慢性丙型肝炎患者血清细胞因子水平的变化及意义

目的:检测慢性丙型肝炎患者血清细胞因子IL-2、IFN-г、IL-5、IL-6、IL-12P70和P40水平,探讨其与患者血清ALT水平、HVC RNA载量、HCV基因型及干扰素疗效的关系。方法:检测30例健康对照者和30例慢性丙型肝炎患者干扰素治疗前后血清IL-2、IFN-г、IL-5、IL-6、IL-12P70和P40的含量,比较干扰素治疗应答组和无应答组之间细胞因子水平的差异及上述细胞因子水平与血清ALT水平、HCV基因型、HCVRNA载量等的关系。血清细胞因子检测应用ELISA法,HCV基因分型应用直接测序法,HCVRNA载量采用荧光定量PCR法。结果:与健康对照组相比,慢性丙型肝炎患者血清IL-2含量明显降低,IL-5和IL-12P40明显生高;血清IL-6含量与血清ALT水平呈正相关,与RNA载量呈负相关;HCV基因型1型患者血清IL-6含量明显高于2型,其他基因型和亚型之间细胞因子水平均无显著性差异;干扰素治疗的持续应答率为46.7%,应答组和无应答组治疗前血清细胞因子水平均无显著性差异,但应答组治疗结束时IFN-γ含量较治疗前明显升高。结论:血清Th1/Th2细胞因子水平失衡与丙型肝炎的慢性化和肝脏炎症活动相关;干扰素治疗前血清Th1/Th2细胞因子水平与干扰素治疗效果无关,不能对疗效进行预测,干扰素诱导的Th1细胞优势反应与持续应答有关。     

丙型肝炎病毒NS5A区与干扰素敏感性间关系的研究

日本学者首先发现丙型肝炎病毒NS5A区存在干扰素敏感决定区(ISDR),可预测干扰素疗效,但随后西欧学者的多项研究并不支持此观点.本文对ISDR与干扰素疗效、病毒滴度、准种选择性的关系以及ISDR的体外研究等方面的现状进行了综述.     

慢性丙型肝炎患者HCV HVR1准种异质性与干扰素疗效关系的研究

目的：研究HCV HVR1准种异质性与干扰素疗效以及与HCV RNA载量之间的关系，为临床选择应用干扰素抗病毒治疗适应症及预测疗效提供理论依据。方法：采用核苷酸序列测定法进行HCV基因分型；分别采用单链构象多态性聚合酶链反应法（SSCP）及克隆测序法进行HVR1准种异质性检测；采用荧光特异性PCR法进行HCV RNA载量检测。结果：14例1b型慢性丙肝患者干扰素治疗前5例为SSCP低复杂性（SSCP条带数≤3），9例为高复杂性（SSCP条带数＞3），干扰素治疗应答组SSCP条带数明显少于无应答组。1b型患者中无应答组HVR1变异株的数目（准种数）和基因的差异性（每个基因位点的平均变异率）均明显高于应答组。HVR1准种异质性程度与HCV RNA含量无正相关关系。结论：感染HCV基因型1b型的慢性丙型肝炎患者HVR1准种异质性程度越高对干扰素无应答的可能性越大。HVR1准种的复杂性程度与HCV RNA含量无关，是预测干扰素疗效的一个独立因素。     

