拉米夫定抗乙型肝炎病毒治疗的耐药问题

拉米夫定耐乙型肝炎病毒（HBV）治疗中出现的耐药性与病毒基因变异有关，最常见于YMDD区域变异；拉米夫定耐药性可能诱发病情恶化并伴随HBeAg血清学转换，病毒变异发生率随疗程延长而增加，可能与治疗前HBV DNA及谷再转氨酶水平有关；合理的联合或序贯抗HBV治疗是减少病毒耐药性的可行策略，对于已发生耐药性病人应考虑有效替换治疗，联合治疗或继续拉米夫定治疗，并监测病情发展。     

乙型肝炎病毒拉米夫定耐药的临床监测

我国是病毒性肝炎高发地区 ,以乙型病毒性肝炎为例 ,全国估计有 1 .3亿慢性乙型肝炎病毒(ＨＢＶ)感染者 ,其中约有 2 0 0 0万是需要抗病毒治疗的慢性进展性肝病患者。新近报道的核苷类似物可以抑制ＨＢＶ复制 ,是治疗慢性乙型肝炎的一大突破。拉米夫定是这类核苷类似物的代表性药物 ,对临床慢性乙型肝炎的疗效已经得到充分肯定。拉米夫定长期应用可能发生耐药 ,现就ＨＢＶ拉米夫定耐药相关的问题进行讨论。一、拉米夫定耐药与ＨＢＶ聚合酶基因变异1 996年在临床应用拉米夫定治疗的病例中首次发现ＨＢＶ耐药毒株的存在[1 ] 。目前认为ＨＢＶ…     

基因芯片监测拉米夫定致乙型肝炎病毒耐药突变的临床研究

目的 研究基因芯片技术在监测拉米夫定致乙型肝炎病毒(HBV)耐药突变中的临床意义。方法应用前瞻性方法,对20例经拉米夫定治疗和10例未治疗的乙型肝炎患者观察18个月,以聚合酶链反应扩增血清HBV,应用已研发的4位点拉米夫定耐药检测芯片监测YMDD相关突变。结果 基因芯片技术监测能有效分辨野生型和突变型HBV。HBV的耐药突变随用药时间延长,突变率显著增加(x~2=6.6 9,P<0.01),突变类型以M539V L515M为主,次之为M539I。HBV在YMDD突变后,继续应用拉米夫定对突变型病毒无效。结论 在应用拉米夫定时需要定期检测YMDD突变,常规的HBV DNA定性技术与基因芯片相比,可能会出现结论偏差,后者是最好的方法之一。出现耐药突变后,继续使用拉米夫定对耐药株无效,应停用或更换其它治疗方案。     

拉米夫定耐药后阿德福韦酯治疗应答欠佳患者乙型肝炎病毒耐药变异模式

目的 观察拉米夫定(LAM)耐药后单用或联合阿德福韦酯(ADV)治疗应答欠佳患者HBV耐药变异模式. 方法收集15例LAM耐药后采用ADV治疗病毒学应答欠佳患者的血清,对HBV聚合酶逆转录区进行聚合酶链反应、扩增、克隆、测序,分析与耐药相关的变异模式.组间HBV DNA水平比较采用t检验.结果 单用ADV组检测出A181T+N236T、A181V和A181T 等模式的ADV耐药变异,而联合治疗组中主要检测出M204V+L180M、M204V+L180M+L229V、M204I+L80I和M204V+L180M+V207I等LAM耐药变异模式.另外,在联合治疗组的3份血清中,20%的克隆上同时出现对LAM和恩替卡韦耐药的变异,分别为M204I+L80I+T184I(2/10)、M204V+L180M+T184S(2/10)和M204V+L180M+G173L+S202G(2/10).两组中各有1份未检测出已知耐药变异的血清,在它们的测序结果中发现所有克隆均出现1269L变异,且其中单用组中所有克隆均出现P109S变异.联合治疗组和单用ADV组患者血清HBV DNA水平分别为(3.86±0.85)log10拷贝/ml和(5.71±0.94)log10拷贝/ml,差异有统计学意义(t=3.947,P<0.01).结论 LAM耐药后ADV治疗病毒学应答欠佳的患者中,单用ADV治疗容易筛选出A181T+N236T和A181V/T等ADV耐药变异模式,而联合ADV治疗组仍以M204V+L180M、M204V+L180M+L229V、M204I+L80I和M204V+L180M+V207I等LAM耐药变异模式为主.联合治疗时由于LAM的持续使用可选择出恩替卡韦耐药变异模式T184I/S和S202G;对于部分患者,1269L和P109S变异可能影响ADV治疗应答.     

