树突状细胞表面特异性非整联蛋白同源物基因多态性与丙型肝炎病毒感染的相关性

目的 研究丙型肝炎患者树突状细胞表面特异性非整联蛋白同源物(DC-SIGNR)外显子4基因颈区重复序列的遗传多态性分布,探讨DC-SIGNR基因多态性与HCV病毒基因分型及HCV载量的关系. 方法采用PCR结合DNA测序对268例丙型肝炎患者DC-SIGNR重复序列多态性进行基因分型和测序分析,同时检测患者的HCV病毒载量及HCV病毒基因分型.组间两两比较用LSD法.结果 DC-SIGNR基因型或等位基因与HCV基因分型的相关性不显著.HCV载量携带7等位基因的患者为(4.6722±1.9766)log10拷贝/ml,携带9等位基因的患者为(5.3073±1.6795)log10拷贝/ml,P=0.036,两组差异有统计学意义.7/7基因型的患者HCV载量水平为(4.5974±2.0067)log10拷贝/ml,9/7基因型的患者组为(5.2771±1.8587)log10拷贝/ml,P=0.025,两组差异有统计学意义.提示HCV更易与携带较长DC-SINGR等位基因的患者结合.结论 DC-SIGNR遗传多态性可能与HCV在个体内的复制有关,但与HCV基因分型不相关.     

树突状细胞表面特异性非整联蛋白同源物基因多态性与丙型肝炎病毒感染的相关性

目的 研究丙型肝炎患者树突状细胞表面特异性非整联蛋白同源物(DC-SIGNR)外显子4基因颈区重复序列的遗传多态性分布,探讨DC-SIGNR基因多态性与HCV病毒基因分型及HCV载量的关系. 方法采用PCR结合DNA测序对268例丙型肝炎患者DC-SIGNR重复序列多态性进行基因分型和测序分析,同时检测患者的HCV病毒载量及HCV病毒基因分型.组间两两比较用LSD法.结果 DC-SIGNR基因型或等位基因与HCV基因分型的相关性不显著.HCV载量携带7等位基因的患者为(4.6722±1.9766)log10拷贝/ml,携带9等位基因的患者为(5.3073±1.6795)log10拷贝/ml,P=0.036,两组差异有统计学意义.7/7基因型的患者HCV载量水平为(4.5974±2.0067)log10拷贝/ml,9/7基因型的患者组为(5.2771±1.8587)log10拷贝/ml,P=0.025,两组差异有统计学意义.提示HCV更易与携带较长DC-SINGR等位基因的患者结合.结论 DC-SIGNR遗传多态性可能与HCV在个体内的复制有关,但与HCV基因分型不相关.     

血管生长素基因与中国汉族人群糖尿病周围神经病遗传易感性的关系

目的探讨血管生长素（ANG）基因与中国汉族人群糖尿病周围神经病（DPN）遗传易感性的关系。方法采用病例一对照研究方法,对129例DPN患者和268例健康对照者,应用基因测序技术,检测ANG基因外显子区序列,分析比较DPN患者和健康对照者之间基因型和等位基因分布频率的差异。结果①PCR扩增产物片段长度为736bp,包含ANG基因整个外显子区和5’侧翼区,DPN组未检测出ANG基因突变;②DPN组和健康对照组的ANG基因外显子区单核苷酸多态性rs11701的基因型（T442T和T442G）和等位基因频率（442T和442G）比较后,差异无统计学意义,P〉0．05;③按性别分层后,DPN组和健康对照组的ANG基因外显子区单核苷酸多态性（SNP）rs11701的基因型和等位基因频率比较后,差异均无统计学意义,两组P〉0．05。结论ANG基因与中国汉族人群DPN遗传易感性无关。     