难治性慢性丙型肝炎强化治疗疗效研究

目的探讨难治性慢性丙型肝炎强化治疗疗效,通过优化治疗剂量和疗程来提高慢性丙型肝炎患者对干扰素联合利巴韦林治疗的持续病毒应答率。方法对常规治疗的干扰素剂量（聚乙二醇干扰素α每周皮下注射1次）和利巴韦林（每天10．5mg／kg）经治的无应答和部分患者,根据患者的意愿进行标准干扰素α10 MU隔日注射1次或聚乙二醇干扰素α-2a（PEG—IFN α-2a）360μg每周注射1次,并根据体重每天给予15mg／kg的利巴韦林的强化剂量治疗,在治疗的0、4、12周和以后的每间隔12周、治疗结束后的24周进行HCV RNA含量检测,根据患者治疗过程中的病毒应答情况给予72～96周的疗程,以持续病毒应答（sustained viral response,SVR）作为疗效的评判指标。结果18例患者完成全程治疗和观察,12例获得持续病毒学应答,5例治疗无效,1例复发。3例患者获得RVR,RVR获得者的cEVR和SVR均为3／3,RVR组治疗前的病毒载量显著低于未获得RVR组（t=4．687,P〈0．001）。15例无快速病毒应答者,8例获得完全早期病毒应答,9例获得SVR。聚乙二醇干扰素α-2a 360μg每周注射1次的SVR为4／5。11例获得cEVR患者均获得SVR,7例无cEVR的患者,仅1例获得SVR。结论强化剂量的干扰素和RBV可以使较高比例的既往规范抗病毒治疗无应答、部分应答获得SVR。在强化治疗过程中根据病毒的应答情况及时调整和延长HCV RNA阴性的疗程是提高难治性慢性丙型肝炎持续病毒应答率的重要措施。     

基因1b型丙型肝炎病毒NS5A区变异及其与聚乙二醇干扰素α-2a联合利巴韦林治疗应答的相关性

目的探讨基因1b型慢性丙型肝炎患者NS5A区基因变异与聚乙二醇干扰素α-2a（PEG—IFNα-2a）联合利巴韦林（RBV）抗病毒治疗疗效的关系。方法回顾性选择15例应用PEG—IFNα-2a／RBV抗病毒治疗的基因1b型慢性丙型肝炎患者,其中7例为快速应答（RVR）,8例为无应答（NR）,应用RT—PCR法扩增NS5A全长片段,用克隆测序方法进行核苷酸和氨基酸序列测定。结果没有发现与治疗应答相关的单个氨基酸或基序变异,RVR组和NR组在NS5A、ISDR、PKRBD和IRRDR区的氨基酸突变数目差别均无统计学意义,RVR组在V3区（aa2356～2379）的氨基酸突变数目高于NR组（分别为5．3±0.5和3．4±0．6,P=0．03）。结论V3区的氨基酸突变数目与PEG—IFNα-2a联合RBV抗病毒疗效可能相关。     

1b型丙型肝炎病毒基因组不同区域基因变异对干扰素疗效的影响

本研究对14例基因型1b型慢性丙型肝炎患者血清HCV基因组中E2/NS1(含HVR1和HVR2)、NS5A区准种异质性进行了检测,对HVR区准种异质性程度与干扰素(IFN)疗效的关系、NS5A2209-2248区是否存在干扰素敏感决定区(ISDR)等热点问题进行了探讨,为1b型慢性丙型肝炎患者应用IFN抗病毒治疗时     

丙型肝炎病毒ＮＳ５Ａ区与干扰素敏感性间关系的研究

日本学者首先发现丙型肝炎病毒NS5A区存在干扰素敏感决定区（ISDR），可预测干扰素疗效。但随后西欧学者的多项研究并不支持此观点，本文对ISDR与干扰素疗老头儿 ，病毒滴度，准种选择性的关系以及ISDR的体外研究等方面的现状进行了综述。     

HCV 1b亚型ISDR变异影响PEG-IFN/RBV抗病毒疗效的新特点分析

目的探讨HCV干扰素敏感决定区（ISDR）氨基酸（aa）序列变异度对聚乙二醇干扰素（PEG-IFN）联合利巴韦林（RBV）治疗1b亚型慢性丙型肝炎（CHC）疗效的影响。方法 58例HCV1b亚型慢性感染者采用PEG-IFN/RBV联合方案治疗48周,并随访24周。定量检测血清HCV RNA,逆转录-聚合酶链反应扩增治疗前血标本中HCV ISDR片段并测序,MEGA4分析氨基酸序列变异度;二分类Logistic回归分析各变量与持续病毒学应答（SVR）之间的关系。结果治疗前血清HCV的ISDR氨基酸序列与HCVJ株比较,15例为野生型（未突变）,42例为中间型（1-3个突变）,1例为突变型（≥4个突变）。其中2218位点突变最多,约为60.3%（35/58）。ISDRaa突变数目与SVR关系密切（P=0.000）,ISDRaa突变数≥2的CHC组所获得的EVR和SVR明显高于aa突变数〈2的CHC组（P=0.041/P=0.012）。结论华南HCV1b亚型ISDR突变型（氨基酸变异≥4）极少。ISDRaa变异能够预测SVR;采用PEG-IFN/RBV联合方案治疗,对SVR有预测价值的ISDRaa突变数可由4个减少为2个。     

