Natural YMDD-motif mutants affect clinical course of lamivudine in chronic hepatitis B.

AIM: To investigate the prevalence of nature tyrosine-methionine-aspartic acid-aspartic acid motif mutations in chronic hepatitis B (CHB) patients and to evaluate the efficacy of lamivudine. METHODS: A total of 1268 CHB patients were recruited from the outpatient and inpatient departments of six centers. Tyrosine-methionine-aspartic acid-aspartic acid (YMDD) mutations were analyzed using the hepatitis B virus (HBV) drug resistance line probe assay. Forty voluntary patients were selected from those with positive or negative natural YMDD mutations to undergo treatment with lamivudine. RESULTS: YMDD mutations were detected in 288 (22.71%) of the 1268 CHB patients. Multivariate analysis revealed that the patients' HBV DNA level (P=0.0282) and hepatitis B e antigen status (P=0.0133) were also associated with natural YMDD mutations. The rates of normalization of alanine aminotransferase levels and HBV DNA nondetection at 6, 24, 36, and 48 wk were compared between the patients with natural YMDD mutations and those without, and the differences were not significant. However, there was a significant difference in the cumulative emergence rates of virological breakthrough at 48 wk in the patients with natural YMDD mutations and those without (32.5% vs 12.5%, P=0.032). CONCLUSION: Naturally occurring YMDD mutations are detectable in a large proportion of CHB patients; breakthrough hepatitis tended to occur in patients with natural YMDD mutations.

YMDD motif mutations in chronic hepatitis B antiviral treatment naïve patients: a multi-center study.

OBJECTIVE: This study aimed to determine the natural prevalence of variants of tyrosine-methionine-aspartic acid-aspartic acid (YMDD) motif in patients with chronic hepatitis B (CHB), and to explore its relation with demographic and clinical features, hepatitis B virus (HBV) genotypes, and HBV DNA levels. METHODS: A total of 1,042 antiviral treatment naïve CHB patients (including with lamivudine [LAM]) in the past year were recruited from outpatient and inpatient departments of six centers from December 2008 to June 2010. YMDD variants were analyzed using the HBV drug resistance line probe assay (Inno-Lipa HBV-DR). HBV genotypes were detected with polymerase chain reaction (PCR) microcosmic nucleic acid cross-ELISA, and HBV deoxyribonucleic acid (DNA) was quantitated with real-time PCR. All serum samples underwent tests for HBV, HCV, and HDV with ELISA. RESULTS: YMDD variants were detected in 23.3% (243/1042) of CHB patients. YMDD mutation was accompanied by L180M mutation in 154 (76.9%) patients. Both wild-type HBV and YMDD variant HBV were present in 231 of 243 patients. Interestingly, 12 patients had only YIDD and/or YVDD variants without wild YMDD motif. In addition, 27.2% (98/359) of HbeAg-positive patients had YMDD mutations, which was higher than that in HbeAg-negative patients (21.2%, 145/683). The incidence of YMDD varied among patients with different HBV genotypes, but the difference was not significant. Moreover, the incidence of YMDD in patients with high HBV DNA level was significantly higher than that in those with low HBV DNA level. CONCLUSION: Mutation of YMDD motif was detectable at a high rate in CHB patients in this study. The incidence of YMDD may be correlated with HBeAg and HBV DNA level.

YMDD motif mutations in chronic hepatitis B antiviral treatment naïve patients: a multi-center study

OBJECTIVE: This study aimed to determine the natural prevalence of variants of tyrosine-methionine-aspartic acid-aspartic acid (YMDD) motif in patients with chronic hepatitis B (CHB), and to explore its relation with demographic and clinical features, hepatitis B virus (HBV) genotypes, and HBV DNA levels. METHODS: A total of 1,042 antiviral treatment naïve CHB patients (including with lamivudine [LAM]) in the past year were recruited from outpatient and inpatient departments of six centers from December 2008 to June 2010. YMDD variants were analyzed using the HBV drug resistance line probe assay (Inno-Lipa HBV-DR). HBV genotypes were detected with polymerase chain reaction (PCR) microcosmic nucleic acid cross-ELISA, and HBV deoxyribonucleic acid (DNA) was quantitated with real-time PCR. All serum samples underwent tests for HBV, HCV, and HDV with ELISA. RESULTS: YMDD variants were detected in 23.3% (243/1042) of CHB patients. YMDD mutation was accompanied by L180M mutation in 154 (76.9%) patients. Both wild-type HBV and YMDD variant HBV were present in 231 of 243 patients. Interestingly, 12 patients had only YIDD and/or YVDD variants without wild YMDD motif. In addition, 27.2% (98/359) of HbeAg-positive patients had YMDD mutations, which was higher than that in HbeAg-negative patients (21.2%, 145/683). The incidence of YMDD varied among patients with different HBV genotypes, but the difference was not significant. Moreover, the incidence of YMDD in patients with high HBV DNA level was significantly higher than that in those with low HBV DNA level. CONCLUSION: Mutation of YMDD motif was detectable at a high rate in CHB patients in this study. The incidence of YMDD may be correlated with HBeAg and HBV DNA level.