Hepatitis B virus genotypes and lamivudine resistance mutations in Jordan

AIM:To investigate and identify prevalent hepatitis B virus(HBV) genotypes and to explore lamivudine-resistant mutations among treated and untreated patients in Jordan.METHODS:A total of 107 cases with chronic hepatitis B were recruited from different medical centers in Jordan.Serological tests were preformed for all cases using a microparticle enzyme immunoassay.HBV Genotyping was performed for 70 cases using Line probe genotyping assay.The YMDD mutations were explored for 20 cases(4 were lamivudine naive) using the INNO-LiPA HBV DR assay.RESULTS:Genotype D was the only detected genotype.A total of 6 YMDD mutations were detected in 5 treated patients(31%) while one mutation was detected in the naive patients.Seventeen percent of cases were positive for HBeAg and had statistically significant higher levels of serum aminotransferases.CONCLUSION:HBV genotype D appears to be the only circulating type in Jordanian patients.The YMDD mutations were detected in 31% of lamivudine-treated cases with similar patterns to those found in the literature.We also found a relatively low prevalence of HBeAg expression among examined cases(17%).Awareness of these serologic,genotypic and resistance patterns might help in the formulation of management plans and for predicting clinical outcomes.Further larger scale studies are needed to confirm our results and to examine possible associations among clinical,serologic,and genetic patterns of HBV infections in Jordan.

The relationship between HBV lamivudine resistance and HBV genotypes or basic core promoter mutations

OBJECTIVE: To investigate the relationship between HBV Iamivudine resistance and HBV genotypes or basic core promoter (BCP) mutations. METHODS: The common coated probes were synthesized according to the conserved regions of the preC gene of hepatitis B virus (HBV). Different colorized probes were chosen from the sequences of different genotypes of HBV (A to F), BCP and YMDD wild types and mutants, respectively. HBV DNA levels, HBV genotypes, BCP and YMDD resistants were analyzed by PCR microplate hybridization ELISA at the zero and 6th month after the patients were treated with lamivudine. RESULTS: HBV genotyping results showed that HBV types B, C, D accounted for about 30%, 36% and 23% patients respectively. Thirteen BCP mutations (type B in 1 patient, type C in 8 and type D in 4) were found before treatment with lamivudine. HBV DNA levels were lower than 100 pg/ml in 2 patients anti higher than 100 pg/ml in 11. 9.4% of the HBV patients (5/43; type C in 3 and type D in 2) showed YMDD resistants and 4 BCP mutations at the same time. CONCLUSION: Oral treatment of lamivudine decreases the level of serum HBV DNA. The appearance of HBV YMDD resistants is related to certain HBV genotypes, and most of them are BCP mutations.

Lamivudine resistance mutations in patients infected with hepatitis B virus genotype D

AIM: To determine the distribution of viral genotypes for primary or acquired lamivudine resistance. METHODS: A total of 283 patients with chronic hepatitis B virus (HBV) infection (245 patients with chronic hepatitis B and 38 inactive hepatitis B surface antigen carriers) were included in the study. The HBV geno-type was determined by using quantitative real-time polymerase chain reaction and sequence analysis, and tyrosine-methionine-aspartate-aspartate (YMDD) motif mutations were determined using the reverse transcriptase hybridization method. RESULTS: Lamivudine resistance was determined in a total of 25 (10.7%) chronic hepatitis B patients. Eight subjects (4%) had primary resistance to lamivudine, and 17 (53.1%) had secondary resistance to lamivudine. Genotype D, which was isolated from 267 of the patients with chronic HBV infection, was the dominant genotype in Turkey. CONCLUSION: Identification of YMDD motif mutations should have a positive impact on the selection of proper antiviral medication for patients, even for those who are nucleoside nave.