血清Th1/Th2细胞因子水平与慢性丙型肝炎临床及干扰素疗效关系的研究

目的 探讨血清Th1和Th2细胞因子水平与慢性丙型肝炎患者病情进展及干扰素疗效的关系.方法 血清细胞因子检测应用ELISA法,HCV基因分型应用直接测序法,HCVRNA载量采用荧光定量PCR法.结果 慢性丙型肝炎患者血清IL-2和TGF-β含量明显低于健康对照组,IL-5含量明显高于后者;血清IL-6含量与ALT水平呈正相关,与RNA载量呈负相关;HCV基因型1型患者IL-6含量明显高于2型,2a型IL-2含量低于2b型;随着感染时间的延长,血清IL-2呈下降趋势,IL-6呈升高趋势,而TGF-β则先升高之后逐渐下降.干扰素治疗应答组和无应答组治疗前血清细胞因子水平均差异无统计学意义,但应答组治疗结束时IFN-γ含量较治疗前明显升高.结论 慢性丙型肝炎患者存在Th1/Th2细胞因子失衡并与临床表现相关;治疗前血清Th1/Th2细胞因子水平不能对疗效进行预测,干扰素诱导的Th1细胞优势反应与持续应答有关.     

67例慢性丙型肝炎治疗过程及随访中血清ALT、病毒载量及肝纤维化指标的变化

目的 观察聚乙二醇干扰素α-2b联合利巴韦林治疗慢性丙型肝炎过程中肝功能、病毒复制及肝纤维化指标的改变情况.方法 检测67例慢性丙型肝炎患者在干扰素联合利巴韦林治疗开始（0周）、结束（48周）和停药12周（60周）时血清丙氨酸转氨酶（ALT）、丙肝病毒核糖核酸（HCV RNA）、透明质酸（HA）、Ⅲ型前胶原肽（PCⅢ）、Ⅳ型胶原（Ⅳ-C）和层粘连蛋白（LN）水平.结果 治疗后完全应答组（CR-S,43/67） ALT、HCV RNA及血清4项纤维化指标均显著下降（P ＜0.05或P＜0.01）,部分应答组（CR-R,13/67）和无应答组（NR,11/67） ALT、HCV RNA及血清4项纤维化指标变化不明显,反跳甚至更高.结论 聚乙二醇干扰素α-2b联合利巴韦林治疗慢性丙型肝炎约65％患者完全应答,随着肝细胞炎症的改善,病毒RNA滴度、肝纤维化指标水平明显下降,表明干扰素联合利巴韦林能抑制HCV RNA复制,调节机体免疫功能,减轻肝脏炎症反应,改善肝功能,减少肝纤维化.     

丙型肝炎病毒1b型NS5 A区基因结构变异与α干扰？…

目的 观察丙型肝炎患者丙型肝炎病毒（ＨＣＶ）１ｂ型基因组部分ＮＳ５ Ａ区核苷酸,氨基酸的变异情况并探讨其与α干扰素疗效的相关性。方法 患者干扰素治疗前,中,后留血标本,用聚合酶链反应（ＰＣＲ）扩增ＨＣＶ病毒ＮＳ５ Ａ区部分基因片段并用直接测序法测序。与ＨＣＶ－Ｊ株及ＨＣＶ－河北株（ＨＣＶ－ＨＢ）比较核苷酸及氨基酸序列的同源性,根据α干扰素疗效分析ＨＣＶ１ｂ是否存在干扰素敏感决定区。     

Ratio of serum gamma-GT/ALT rather than ISDR variability is predictive for initial virological response to IFN-alpha in chronic HCV infection.