IL-28B基因变异与丙型肝炎的易感性及其自然清除的关系

目的探讨IL-28B基因变异与丙型肝炎的易感性和丙型肝炎病毒（HCV）自然清除之间的关系。方法利用焦磷酸测序的方法对411例HCV感染者（男性225人,女性186人）及100例健康对照人群进行了IL-28B基因变异位点rs12979860的多态性检测;对HCV感染者进行病毒定量的检测,比较HCV感染人群和健康对照人群,慢性丙型肝炎（CHC）人群和丙型肝炎自愈人群IL-28B基因变异位点的差异以及不同基因型的携带者病毒定量的差异。结果中国健康人群IL-28B基因变异位点rs12979860的最小等位基因频率为6%,与日本人相近,与欧洲人群相差较大。SNP（rs12979860）位点的等位基因频率和基因型频率在HCV感染人群和健康对照人群之间差异无统计学意义（P=0.066;P=0.072）,C/C基因型CHC人群病毒定量水平高于C/T基因型,二者之间差异有统计学意义（P=0.02）;丙型肝炎自愈人群中C/C基因型和C/T基因型差异无统计学意义（P=0.64）。结论 CHC人群rs12979860 SNP基因型与健康人群表达无明显差别,该基因型（rs12979860）不是HCV的易感基因,其CC基因型并不能预测丙型肝炎发生自愈的病程。     

湖北汉族人2型糖尿病与Calpain10基因多态性的相关研究

目的探讨Calpain10基因对湖北汉族人2型糖尿病遗传易感性的影响。方法采用病例对照研究,以聚合酶链式反应联合限制性内切酶的多态性（PCR—RFLP）分子生物学技术,选择262例2型糖尿病患者作为试验组和262例血糖正常者为对照组,对其Calpainl0基因上的SNP43及SNPl9位点多态性进行分析。结果在2型糖尿病人群中,SNP43的G等位基因频率,与对照组相比（93．8％比79．97％）,差异有统计学意义（P〈0．05）。而SNPl9位点等位基因频率在2组中的频率分布差异无统计学意义（P〉0．05）。此外,在本研究对照组中,SNP43GG基因型与体质量指数和腰一臀围比值增加相关。结论SNP43位点等位基因G在Calpain10基因中可直接或与其他糖尿病基因相互作用决定湖北汉族人2型糖尿病的遗传易感性。     

斑秃与CTLA-4基因外显子1 A/G49多态性研究

目的探讨细胞毒性T淋巴细胞相关抗原4（CTLA-4）基因外显子1第49位点A/G多态性是否与斑秃的遗传易感性有关。方法采用聚合酶链反应-限制性片段长度多态性分析（PCR-RFLP）对56例斑秃患者和124例正常对照者的CTLA-4基因外显子1的第49位点进行基因分型。结果斑秃患者CTLA-4基因第一外显子第49位点基因型频率与正常对照组比较差异无统计学意义（χ^2=1.768,P〉0.05）;斑秃患者CTLA-4基因第一外显子第49位点等位基因频率与正常对照组比较差异无统计学意义（χ^2=1.676,P〉0.05）。结论CTLA-4基因第一外显子第49位碱基A→G多态性与斑秃的发病可能无相关性。     

内皮素受体B基因多态性与慢性阻塞性肺疾病及吸烟因素的相关性研究

目的探讨内皮素受体B（EDNRB）基因的第4外显子-30G／A处单核苷酸多态性与慢性阻塞性肺疾病（COPD）易感性及吸烟因素之间关系。方法采用PCR—RFLP技术,检测并分析EDNRB基因一30G／A（L277L）单核苷酸多态性位点在COPD组和健康对照组中的基因型频率、等位基因频率,同时分析该多态性位点与吸烟相关COPD之间是否存在相关性。结果研究发现EDNRB基因一30G／A处基因型频率分布在COPD组和对照组之间差异有统计学意义（P〈0．05）,但等位基因频率的分布在两组之间差异无统计学意义（P〉0．05）。在对COPD组和对照组中吸烟者的基因型分布频率和等位基因分布频率比较后,发现两组之间差异无统计学意义（P〉0．05）,提示该突变位点与吸烟所致的COPD之间可能无相关性存在。结论EDNRB一30G／A位点多态性可能与COPD易感性相关,与吸烟相关的COPD无关。     

