Mutations associated with lamivudine-resistance in therapy-naïve hepatitis B virus (HBV) infected patients with and without HIV co-infection: implications for antiretroviral therapy in HBV and HIV co-infected South African patients.

This was an exploratory study to investigate lamivudine-resistant hepatitis B virus (HBV) strains in selected lamivudine-naïve HBV carriers with and without human immunodeficiency virus (HIV) co-infection in South African patients. Thirty-five lamivudine-naïve HBV infected patients with or without HIV co-infection were studied: 15 chronic HBV mono-infected patients and 20 HBV-HIV co-infected patients. The latter group was further sub-divided into 13 occult HBV (HBsAg-negative) and 7 overt HBV (HBsAg- positive) patients. HBsAg, anti-HBs, anti-HBc, and anti-HIV 1/2 were determined as part of routine diagnosis using Axsym assays (Abbott Laboratories, North Chicago, IL). Serum samples were PCR amplified with HBV reverse transcriptase (RT) primers, followed by direct sequencing across the tyrosine-methionine-aspartate-aspartate (YMDD) motif of the major catalytic region in the C domain of the HBV RT enzyme. HBV viral load was performed with Amplicor HBV Monitor test v2.0 (Roche Diagnostics, Penzberg, Germany). HBV lamivudine-resistant strains were detected in 3 of 15 mono-infected chronic hepatitis B patients and 10 of 20 HBV-HIV co-infected patients. To the best of our knowledge, this constitutes the first report of HBV lamivudine-resistant strains in therapy-naïve HBV-HIV co-infected patients. The HBV viral loads for mono-infected and co-infected patients ranged from 3.32 x 10(2) to 3.82 x 10(7) and <200 to 4.40 x 10(3) copies/ml, respectively. It remains to be seen whether such pre-existing antiviral mutations could result in widespread emergence of HBV resistant strains when lamivudine-containing highly active antiretroviral (ARV) treatment (HAART) regimens become widely applied in South Africa, as this is likely to have potential implications in the management of HBV-HIV co-infected patients.

Selabe SG ，Lukhwareni A ，Song E ，Leeuw YG ，Burnett RJ ，Mphahlele MJ ... -  《JOURNAL OF MEDICAL VIROLOGY》

Mutational patterns of hepatitis B virus genome and clinical outcomes after emergence of drug-resistant variants during lamivudine therapy: analyses of the polymerase gene and full-length sequences.

It remains unclear whether mutational patterns of the hepatitis B virus (HBV) genome are associated with the development of severe hepatitis after the emergence of tyrosine-methionine-aspartate-aspartate (YMDD) variants during lamivudine treatment. Thirty patients with chronic hepatitis B who had YMDD variants during lamivudine therapy and were followed up subsequently while receiving lamivudine alone for at least 6 months were examined retrospectively. The lamivudine resistant mutations in the HBV polymerase gene were detected by a line probe assay, and the full-length sequences of HBV DNA were determined in some patients. Between months 5 and 33 of therapy, mutations from methionine to isoleucine at rt204 (rtM204I) were detected in 18 patients, and mutations from methionine to valine at rt204 (rtM204V) were detected in 12. The rtM204V mutations were always accompanied by mutations from leucine to methionine at rt180 (rtL180M), while rtM204I mutations were not. Baseline characteristics, alanine aminotransferase (ALT) levels, and HBV DNA levels within 6 months after the emergence of YMDD variants did not differ significantly between patients with rtM204I alone and those with rtL180M/rtM204V. No specific mutation was identified on full-length sequence analysis in three patients with a hepatitis flare. During long term follow-up, the addition of rtL180M to rtM204I was found in four patients 7-31 months after detecting the change at rt204 and was linked to increased ALT levels. In conclusion, mutational patterns of HBV DNA at the time of emergence of YMDD variants were apparently unrelated to the clinical outcomes in Japanese patients with chronic hepatitis B during lamivudine therapy.

Enomoto M ，Tamori A ，Kohmoto MT ，Morikawa H ，Habu D ，Sakaguchi H ，Takeda T ，Seki S ，Kawada N ，Shiomi S ，Nishiguchi S ... -  《JOURNAL OF MEDICAL VIROLOGY》

Prevalence and profile of mutations associated with lamivudine therapy in Indian patients with chronic hepatitis B in the surface and polymerase genes of hepatitis B virus.

