慢性乙型肝炎病毒基因型与YMDD变异关系

目的探讨慢性乙型肝炎病毒(HBV)基因型与YMDD变异的关系.方法选用200例HBV DNA、HbeAg阳性,血清ALT异常的HBV肝炎患者,服拉米夫定(100mg/d)24个月.用PCR(FQ-PCR)检测HBV DNA,分析乙肝病毒野生型YMDD及突变耐药型YIDD/YVDD,HBV基因分型.结果200例慢性乙肝病人C基因型占39%,B基因型占26%,D基因型占22%,B+C混合基因型占10%,其他占3%,包括1例出现YIDD耐药株.服拉米夫定12个月后,YMDD变异率为6%;24个月后,YMDD变异率为15%.结论乙肝病人HBV基因型以C型为主,次为B型及D型;服拉米夫定后大多数病人的DNA水平明显降低,拉米夫定治疗可加速病毒YMDD变异发生,且与服药时间呈正相关;YMDD突变与乙肝病毒的基因型无关.     

慢性乙型肝炎病毒基因型与YMDD变异关系

目的 探讨慢性乙型肝炎病毒（HBV）基因型与YMDD变异的关系。方法 选用200例HBV DNA、HbeAg阳性，血清ALT异常的．HBV肝炎患者，服拉米夫定（100mg／d）24个月。用PCR（FQ-PCR）检测HBVDNA，分析乙肝病毒野生型YMDD及突变耐药型YIDD／YVDD，HBV基因分型。结果 200例慢性乙肝病人C基因型占39％，B基因型占26％，D基因型占22％，B＋C混合基因型占10％，其他占3％，包括1例出现YIDD耐药株。服拉米夫定12个月后，YMDD变异率为6％；24个月后，YMDD变异率为15％。结论 乙肝病人HBV基因型以C型为主，次为B型及D型；服拉米夫定后大多数病人的DNA水平日月显降低，拉米夫定治疗可加速病毒YMDD变异发生，且与服药时间呈正相关；YMDD突变与乙肝病毒的基因型无关。     

抗病毒治疗对乙型肝炎相关慢加急性肝衰竭患者短期生存率的影响

目的 探讨抗病毒治疗对乙型肝炎相关慢加急性肝衰竭患者短期转归的影响.方法 348例乙型肝炎相关慢加急性肝衰竭患者,分为常规治疗组及抗病毒治疗组,抗病毒组在常规内科治疗基础上加用抗病毒药物治疗(拉米夫定、恩替卡韦、替比夫定),比较两组患者临床特征、生存率及抗病毒治疗短期疗效差异.其中低病毒载量组173例(HBV DNA<105拷贝/ml)、高病毒载量组175例(HBV DNA≥105拷贝/ml).结果 多因素Cox回归分析表明抗病毒治疗是影响预后的有利因素.观察24周,抗病毒治疗的乙型肝炎相关慢加急性肝衰竭患者生存率高于常规治疗者(X~2=32.865,P=0.000).在治疗4周存活患者中,抗病毒治疗组的血清总胆红素水平(Tbil)及HBV DNA降幅就高于常规治疗组,比较差异有统计学意义(P<0.05).治疗24周,低病毒载量及高病毒载量患者抗病毒治疗组的生存率均高于常规治疗组,比较差异有统计学意义(P<0.05).结论 抗病毒治疗可提高乙型肝炎相关慢加急性肝衰竭患者的生存率,低病毒载量患者也需抗病毒治疗.     

慢性乙肝患儿HBV基因型与乙肝病毒大蛋白关系探讨

目的 探讨慢性乙型肝炎患儿HBV基因型与乙肝病毒大蛋白的关系.方法 采用实时荧光PCR法和ELISA法分别检测138例处于乙肝病毒活动期的慢性乙型肝炎患儿血清中的HBV DNA和乙肝病毒大蛋白并鉴定其基因型.结果 乙肝病毒大蛋白吸光度与HBV DNA载量存在正相关（r=0.85,P＜0.05）;HBV基因B型与HBV基因C型的ALT水平、乙肝病毒大蛋白吸光度和HBVDNA载量差异无统计学意义（P＞0.05,P＞0.05,P＞0.05）.结论 乙肝病毒大蛋白水平与HBVDNA载量具有良好的正相关性,表明乙肝病毒活动期的慢性乙肝患者体内乙肝病毒大蛋白与病毒复制程度密切相关,乙肝病毒基因型与乙肝病毒大蛋白无关.     