新发现的蒙古族ABCA1M233V基因和R219K基因多态性

目的探讨ATP结合盒转运子A1基因（ABCAl）M233V和R219K多态性在内蒙古地区蒙古族人群中的分布及其与血脂和冠心病的关系。方法采用聚合酶链反应一限制片段长度多态性（PCR．RFLP）方法检测115例蒙古族冠心病患者和对照组ABCAl基因相应片段的多态性。结果内蒙古地区蒙古族人群中ABCAl基因M233V多态性位点存在MM,MV和vv三种基因型,其在冠心病患者和对照组人群的基因多态性分布差异无统计学意义（P〉0．05）。MM组和MV＋VV组总胆固醇（TC）,甘油三酯（TG）,高密度脂蛋白胆固醇（HDL-C）和低密度脂蛋白胆固醇（LDL-C）比较,差异无统计学意义（P〉0．05）。对照组KK基因型的频率显著高于CHD组（P〈0．05）。KK基因型的HDL-C水平显著高于RR型（P〈0．05）,KK型TG水平明显低于RR型,差异有统计学意义（P〈0．05）。结论内蒙古地区蒙古族人群中存在新发现的ABCAl基因M233V多态性,ABCAl基因R219K多态性与内蒙古地区蒙古族人群冠心病的遗传易感性相关,KK基因型产生有益的临床血脂谱,可能是冠心病患者的低危遗传标记。     

吸毒人群和HIV-1感染者人群DC-SIGN/DC-SIGNR基因多态性分析

目的 研究等位基因DC-SIGN/DC-SIGNR在人类免疫缺陷病毒Ⅰ型(HIV-1)感染者与HIV-1阴性吸毒人群中的分布,筛选出HIV-1抗性基因.方法 选择深圳市戒毒所HIV抗体阴性戒毒者的样本257份,HIV-1感染者的样本220份.提取外周血基因组DNA,对DC-SIGN/DC-SIGNR颈区基因进行特异性聚合酶链反应(PCR)扩增,PCR扩增产物行琼脂糖凝胶电泳检测和基因序列测定分析.结果 通过统计学分析发现,DGSIGNR颈区中杂合子7/5、7/6和7/7在HIV阴性吸毒者中出现的频率为13.33%、7.50%、49.4%,在HIV-1感染者中出现的频率为11.05%、4.65%、51.74%,两者无明显差异.说明DC-SIGN在吸毒者与HIV-1感染者中的基因型及等位基因的分布无明显差异.结论 深圳市吸毒人群中DC-SIGNR和DC-SIGN基因型分布和等位基因出现频率,与HIV-1感染者无显著性差异,推测DC-SIGNR和DC-SIGN基因多态性对HIV-1易感性无明显影响.     

IL-28B基因多态性与丙型肝炎易感性的关系

目的:探讨白介素-28B(interleukin-28B,IL-28B)单核苷酸多态性位点rs8099917与中国丙型肝炎易感性的关系.方法:采用TaqMan SNP基因分型的方法检测中国天津地区263名丙型肝炎患者和244名健康人IL-28B rs8099917基因型和等位基因分布情况,并统计分析rs8099917基因型和等位基因在2组中分布的差异.结果:在263名丙型肝炎患者中,TT基因型223人(84.8%),TG基因型39人(14.8%),GG基因型1人(0.4%).T等位基因频率为92.2%.244名健康对照者中,TT基因型222人(91.0%),TG21人(8.60%),GG1人(0.40%),T等位基因频率为95.3%.丙型肝炎患者和健康人群TG/GG基因型频率差异有统计学意义(OR=1.810,95%CI:1.042-3.145;P=0.033).丙型肝炎患者G等位基因频率也高于健康人(OR=1.709,95%CI:1.010-2.893;P=0.044).结论:中国人群IL-28B rs8099917基因多态性与丙型肝炎病毒(hepatitis C virus,HCV)感染易感性相关联.G为HCV感染的风险等位基因.     

Polymorphism of codon25 in signal peptide region of transforming growth factor beta 1 and its association with chronic hepatitis C virus infection

OBJECTIVE: To investigate the possible relationship between polymorphism of codon25 in signal peptide region of transforming growth factor beta 1 (TGFb1) and hepatitis C virus (HCV) infection susceptibility. METHODS: Genotypes of TGFb1 of 191 subjects (85 HCV infected patients and 106 healthy controls) were studied. Genotypes of TGFb1 codon25 were determined by amplification refractory mutation system (ARMS). RESULTS: Differences of codon25 polymorphism were not found between HCV infected patients and the controls (P more than 0.05), which showed a similar pattern between the chronic hepatitis C group and HCV-associated liver cirrhosis group (P more than 0.05). There were no differences of genotype distribution of codon25 between ALT normal and ALT elevated patients (P more than 0.05), but G allele frequency was higher in ALT elevated group (P=0.040). There were great differences between the distribution of genotypes (P=0.005) and allele frequency (P=0.000) of the HCV RNA positive and the negative groups in that the HCV RNA positive group differed greatly from the negative group. CONCLUSION: Polymorphism of TGFb1 codon25 may influence the grade of liver inflammatory activity. High G allele frequency of codon25 may be associated with viremia in patients with chronic HCV infection. It seems that polymorphism of codon25 in the signal peptide region of TGFb1 may contribute to the outcome of HCV infected patients.     

