拉米夫定耐药株感染者HBV基因型和逆转录酶区变异分析

目的了解拉米夫定耐药株感染者HBV基因型特征并分析耐药株HBV逆转录酶（RT）区变异位点和变异类型。方法应用PCR扩增和直接测序HBV逆转录酶区并与Genebank中90株不同基因型野毒株序列进行比较,确定54例耐药株感染者HBV基因型和HBVRT核苷酸的变异特点。结果在54例拉米夫定耐药株感染者中,HBVB基因型占27．78％,C型占70．37％,B／C混合型占1．85％;51例患者出现RT保守区氨基酸变异（包括550和526位氨基酸变异）;18例患者出现除主型区外HBVRT非主型区伴随变异;3例患者未检测到与拉米夫定相关性变异。结论拉米夫定耐药株感染者HBV基因型主要为B型和C型;拉米夫定耐药株的氨基酸变异不仅见于RT区的526和550两个位点,其他位点以及RT非保守区也可发生变异。     

拉米夫定耐药与HBV YMDD变异关系的研究

探讨拉米夫定耐药与HBVYMDD变异之间关系。对拉米夫定治疗的慢性乙型肝炎进行肝功能、乙肝病毒血清学指标、YMDD耐药基因变异检测。 10 2例慢性乙型肝炎血清中 ,HBVDNA阴性 6 3例 (6 1 8% ) ,39例阳性 ,其中HBVYMDD变异 2 2例 ,变异率为 5 6 4 % ,并与用药时间长短有关 ,9- 17个月和 18- 30个月变异检出率分别为5 1 7%和 70 % ,HBVYMDD变异组ALT为 (5 9 94± 8 6 0 )U/L ,显著高于无HBVYMDD变异组的 (5 0 6 0± 6 12 )U/L。基因芯片技术检测HBVYMDD变异有一定的临床意义 ,YMDD变异是HBV对拉米夫定耐药的原因之一。     

乙型肝炎病毒基因型、YMDD变异与拉米夫定治疗后HBV DNA反弹关系的研究

目的探讨HBV基因型、YMDD变异与拉米夫定抗病毒治疗后HBV DNA反弹的关系。方法应用多引物对巢式PCR法、PCR-序列分析法检测拉米夫定治疗的27例乙型肝炎患者和19例从未用过抗病毒治疗的患者HBV基因型和P区（YMDD）的突变位点。结果在27例HBV DNA反弹的患者中，13例（48．15％）检出YMDD变异，而对照人群无YMDD变异（P〈0．05）。YMDD变异的位点为rtM204V／I（C区）±rtL180M（B区）；在治疗组YMDD变异的患者中，B、C基因型构成比（46．15％和59．26％）与对照组（53．85％和68．42％）比较无显著性差异（P〉0．05）。结论YMDD变异是拉米夫定治疗后出现耐药导致HBV DNA反弹的主要原因；YMDD变异的常见位点依然为rtM204V／I（C区）±rtL180M（B区）；YMDD变异在B、C基因型病人中无差别。     

拉米夫定治疗慢性乙型肝炎过程中HBV YMDD变异与临床

目的:探讨拉米夫定治疗慢性乙型肝炎过程中HBV YMDD变异与临床的关系。方法:对应用拉米夫定治疗的19例慢性乙型肝炎患者进行肝功能、乙肝病毒血清学标志物、HBV YMDD变异检测,个别病例进行肝组织病理学检查。结果:ALT异常率为47％,HBeAg血清转换率为15.8％,HBV YMDD变异发生率为25％,肝组织中HBsAg和HBcAg依然阳性。结论:运用拉米夫定治疗慢性乙型肝炎6个月后可出现HBV YMDD变异,随着治疗时间延长,其变异发生率越高;该药远期降酶作用不够理想;HBeAg血清转换率不高;肝组织内仍处于炎症状态。     

乙肝病毒基因型与YMDD变异率的关系

2004年10月～2005年10月,我们对42例应用拉米夫定过程中出现肝功能再次异常及HBV-DNA〉10^5 copies／ml的HBV患者行HBV基因型检测及YMDD变异检测,以探讨二者的关系。现报告如下。     

拉米夫定耐药HBV毒株的RT区序列分析

目的分析拉米夫定耐药HBV毒株部分RT区序列，以了解RT区YMDD基序之外HBV的变异情况。方法采用PCR方法对拉米夫定临床耐药患者治疗前及耐药后血清HBV部分RT区序列进行扩增，扩增的核苷酸片段覆盖HBV RT的B区～E区及S基因“a”决定簇，对PCR产物进行直接测序，将HBV RT区核苷酸和推导的氨基酸序列-与治疗前50株HBV野毒株序列和Genebank中77株不同基因型野毒株序列进行比较，同时对HBV进行血清分型。结果60例患者有YMDD变异，其中26例为adw亚型，占43．33％；34例为adr亚型，占56．67％。另外12例患者(16．67％)未发现YMDD变异。16例患者出现11个RT保守区氨基酸变异(不包括550和526位氨基酸变异)；25例患者出现19个HBVRT非保守区氨基酸变异。结论拉米夫定耐药株的氨基酸变异不仅见于RT B区的526和C区550两个位点，B、C区的其他位点、保守区以及RT非保守区也可发生多个变异。     