Mutations outside the YMDD motif in the P protein can also cause DHBV resistant to Lamivudine

AIM: To observe the Lamivudine resistance character of a DHBV strain in vitro and in vivo, and to analyze if the Lamivudine resistance character is caused by gene mutation or by abnormity of the Lamivudine metabolism.METHODS: Congenitally DHBV-negative Guangdong brown ducks and duck embryo liver cells were respectively taken as animal and cell model. The Lamivudine-susceptive DHBV and Lamivudine-resistant DHBV (LRDHBV) were infected and Lamivudine was administrated according to the divided groups. The changes of DHBV quantity in the animal and cell model were tested. Three Lamivudineresistant and two Lamivudine-susceptive DHBV complete genomes were successfully amplified, sequenced and then submitted to GenBank. All the DHBV complete sequences in the GenBank at present were taken to align with the three LRDHBV to analyze the mutational points related to the Lamivudine-resistant mutation.RESULTS: Both the animal and cell model showed that the large and the small dosage Lamivudine have no significant inhibitory effect on the LRDHBV. Five sequences of DHBV complete genomes were successfully cloned. The GenBank accession numbers of the three sequences of LRDHBV are AY521226, AY521227, and AY433937. The two strains of Lamivudine-susceptive DHBV are AY392760and AY536371. The correlated mutational points are KorR86Q and AorE591T in the P protein.CONCLUSION: The Lamivudine resistance character of this DHBV strain is caused by genome mutation; the related mutational points are KorR86Q and AorE591T and have no relations with the YMDD motif mutation.

Correlation of the occurrence of YMDD mutations with HBV genotypes,HBV-DNA levels,and HBeAg status in Chinese patients with chronic hepatitis B during lamivudine treatment

BACKGROUND:Continuous lamivudine therapy is associated with high rates of YMDD mutations,which are the main causes of drug resistance.The current study explores the association of the emergence of YMDD mutations with pretherapy HBV genotype,HBV-DNA levels,HBeAg status,and serum alanine aminotransferase(ALT) levels in Chinese patients receiving lamivudine therapy for chronic hepatitis B.METHODS:A total of 319 chronic hepatitis B patients who received lamivudine therapy for more than a year were enrolled in this study.YMDD mutations,HBV genotype,HBV-DNA levels,HBeAg status,and ALT levels were determined prior to their lamivudine treatment and every three months for a year of this therapy.RESULTS:Among the 319 patients,137(42.95%) were infected with genotype B and 182(57.05%) with genotype C.Up to 94 patients(29.47%) developed YMDD mutations within one year of lamivudine therapy.Furthermore,50 patients with HBV genotype B and 44 patients with genotype C developed YMDD mutations(36.50% vs 24.18%,P<0.05).Logistic regression analysis showed that pretherapy HBV genotype,HBV-DNA levels,and HBeAg status are independent factors for the emergence of YMDD mutations(HBV genotype:OR=2.159,95% CI 1.291-3.609,P=0.003;HBV-DNA:OR=1.653,95% CI 1.231-2.218,P=0.001;HBeAg:OR=2.021,95% CI 1.201-3.399,P=0.008).CONCLUSIONS:HBV genotype,HBV-DNA levels,and HBeAg status at baseline are the independent factors associated with the emergence of YMDD mutations among Chinese patients receiving lamivudine therapy for chronic hepatitis B.These findings are helpful to the development of therapeutic strategies for these patients.

Clinical features of chronic hepatitis B patients with YMDD mutation after lamivudine therapy

Objective: To study the clinical features of chronic hepatitis B (CHB) patients with tyrosine-methionine-aspartateaspartate (YMDD) mutation after lamivudine therapy. Methods: This investigation was a retrospective study of 63 CHB patients with YMDD mutation during lamivudine therapy. Clinical data, including period and types of YMDD mutation; hepatitis B virus (HBV) DNA levels and alanine aminotransferase (ALT) levels before and after YMDD mutation were measured. YMDD mutation in the HBV DNA polymerase gene was determined using polymerase chain reaction (PCR) and direct sequencing. HBV DNA quantification was determined using real-time PCR. Relevant serum markers of HBV were measured. The follow-up period was 12 months after YMDD mutation. Results: YMDD mutation occurred 7～44 months (median, 21.5 months) after the start of lamivudine therapy. The majority of the cases (42/63, 66.6%) had YMDD mutants detected between 12 and 24 months. Four types of YMDD mutation were observed in this study, rtL180M/M204V mutation was the predominant type (26/63, 41.3%). A proportion of patients (16/63, 25.4%; 12/63, 19.1%) had higher HBV DNA levels and ALT levels (after mutation vs before mutation),respectively. Conclusion: The majority of patients with YMDD mutants had similar or lower HBV DNA levels and ALT levels compared with baseline values. This subset of patients might have benefited from the continued lamivudine therapy. The patients with increased ALT and HBV DNA levels (breakthrough hepatitis) should benefit from the addition of a newer nucleotide analogue (e.g. adefovir).