转化生长因子β1信号肽区单核苷酸多态性与慢性丙型肝炎的相关性

目的 探讨HCV感染者转化生长因子β1(TGF β1)信号肽区密码子25基因多态性与HCV感染的相关性. 方法 采用扩增阻碍突变系统方法,分析106名健康对照者和85例慢性HCV感染者的TGF β1信号肽区密码子25基因多态性. 结果 TGF β1信号肽区密码子25的基因型分布与基因频数在HCV感染组和对照组之间,慢性丙型肝炎组和HCV相关肝硬化组之间的差异均无统计学意义.密码子25基因型分布在ALT正常组和ALT升高组之间的差异无统计学意义,但G基因频数在ALT升高组(G=108)较ALT正常组(G=47)高(P-0.040).密码子25基因型分布在尢病毒血症组(GG=18,CG=5,CC=3)和病毒血症组(GG=55,CG=4)之间的差异有统计学意义(P=0.005),且G等位基因更多出现干病毒血症组(P=0.000).结论 TGF β1信号肽区密码子25G→C突变影响HCV感染肝脏炎性反应,G等位基因与HCV感染病毒血症相关,TGF β1信号肽区密码子25G→C突变可能是影响HCV感染结局的因素之一.     

Distribution of IL28B Genotypes in Iranian Patients with Chronic Hepatitis C and Healthy Individuals

Background

IL28B polymorphism is recognized as one of the most prominent predictors of hepatitis C spontaneous and treatment-induced clearance. Interestingly, the favorable genotypes of IL28B are found to be more frequent in Asian ethnicity than Caucasian and African populations, respectively. A few studies reported that there is a mysterious association between the IL28B polymorphism and the hepatitis C virus (HCV) genotype in patients with chronic hepatitis C but they did not give any reason for this phenomenon.

Objectives

The foremost purpose of this study was to compare the distribution of IL28B genotypes between Iranian healthy individuals and patients with chronic hepatitis C.

Patients and Methods

In this study, 921 patients with chronic hepatitis C and 142 healthy individuals were included. The IL28B rs12979860 and rs8099917 polymorphisms were genotyped using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

Results

The frequency of IL28B rs12979860 CC, CT, and TT genotypes in chronic hepatitis C patients was 38%, 48.8%, and 13.2% and in healthy individuals was 43.7%, 48.6%, and 7.7%. Also, the frequency of IL28B rs8099917 TT, GT, and GG genotypes in chronic hepatitis C patients was 58.3%, 37.1%, and 4.6% and in healthy individuals was 64.1%, 32.4% and 3.5%. The differences in the distribution of IL28B rs12979860 and rs8099917 genotypes between patients with chronic hepatitis C and healthy individuals were not statistically significant. When we compared the distribution of IL28B genotypes between the healthy group and the HCV infected patients by HCV genotype, we found 9.8% higher frequency of rs12979860 CC genotype in the healthy individuals than HCV genotype 1 infected patients (P = 0.03) however there was no significant difference in the distribution of rs12979860 genotypes between the healthy and HCV genotype 3 infected groups (P = 0.46).

Conclusions

It seems that the impact of IL28B polymorphism on the spontaneous clearance of HCV genotype 1 is more prominent than HCV genotype 3 which results in the observation of higher rs12979860 C allele frequency in chronic hepatitis C patients with HCV genotype 3 than HCV genotype 1.     

