New amino acid changes in drug resistance sites and HBsAg in hepatitis B virus genotype H.

Long-term treatment with retrotranscriptase (RT) inhibitors eventually leads to the development of drug resistance. Drug-related mutations occur naturally and these can be found in hepatitis B virus (HBV) carriers who have never received antiviral therapy. HBsAg are overlapped with RT domain, thus nucleot(s)ide analogues (NAs) resistance mutations and naturally-occurring mutations can cause amino acid changes in the HBsAg. Twenty-two patients with chronic hepatitis B were enrolled; three of them were previously treated with NAs and 19 were NAs-naïve treated. HBV reverse transcriptase region was sequenced; genotyping and analysis of missense mutations were performed in both RT domain and HBsAg. There was predominance of genotype H. Drug mutations were present in 18.2% of patients. Classical lamivudine resistance mutations (rtM204V/rtL180M) were present in one naïve-treatment patient infected with genotype G. New amino acid changes were identified in drug resistance sites in HBV strains from patients infected with genotype H; rtQ215E was present in two naïve-NAs treatment patients and rtI169M was identified in a patient previously treated with lamivudine. Mutations at sites rt169, rt204, and rt215 resulted in the Y161C, I195M, and C206W mutations at HBsAg. Also, new amino acid changes were identified in B-cell and T-cell epitopes and were more frequent in HBsAg compared to RT domain. In conclusion, new amino acid changes at antiviral resistance sites, B-cell and T-cell epitopes in HBV genotype H were identified in Mexican patients.

Effect of pentoxifylline on levels of pro-inflammatory cytokines during chronic hepatitis C.

The cellular and humoral natural immune response induced by hepatitis C virus (HCV) is commonly unable to eradicate the virus. HCV is a highly mutable, hepatotropic RNA virus that causes acute and chronic hepatitis, an infection that involves the production of various cytokines. The aim of the study is to analyse the expression of pro-inflammatory cytokines IL-1beta, TNF-alpha, IFN-gamma and the chemokine CXCL8 (IL-8) in liver tissue and their expression and secretion in PBMC of patients with chronic hepatitis C (CHC), in response to pentoxyfilline (PTX). We studied six CHC patients, naive to treatment. Patients received PTX 400 mg twice a day/8 weeks. Pentoxyfilline resulted in decreased expression of mRNA of liver IL-1beta, TNF-alpha and IFN-gamma: 144.2 versus 83.5 molecules of IL-1beta (P < 0.05), TNF-alpha 194.3 versus 17.6 molecules (P = 0.03) and IFN-gamma 26.1 versus 0.5 molecules (P = 0.04). Following PTX, PBMC exhibited a decrease in IFN-gamma mRNA 12.2 versus 1.5 molecules (P = 0.028) and CXCL8 4.2 versus 2.5 molecules (P = 0.027). In PBMC, only the secretion of TNF-alpha was decreased 1109 versus 933.5 pg/ml, P = 0.046. Production of cytokines both locally (within the liver) and systemically (PBMC) may serve as biomarkers of the infection with hepatitis C. PTX inhibits the expression of several pro-inflammatory cytokines in the liver. These results indicate that it is worth exploring PTX in hepatitis in future clinical trials in nonresponders to antiviral treatment.

Triple combination of thymalfasin, peginterferon alfa-2a and ribavirin in patients with chronic hepatitis C who have failed prior interferon and ribavirin treatment: 24-week interim results of a pilot study.

Despite steady progress in antiviral treatment for patients with chronic hepatitis C virus (HCV), many patients still have detectable serum HCV RNA levels by the end of interferon-based treatment and are known as virological non-responders. Re-treatment of these patients not responding to previous therapy remains challenging. Studies of the dynamics of the HCV population show a marked decline in new cases since 1996; however, the relative proportion of non-responders is expected to increase over time and, similarly, the number of patients eligible for first-line treatment is expected to decrease. The current standard of care for treatment involves the use of pegylated interferons in combination with ribavirin. However, many difficult-to-treat groups still have low response rates. Newer combinations are being investigated to optimize chances of attaining a sustained response in these groups: one such triple therapy regimen is peginterferon alfa-2a, ribavirin and thymalfasin, which was given to 23 previously non-responder patients. Viral response was 60.8% at week 12 and 47.8% at week 24. These preliminary results encourage further evaluation of this promising combination.

Triple combination of thymalfasin, peginterferon alfa-2a and ribavirin in patients with chronic hepatitis C who have failed prior interferon and ribavirin treatment: 24-week interim results of a pilot study.

Despite steady progress in antiviral treatment for patients with chronic hepatitis C virus(HCV), many patients still have detectable serum HCV RNA levels by the end of interferon-based treatment and are known as virological non-responders. Re-treatment of these patients not responding to previous therapy remains challenging. Studies of the dynamics of the HCV population show a marked decline in new cases since 1996; however, the relative proportion of non-responders is expected to increase over time and, similarly, the number of patients eligible for first-line treatment is expected to decrease. The current standard of care for treatment involves the use of pegylated interferons in combination with ribavirin. However, many difficult-to-treat groups still have low response rates. Newer combinations are being investigated to optimize chances of attaining a sustained response in these groups: one such triple therapy regimen is peginterferon alfa-2a, ribavirin and thymalfasin, which was given to 23 previously non-responder patients. Viral response was 60.8% at week 12 and 47.8% at week 24. These preliminary results encourage further evaluation of this promising combination.

Two years of lamivudine therapy in anti-HBe-positive patients with chronic hepatitis B.

There is no standard therapy for patients with anti-HBe-positive chronic hepatitis B. The aims of this study were to analyse the efficacy of lamivudine therapy for two years in these patients and to study the sequence variations in the precore and polymerase hepatitis B virus (HBV) regions in relation to therapy. Sixteen patients with chronic anti-HBe-positive hepatitis were treated with lamivudine (100 mg) once daily for 2 years. Levels of alanine aminotransferase (ALT), HBV-DNA and HBsAg were monitored during therapy. The polymerase and precore genes were amplified by polymerase chain reaction and their products were sequenced directly. Thirteen of 16 patients (81%) had a virological and biochemical response after 1 year of therapy and 11 (69%) maintained the complete response after 2 years of lamivudine therapy. Among the three patients without initial virological or biochemical response at year 1, prolonging therapy to 2 years was not associated with an increase in the response. YMDD variants were detected in 19% of cases in the first year and in 44% in the second year: YVDD being the most frequent mutations detected during year 1 and YIDD during year 2 of therapy. YMDD variants were found in 7-27% of cases with complete response depending on the duration of therapy. Our results show that prolonging lamivudine therapy is safe, well tolerated and maintains viral inhibition in anti-HBe-positive patients. However, its efficacy tends to decrease overtime and it is associated with an increase in YMDD variants, even in some cases, of complete response.