YVDD Mutation of Hepatitis B Virus, a Dominant Lamivudine-Resistant Type in Guangzhou, South China

The epidemiological effects of native and mutated YMDD motif in the HBV genome under the selective pressure of lamivudine were investigated. YMDD wild and mutation motif in HBV genome were detected by flow through reverse dot blots （PT-RDB） with KaiPuTM DNA HybriMax Rapid Hybridization Machine based on the principle of ＂Flow-through hybridization＂ and by the traditional Reverse Dot Blot assay. Sera from 1 021 suspected lamivudine-resistant chronic HBV carriers after more than 8 months of lamivudine therapy and the corresponding archived sera were collected and assayed. We found 35.94% were single type infections with 8.03% YMDD, 7.93% YIDD and 19.98% YVDD. It was also found that 64.06% were mixed infections including 1.96% YMDD and YIDD, 51.62% YMDD and YVDD, 1.96% YIDD and YVDD, 8.52% YMDD, YIDD and YVDD. The levels of infections containing YVDD motif reached 82.08%. The pretreatment infectious status were： YMDD single infection was 36.93%; YIDD single infection was 6.07%; YVDD single infection was 17.04%; YMDD and YIDD mixed infection was 0.97%; YMDD and YVDD mixed infection was 33.99%; YIDD and YVDD mixed infection was 0.98%; YMDD, YIDD and YVDD mixed infection was 4.02%. Infections containing YVDD motif were only 56.03%. The 34.32% mutation rate of YMDD motif to YVDD was significantly higher than the 10.97% of YMDD to YIDD （U=10.98, P〈0.05）, as estimated by Mann-Whitney U-test for non-parametric data. HBV containing YVDD motif might have an evolutionary ascendancy and become the dominant type under the selective pressure of lamivudine.

Lamivudine resistance in children with chronic hepatitis B

Currently, although lamivudine(LAM) has a low genetic barrier, only interferon-alpha and LAM are available as a first-line treatment in children with chronic hepatitis B(CHB). LAM is a potent inhibitor of hepatitis B virusdeoxyribonucleic acid(HBV-DNA) polymerase replication by termination of the proviral HBV-DNA chain. LAM has a good safety and tolerability profile in CHB patients with hepatic decompensation. However, the main disadvantages of this HBV reverse transcriptase inhibitor are:(1) pre-existing covalently closed circular DNA cannot be eradicated by LAM, thus relapse after therapy withdrawal is frequent; and(2) although the longer LAMtreatment induced the higher seroconversion rate, the risk of viral resistance increased through the selection of YMDD(tyrosine, methionine, aspartate, aspartate) motif. Insufficient suppression of viral replication leads to the emergence of resistant strains that could result in virological breakthrough which is usually followed by biochemical breakthrough. Mutant strains affects additional resistance and cross resistance, leading to drug resistance in a significant number of CHB patients. In this case, efficacy of more powerful anti-viral agents with higher genetic barrier against development of resistance is diminished. Furthermore, strains that are resistant to LAM could bring about vaccine escape mutants, decreasing the efficacy of HBV vaccine. A more potent drug with a high genetic barrier to resistance needs to be approved as the first-line treatment option for CHB in children.

Clonal evolution of hepatitis B virus polymerase gene mutations during lamivudine-adefovir combination treatment