海南地区HBV基因分型与YMDD变异

本研究旨在探讨海南地区慢性乙型肝炎病毒发生YMDD变异与基因型之间的关系. 材料和方法 一、病例选择     

秦皇岛市136例慢性乙型肝炎患者拉米夫定的疗效及其与HBV基因型的关系

目的:探讨秦皇岛市慢性乙型肝炎(CHB)患者拉米夫定治疗疗效与基因型的关系。方法:136例CHB患者口服拉米夫定,100mg/次,1次/d,疗程48周,用药前采用PCR方法测定乙型肝炎病毒(HBV)A～D基因型。结果:秦皇岛市CHB患者基因型以C型为主,占75.74%,其次为B基因型占16.91%,B/C混合型占7.35%,B基因型在拉米夫定抗病毒治疗48周时显示HBV DNA阴转率、HBeAg血清转换率、ALT复常率、治疗有效率4方面均高于C型及B/C基因型(P0.05),B基因型HBV感染者有较低的YMDD变异发生率。结论:拉米夫定抗病毒疗效与基因型有关,HBV基因型测定可作为预测拉米夫定抗病毒疗效的指标。     

HBV P基因YMDD变异的检测及临床应用的研究

目的　采用错配PCR扩增方法进行HBVP基因YMDD变异的检测 ,对其临床意义进行初步的研究。方法　应用分子克隆方法 ,构建YMDD、YVDD、YIDD变异的阳性质粒 ,并进行敏感性及特异性试验。对 44例经拉米夫定治疗 1年HBVDNA持续阳性的乙型肝炎患者检测YMDD变异情况。结果　经PCR方法、酶切鉴定及直接测序鉴定出YMDD、YVDD、YIDD质粒构建成功 ,且该方法具有较好的敏感性和特异性。 44例拉米夫定治疗 1年HBVDNA持续阳性的乙型肝炎患者存在YMDD变异 ,半年出现变异 5例 ,变异率为 11 . 3 6%:1年出现变异 7例 ,变异率为 15 . 91%。结论　本检测方法简便、实用 ,抗病毒药物压力是导致HBVYMDD变异的重要因素。     

YSDD: a novel mutation in HBV DNA polymerase confers clinical resistance to lamivudine

The emergence of drug-resistant virus in hepatitis B virus (HBV) patients treated with lamivudine is well documented. In this study, we determined the mutations occurring in the tyrosine-methionine-aspartate-aspartate (YMDD) amino acid motif of the HBV DNA polymerase gene, as well as upstream and downstream of this region, in patients with breakthrough virus during lamivudine therapy. Thirty-one Turkish patients (20 patients HBeAg positive, 11 patients HBeAg negative and anti-HBe positive) with chronic HBV infection who completed at least 104 weeks of lamivudine treatment were investigated. All patients received lamivudine, (150 mg/day), for 104 weeks, with or without 4 months of interferon (IFN) combination. HBV-specific sequences were amplified by polymerase chain reaction (PCR) from sera of patients with breakthrough virus, and the PCR products were directly analysed by sequencing. Breakthrough virus was detected in seven of the 31 patients (22.6%) between 9 and 18 months of therapy. Of the seven patients, six were HBeAg positive at baseline, and four had a double mutation consisting of rtM204V and rtL180M, while two had an rtM204I change. In one patient, two base substitutions at rt204 (ATG --> AGT; T to G and G to T) lead to a methionine to serine change (YMDD --> YSDD). This novel DNA pol mutation was detected at month 18 of lamivudine treatment. In addition, this new variant had the rtL180M mutation and a 12 base pair deletion in the pre-S1 region between nucleotides 43-54. The YSDD mutation was still present 6 months after lamivudine discontinuation. In vitro transfection studies also confirmed that the YSDD strain is resistant to lamivudine. In conclusion, the results indicate that, in addition to a Met --> Val and Met --> Ile change in YMDD, a Met --> Ser change at rt204 (YMDD --> YSDD) associated with the rtL180M change can also emerge during lamivudine treatment, which confers lamivudine resistance in vivo and in vitro, leading to virological breakthrough and ALT increases.     

