慢性乙型肝炎免疫清除期患者HBsAg基因多态性

目的 研究慢性乙型肝炎免疫清除期患者乙型肝炎病毒表面抗原(HBsAg)基因多态性.方法 设计特异性引物,自10例慢性乙型肝炎免疫清除期患者血清中扩增S基因片段,TA克隆法克隆到T载体中,随机选择克隆测序.结果 共20个克隆被测序,20个克隆S蛋白发现12个不同位点的32次变异.主要集中在T细胞表位,B细胞表位及a决定簇.结论 慢性乙型肝炎免疫清除期患者存在HBsAg变异,可能仍然存在HBsAg免疫耐受.     

升麻葛根汤治疗免疫清除期慢性乙型肝炎临床研究

目的:研究升麻葛根汤治疗免疫清除期慢性乙型肝炎(CHB)的疗效。方法:100例免疫清除期CHB患者随机分为治疗组60例和对照组40例,治疗组患者采用升麻葛根汤,1剂/d,水煎分两次服;对照组患者服用双虎清肝颗粒12g/次,2次/d;24周为1个疗程。对比观察治疗前后两组患者症状体征、ALT、AST、Alb、TBil,HBV-M(HBV标志物)、HBV DNA。结果:治疗组总有效率优于对照组(P0.05)。两组患者治疗前后症状体征均有显著改善,胁肋疼痛和食欲不振方面,治疗组改善更优于对照组(P0.05)。两组患者TBil、AST、ALT与治疗前比较,差异均有显著性意义(P0.05),与对照组比较,治疗组患者肝功能指标下降水平更优(P0.05)。两组患者病毒学应答治疗组优于对照组(P0.05)。结论:升麻葛根汤治疗免疫清除期CHB,能够改善患者临床症状、体征及肝功能,能够抑制病毒复制,疗效可靠。     

免疫疗法联合干扰素治疗慢性乙型肝炎的初步研究

探讨免疫疗法联合干扰素治疗不同免疫应答期慢性HBV感染患者的疗效.145例慢性乙型肝炎患者(免疫耐受期66例,免疫清除期64例,残余整合期15例)随机分为联合治疗组(乙肝疫苗 胸腺肽 绿脓杆菌菌毛 干扰素,其中免疫耐受期42例,免疫清除期46例.共88例)和对照组(单用干扰素治疗,其中免疫耐受期24例,免疫清除期18例.共42例),观察ALT及病毒标志物变化.治疗后,免疫清除期联合治疗组的ALT复常率、HBeAg、HBV DNA阴转率和HBeAg/抗-HBe血清转换率均显著高于对照组(P＜0.05).免疫耐受期,治疗组HBeAg、HBV DNA阴转率和HBeAg/抗-HBe转换率均明显高于对照组(P＜0.05).免疫疗法联合干扰素治疗慢性乙型肝炎,疗效明显优于单用干扰素治疗.     

20～40岁慢性 HBV 感染者临床特征分析

目的：在慢性乙型肝炎病毒感染自然史的背景下，探讨20～40岁年龄段的慢性 HBV 感染者临床特征，以指导临床治疗。方法用实时荧光定量聚合酶链反应（FQ-PCR）及时间分辩荧光免疫分析（TRFIA）技术检测1000例（20～40岁）慢性 HBV 感染者血清中 HBV DNA、HBV M（hepatitis B virus marker）含量，用速率法检测 ALT 水平。结果男性患者在免疫清除期和再活动期的比例明显高于女性（P ＜0．05）；水平传播感染的患者在非活动期和再活动期的比例明显高于垂直传播（P ＜0．05）；垂直传播的患者 HBsAg 水平明显高于水平传播的患者（P ＜0．05）。结论20～40岁慢性 HBV 感染者传播途径、性别可影响其自然病程。     

HBV感染免疫耐受期患者应进行抗病毒治疗降低病毒量

传统观念认为免疫耐受期患者的病情是良性的,不会导致不良预后,不推荐抗病毒治疗。但是随着研究的深入以及防控理念的改变,这种观念面临极大的挑战。1免疫耐受期的概念慢性HBV感染的自然史很复杂,根据患者感染病毒与宿主免疫状态及其相互作用对肝脏的影响,传统上分为4个期,即免疫耐受期(慢性HBV携带状态)、免疫清除期(HBeAg阳性慢性乙型肝炎)、免疫控制期(非活动性HBsAg携带状态)和再活动期(HBeAg阴性慢性乙型肝炎)。     