AIM:To identify hepatitis B virus polymerase gene mutations during antiviral therapy using lamivudineadefovir sequential monotherapy followed by lamivudine-adefovir combination therapy.METHODS:The patient cohort included four adult chronic hepatitis B patients who had undergone sequential monotherapy,first with lamivudine(LMV) and then,after developing viral breakthrough,with adefovir(ADV) therapy.All of the patients had non-response or viral breakthrough after LMV-ADV sequential monotherapy,which resulted in the switching of their antiviral regimen to LMV-ADV combination therapy.Eleven serum samples from the four patients who showed non-response to rescue LMV-ADV combination therapy were collected sequentially at a time before the antiviral treatment and then during the LMV monotherapy,ADV monotherapy,and LMV-ADV combination therapy.For the genotypic analysis,the whole 1310-bp polymerase gene region was amplified,cloned and sequenced.RESULTS:All patients had been previously treated with 100 mg of LMV once daily for a 15-to 26-mo period.The emergence of resistance mutations to LMV,such as rtM204V/I and/or rtL180M,were found in all patients.Their antiviral regimens were switched to ADV monotherapy as the second line treatment.All patients had viral breakthrough or non-response after the LMV-ADV sequential monotherapy.ADV-resistant mutations were detected after 13 to 19 mo of LMV-ADV sequential monotherapy.The rtA181V/T mutations were predominantly identified during the ADV treatment in the LMV-resistant patients.Twenty-seven of 38 clones were combined with an amino acid change at rt181;three clones had mutations in rt236 and one clone had a combined mutation.The rtA181V/T mutations were not suppressed by the LMV-ADV combination therapy.Thirty-nine of 64 clones showed an rtA181V/T mutation and six clones showed combined mutations in rt181 and rt236.Mutations in rt204 re-emerged during the combination treatment.The rt181 and rt204 mutations did not co-exist in one clone.CONCLUSION:Add-on lamivudine therapy with adefovir for adefovir resistance may not suppress the pre-existing adefovir-resistant mutation that develops during lamivudine-adefovir sequential monotherapy.

YMDD mutations in patients with chronic hepatitis B untreated with antiviral medicines

AIM: To polymerase P region (YMDD) mutations of hepatitis B virus gene (HBV DNA) in patients with chronic hepatitis B (CHB) untreated with antiviral medicines and to explore its correlation with pre-c-zone mutations, HBV genotypes and HBV DNA level, and to observe its curative effect.METHODS: A total of 104 cases (38 cases in group of familial aggregation and 66 cases in group of non-familial aggregation) were randomly chosen from 226 patients with CHB who did not receive the treatment of lamivudine (LAM)and any other antivirus drugs within the last one year.Their serum YMDD mutations were detected by microcosmic nucleic acid and cross-nucleic acid quantitative determination,HBV genotypes by PCR-microcosmic nucleic acid crossELISA, HBV DNA quantitative determination and fluorescence ration PCR analysis, hepatitis B virus markers (HBVM) by ELISA. LAM was taken by 10 patients with YMDD mutations and its curative effect was observed.RESULTS: Twenty-eight cases (26.9%) had YMDD mutations, of them 11 cases (28.9%) were in familial aggregation group (38 cases) and 17 cases (25.8%) in nonfamilial aggregation group (66 cases) with no significant difference between the two groups. Twenty-seven point one percent (16/59) cases were positive for HBeAg YMDD mutations, and 26.7% (12/45) cases were negative for HBeAg and positive for anti-HBe. There was also no significant difference between the two groups. Different YMDD incidence rate existed in different HBV genotypes.HBV DNA level did not have a positive correlation with the incidence of YMDD mutations. LAM was effective for all patients with mutations.CONCLUSION: Wild mutant strains in HBV and their incidence rate have no significant difference between familial aggregation and non-familial aggregation. It may have no significant relationship between YMDD mutations and pre-c-zone mutations. HBV DNA level may not have a positive correlation with YMDD mutations. LAM is clinically effective for CHB patients with YMDD mutations.

Fatal liver failure due to reactivation of lamivudine-resistant HBV mutant

We report a case of fatal liver failure due to reactivation of lamivudine-resistant HBV. A 53-year-old man was followed since 1998 for HBV-related chronic hepatitis. Serum HBV-DNA was 150 MEq/mL (branched DNA signal amplification assay) and ALT levels fluctuated between 50-200 IU/L with no clinical signs of liver cirrhosis. Lamivudine (100 mg/d) was started in May 2001 and serum HBV-DNA subsequently decreased below undetectable levels. In May 2002, serum HBV-DNA had increased to 410 MEq/mL, along with ALT flare (226 IU/L). The YMDD motif in the DNA polymerase gene had been replaced by YIDD. Lamivudine was continued and ALT spontaneously decreased to the former levels. On Oct 3 the patient presenting with general fatigue, nausea and jaundice was admitted to our hospital. The laboratory data revealed HBV reactivation and liver failure (ALT: 1828 IU/L, total bilirubin: 10 mg/dL, and prothrombin INR: 3.24). For religious reasons, the patient and his family refused blood transfusion, plasma exchange and liver transplantation. The patient died 10 d after admission. The autopsy revealed remarkable liver atrophy.