Chronic hepatitis C virus (HCV) infection in humans is treated at present with interferon (IFN)-alpha. Because the proportion of patients responding to therapy with sustained or even just with transient elimination of viral RNA is low, several potential prognostic parameters have been evaluated to predict the outcome of the therapy. The present study aimed to prove the validity of a predictive parameter described previously for initial virological response, namely the ratio of serum gamma-glutamyltransferase/alanine transaminase (gamma-GT/ALT) activity in connection with virus genotypes 1a, 1b, and 3a, prospectively and to compare the predictive value of these combined parameters with amino acid variability within the interferon sensitivity determining region (ISDR). The prospective analysis confirmed previous data on the predictive value of the serum gamma-GT/ALT ratio. Concerning ISDR variability, the majority of ISDR sequences obtained from the mostly nonresponding type 1b-infected individuals (23/28) resembled nonmutant types (27/ 28). Isolates from type 3a-infected patients responding to therapy in the majority of cases (13/ 20) exclusively resembled nonmutant types when compared with databank type 3a sequences, but were mutant when compared with the prototype sequence HCV-J. However, the initial virological responsiveness among both type 1b- and type 3a-infected patients did not correlate to ISDR variability. In contrast, virological responsiveness was closely related to serum gamma-GT/ALT ratio. The data are not necessarily contrary to the concept that the number of amino acid exchanges within the ISDR compared with the prototype HCV-J sequence is related to some extent to IFN-alpha sensitivity. The ratio of serum gamma-GT/ALT in combination with HCV genotype, however, was found to be a more reliable and stringent predictive parameter.     

Molecular characterization of hepatitis C virus genotype 2a from the entire sequences of four isolates

Genotype 2a hepatitis C virus (HCV) has different characteristics from genotype 1b, such as responsiveness to interferon therapy. Such type-specific characteristics appear to be due to differences in the HCV genome sequence. The complete sequences of genotype 2a HCV genome isolated from four patients with chronic hepatitis C were determined, and nucleotide and deduced amino acid sequences were compared within genotype 2a, as well as between genotype 2a and 1b. Whereas the amino acid sequence similarity of the core region was highest within genotype 1b, the NS3 and NS4B regions of exhibited greater similarity than the core region in genotype 2a. The serine protease and helicase motifs in the NS3 region were well conserved in genotype 2a to the same degree as in genotype 1b. However, the putative secondary structure of 2a isolates was significantly different from that of the 1b isolates. Analysis of amino acid similarity between genotypes 2a and 1b revealed the lowest degree of similarity in the E1 region, followed by the NS2 and NS5A region. Sequences of genotype 2a in the interferon-sensitivity determining region (ISDR) located in the NS5A region had a deletion of four amino acids compared with that of genotype 1b. When the ISDR of the genotype 2a was aligned for maximal similarity, it exhibited similarity of only 52.5-55.0% when compared with that of HCV-J, which belongs to genotype 1b. These findings for the entire sequences of genotype 2a isolates will contribute to virological studies of HCV.     

Hepatitis C virus: The role of molecular mimicry in response to interferon treatment

Chronic hepatitis C virus (HCV) infection is one of the major causes of chronic liver disease worldwide. In order for HCV to persist, the virus must escape immune recognition or inhibit the host immune response. The NS5A protein contains the interferon sensitivity‐determining region (ISDR) and is able to repress dsRNA‐dependent protein kinase (PKR) thus influencing the response to interferon (IFN) therapy. Patients who respond to IFN therapy have stronger antibody reactivity against the NS5A compared to IFN non‐responders. Therefore, given the possible role for the ISDR in IFN resistance and differential antibody reactivity, it is possible that variation in ISDR may be involved in viral immune escape and development of persistent HCV infection employing aspects of host mimicry. In this study, pre‐treatment samples obtained from HCV infected patients were used to investigate the effect of different NS5A ISDR variants on the IFN antiviral response and their involvement in immune evasion. The NS5A was identified as a homologue of the variable region of immunoglobulins (Ig). The IFN resistant genotypes had higher levels of similarity to Ig compared to IFN sensitive genotypes. Expression of NS5A‐6003 (HCV genotype 1b) and NS5A‐6074 (HCV genotype 2a) was able to rescue vesicular stomatitis virus (VSV) from IFN inhibition and restore luciferase activity. A correlation between Ig‐like NS5A structure and also antibody response with the outcome of IFN treatment was observed. J. Med. Virol. 84:1571–1585, 2012. © 2012 Wiley Periodicals, Inc.     

