[Detection of YMDD mutations in hepatitis B virus DNA with the use of allele specific polymerase chain reaction]. / Detektsiia YMDD-mutatsii v DNK virusa gepatita B s pomoshch'iu allel'spetsificheskoi polimeraznoi tseppnoi reaktsii.

Antiviral drug lamivudine has been widely used in the treatment of hepatitis B. However, it was demonstrated recently, that therapy by the drug is related with the selection of viral strains carrying mutations in C-domain of DNA polymerase/reverse transcriptase (YMDD-mutation). The mutation is the cause of resistance to lamivudine. An increase of the mutant population in the course of a long-term lamivudine therapy makes the monotherapy by the discussed drug ineffective. Therefore, the monitoring of YMDD mutations is important in the treatment of chronic hepatitis B (CHB) by lamivudine. The results of using the allele-specific polymerase chain reaction (AS PCR) for the detection of YMDD mutations are presented in the offered case study. Sera from CHB patients were used in research. A system of allele-specific primers was designed for the HBV DNA region from base 720 to base 978, which enabled us to detect possible substitutions in an appropriate ATG-triplet, i.e. the YMDD-mutations locus--positions 741-743 of the HBV DNA nucleotide sequence. The obtained DNA fragments were analyzed by electrophoresis in the agar gel. AS PCR was used to test the sera of HBV patients. Samples were detected, which contained the "wild" virus type, different YMDD mutations and mixed (the "wild" type plus a mutation) HBV variants. It was shown that reliable AS PCR results could be obtained only in those sample, whose HBV titer is no more than 10(6) genome per ml. The offered AS PCR procedure can be applied in the detection of YMDD mutations of HBV DNA in sera of patients with hepatitis B. Sera with a high virus titer must be diluted, prior to testing, to 10(6) genomes per ml. to ensure the reliable AS PCR results.

[Efficacy of lamivudine in HBeAg-negative chronic hepatitis B]. / Effektivnost' lamibudina pri HBeAg-hegativnom khronocheskom gepatite B.

The necessity of the search for new drugs to treat chronic hepatitis B (CHB) is explained by the necessity to prevent hepatic cirrhosis (HC) and hepatocellular carcinoma. Treatment of HBeAg-negative CHB rests on the same principles as of HBeAg-positive one. Efficacy of nucleoside analogue lamivudin is well studied in HBeAg-positive CHB. The aim of this study was to evaluate lamivudine efficacy in therapy of HBeAg-negative CHB. Lamivudine (epivir--150 mg/day or zeffix--100 mg/day) was given for 1 year to 10 patients (5 males, 5 females, mean age 49.5 +/- 13.5). Their blood serum contained no HBeAg but contained HBeAb and HBVDNA. Chronic hepatitis was verified morphologically in 9 patients of whom 2 had HC and 2 developing HC. Moderate activity of the disease was in 4 patients, low--in 5. All the patients had a high ALT level (150 +/- 140 U/l, 60-528 U/l, high normal value 40 U/l). ALT and HBV DNA in the serum were examined by polymerase chain reaction in the course of treatment and for 6 months after its end. To the end of the treatment a complete response (absence of HBVDNA and normalization of ALT) was achieved in 8 (80%) patients. 5 (63%) of them 2-4 months after the end of the treatment had the exacerbation with appearance of HBVDNA in the serum and elevation of ALT level. A persistent response (6 months after lamivudin treatment) was in 3 (30%) patients, in 2 of them HBsAg was not detected. Lamivudin therapy is effective in HBeAg-negative CHB. In this study a high baseline level of ALT was the factor predisposing to a lasting response to treatment.