Lamivudine results in the selection of resistant hepatitis B virus (HBV) variants. Because the surface gene of HBV overlaps completely the polymerase gene, the incidence and profile of surface and polymerase gene mutations were investigated prospectively in chronic HBV patients who were on lamivudine therapy. Twenty-six patients with chronic liver disease confirmed histologically were included in this study. Extracted HBV DNA from sera samples were subjected to PCR amplification for the mutation prone regions of the surface and polymerase genes of the HBV genome. The emergence of mutant forms and biochemical derangements were studied carefully during the course of the therapy. In six of 26 (23%) patients, mutations emerged on lamivudine therapy. YM552I/VDD resistant mutants were observed in one (6%) and five (29%) patients at Month 12 and 18, respectively, out of 17 patients, who had completed more than 9 months of therapy. The mean time of emergence of resistance was 16.4 +/- 6.8 months. In three of the five patients, emergence of YM552I/VDD mutation was accompanied with a rise in HBV DNA levels. In two patients, mutations were noticed at the end of the viral breakthrough; when the DNA level went down to undetectable levels (<0.5 pg/mL). In two patients, normal ALT levels were found at the time of emergence of the YMDD mutation. YM552I/VDD mutations were observed in 43% of HBeAg positive and 20% of anti-HBe positive patients (P = ns). Although the 'a'-determinant region was found to be unaffected; in one patient, a novel pattern due to emergence of YIDD mutant was observed; the corresponding aa in the S-ORF turned to a stop codon. In summary, the frequency of emergence of YM552I/VDD mutations was 29% at Month 18 in the Indian patients. The presence of normal ALT and low levels of HBV DNA do not exclude the existence of resistant mutants. Novel mutations in the S-ORF, which lead to premature surface gene termination might affect the production of HBsAg and need further study.

Wakil SM ，Kazim SN ，Khan LA ，Raisuddin S ，Parvez MK ，Guptan RC ，Thakur V ，Hasnain SE ，Sarin SK ... -  《JOURNAL OF MEDICAL VIROLOGY》

Effect of HIV co-infection on mutation patterns of HBV in patients with lamivudine-resistant chronic hepatitis B.

A retrospective review was performed comparing lamivudine-resistance mutation patterns between patients infected with hepatitis B virus (HBV) with or without human immunodeficiency virus (HIV) co-infection. Medical records that included a genotypic test of patients infected with HBV and treated with lamivudine as the only anti-HBV drug were reviewed. Pol gene mutations were assessed by direct sequencing of the reverse transcriptase fragment 125-213 aa. Eighty-nine patients infected with HBV (29 co-infected with HIV) with rtM204V or rtM204I mutations were included. Multiple mutations associated with the YMDD motif were observed in 33 (55%) of 60 patients infected with HBV only and in 28 (96.6%) of patients co-infected with HIV/HBV. In this latter group, the prevalence of the rtV173L + rtL180M + rtM204V triple mutation was 31% versus a prevalence of 3.4% observed among patients infected with HBV only. All patients with the triple mutational pattern showed sE164D + sI195M changes in the envelope gene. Multivariate analysis demonstrated that HIV co-infection (adjusted OR 11.2, 95% CI 2.0-61.0) and HBV genotype A (adjusted OR 7.2, 95% CI 1.5-34.8) were the only independent variables associated with the chance of harboring rtM204V. Patients with HBV genotype A or HIV co-infection were more likely to harbor the rtM204V mutation. Patients co-infected with HIV showed multiple mutations more frequently, including the triple mutation that may elicit a vaccine escape phenotype. Among patients co-infected with HIV/HBV, strict HBV DNA monitoring is essential to detect treatment failure and adapt therapy to avoid limitations of future therapeutic options or the emergence of a public health threat.

Iacomi F ，Vincenti D ，Vairo F ，Solmone M ，Mariano A ，Piselli P ，Puro V ，Capobianchi MR ，Antonucci G ... -  《-》

Frequent detection of hepatitis B virus variants associated with lamivudine resistance in treated South African patients infected chronically with different HBV genotypes.

Selabe SG ，Song E ，Burnett RJ ，Mphahlele MJ ... -  《-》