Cytotoxic T lymphocyte associated antigen-4 gene polymorphisms confer susceptibility to primary biliary cirrhosis and autoimmune hepatitis in Chinese population

AIM: To investigate the association between Chinese patients with autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC) and the polymorphisms of cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) gene promoter (-318) and exon 1 (+49). METHODS: CTLA-4 promoter (-318 T/C) and exon1 (+49A/G) polymorphisms were genotyped via restriction fragment length polymorphism methods in 62 Chinese AIH patients, 77 Chinese PBC patients and 160 healthy controls. RESULTS: We found a significant association in CTLA-4 gene exon1 49 A/G polymorphism between PBC patients and controls (P = 0.006) and the frequency of G alleles was significantly increased in comparison with controls (P = 0.0046, OR = 1.8). We also found the frequency of C alleles in promoter -318 was significantly increased in AIH patients compared with controls (P = 0.02, OR = 0.41). Although the genotype distribution of the CTLA-4 exon 1-promoter gene was not significantly different between AIH and PBC patients and controls, the occurrence of GG-CC was increased in two groups of patients (AIH: 32.3%, PBC: 37.7%, control: 22.5%). CONCLUSION: Polymorphisms of CTLA-4 gene probably confer susceptibility to AIH and PBC in Chinese population.     

Cytokine gene polymorphisms and the susceptibility to liver cirrhosis in patients with chronic hepatitis C

Background: The speed of fibrosis progression varies considerably between patients with chronic hepatitis C. This study analyzed whether cytokine gene polymorphisms are associated with a progressive course of the disease. Methods: Leukocyte DNA from 101 patients with chronic hepatitis C, 52 patients with hepatitis C virus (HCV)‐induced cirrhosis and 200 Caucasian blood donors was prepared. Using PCR, RFLP and PAGE, gene polymorphism analysis of the interleukin (IL)1α(?889), IL1β(?511 and +3954), IL1 receptor agonist (RA)(intron2 VNTR), IL4(intron3 VNTR) and TNFα(?308) loci was performed. Results: Of the polymorphisms analyzed, IL1β(?511) and IL1RA(intron2 VNTR) were unevenly distributed between the study groups. The IL1β(?511)^*A2A2 genotype occurred significantly more often in chronic hepatitis C and HCV‐induced liver cirrhosis than in the controls (P<0.01, P<0.05, respectively). Patients with HCV‐induced cirrhosis displayed a significantly higher frequency of the IL1RA(intron2 VNTR)^*A2 polymorphism than patients with chronic hepatitis C and controls (P<0.05). Conclusions: Although the IL1β(?511)^*A2A2 genotype may increase the susceptibility to acquire chronic hepatitis C and IL1RA(intron2 VNTR)^*A2 polymorphism is associated with disease progression to cirrhosis, our results indicate that the analyzed cytokine gene polymorphisms have an overall low impact on the natural course of chronic hepatitis C infection.     

干扰素-α/β受体基因多态性与HBV感染结局的关系

目的：探讨IFN-α/β受体基因多态性与HBV（乙肝病毒）感染不同临床转归之间的相关性。方法：应用基因测序检测80例自限性HBV感染者（SR组）和220例慢性持续性HBV感染者（PC组）[包括无症状HBV携带者（AsC组）88例和进展性肝病者132例（慢性乙型肝炎76例、肝硬化56例）]的IFN（干扰素）-α/β受体基因-568G→C、-408C→T两个位点的多态性,比较各组间基因型和等位基因频率。结果：①-568G→C位点多态性中,PC组总GG基因型频率比SR组显著升高,差异有显著性意义（P〈0.05）。等位基因G的频率,进展性肝病组均显著高于SR组（P〈0.05）。②-408C→T位点多态性中,进展性肝病组总CC基因型显著高于SR组（P〈0.05）,而肝硬化组和慢性乙型肝炎组之间,SR组和AsC组之间差异均无显著性。结论：IFN-α/β受体基因-568G→C、-408C→T两个位点的多态性,与HBV感染不同结局之间有关,携带-568G→C GG基因型和G等位基因的HBV感染者容易发展为慢性,G等位基因更趋向于进展性肝病,而携带-408C→T CC基因型患者则容易进展为慢性乙型肝炎甚至肝硬化。     

CCR△532 mutation does not influence the susceptibility to HCV infection, severity of liver disease and response to therapy in patients with chronic hepatitis C

