QUANTITATION OF HBV DNA BY REALTIME PCR FOR HBV DETECTION AND FOLLOW-UP VIRAL LOAD IN PATIENTS WITH CHRONICHBV HEPATITIS USING ANTIVIRAL DRUGS

Background: Real-time PCR assay has been routinely used in many laboratories for HBV determination and follow –up of the HBV DNA levels in serum of chronic HBV patients during antiviral therapy. We used a commercialized real-time PCR procedure based on TaqMan chemistry to quantify HBV DNA levels from patients with chronic HBV hepatitis for HBV detection and monitoring HBV DNA during antiviral drug using. Materials and method: This study was carried out in 56 patients with chronic HBV hepatitis using antiviral drugs. A commercialized real-time PCR assay based on TaqMan chemistry was used to quantify HBV DNA concentration in double serum samples from each patient, the first sample was collected at the first quantificative testing and the second sample was collected for a follow-up in 6 or 9 months of interval. The assay has a dymnamic range from 3 x 102 copies/ml at minimun level to 1010copies /ml. Sample testing was always run with triple dilutions of standard, the HBV DNA quantitations were analysed by Stratagene software and calculated in number of copies per ml of serum sample. Results: The HBV DNA levels in all the first serum samples had a wide range from 3x102 to 1010 copies/ml, of these first samples there were 30% (17/56) with the highest levels from 108 to 1010copies/ml and there was no sample negative for HBV DNA. With the second serum samples, there were 23,2% (13/56) underdetectable for HBV DNA and the sample percentage with the highest HBV DNA levels was only 5,3% (3/56). The HBV DNA levels at the second serum samples were lower in 44 patients (78%) and were higher in 12 patients (21,4%) in comparision with that of the first samples. The average amounts of HBV DNA decrease in patients using antiviral drugs were 2,3 x 108 copies/ml with adefovir and 4,2 x108 copies/ml with lamivudine, and the average numbers of HBV DNA increase were 1,4 x 108 copies/ml with lamivudine and 7,5 x 107 copies/ml with entecavir. Conclusions: Real-time PCR assay was found to be very useful in quantification of HBV DNA level in chronic HBV patients and also for monitoring the therapeutic effects of antiviral drugs.