北京市部分艾滋病患者的耐药性分析及对抗病毒治疗效果的影响

目的了解北京市部分艾滋病患者抗病毒治疗后耐药发生情况及其对抗病毒治疗效果的影响。方法以北京市部分未经抗病毒治疗的艾滋病患者（17人）以及经抗病毒治疗的患者（51人）为研究对象，通过问卷调查了解一般情况、服药方案、服药依从性及抗病毒治疗前后的临床表现等。同时采集10ml EDTA抗凝静脉血，检测CD4／CD8细胞数、病毒载量及基因型耐药性。结果未服药患者耐药性突变位点主要有118位密码子；服药患者耐药性突变位点和突变的频次显著增加，发生率大于10％的突变位点有103位、118位、151位、181位、184位和190位密码子，并发现TAM突变（M41L、K70R）和Q151复合体突变（A62V、V751、F77L、F116Y和Q151M）。病毒耐药谱表现为出现对非核苷类逆转录酶抑制剂（NNRTI）类药物（DLV、EFV和NVP）和核苷类逆转录酶抑制剂（NRTI）类药物（AZT、DDI、IMT、OOC）具有高度耐药性的毒株，及对NRTI和蛋白酶抑制剂（PI）具有中度和低度耐药性的毒株。未服药人群的耐药性毒株的流行率为6．7％，服药患者为45．0％，交叉耐药和多重耐药严重。抗病毒治疗后没有发生耐药患者病毒载量对数的平均值为1．9 log（拷贝／m1），明显低于耐药组病人的3．8 log（拷贝／m1）。结论北京市部分HIV感染者耐药性毒株的流行已经达到较高的水平，并且多重耐药严重。耐药发生后影响治疗效果，规范治疗及提高服药依从性是治疗取得良好效果的重要因素。     

河南省长期接受抗病毒治疗的艾滋病患者耐药横断面分析

目的 阐明河南省长期接受艾滋病抗病毒治疗患者的耐药情况,为这类患者继续有效的治疗提供参考依据.方法 抽取河南省两个艾滋病重点县中2004年左右开始接受一线抗病毒治疗的艾滋病患者,进行CD4+T淋巴细胞、病毒载量和基因型耐药检测.结果 两个县共抽取164例艾滋病患者,这些患者的CD4+T淋巴细胞计数的中位数(四分位数)为398.00(242.00 ～489.50)个/μl,有32.32％的患者体内检测不到病毒.有95例患者的病毒载量大于1000拷贝/ml,其中的77例患者完成了耐药检测.在这77例患者中,有耐药突变(任意一种)发生的患者占到68.83％,其中NNRTIs类突变较高为64.94％,NRTIs类突变为55.84％,无PIs类突变发生.NNRTIs类耐药突变中发生最多的是K103N/S(44.16％),其次为G190A/S(19.48％)和Y181C/V(14.29％).NRTIs类耐药突变中发生最多的是胸苷类似物突变(thymidine analogue mutations,TAMs),≥1TAM占46.75％,TAM-1/TAM-2占24.68％,M184V/I为24.68％.77例患者中,对NRTIs类药物ddI、3TC、AZT、D4T和TDF产生耐药的患者分别占50.65％、33.77％、48.05％、50.65％和46.75％.对NNRTIs类药物EFV、NVP和DLV产生耐药的患者分别占64.94％、64.94％和62.34％.结论 河南省长期接受抗病毒治疗的艾滋病患者的耐药情况严峻,需要对这部分患者重点关注并及时调整治疗方案.     

