Analysis Of Drug-resistant Mutations Of HBV And Factors Affecting Mutations In Patients With Chronic Hepatitis B From Qingdao Area

Objective: To analyze the drug-resistant mutations in reverse transcriptase(RT) region of P gene in hepatitis B virus(HBV) genome and investigate the factors affecting mutations in HBV-infected patients receiving nucleos(t)ide analogue therapy.Methods: A total of 326 serum samples were obtained from chronic hepatitis B patients receiving nucleos(t)ide analogue therapy from August, 2012 to August, 2013 in Qingdao Infection Diseases Hospital. The nine classical antiviral drug-resistant mutations in RT region of P gene, including I169 T, V173 L, A181V/T, T184A/G/I/S, S202G/I, N236 T, M250 V, L180 M and M204V/I/S, were assayed by pyrosequencing. The baseline levels of HBs Ag, HBe Ag, HBs Ab, HBe Ab, HBV DNA, alanine aminotransferase(ALT) and aspartate aminotransferase(AST) in serum were detected and their correlations with drug-resistant mutations were analyzed.Results: 1.The drug-resistant mutations were found in 70 cases(21.5%) of 326 samples. All the nine drug-resistant sites showed mutations, with the highest incidence in L180 M, followed by M204V/I, accounting for 11.7%(38/326) and 11.3%(37/326) of the samples, respectively. Twenty-six mutation patterns were found in 70 cases with mutations. Among them, 33(47.4%, 33/70) and 37(52.6%, 37/70) samples showed single-site and multi-site mutations, respectively, and 41(58.6%, 41/70) samples demonstrated multi-drug resistant mutations. 2.The incidence of resistant mutations related to lamivudine was highest, accounting for 70%(49/70) of 70 samples with mutations, in which L180M(18.4%, 9/49) and L180M+M204V/I(18.4%, 9/49) were the most common mutation patterns. The mutations related to entecavir were often companied with mutations related to lamivudine, and L180 M was most common(24.3%, 9/37). The incidence of mutations related to adefovir dipivoxil was 31.4%(22/70), in which N236 T was most common(40.9%, 9/22). 3.There were no significant differences of the levels of HBe Ag, HBs Ab, HBe Ab, ALT and AST between the mutation group and the non-mutation group(P>0.05), while the levels of HBs Ag and HBV DNA in mutation group were significantly higher than those in non-mutation group(P<0.05). Positive correlation was found between the level of HBs Ag or HBV DNA with drug-resistant mutations(HBs Ag, OR=3.228, 95%CI 1.712-6.086; HBV DNA, OR=5.717, 95%CI 3.005-10.876).Conclusions: 1.L180 M and M204V/I are most common drug-resistant mutations in RT region of HBV in Qingdao area, and the incidence of mutations related to lamivudine is highest. With the extensive use of various antiviral drugs, the patterns of drug-resistant mutations are complex with increasing multi-drug resistance. 2.The level of HBs Ag or HBV DNA in serum is correlated with viral mutation; therefore, attentions should be paid to the occurrence of drug resistant mutations in patients with higher level of HBs Ag or HBV DNA.