免疫清除期相同肝实质细胞体积分摊的血清HBV DNA载量与肝组织炎症分级的关系

目的 阐明慢性乙型肝炎自然病程中免疫清除期相同肝实质细胞体积分摊的血清HBVDNA载量水平与肝组织炎症分级的关系. 方法 使用荧光多聚酶链反应分别检测和比较慢性乙型肝炎免疫清除期患者肝组织病理炎症分级1、2、3、4级的血清HBV DNA载量,以及肝组织炎症分级1、2,3、4级所在肝纤维化分期用相同肝实质细胞体积分摊的血清HBV DNA载量.多组资料两两比较采用ANOVA检验分析. 结果 176例处于免疫清除期慢性乙型肝炎患者肝组织病理学炎症分级1、2、3、4级血清HBV DNA载量分别为(8.20×10~5±9.11×10~1)拷贝/ml、(16×10~6±5.96×10~1)拷贝/ml、(8.12×10~5±8.01×10~1)拷贝/ml和(2.08×10~6±3.69×10~1)拷贝/ml,差异无统计学意义(P>0.05).然而,肝组织病理炎症1、2、3、4级所在肝纤维化分期用相同肝脏实质细胞体积分摊后的血清HBV DNA载量分别为(9.24×10~8±9.35×10~2)拷贝/ml、(5.33×10~9±7.56×10~2)拷贝/ml、(1.06×10~(10)±1.77×10~3)拷贝/ml、(3.31×10~(11)± 5.18×10~2)拷贝/ml,差异有统计学意义(P<0.05).结论 在HBV感染的自然病程中,从免疫耐受期进入免疫清除期后,肝细胞反复出现炎症,坏死,同时伴纤维组织增生.不同肝纤维化分期中相同肝实质细胞体积分摊的血清HBV DNA载量水平与肝组织炎症分级有关.     

慢性乙型肝炎患者不同免疫状态下外周血自然杀伤细胞亚群的特点及其临床意义

背景:外周血自然杀伤细胞(NK细胞)亚群在各种病毒感染性疾病中有不同程度的改变,其在HBV感染不同免疫状态下的变化尚不明确。目的:研究慢性乙型肝炎(CHB)患者不同免疫状态下外周血NK细胞亚群的变化特点及其临床意义。方法:采用流式细胞术检测46例CHB患者(免疫耐受期25例,免疫清除期21例)和10例健康志愿者的外周血NK细胞亚群比例,采用实时荧光定量PCR技术检测血清HBV DNA载量,同时检测血清ALT水平。结果:免疫清除期CHB患者外周血CD56~(bright)NK细胞比例明显高于免疫耐受期和健康对照组,差异均有统计学意义(0.877±0.493对0.647±0.294和0.546±0.173,P0.05);三组间CD56~(dim)NK细胞比例差异无统计学意义。外周血CD56~(bright)NK细胞比例与血清HBV DNA载量在免疫耐受期呈负相关(r=-0.575,P0.05),在免疫清除期则无相关性。各组不同免疫状态下外周血NK细胞亚群比例与血清ALT水平均无相关性。结论:外周血CD56~(bright)NK细胞比例增高可能是反映CHB患者进入免疫清除期的潜在指标之一,NK细胞及其亚群在抗HBV的适应性免疫中发挥重要调节作用。     