HBV拉米夫定耐药株及BCP、Pre-C突变株芯片检测方法的应用研究

目的 构建针对HBV拉米夫定耐药株及c区启动子(basal core promoter,BCP)、前C区(Pre-C)突变株,多位点突变的基因芯片检测方法.并与DNA测序法比较,以了解该芯片的灵敏度、特异性、稳定性等性能并初步应用于临床实践.方法 该基因芯片能对HBV DNA及P区(DNA多聚酶区):180、204、207三个拉米夫定耐药突变位点;C区启动子(basal core promoter,BCP)及前C区(Pre-C):nt1896、nt1899、nt1862、nt1764、nt1762 5个突变热点,共8个HBV突变位点进行检测,并用测序法对该基因芯片进行验证.结果 ①检测HBV DNA方面,两种方法检测结果100%相符.②检测突变位点方面:总体统计32份阳性血清共有256(32×8)个突变位点.两种方法检测结果有251个突变位点完全相符;5个突变位点不完全相符,基因芯片法检测为混合型,测序法检测为野生型或突变型之一.结论 结果提示该基因芯片和DNA测序法检测结果阳性率无差异,特异性与DNA测序法相当,检测混合株有更大优势.     

拉米夫定耐药毒株的P基因序列特点

目的探讨拉米夫定耐药毒株P基因序列特点。方法分析247例慢性乙型肝炎患者血清标本,利用PCR-RFLP筛检YMDD变异株,对YMDD变异阳性的部分患者标本进行P基因测序。结果应用PCR-RFLP筛检发现了42例感染YMDD变异株的患者,对其中的19例患者进行测序分析有10例除发生YMDD变异外还有P基因A-E区其他部位氨基酸的突变,有4种点突变同时在2个以上的患者中发生,包括rtL80I,rtG172E,rtG174C和rtG172E/rtG174C联合突变。结论拉米夫定耐药毒株除了常见的C区YMDD变异和B区rtL180M变异之外,还可以发生其他位点的突变,但这些位点的突变是否与拉米夫定耐药有直接关系还有待进一步证实。     

体外无药物选择压力条件下HIV-1耐药基因突变的演变

目的 分离培养体外稳定传代的原代HIV-1耐药毒株,观察失去药物压力下,耐药毒株的体外生长以及主要耐药突变的演化趋势.方法 采集15例服用拉米夫定+司他夫定+萘韦拉平(3TC+D4T+NVP)的HIV-1感染者的外周血单个核细胞(PBMC),用体外共培养的方法从中分离原代HIV-1毒株;RT-PCR扩增耐药毒株历代培养上清的HIV-1 pol区基因并测序,在Stanford HIV Drug Resistance Database数据库进行耐药性分析.结果 15例患者中病毒载量>1000拷贝/ml的有8例,均成功分离出稳定传代的原代毒株,其中2株为耐药毒株,所携带的主要耐药突变分别是K103N/K238T和M184V/K103N/Y181C/H221Y,分别对NVP和3TC/NVP高度耐药;无药物压力的体外培养过程中,M184V、K103N、Y181C和H221Y等耐药突变可以稳定传代,但是K238T发生了回复突变.结论 分离出2株稳定传代的HIV-1耐药毒株,无药物压力情况下,携带K103N突变的毒株具有较好的复制适应性,可稳定传代;携带M184V和K103N/Y181C/H221Y的毒株也能够稳定复制;本研究中发现K238T耐药突变在失去药物的条件下稳定性差,提示该位点易发生回复突变.     

