Clinical utility in quantifying serum HBV DNA levels using PCR assays

Abstract

Background/Aims: A recent NIH research workshop on hepatitis B virus (HBV) revisited the definition of healthy HBsAg carriers. The new definition inactive surface antigen (HBsAg) carriers includes an estimated serum HBV DNA level below 10 5 copies/ml. However, this cut-off value needs to be confirmed. Methods: Eighty-five consecutive patients, HBsAg-positive/HBeAg-negative with persistently normal alanine aminotransferase (ALT) and undetectable serum HBV DNA with standard assay (Versant HBV DNA Assay (bDNA), Bayer) were prospectively followed for 3.2 ± 2.6 (range 0.5-11) years; 58 underwent a liver biopsy. Serum HBV DNA was quantified with a sensitive polymerase chain reaction assay (Cobas Amplicor HBV Monitor, Roche) (sensitivity 200 copies/ml), and liver histology was assessed using the Ishak scoring system. Results: The median serum HBV DNA level was 1300 copies/ml ( <200-179 × 10 3 copies/ml), 16% of the subjects had no detectable serum HBV DNA and 98% had levels below 105 copies/ml. Histologic lesions were mild (total score <7) in all cases. Loss of HBsAg was observed in three patients, three patients experienced a transient increase in ALT (<2 × upper limit of normal), and serum HBV DNA levels remained stable (1-6 years) in 97% of the 38 patients retested. Conclusions: In our study of inactive HBsAg carriers, the median serum HBV DNA level was 1300 copies/ml, the serum HBV DNA level was below 10 5 copies/ml in 98% of the patients, and remained stable; histological lesions were mild in all cases.