拉米夫定治疗2年时乙肝病毒的YMDD变异情况

观察核苷类似物拉米夫定治疗慢性乙肝病人２年时ＹＭＤＤ变异情况及其与血清ＨＢＶＤＮＡ，ＡＬＴ水平等指标的关系。第一阶段（１－１２周）为随机、双盲、安慰剂对照研究，７２名ＨＢｓＡｇ．ＨＢｅＡｇ阳性至少６个月，ＨＢＶ－ＤＮＡ阳性的慢性乙肝患者分别口服拉米夫定１００ｍｇ／ｄ（ｎ＝５４）或安慰剂（ｎ＝１８）；第二阶段（１３－１０４周）所有患者均服用拉米夫定 １００ｇ／ｄ。５２周和 １０４周检查病毒的 ＹＭＤＤ变异．其总变异率分别为 １３．７％（８／５８）和 ３９．７％（２３／５８）。１０４周时变异组血清 ＨＢＶＤＮＡ，ＡＬＴ水平高于无变异组（３９４．９±７２７．９比 １６．３±５０．９，Ｐ＝０．００４８；６２．７±５７．９比２６ ４±２７．５，Ｐ＝０．００３），ＨＢＶＤＮＡ阴转率低于未变异组（１７．４％比４８．６％，Ｐ＜０．０５）；服用拉米夫定的慢性乙肝患者的ＹＭＤＤ发生率与服药时间长短有关，血清ＨＢＶＤＮＡ及ＡＬＴ水平与ＹＭＤＤ相关。     

乙肝病毒携带者病毒基因型与肝组织病理变化的关系

目的探讨乙肝病毒(HBV)携带者病毒基因型与肝组织病理变化的关系。方法采用PCR-微板核酸分子杂交-ELISA法检测139例血清HBV DNA阳性的慢性HBV携带者的乙肝病毒基因型,并进行肝组织病理检查,研究病毒基因型与肝组织病理变化的关系。结果139例HBV携带者中感染B基因型42例(30.2),C基因型97例(69.8)。B基因型感染者中肝组织病理正常者5例,符合慢性肝炎轻度34例,中度3例;而C基因型组中肝组织病理正常者仅2例,符合慢性肝炎轻度47例、中度39例、重度5例,肝硬化2例;两组的构成比差异有显著性(P<0.005)。结论对于临床诊断乙肝病毒携带者,感染C基因型者较B基因型者肝组织损伤重。     

乙型肝炎病毒基因型与拉米夫定疗效关系的研究

探讨乙型肝炎病毒(HBV)基因型与拉米夫定治疗慢性乙型肝炎(CHB)疗效的关系。采用PCR、核酸杂交和酶联显色技术对CHB进行HBV基因分型,观察123例(B型93例和C型30例)CHB患者拉米夫定治疗1年后肝功能、病毒学指标和YMDD变异的变化。ALT复常率为92.47%,HBeAg阴转率为27.96%,HBVDNA阴转率为82.80%,有效应答率为89.25%,与C基因型相比差异有显著性(P<0.05或P<0.005)。B型YMDD变异的发生率为9.68%,显著低于C型的26.67%(P<0.05)。B型对拉米夫定的抗病毒疗效高于C型,YMDD变异的发生率则低于C型。HBV基因型是影响拉米夫定疗效和变异的重要因素之一。     

HBV基因型的研究现状与发展趋势探讨

[摘要]?目前研究已知HBV有多种基因型,不同基因型在不同的种族、地域方面分布特点不同且HBV基因型是造成慢性感染自然史差异的原因之一,它们在感染的临床表现和抗病毒治疗的反应中起着重要作用。检测HBV基因型和了解HBV不同基因型对疾病预后的影响,对评估患者疾病结局和指导临床规划最佳治疗方案具有重要意义。　　[关键词]　乙型肝炎病毒;基因型;基因突变;治疗     

Response to long-term lamivudine treatment (up to 5 years) in patients with severe chronic hepatitis B, role of genotype and drug resistance

Lamivudine is effective in suppressing viral replication, normalizing alanine aminotransferase (ALT), and improving histological appearance in HBe positive and negative hepatitis. It is unclear whether hepatitis B virus (HBV) genotype influences the response to lamivudine. We report the long-term response of patients with chronic hepatitis B with and without cirrhosis at baseline treated with lamivudine according to HBV genotype. Retrospective review of charts of all patients treated with lamivudine monotherapy between 1993 and 2002. Response to therapy defined as ALT in the normal range, undetectable HBV DNA, and in the HBeAg positive group loss of HBeAg and/or the development of anti-HBe. HBV DNA measured by the Digene Hybrid capture assay (sensitivity 1.4 x 10(6) copies/mL). YMDD mutation at rtL180M and rtM204V/I measured by restriction digest of amplified products. Genotyping performed by sequencing and phylogenetic tree analysis of the preS region of the virus genome. Seventy-one patients treated with lamivudine for 6 months or more, 53 (75%) were male, average age 47 years, 38 (54%) were HBeAg+ and 33 (46%) HBeAg-. Mean baseline HBV DNA viral titre was 1280.2 copies/mL and 518 copies/mL respectively. Cirrhosis was present in 30 (42%). Sera were examined for YMDD mutations at last patient visit in 61 (86%), and were detected in 45 (74%), there being no association with a particular genotype. Data from up to 5 years on lamivudine indicated no difference in biochemical or virological response between genotypes. Cirrhosis was more prevalent with specific genotypes. We found no influence of HBV genotype on the development of resistance to lamivudine, however liver disease severity was influenced by genotype.     