阿德福韦酯抗乙肝病毒治疗进展

慢性乙型肝炎是我国乃至世界突出的公共卫生健康问题.抗病毒治疗是慢性乙肝治疗的主要手段,既往主要是干扰素（interferon,IFN）和拉米夫定（lamivudine,3TC）.IFN由于副作用较多、耐受性差而限制了其使用;3TC虽然耐受性和安全性都良好,但长期使用会病毒变异以每年14～32%逐年递增,并且停药后病毒学和生化指标反跳,因而其临床价值也受限制.最近,一种新的核苷类似物-阿德福韦酯（Adefovir dipivoxil,ADV）获得美国等多国FDA批准用于慢性乙肝的治疗.ADV是一种口服制剂,通过与dATP竞争逆转录酶结合位点,结合并阻断DNA链的延伸而抑制病毒的复制.临床观察提示它对慢性乙肝代偿期和失代偿期及3TC耐药均有效.与3TC比较,它具有耐药变异出现晚、耐药发生率低、变异株对ADV药敏性轻微下降等优点.本文就ADV抗乙肝病毒治疗,从药理、临床疗效、耐药变异等进行综述.     

Detection of YMDD motif mutants by oligonucleotide chips in lamivudine-untreated patients with chronic hepatitis B virus infection

Lamivudine, a nucleoside analogue, has been used widely as an effective antiviral agent for the treatment of patients with chronic hepatitis B virus (HBV) infection. However, the YMDD motif mutation of HBV polymerase resistant to lamivudine occurs very frequently after long term therapy. We developed an oligonucleotide chip for the detection of YMDD motif mutants resistant to lamivudine and investigated the prevalence of the mutants in patients with chronic HBV infection who had not been treated by lamivudine before. Forty patients who had not been treated with lamivudine were included in this study. Serum samples were tested by the oligonucleotide chips designed for detection of wild-type YMDD motif, M552V and M552I. Samples were confirmed by restriction fragment length polymorphism (RFLP) and direct sequencing. M552I mutants were detected by the oligonucleotide chips in 7.5% (3/40) of chronic HBV infected patients (2 chronic hepatitis and 1 cirrhosis). The results were in accordance with those of RFLP. YMDD motif mutants occur as natural genome variabilities in patients with chronic HBV infection who had not been treated with lamivudine before. Oligonucleotide chip technology is a reliable and useful diagnostic tool for the detection of mutants resistant to antiviral therapy in chronic HBV infection.     

PCR-RFLP结合克隆测序监测乙肝病毒拉米夫定耐药突变株的产生

目的 建立PCR结合酶切的方法监测慢性乙型肝炎患者体内拉米夫定耐药突变株的产生,并与PCR产物克隆后测序相结合。了解此方法的可靠性和可行性,同时用此方法筛查50例应用拉米夫定治疗的慢性乙型肝炎患者中耐药株的发生情况。方法 拉米夫定治疗的慢性乙型肝炎患者50例,治疗时间9个月-24个月,设计错配PCR结合限制性片段长度多态性方法,快速检测患者体内乙型肝炎病毒（HBV）酪氨酸-蛋氨酸-天门冬氨酸-天门冬氨酸（Tyrosine-Methionine-Aspartic acid-Aspartic acid,YMDD)变异株的发生情况,对筛检耐药株阳性的标本应用PCR产物克隆后测序加以证实。结果 在50例服用拉米夫定患者中发现9斧正患者在用药超过9个月时出现拉米夫定耐药突变株（YMDD变异株）,其中YIDD变异5例,YVDD变异4例,后者有3例合并有1526M突变。结论 本方法在检测YMDD变异方面具人快速简便的特点,经克隆后测序证实,具有较好的可靠性。     

Emergence of YMDD motif mutants of hepatitis B virus during lamivudine treatment of immunocompetent type B hepatitis patients

Lamivudine is an effective antiviral agent for the treatment of chronic type B hepatitis. Recent studies have shown the appearance of lamivudine resistant viruses with mutations at the tyrosine-methionine-aspartate-aspartate (YMDD) motif of the viral polymerase in hepatitis B virus (HBV) infected patients who received orthotopic liver transplantation. In order to confirm the appearance of such mutant HBV in immunocompetent patients, the HBV sequences in and around the YMDD motif of HBV DNA polymerase were examined in the sera from 16 lamivudine treated and 10 untreated control patients. Approximately 200 bases including the YMDD motif of HBV DNA polymerase were amplified by polymerase chain reaction (PCR) and sequenced directly by an automated sequencer. Of the 16 patients receiving lamivudine, mutant viruses with mutations in the YMDD motif were found in 3 of 8 patients treated with lamivudine for 52 weeks. However, this mutation was not found in any of the 8 patients treated for 32 weeks or a shorter period. Mutant viruses appeared after 40 weeks of treatment and were undetectable within 12 weeks after the cessation of the treatment. Such mutant viruses were not detected in any of the 10 untreated patients. This study confirms the emergence of YMDD mutant viruses during long-term lamivudine treatment in immunocompetent type B hepatitis patients. The results from this study suggest the need for combination therapies to reduce the levels of such mutant viruses in some patients.     

