATION OF HEPATITIS-B VIRUS-DNA OVER A WIDE-RANGE FROM SERUM FOR STUDYING VIRAL REPLICATIVE ACTIVITY IN RESPONSE TO TREATMENT AND IN RECURRENT INFECTION

A new standardized test for hepatitis B virus (HBV) DNA with increased sensitivity and range over previous assays (30 to 10(6) HBV genomes/t est) was evaluated in this study, The quantitative results from the te st have been validated using international reference specimens of know n titer and a reference solution hybridization test. The test has smal l variability considering the wide dynamic range. The CV was 14% withi n one experiment and 32% to 39% between independent experiments, Hepat itis B surface antigen (HBsAg)-negative, anti-HBc-positive blood donor sera (n = 25) were all negative for HBV DNA in the new test, whereas 63% (n = 19) of HBsAg-positive healthy carriers had measurable quantit ies of HBV DNA. In five example cases of chronic hepatitis B patients responding to alfa-interferon treatment but remaining virus positive, HBV DNA was consistently present in posttreatment sera in a titer rang e 4 X 10(3) to 10(6)/mL not detectable by the conventional hybridizati on test. In two complete responders, the HBV DNA titer decreased over six orders of magnitude to below cutoff of the test. In four liver tra nsplant recipients with chronic hepatitis B, viral recurrence was dete cted by the new test at an early stage much before the clinical relaps e. Unlike serology, the test was suitable also in patients under anti- HBs immunoprophylaxis. In conclusion, the new colorimetric polymerase chain reaction (PCR) test allowed thousandfold increased sensitivity i n quantification of HBV DNA in patient sera. The test may have future applications in improving assessment of efficacy of antiviral treatmen t and guiding therapeutic interventions.