Amino acid substitutions in NS5A region of GB virus C and response to interferon therapy

GB virus C (GBV-C) is related to hepatitis C virus (HCV) and has a similar genomic structure. Some predictors for the efficacy of interferon (IFN) therapy on HCV have been reported: genotype, viral load, IFN dose, and the amino acid substitutions in the NS5A region, designated as the interferon sensitivity determining region (ISDR). To evaluate the correlation between the amino acid substitutions in the GBV-C NS5A region and the response to IFN therapy, single-strand conformation polymorphism (SSCP) analysis was performed in the 12 concomitantly GBV-C-and HCV-infected patients who received IFN therapy at three time points: before, end-point, and after the IFN therapy. The region in the GBV-C NS5A studied includes the amino acids that exhibit some homology to the ISDR and the various substitutions. By SSCP analysis, amplicons were separated into 1-4 bands, which indicated the existence of heterogeneity in each host. However, the deduced amino acid sequences in these bands exhibited no characteristic differences among these strains irrespective of response to IFN therapy. Of the 32 strains separated by SSCP, 7 strains were responders, and 25 were nonresponders. The mean amino acid substitution, compared with the consensus sequence of nonresponders, was 1.00+/-0.93 among responders, and 1.40+/-0.85 among non-responders (P= NS). No correlation between the amino acid sequence in the GBV-C NS5A region and response to IFN therapy was found, indicating that the GBV-C NS5A region dose not act as the ISDR.     

Genetic variability of hepatitis C virus in chronically infected patients with viral breakthrough during interferon-ribavirin therapy

Little is known about hepatitis C virus (HCV) breakthrough during antiviral therapy, although it would help in understanding HCV resistance to current antiviral treatments. To analyse the implication of virological factors and the vigour of humoral immune responses in this phenomenon, we studied nine chronic hepatitis C patients with a viral breakthrough during IFN/ribavirin combination therapy, as well as five responders and five non-responders. The IRES and regions coding for the capsid protein, the PePHD domain of envelope glycoprotein E2 and the NS5A and 5B proteins were amplified by RT-PCR before treatment, before and during breakthrough, and after treatment. The major variant sequence was obtained by direct sequencing. The heterogeneity of quasispecies was studied by SSCP in all patients and sequencing after cloning in seven genotype 1b-infected patients. Humoral responses against HCV epitopes were also analysed. The major sequences of IRES, PePHD, and NS5B remained stable during treatment, regardless of the treatment response. However, the capsid protein and the regions flanking PePHD showed sequence variations in breakthrough patients, although no specific mutation was identified. The variable V3 region of NS5A, but not the PKR-binding domain and the ISDR, seemed to be associated with differences in response to treatment. The analysis of HCV quasispecies revealed no characteristic pattern during treatment in breakthrough patients, whose HCV genome profiles looked most similar to that of non-responders. The humoral response was similar between groups. In conclusion, viral breakthrough does not seem to be due to selection of resistant strains with signature mutations.     

Suppression of interferon-induced antiviral activity in cells expressing hepatitis C virus proteins.