Clinical and virological characteristics of lamivudine resistance in chronic hepatitis B patients: a single center experience

We have investigated the characteristics of lamivudine-resistant strains in patients with chronic hepatitis B in Guangdong, China, where the predominant genotypes are B and C. Two hundred forty-seven patients treated with lamivudine in Nanfang Hospital were followed-up. Patients with hepatitis B e antigen (HBeAg) positive and hepatitis B virus (HBV)-DNA levels over 7.5 x 10(6) copies/ml at baseline had a shorter time to the selection of YMDD mutant (P = 0.02 and 0.00, respectively). The detection of YMDD mutant precedes HBV-DNA breakthrough and alanine transaminase (ALT) flare in about 2 and 3 months, respectively. The ALT flare after the appearance of YMDD mutants was more evident in HBeAg positive patients than HBeAg negative patients (P = 0.02). After emergence of YMDD mutant, the HBV-DNA level was significantly higher in genotype C patients compared with genotype B patients (P = 0.02). No significant difference of YMDD mutant pattern was found between patients with genotype B and C. Four kinds of new mutants were found in over two patients including rtL80I, rtG172E, rtG174C, and rtG172E/rtG174C. In vitro transfection and real-time analysis showed that rtG172E, rtG174C, and rtG172E/rtG174C mutants had a decreased replication competence compared with wild type (33%, 27%, and 15% of the wild type HBV, respectively). Our result suggest that genotypic monitoring of YMDD mutant is important for the management of patients treated with lamivudine.     

Evolution of viral load and changes of polymerase and precore/core promoter sequences in lamivudine-resistant hepatitis B virus during adefovir therapy

Adefovir dipivoxil (ADV) has demonstrated clinical activity against both wild-type and lamivudine-resistant hepatitis B virus (HBV). We analyzed the evolution of viral load and the changes of polymerase and precore/core promoter sequences in lamivudine-resistant virus during ADV therapy. The authors studied 14 patients who had breakthrough hepatitis after lamivudine therapy. Serial sera were obtained prior to adefovir administration and at 3, 6 and 12 months after ADV therapy. Nucleotide sequences of polymerase and the precore/core promoter from the hepatitis B virus were analyzed. The median serum HBV DNA decrease with adefovir treatment was 4.35 log(10) copies/mL at 12 months. Tyrosine-methionine-aspartate-aspartate (YMDD) mutants were found in 12 patients among the 14 patients with lamivudine resistance. The YMDD mutant viruses reversed to the wild-type in 6 patients out of the 12 patients after 3-6 months of ADV after discontinuing lamivudine therapy. In the analysis of the nucleotide sequences of the precore/core promoter gene, core promoter mutants in 12 patients were replaced by wild-type virus in three patients (25%), while precore mutants in four patients were replaced by the wild-type in three patients (75%). The results demonstrate the patterns of polymerase and precore/core promoter mutations in lamivudine-resistant hepatitis B viruses and the reversion from the mutant to the wild-type in some patients. In addition, despite several mutations in the polymerase during ADV therapy, ADV effectively suppressed HBV replication without the emergence of resistant viral mutants.     