Outcome of lamivudine-resistant hepatitis B virus is generally benign except in cirrhotics

AIM： We set to determine factors that determine clinical severity after the development of resistance.METHODS： Thirty-five Asian patients with genotypic lamivudine resistance were analyzed in three groups： 13/35 （37%） were non-cirrhotics with normal pre-treatment ALT （Group IA）, 12/35 （34%） were non-cirrhotics with elevated pre-treatment ALT （Group IB）, and 10/35 （29%） were cirrhotics （Group II）. Patients were followed for a median of 98 wk （range 26-220） after the emergence of genotypic resistance.RESULTS： Group IA patients tended to retain normal ALT. Group IB patients showed initial improvement of ALT with lamivudine but 9/12 patients （75%） developed abnormal ALT subsequently. On follow-up however, this persisted in only 33%. Group II patients also showed improvement while on treatment, but they deteriorated with the emergence of resistance with 30% death from decompensated liver disease. Pretreatment ALT levels and CPT score （in the cirrhotic group） were predictive of clinical resistance and correlated with peak ALT levels and CPT score.CONCLUSION： The phenotype of lamivudine-resistant HBV correlated with the pretreatment phenotype. The clinical course was generally benign in non-cirrhotics. However, cirrhotics had a high risk of progression and death （30%） with the development of lamivudine resistance.

Treatment of chronic hepatitis B patients with tyrosinemethionine-aspartate-aspartate mutations

Lamivudine is an antiviral used for the treatment of chronic hepatitis B. Several studies have reported various mutations that are induced by lamivudine therapy. These mutations in the tyrosine-methionineaspartate-aspartate(YMDD) motif are necessary and sufficient to confer high-level lamivudine resistance. During treatment with lamivudine, mutations develop in the YMDD motif of the hepatitis B virus(HBV) polymerase gene and lamivudine cannot prevent the replication of the mutant form. The virulence strain of developed mutation in the polymerase gene is lower than the original virus and they are susceptible to treatment with some other nucleoside analogs except lamivudine. Entecavir and tenofovir are potent HBV inhibitors and they can be confidently used as first line monotherapies. We read the article written by Tan et al that lamivudine therapy improved the clinical course in HBV patients with natural YMDD mutations. We think that lamivudine use for this patient group is not appropriate. These patients should use YMDD mutant form-effective drugs such as adefovir, tenofovir.

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。

拉米夫定治疗慢性乙型肝炎发生病毒学反弹患者YMDD变异分析

选取402例服用拉米夫定后出现乙型肝炎病毒(HBV)DNA反弹的慢性乙型肝炎(CHB)患者血清样品,应用荧光PCR法定性检测YMDD变异情况。402例中有309例(76.87%)检测出YMDD变异,其中120例为YVDD变异,74例为YIDD变异,115例为YVDD+YIDD联合变异;309例YMDD变异患者中同时检测出变异株与野生株占69.26%(214/309),仅检测出变异株占30.74%(95/309)。另外,93例为YMDD野生型阳性。

阿德福韦酯联合拉米夫定治疗YMDD变异的慢性乙型肝炎疗效相关因素分析

目的研究分析影响阿德福韦(ADV)联合拉米夫定(LAM)治疗YMDD变异的慢性乙型肝炎疗效的相关因素。方法应用ADV联合LAM治疗71例YMDD变异的患者48周,采用Logistic回归分析影响疗效的相关因素。结果治疗48周时,HBV DNA转阴率为78.9%(56/71),ALT复常率为80.3%(57/71),HBeAg阳性患者HBeAg转阴或血清转换率为26.7%(12/45);治疗24周和48周HBV DNA转阴、48周HBeAg转阴或血清转换和48周ALT复常者较相应时间点未转阴者的基线HBV DNA水平低(P<0.05);Logistic回归分析结果显示,基线HBV DNA低水平、24周HBV DNA转阴、12周YMDD变异转阴是48周获得较好疗效的相关因素。结论采用ADV联合LAM治疗YMDD变异的慢性乙型肝炎患者,其基线HBV DNA低水平、24周HBV DNA转阴、12周YMDD变异转阴是48周疗效较好的预测因素,发生病毒学突破而无生化学突破的患者早期联合治疗可获得更佳的疗效。