Adding interferon to lamivudine enhances the early virologic response and reversion of the precore mutation in difficult-to-treat HBV infection

BACKGROUND: The virologic impact of adding interferon to antiviral nucleoside therapy was studied in Japanese patients having perinatally transmitted hepatitis B virus (HBV) genotype C. METHODS: Sixty-four patients including 41 positive for hepatitis B e antigen (HBeAg) were assigned to receive either (1) a combination of interferon-alpha (6 million units daily for 2 weeks, then three times weekly) plus lamivudine (100 mg daily) for 24 weeks followed by lamivudine alone for 28 weeks (n = 30) or (2) 52-week lamivudine monotherapy (n = 34). RESULTS: The combination treatment enhanced the early virologic response, and HBV clearance was more frequent at week 8 for patients with baseline HBV DNA < or = 7 log copies/ml (90% vs. 33%, P = 0.013) and at week 24 for patients with baseline HBV DNA > 7 log copies/ml (75% vs. 40%, P = 0.080). In the combination arm, YMDD mutants emerged less often at week 52 (8% vs. 30%, P = 0.047). However, reversion of the precore mutation was more prominent with combination treatment than with monotherapy (McNemar test, P = 0.014 and P = 0.103, respectively). HBeAg seroconversion (P = 0.429) and sustained off-treatment HBV suppression to < or =5 log copies/ml (log-rank test, P = 0.195) were not improved. CONCLUSIONS: Simultaneous commencement of treatment with interferon and a nucleoside analog may be worthy as a treatment option to augment the early virologic response and prevent drug resistance in difficult-to-treat patients. Combination treatment was also shown to enhance reversion of the precore mutation. Further studies are warranted to clarify the therapeutic implications of this phenomenon.     

拉米夫定治疗慢性乙型肝炎过程中HBV YMDD变异及基因芯片检测

建立乙型肝炎病毒变异基因诊断芯片对拉米夫定治疗慢性乙型肝炎过程中出现的肝炎病毒P基因区YMDD变异进行快速准确的检测方法。设计特异性寡核苷酸探针数组 ,特殊处理芯片载体。用点样法制备乙型肝炎病毒变异基因诊断芯片。在本院住院治疗病人中选择 3 0例服用拉米夫定后 ,可能出现YMDD变异的病人进行基因芯片杂交检测分析 ;同时用PCR直接测序法对上述 3 0例病人血清标本进行双盲HBVDNA聚合酶活性区域测序对照。 3 0例服药后HBVDNA反跳病人中 ,基因芯片测得HBVYMDD变异 2 1例 ,其中YVDD变异 11例。YIDD变异 10例。HBVDNAPCR直接序列测定结果与基因芯片检测结果完全一致。乙型肝炎病毒变异基因诊断芯片可以同时检测YVDD、YIDD变异 ,同PCR直接测序法比较 ,准确率达 10 0 % ,无假阳性     

拉米夫定对免疫受损HBsAg携带者HBV再激活预防和治疗

目的观察拉米夫定对免疫受损宿主HBV再激活的预防和治疗作用。方法将HBsAg阳性免疫受损宿主分为两组：拉米夫定预防组和对照组；预防组在使用免疫抑制剂或细胞毒性化疗之前2～3周开始使用拉米夫定0．1g口服1次／d，进行预防性治疗，对照组在宿主出现HBV再激活表现时开始用相同剂量进行治疗，分别于拉米夫定治疗后或免疫抑制治疗开始后2周、4周、6周、12周、24周检测肝功、HBVM及HBV病毒定量。结果拉米夫定预防组在使用免疫抑制剂或细胞毒性药物过程中或结束后，18．5％（3／16）出现HBV再激活表现；对照组53％（7／13）出现HBV再激活，拉米夫定治疗后71．4％（5／7）病毒转阴，肝功恢复正常，其中2例死于暴发性肝衰竭。结论早期应用拉米夫定可有效预防及治疗免疫受损宿主HBV再激活。