限制性片段长度多态性分析拉米夫定治疗引起乙型肝炎病毒耐药基因变异的研究

目的　应用聚合酶链反应限制性片段长度多态性分析方法 (PCRRFLP) ,研究拉米夫定治疗引起慢性乙型肝炎患者血清中乙型肝炎病毒耐药基因 (HBVDNA)变异。方法　收集 2 4 0例用拉米夫定治疗 5 2～ 78周慢性乙型肝炎患者的血清标本 ,应用PCRRFLP方法扩增HBV 5 5 2 ,5 2 8两个基因位点片段 ,用限制性内切酶NdeⅠ ,NlaⅢ酶切分析 ,同时测定HBVDNA含量 ,并用DNA序列分析测定 3例患者HBVDNAP区基因序列 (1例野毒株 ,1例M5 5 2V伴L5 2 8M变异 ,1例M5 5 2I变异 )。结果　 2 4 0例患者应用拉米夫定治疗 5 2～ 78周后 ,5 1例血清HBVDNA出现YMDD变异 ,其中M5 5 2V变异 38例 ,M5 5 2I变异 13例 ,L5 2 8M和M5 5 2V同时变异 2 6例 ,L5 2 8M和M5 5 2I同时变异 1例。与定量PCR比较 ,可以测定YMDD变异的最低含量为 1× 10 4 copies mlHBVDNA序列分析结果与RLFP测定一致。结论　PCRRLFP方法是一种快速、简便的检测HBVDNA聚合酶变异的方法 ,可以用来筛查大量的血清标本 ,适宜作为临床用来观察拉米夫定治疗慢性乙型肝炎患者检测HBV变异的方法     

A novel accurate ACRS-PCR method with a digestion internal control for identification of wild type and YMDD mutants of hepatitis B virus strains

As a consequence of the point mutation in the YMDD motif of the hepatitis B virus (HBV) polymerase gene, lamivudine-resistant mutants have been reported in chronic hepatitis B patients who underwent lamivudine therapy. The objective of the study was to develop a novel accurate artificially created restriction site (ACRS) method with a digestion internal control for identification of YMDD, YIDD and YVDD HBV strains. Three conserved, specific and diagnostic primers introducing NdeI, SspI and AleI cleavage sites were designed in order to identify YMDD, YIDD and YVDD strains, respectively; while, their reverse primers also modified with the above recognition sites in order to enzyme correctness monitoring and false outcome avoiding. Thirty-two chronic hepatitis B patients who had taken lamivudine for 1-3 years and checked by the Inno-LiPA HBV DR kit, were evaluated by the ACRS method and then compared to sequencing data. The results of the ACRS method revealed the YMDD mutant strain in 20 patients, YMDD plus YIDD pattern in 1 patient, YMDD plus YVDD in 4 patients, the YIDD in 4 patients and mixed infection with each three strains in 1 patient. The sequencing and Inno-LiPA results were in agreement with the ACRS results. The novel ACRS method is a reliable, rapid and a cost-effective technique for determination of HBV strains with the wild type and YMDD mutant patterns.     

SNaPshot技术检测乙型肝炎病毒基因组P基因区单核苷酸多态性的研究

目的　建立SNaPshot技术对乙型肝炎病毒(HBV)基因组P基因区单核苷酸多态性(SNP)的分析。方法　针对HBVYMDD变异位置的上、下游设计引物,用PCR方法进行DNA扩增,产物直接测序或克隆测序。再针对变异位点74 1A G变异型(YVDD)和74 3G T变异型(YIDD)的紧邻上游设计高度特异的SNaPshot检测引物,用不同荧光标记的ddNTP对PCR产物进行一步延伸,然后置于310型DNA测序仪上观察荧光信号,可直观的检测上述两位点的单核苷酸多态性。结果　在拉米夫定治疗的慢性乙型肝炎患者中,经测序证实P基因区不仅存在74 1、74 3位点的变异,还存在5 14C A、5 2 3C A、5 6 2T A、6 6 7C A等位点的变异。对已证实P基因区变异的13例患者血清用SNaPshot技术检测YMDD结果与测序结果完全相同,显示SNaPshot技术高度的特异性。结论　SNaPshot技术检测HBV基因组SNPs具有快速、简便、准确特异的特点,还检测到野生株和变异株的混合存在。