To elucidate the mechanism of the persistent nature of hepatitis C virus (HCV) infection, we examined whether the expression of HCV proteins affect the antiviral activity of interferon (IFN). Antiviral activity of IFN in HepG2 cells expressing all HCV (type 1b) proteins was much lower than vector control (VC) HepG2 cells when encephalomyocarditis virus (EMCV) was used as a challenge virus. Lesser sensitivity to IFN was also observed in cells expressing NS3, NS4, and NS5 and in cells expressing only NS5A. In contrast, HepG2 cells expressing core, E1, E2, NS2, and NS3 proteins were equally sensitive to IFN as VC cells. We then tested the antiviral activity by IFN in two human amnion-derived FL cell lines expressing NS5A from two different clones, one with an intact sequence of IFN sensitivity-determining region (ISDR) and the other with a mutated ISDR sequence. They were almost equally insensitive to IFN treatment when EMCV was challenged. HCV thus has functional protein(s), possibly NS5A, to suppress IFN-induced antiviral activity and plays an important role in virus-cell interaction and regulation of viral replication.     

Mutations of the interferon sensitivity-determining region (ISDR) correlate with the complexity of hypervariable region (HVR)-1 in the Japanese variant of hepatitis C virus (HCV) type 1b

Hepatitis C virus (HCV) genotype 1b comprises mainly two subtypes in Japan, each named for its geographic prevalence (Japan-specific, J type; worldwide, W type). Because the newly identified subtypes have not been fully characterized, the present study directed this issue from virological viewpoints such as hypervariable region (HVR)-1 as well as interferon (IFN) sensitivity-determining region (ISDR). Fifty chronic hepatitis patients with HCV 1b (31 men and 19 women; mean age 50.5 years) were enrolled, and J/W type was determined according to envelope 1 (E1) sequence as described previously (23 J type and 27 W type). Correlations between age, number of HVR-1 clones, HVR-1 diversity, and ISDR mutations were analyzed in J and W type patients independently. In addition, the sequences of the three HCV regions obtained for the determination of the above genetic factors were studied phylogenetically. The number of HVR-1 clones was significantly higher for J type in comparison with W type (P = 0.044). In the J type-infected patients, the ISDR mutation number was correlated inversely with HVR-1 clone number (P = 0.0001, r = -0.734) and HVR-1 diversity (P = 0.0001, r = -0.722). However, this correlation was not observed in the W type patients. W type patients showed a significant correlation between age and HVR-1 clone number (P = 0.015, r = 0.462). Phylogenetic study revealed that the nonstructural (NS) 5A sequence, which is obtained for ISDR type determination, can distinguish between J and W types. The inverse correlation in J type patients between ISDR mutations and HVR-1 complexity may explain the usefulness of the ISDR for prediction of IFN response only in Japanese patients. This suggests that the ISDR is not directly related to IFN responsiveness, but the degree of HVR-1 complexity may be more important.     

Statistical analysis of combined substitutions in nonstructural 5A region of hepatitis C virus and interferon response

Interferon (IFN) therapy (+/- ribavirin) is the only currently available treatment for chronic hepatitis C virus (HCV), but is not effective for a majority of patients. Several studies have correlated IFN response with substitutions in a small region of the nonstructural 5A (NS5A) gene product of HCV, termed the interferon sensitivity determining region (ISDR). Many other studies, however, have been unable to verify this correlation. To address this issue, available data from published studies was used to create a database of 675 individual ISDR sequences. The database was used to analyze substitutions in the ISDR with regard to IFN response. Combined data was analyzed by the chi-square independence test and by logistic regression analysis. Each statistical analysis demonstrated a strong correlation between IFN response and substitutions in the ISDR. A statistically significant correlation was also found between IFN-response and substitutions in ISDRs of combined studies that independently were unable to detect a correlation. The failure of these individual studies to verify a correlation seems to be at least partially due to inadequate sample size. A new model for chi-square analysis is proposed that could allow a correlation between IFN-response and ISDR sequence to be detected for data sets with less statistical power than that required for the current model. The ISDR database was also used to analyze individual substitutions in the ISDR. The results show that IFN-sensitive viruses contain a larger number and more diverse collection of substitutions than IFN-resistant viruses. Substitutions that are most likely to be tolerated or detrimental to NS5A function in the IFN-response mechanism were identified as a first step toward site directed mutagenesis of the ISDR.