[Variants and quasispecies of reverse transcriptase region in polymerase gene of hepatitis B virus during lamivudine treatment].

OBJECTIVE: To investigate the variants and quasispecies of reverse transcriptase region in polymerase gene of hepatitis B virus (HBV) during lamivudine treatment and their relationship with genotypes and viral loads. METHODS: HBV DNA of 117 chronic hepatitis B patients treated with lamivudine were amplified by using PCR. The PCR products including the YMDD motif were sequenced by DNA sequencer, of which, HBV DNA viral loads of 99 patients were determined by real-time PCR and 64 samples were sequenced by Pyrosequencing. RESULTS: In HBV YMDD variant group and no variant group, the HBV genotypes were 79.6% and 86.7% of type C, 18.5% and 12.7% of type B, 1.9% of A/B recombinant type and 2.6% of type D, respectively. The viral loads (log 10) were 6.5699 and 6.6165, respectively. There was no significant difference in HBV genotypes and viral loads between these two groups. The rtL180M variant was found in association with the rtM204I/V variant, HBV variants and wild-type in YMDD motif all existed together in these two groups. CONCLUSIONS: HBV variants (quasispecies) in YMDD motif could be quantified by pyrosequencing, which would be a feasible measure during nucleoside or nucleotide analogue therapy against chronic HBV infection.

[Detection and the production mechanism of antinuclear antibodies (ANA) and anti-liver/kidney microsomal tpe 1 antibodies (anti-LKM1) in patients with chronic hepatitis C].

OBJECTIVE: To investigate the prevalence of antinuclear antibodies (ANA) and anti-liver/ kidney microsomal type 1 antibodies (anti-LKM1) in patients with chronic hepatitis C (CHC)and to explore the mechanism of production of these autoantibodies. METHODS: Serum samples were collected from 360 patients with CHC (case group), 69 patients with chronic hepatitis B (CHB) and 69 patients with autoimmune hepatitis (AIH) (control group). Serum ANA and anti-LKM1 were detected by indirect immunofluorescence (HF) technique and enzyme-linked immunosorbent assay (ELISA), respectively. Multi-factor analysis was performed to explore the correlations of the production of autoantibodies with some factors such as age, sex, viral loads, HCV genotype, biochemical parameters and clinical characteristics. RESULTS: Fifty-four (15%) of 360 patients infected with HCV were positive in autoantibodies. The prevalence of ANA and anti-LKM1 were 12.5% (45/360) and 2.5% (9/ 360), respectively. The positive rate of autoantibodies in patients with CHC was significantly higher than that in patients with CHB (15% vs 2.9%, P = 0.006), but significantly lower than that in patients with AIH (15% vs 47.9%, P < 0.001). Twenty-one (11.35%) of 185 male patients and 33 (18.86%) of 175 female patients were positive in autoantibodies, the difference in positive rate was significant (P < 0.05). HCV virus loads in the autoantibodies negative group were higher than that in the autoantibodies positive group (7.2 x 10(7) copies/L vs 1.23 x 10(7) copies/L, P < 0.05). There were not significant differences in age and genotype between the autoantibody positive group and the autoantibody negative group. The serum biochemical parameters of the autoantibody positive group were similar to those of the autoantibody negative group. The differences were not significant for the course of disease, clinical symptom, the incidence of cirrhosis between the autoantibody positive group and the autoantibody negative group. The prevalence of autoantibodies was not different for patients with or without interferon treatment (P > 0.05). CONCLUSION: Autoantibodies related to AIH can be detected in CHC patients; interferon may not induce the production of autoantibodies; it is very likely that HCV infection induces the autoimmune reaction and the production of autoantibodies.

[Establishment and application of a real-time PCR method to detect hepatitis B virus cccDNA quantitatively].

