阿德福韦酯治疗慢性乙型肝炎的耐药性分析

Dissection of mechanism for the adefovir dipivoxil resistance in chronic hepatitis B patients

目的探讨阿德福韦酯治疗慢性乙型肝炎耐药性产生的原因。方法从阿德福韦酯Ⅲ期临床试验中筛选出30例原发治疗失败或继发耐药患者，应用巢式逆转录聚合酶链反应扩增HBVRT区，比对RT区核苷酸及氨基酸序列，找出变异位点。结果30株阿德福韦酯治疗失败者中有21株HBV表现出原发性耐药，其中5株具有多态性位点rtN118H（23．8％，5／21）。另外9株发生继发性耐药，继发耐药毒株在RT保守区（C结构域rtM207V）和非保守区多个区域均有变异。没有发现典型的rtN236T和rtA181V／T突变。结论多态性位点rtN118H与阿德福韦酯原发耐药可能有关。HBVRTC结构域rtM207V变异及其他处于非保守区的变异可能与HBV继发性耐药有关，天然耐药准种的存在可能是HBV对阿德福韦酯迅速耐药（继发性）的基础。上述结论有待进一步表型验证实验加以证实。

Objective To explore the mechanism for adefovir dipivoxil （ADV） resistance occurred in chronic hepatitis B patients of a series of phase In clinical trails. Methods 30 resistant HBV strains were selected out from 177 cases of ADV treated chronic hepatitis B patients. HBV polymerase RT region were amplified by nested PCR and analyzed with the standard neucleiotide sequence of HBV strains deposited in GeneBank. Results 21 out of 30 HBV strains were primary resistant strains, among them 5 HBV strains （23.8%, 5/21） had the polymorphism site of rtN118H. While the other 9 HBV strains showed secondary resistance, variations in conservative region C （rtM207V） and other non-conservative regions were found. The classic mutation sites such as rtN236T and rtA 181V/T were not found. Conclusions Polymorphism site of rtN118H might be responsible for HBV primary resistance to ADV therapy, rtM207V variation in HBV RT C domain and other variation sites might play a role in HBV secondary resistance to ADV treatment, and natural resistant quasispecies may be the basis for the ADV quick resistance. These conclusions await further confirmation by phenotype test.