AIM: To study whether CCR5Delta32 mutation was associated with viral infection and severity of liver disease. METHODS: Two hundred and fifty two histologically proven, chronic HCV patients (mean age: 41 +/- 14 years; M/F: 164/88) were genotyped. PCR based genotyping of 32 bp deletion at the CCR5 locus was done. Four-hundred and eight matched healthy controls were studied to assess susceptibility to HCV infection. To assess correlation of immune gene polymorphism with severity of HCV related liver disease, patients with chronic HCV infection were divided into those with a fibrosis score of <= 2 (mild) or > 2 (severe) and histological activity index (HAI) of <= 5 or > 5. For correlation between CCR5Delta32 mutations and response to therapy, 129 patients who completed therapy were evaluated. RESULTS: The majority (89.4%) of the patients were infected with genotype 3. The frequency of homozygous CCR5Delta32 mutants was comparable to HCV patients as compared to the healthy controls (0.7% vs 0%, P = 0.1). Further more, the frequency of CCR5Delta32 mutation was comparable in patients with mild or severe liver disease. (P = NS). There was also no association observed with response to therapy and CCR5Delta32 mutation. CONCLUSION: CCR5Delta32 mutation does not have a role in disease susceptibility, severity or response to therapy in patients with chronic hepatitis C infection.     

CCR5△32 mutation does not influence the susceptibility to HCV infection, severity of liver disease and response to therapy in patients with chronic hepatitis C

AIM: To study whether CCR5△32 mutation was associated with viral infection and severity of liver disease.METHODS: Two hundred and fifty two histologically proven, chronic HCV patients (mean age: 41 ± 14 years;M/F: 164/88) were genotyped. PCR based genotyping of 32 bp deletion at the CCR5 locus was done. Fourhundred and eight matched healthy controls were studied to assess susceptibility to HCV infection. To assess correlation of immune gene polymorphism with severity of HCV related liver disease, patients with chronic HCV infection were divided into those with a fibrosis score of ≤ 2 (mild) or ＞ 2 (severe) and histological activity index (HAI) of ≤ 5 or ＞ 5. For correlation between CCR5△32 mutations and response to therapy, 129 patients who completed therapy were evaluated.RESULTS: The majority (89.4%) of the patients were infected with genotype 3. The frequency of homozygous CCR5△32 mutants was comparable to HCV patients as compared to the healthy controls (0.7% vs 0%, P = 0.1).Further more, the frequency of CCR5△32 mutation was comparable in patients with mild or severe liver disease.(P = NS). There was also no association observed with response to therapy and CCR5△32 mutation.CONCLUSION: CCR5△32 mutation does not have a role in disease susceptibility, severity or response to therapy in patients with chronic hepatitis C infection.     

Single nucleotide polymorphism at exon 7 splice acceptor site of OAS1 gene determines response of hepatitis C virus patients to interferon therapy

Background and Aim: Response to interferon therapy and disease progression in hepatitis C virus (HCV) infected patients differs among individuals, suggesting a possibility of a contribution of host genetic factors. 2′‐5′‐oligoadenylate synthetase 1 (OAS1), an important component of the innate immune system with a proven antiviral function, may therefore have a relationship with the response to interferon therapy and clinical course of HCV disease. Our aim was to determine the frequency of single nucleotide polymorphism (SNP) at exon 7 splice acceptor site (SAS) of the OAS1 gene in relation to the interferon response and status of HCV infection. Methods: A 203 bp fragment containing exon 7 SAS was amplified in 70 HCV chronic patients and 50 healthy controls. SNP was examined using restriction fragment length polymorphism (RFLP) genotyping method. Correlations of SNP genotypes with response to interferon and clinical status of patients were statistically analyzed. Results: There was an increasing trend of response from AA to AG to GG genotypes (P = 0.007). Genotype AA was associated with non‐response to interferon and higher degree of liver fibrosis (P = 0.05). Multivariate analysis showed this SNP as independent and a significant determinant of the outcome of interferon therapy (odds ratio 4.913 [95% confidence interval 1.365–8.2], P = 0.006). Conclusions: This is the first study to show a significant association between the functional SNP at exon 7 SAS of OAS1 gene and the viral response to interferon in chronic HCV patients. Patients with AA genotype were associated with progressive HCV disease and viral resistance to interferon therapy. This OAS SNP is a potential bio‐marker to predict IFN response in chronic hepatitis C patients.