拉米夫定对湖北地区乙型肝炎病毒基因型的影响

目的研究拉米夫定对湖北地区乙型肝炎病毒基因型的影响及其临床意义。方法采用多对型特异性引物-聚合酶链反应检测160例慢性乙型肝炎患者血清HBV基因型;采用基因芯片技术对86例拉米夫定治疗18个月的慢性乙型肝炎患者进行酪氨酸—蛋氨酸—天冬氨酸—天冬氨酸(YMDD)基序、G1896A、A1814C、A1792T和G1764A单碱基变异检测。结果160例慢性乙型肝炎患者,B基因型127例(79%),C基因型24例(15%),BC混合型9例(6%),未发现A、D和E基因型。拉米夫定治疗的86例患者中,17例(19.7%)发生YMDD变异,B型14例,C型2例,BC混合基因型1例,其中6例发生多重变异,包括B型4例,C型2例;HBeAg/HBeAb血清转换率B型41例(68.3%)高于C型8例(40%)(P<0.05)。另外17例患者,经拉米夫定治疗后,HBVDNA仍阳性,亦未发现YMDD变异株。结论湖北地区HBV存在B、C和BC混合基因型,B型为本地区优势基因型,B型在拉米夫定治疗中更易发生YMDD变异;未变异者,血清HBeAg/HBeAb转换率高。     

340例慢性乙型肝炎患者乙型肝炎病毒多位点耐药相关突变分析

目的 分析慢性乙型肝炎患者HBV逆转录酶基因与核苷(酸)类似物耐药相关的12个位点上的突变情况及其临床意义.方法 提取血清HBV DNA,扩增HBV逆转录酶基因,对PCR产物进行DNA双向测序,对测序成功的样本进行基因型分析.检测逆转录酶基因12个位点上的碱基突变情况,分析不同核苷(酸).类似物使用情况、患者的耐药相关突变情况及不同核苛(酸)类似物耐药的突变形式. 结果 检出拉米夫定耐药突变63例,阿德福韦耐药突变10例,恩替卡韦耐药突变8例,替比夫定耐药突变1例.拉米夫定耐药突变中以M204V和M204I最常见,前者通常伴随L180M突变,后者常单独出现,阿德福韦耐药中以N236T±A181位碱基替换为主;恩替卡韦耐药突变发生在拉米夫定耐药基础上,以T184位碱基替换为主;替比夫定的耐药突变为M204I.少数未接受过核苷(酸)类似物治疗的患者也可检出耐药相关突变.结论 检测HBV逆转录酶基因多位点耐药相关突变,有助于临床及时发现和确认乙型肝炎患者是否存在HBV耐药,合理进行抗病毒治疗.     

基因芯片高通量检测乙型肝炎病毒拉米夫定耐药株及对其突变热点的分析

目的 通过大规模、多位点检测深圳地区拉米夫定耐药株，进一步了解拉米夫定耐药突变的各种分布状况。方法 用基因芯片法对552份乙型肝炎患者血清进行检测，得出l92份拉米夫定耐药突变标本，再对192份耐药标本检测结果进行分析。结果 192份耐药标本中，191份YMDD突变，124份528位点突变，9份555位点突变。YMDD突变中88％为：YVDD、528位点同时突变；YIDD单独突变；YIDD、528位点同时突变。YMDD突变密码子91％为：GTG、ATT；9％为：ATA、ATC。结论 552位点(YMDD)突变为核心突变，528、555位点的突变为协同突变。YVDD突变总是与528位点同时出现；YIDD突变则表现为多样化。YMDD突变密码子约有9％为少见密码子ATA、ATC，这可能是传统聚合酶链反应法检测YMDD突变阳性率较低的原因。     

乙型肝炎病毒拉米夫定耐药株的重组逆转录病毒载体及其包装细胞系的建立

目的构建1.3拷贝乙型肝炎病毒(HBV)拉米夫定耐药株的重组逆转录病毒载体及其包装细胞系。方法在野毒株1.3拷贝HBV载体的基础上采用定点突变的方法将rtL180M,rtM204V位点突变,构建拉米夫定耐药病毒株,并通过PCR、限制性内切酶酶切,分别以正向和反向将野毒株和耐药株分别连接于逆转录病毒载体pLNCX2的相应酶切位点,构建成重组逆转录病毒载体,经双酶切及PCR扩增鉴定。重组载体转染包装细胞,筛选培养细胞克隆并进行病毒滴定。结果通过双酶切、PCR扩增、测序鉴定证实成功构建了1.3拷贝HBV拉米夫定耐药株的逆转录病毒载体。成功建立包装细胞系并测得病毒滴度均为1×105cuf/ml。结论含正向及反向1.3拷贝HBV拉米夫定耐药的重组逆转录病毒载体及其包装细胞系构建成功,可以用于拉米夫定耐药细胞模型研究。     