OBJECTIVE: To establish a new method to detect HBV cccDNA quantitatively and to apply it to detect cccDNA in liver needle biopsy specimens of chronic hepatitis B patients. METHODS: The sequences of HBV DNA genotypes A through G were analyzed. According to the different sequence structure of cccDNA and rcDNA, primes and probe were designed in highly conservative region outside the nick of cccDNA in order to amplify cccDNA but not rcDNA. The best conditions of this method were found after testing experiments. Also we checked its specificity and sensitivity and reproducibility. The products of PCR were sequenced in order to ascertain if it was the right region expected. To amplify with standard plasmid ranged from 10(2) to 10(10) copies/ml to measure the sensitivity and amplify in parallel with standard plasmid of 10(6) copies/ml for 30 replicates so as to measure its reproducibility. DNA was extracted from 32 needle liver biopsy specimens of chronic hepatitis B patients. The cccDNA was quantitatively detected with this method. The data of cccDNA obtained before and after therapy and their relationship with total HBV DNA were analyzed. RESULTS Results of sequencing showed that the PCR product was from the right region. The sensitivity was 10(3)-10(10) copies/ml. The Ct value was 29.69+/-0.31 and the coefficient of variability was 1.04 percent calculated from the data of 30 PCR reactions with standard plasmid. The percentage of decrease in serum HBV DNA, total HBV DNA in liver and cccDNA in liver were 0.49+/-0.17, 0.22+/-0.18 and 0.16+/-0.28 respectively. There is 47 percent-98 percent cccDNA in total HBV DNA in liver and the mean is 81.5 percent. CONCLUSION: The method is good because of the simple and convenient operation, the high specificity, the wide linear detection range and the fine reproducibility. Therefore it can be used for both scientific research and clinical purpose. Lamividine can significantly inhibit serum HBV DNA by, but its inhibitory effect on cccDNA in liver was rather weak.

[Clinical characteristies and distribution of hepatitis B virus genotype and sub-genotype].

OBJECTIVE: To determine the distribution and virologic characteristics of HBV genotypes, sub-type and possible association with the severity of liver disease. METHODS: 884 patients infected with HBV were enrolled from 8 provinces in China. HBV genotype and sub-type was determined, using PCR-RFLP method. RESULTS: The most common HBV genotypes were B (20.77% ) and C (78.22 % ) but only 1 patient showed genotypes D. We found sub-type Ba in patients with genotype B, C1 and C2 sub-type in patients with genotype C. Genotype C (83.62%) and sub-type C2 (90.32%) were predominant in northern China. Patients with genotype B were much younger than those with genotype C. There was no significant difference between patients with sub-type C1 and C2. There was no significant difference in liver function and serum HBV-DNA load between patients with genotype B and C,or between patients with sub type C1 and C2. However, hepatic inflammation and fibrosis score in patients with genotype B were significantly lower than those with genotype C. CONCLUSION: There were no significantly differences in liver function and HBV-DNA load between patients with genotype B and C, or between patients with sub-type C1 and C2. Hepatic inflammation and fibrosis score in patients with genotype B were significantly lower than those with genotype C. Genotype C/sub-type C2 were preponderance in northern China.

Mutations in surface and polymerase gene of chronic hepatitis B patients with coexisting HBsAg and anti-HBs.

AIM: To investigate the clinical significance and presence of mutations in the surface (S) and overlapping polymerase gene of hepatitis B patients with coexisting HBsAg and anti-HBs. METHODS: Twenty-three patients with chronic hepatitis B were studied. Of the 23 patients, 11 were both positive for hepatitis B virus (HBV) surface antigen (HBsAg) and antibody to HBV surface antigen (anti-HBs), 12 were negative for anti-HBs while positive for HBsAg. DNA was extracted from 200 muL serum of the patients. Nucleotide of the surface and overlapping polymerase gene from HBV-infected patients was amplified by PCR, and the PCR products were sequenced. RESULTS: Forty-one mutations were found within the surface gene protein of HBV in 15 patients (10 with coexisting HBsAg and anti-HBs). Six (14.6%) out of 41 mutations were located at "alpha " determinant region in 5 patients (4 positive for HBsAg and anti-HBs). Eleven mutations (26.8%) occurred in the downstream or upstream of "alpha " determinant region. Lamivudine (LMV)-selected mutations were found in three patients who developed anti-HBs, which occurred in amino acid positions (196, 198, 199) of the surface protein and in YMDD motif (M204I/V) of the polymerase protein simultaneously. Presence of these mutations did not relate to changes in ALT and HBV DNA levels. CONCLUSION: Besides mutations in the "alpha " deter-minant region, mutations at downstream or upstream of the "alpha " determinant region may contribute to the development of anti-HBs. These mutations do not block the replicating competency of HBV in the presence of high titer of anti-HBs.