拉米夫定干扰素α联合治疗慢性乙型肝炎对YMDD产生的影响

目的探讨拉米夫定联合干扰素α治疗慢性乙型肝炎YMDD变异的发生率。方法112例慢性乙型肝炎患者随机分为2组,治疗组60例,用拉米夫定、干扰素α治疗26周,后单用拉米夫定26周;对照组52例,单用拉米夫定治疗52周;所有病例均于治疗前检测丙氨酸转氨酶(ALT)、HBeAg/AntiHBeHBVDNA及YMDD变异。结果112例患者治疗52周后,HBeAg/AntiHBe转换率治疗组为46.7%、对照组为23.1%,两组比较差异有明显性(P<0.05);YMDD变异发生率治疗组为3.3%、对照组为17.3%,两组对照差异有明显性(P<0.05);HBVDNA总转阴率治疗组为83.3%、对照组为67.3%,经统计学处理,差异有明显性(P<0.05)。结论拉米夫定与干扰素α联合治疗对HBeAg/AntiHBe转换率及HBVDNA转阴率均明显优于单用拉米夫定组,并对于延迟及减少YMDD变异相关性耐药有一定的作用。

拉米夫定治疗中国乙型肝炎患者中发现YMDD耐药变异株

为了监测拉米夫定临床治疗过程中耐药性的产生 ,更好地指导临床用药。采用 PCR产物克隆后测序的方法 ,对 2 0例服用拉米夫定病人进行随访观察 ,检测其体内乙型肝炎病毒 (HBV)聚合酶基因 (P gene) )酪氨酸 -蛋氨酸 -天门冬氨酸 -天门冬氨酸 (YMDD)区域变异情况 ,同时观察其 HBV DNA定量和肝功能指标变化。结果发现 ,1例病人在服用拉米夫定 9个月时出现 HBV YMDD变异株 ,并由混合感染逐渐进展为单一的变异株感染 ,出现耐药时伴有 HBV DNA定量反跳和 AL T的上升。表明拉米夫定长期治疗 (>6个月 )可能出现耐药 ,耐药变异株由弱势株逐渐演变为优势株 ,耐药出现时可伴有 HBV

拉米夫定治疗后乙肝病毒发生YMDD变异的研究

目的 观察拉米夫定治疗后乙肝病毒发生YMDD变异情况。方法 87例慢性乙肝患者分成两组 ,一组 5 1例接受拉米夫定及保肝治疗 ,另一组 36例做为对照组只给予保肝治疗 ,治疗 1年后对患者HBV多聚酶基因YMDD基序进行定性检测 ,观察是否有突变。结果 拉米夫定治疗组在用药 1年后有 8例发生YMDD突变 ,其中YIDD变异有 5例 ,YVDD变异 3例 ,变异株中有 5例伴HBVDNA、ALT水平升高 ,而对照组无变异株产生。结论 拉米夫定可诱导HBV多聚酶基因 (P基因 )YMDD基序发生基因突变 。

乙型肝炎病毒感染者YMDD自然变异研究

目的了解未经抗病毒治疗的慢性乙型肝炎患者中HBVP基因YMDD变异情况,并观察YMDD自然变异组与非变异组临床病情轻重的关系。方法采用PCR和荧光探针杂交检测技术,检测60例慢性乙型肝炎患者血清HBV YMDD自然变异情况。结果在60例患者中,YMDD变异阳性5例(8.33%),阴性55例,5例变异中2例为YIDD阳性,3例为YVDD阳性。结论未经抗病毒治疗的慢性乙型肝炎患者存在YMDD自然变异株;YMDD自然变异的患者没有临床病情加重的趋势。