拉米夫定联合左旋咪唑抗乙型肝炎病毒疗效观察

目的探讨拉米夫定联合左旋咪唑抗乙型肝炎病毒疗效。方法将入选病例随机分为3组。研究组:拉米夫定0.1g,1/d,疗程6个月;左旋咪唑搽剂5ml,涂于双大腿内侧,隔3d涂1次,疗程6个月。对照A组:拉米夫定用法同上,苦参素胶囊0.2g,2/d,疗程6个月。对照B组:拉米夫定用法同上。观察肝功能,HBV血清5项标志,HBV DNA。结果研究组ALT复常率为89.09%,与对照A组(88.37%)比较,无显著性差异(P>0.05),但高于对照B组(66.67%,P<0.01)。研究组ALT复常率、平均天数与2对照组比较,无显著性差异。研究组HBeAg转阴率与对照A组比较,无显著性差异(P>0.05),与对照B组比较,有显著性差异(P<0.05)。研究组HBV DNA阴转率与2对照组比较均有显著性差异(均P<0.01)。结论拉米夫定联用左旋咪唑搽剂在慢性乙型肝炎的ALT复常和HBV DNA阴转方面优于联用苦参素或单用拉米夫定。     

乙型肝炎病毒基因自然变异耐药性的研究

我们用DNA测序法对102例未经核苷(酸)类似物治疗的慢性乙型肝炎(CHB)患者HBV逆转录酶基因的10个突变位点进行了检测分析,现报道如下.一、资料与方法1.研究对象:收集2008年3月-2010年3月天津塘沽传染病医院住院治疗的CHB患者的血清标本.所有患者均符合2000年西安病毒性肝炎学术会议修订的《病毒性肝炎防治方案》诊断标准[1].     

Lamivudine treatment during pregnancy to prevent perinatal transmission of hepatitis B virus infection

Summary.  Vertical transmission of hepatitis B virus (HBV) can occur occasionally despite vaccination of the child. This vaccination breakthrough has been associated with high maternal viraemia. We treated eight highly viraemic (HBV-DNA ≥ 1.2 × 10⁹ geq/mL) mothers with 150 mg of lamivudine daily during the last month of pregnancy. HBV-DNA, hepatitis B surface antigen (HBsAg), anti-HBs and anti-HBc of their offspring were measured at birth and at 3, 6 and 12 months, respectively. Twenty-four children, born to untreated HBsAg-positive mothers with HBV-DNA levels ≥1.2 × 10⁹ geq/mL served as historical controls. All children received passive-active immunization at birth and were followed-up for 12 months. In the lamivudine group one of the eight children (12.5%) was still HBsAg and HBV-DNA positive at the age of 12 months. All other children seroconverted to anti-HBs and maintained seroprotection. In three children, HBV-DNA was temporarily detected by polymerase chain reaction. In the untreated historical control group, perinatal transmission occurred in seven of 25 children (28%). In highly viraemic HBsAg-positive mothers, reduction of viraemia by lamivudine therapy in the last month of pregnancy may be an effective and safe measure to reduce the risk of child vaccination breakthrough. This approach should be evaluated in a large controlled trial.     

Excellent outcome of Lamivudine treatment in patients with chronic renal failure and hepatitis B virus infection

Chronic hepatitis B virus (HBV) is associated with increased morbidity and mortality in patients with chronic renal failure (CRF) and renal transplant recipients. Lamivudine (3TC) has been shown to be a potent inhibitor of HBV replication. It appears to be safe and effective in patients with CRF, though experience is still limited. We describe 4 patients with CRF on hemodialysis who showed a rapid and full response to 3TC, administered for a median of 10 months. All patients had serum alanine transferase (ALT) levels 3 to 6 times the upper limit of normal prior to treatment, and different degrees of histologic inflammatory activity (Knodell score 4 to 8, median 6). All were serum HBsAg- and HBeAg-positive, with serum HBV DNA 1-3.9 x 107 copies/mL (median 1 x 107 copies/mL). Within 4 to 8 weeks of initiation of therapy, HBV DNA became undetectable and serum ALT normalized. Serum HBeAg disappeared in all 4 patients, with the emergence of anti-HBeAb in 3 of them. Three patients also lost HBsAg with the evolution of a protective anti-HBsAb titer. One patient has already undergone successful kidney transplantation with no evidence of HBV recurrence (serum HBV DNA negative) 16 months postoperatively.Although our study sample is small, these data suggest that 3TC can induce a complete biochemical, virological and serological response in patients with CRF and HBV infection. Its use may enable safe kidney transplantation in selected patients.     

Lamivudine for treatment of spontaneous exacerbation and reactivation after immunosuppressive therapy in patients with hepatitis B virus infection

BACKGROUND/AIMS: We evaluated the efficacy of lamivudine therapy for treatment of spontaneous exacerbation and reactivation after immunosuppressive therapy in patients with hepatitis B virus infection. Lamivudine is an effective therapy if used in early stages of both spontaneous exacerbation and reactivation after immunosuppressive therapy. METHODOLOGY: In our study, twelve patients experienced flares of chronic hepatitis B over a three-year period. RESULTS: Three patients whose pretreatment total bilirubin levels were more than 7mg/dL died of fatal liver failure despite lamivudine therapy. CONCLUSIONS: We concluded that if pretreatment serum bilirubin levels are higher than 7 mg/dL, lamivudine therapy alone may be insufficient and more effective therapies should be considered concomitantly with lamivudine.