护肝抑毒方清除慢性乙型肝炎免疫耐受及抑制病毒复制的临床研究

目的:观察护肝抑毒系列方治疗慢性乙型肝炎(CHB)免疫耐受期及免疫清除期患者的临床疗效.方法:免疫耐受期:治疗组684例口服护肝抑毒Ⅰ号方激活免疫耐受,待ALT＞正常值上限5~10倍(＜20倍)后改用护肝抑毒Ⅱ号方;对照组326例口服香菇菌多糖片及叶下珠胶囊.免疫清除期:治疗组[免疫耐受期患者经上述治疗后肝功能未复常,乙肝病毒标志物(HBV-M)未阴转者]282例口服护肝抑毒Ⅲ号方;对照组(免疫耐受期对照组中未显效者及新增病例)228例口服双虎清肝颗粒.免疫耐受期及免疫清除期病例治疗均3个月为1个疗程,连续观察6个疗程,疗程结束后治疗组中完全应答者随访1年.观察患者症状、体征、肝功能及HBV-M的变化.结果:免疫耐受期治疗中不同时段ALT上升率治疗组明显高于对照组(P＜0.05或P＜0.01).两组患者治疗前后血清HBV-M变化比较差异有显著性意义(P＜0.01).免疫耐受期治疗组中完全应答者经1年随访,持久应答率稳定(P＞0.05).免疫清除期两组患者治疗前后肝功能变化差异有显著性意义(P＜0.05或P＜0.01).两组患者治疗后血清HBV-M阴转率比较差异有显著性意义(P＜0.05或P＜0.01).免疫清除期治疗组完全应答者经1年随访,持久应答率稳定(P＞0.05),应答率明显高于免疫耐受期(P＜0.05),但持久应答率两组相近,差异无统计学意义(P＞0.05).结论:护肝抑毒Ⅰ号方能有效激活CHB患者的免疫耐受,护肝抑毒Ⅱ、Ⅲ号方可显著抑制HBV复制,使HBV-M阴转率明显提高,并可达到较好的持久应答效果.     

HBV—DNA定量检测的临床意义探讨

血清乙肝病毒 ( HBV)抗原抗体五项指标 ( HBV-M)是临床诊断乙型肝炎的常用指标。因 HBV为逃避人类免疫清除不断地发生变异 ,故定量观察血清HBV- DNA含量对诊断和治疗慢性乙型肝炎具有重要意义。我们对 40 0例不同 HBV- DNA表现形式的患者采用 PCR荧光定量法进行 HBV- DNA含量检测 ,并对其临床意义讨论 ,现将结果报告如下。1　资料与方法本文 40 0例患者均系我院 2 0 0 0年 9～ 1 2月诊治的慢性乙肝患者 ,其中男 30 8例 ,女 92例 ;年龄 1 1～67岁。均符合 1 995年全国肝炎会议制定的诊断标准。按 HBV- M表现形式分为 8组 ,每组…     

乙肝病毒基因型与肝脏病理改变的关系

目的:探讨乙型肝炎病毒基因型与慢性乙型肝炎患者肝脏病理变化的关系.方法:应用乙肝病毒型特异性引物采用巢式聚合酶链反应(PCR)和荧光定量聚合酶链反应(FQ-PCR),对北京佑安医院住院92例慢性乙型肝炎患者进行乙型肝炎病毒基因型及亚型分析,参照2000年《病毒性肝炎防治方案》对慢性肝炎进行病理分级、分期诊断.结果:92例慢性乙型肝炎患者中HBV基因型分布为B型17例(B2亚型),B/C混合型17例(B2/Ca亚型),C型58例(Ca亚型).17例HBV B型感染患者中病理诊断肝脏炎症活动分级为G1-G3期分别为35.29%,58.82%,5.88%;肝脏纤维化程度分级为S1-3级分别为58.82%,29.41%,11.76%,17例HBV B/C型感染患者中病理诊断肝脏炎症活动分级为G1-G3期35.29%,52.94%,11.76%;肝脏纤维化程度分级为S1-3级23.52%,52.94%,23.52%,58例HBV C型感染患者中病理诊断肝脏炎症活动分级为G1-G4期31.03%,24.14%,36.21%,8.62%;肝脏纤维化程度分级为S1-4级25.86%,39.66%,5.17%,29.31%;HBV三组不同基因型的慢性乙型肝炎患者肝组织病理检查有统计学意义(x~2=15.13,P<0.01).HBV B型与B/C型感染患者年龄在21-30岁组58%-76%,31-40岁组17.6%-29.4%,C型感染患者年龄在21-30岁组25%,31-40岁组46.6%,40岁以上有24.24%;不同HBV基因型感染患者的年龄分布有显著性差异(x~2=9.54,P<0.05).结论:慢性乙型肝炎患者HBV基因型中C型比例明显高于B型与B/C型.HBV C型患者肝脏病理变化较B型与B/C型严重.不同HBV基因型感染患者的年龄分布不同.     

Management of chronic hepatitis B in treatment-naive patients

Chronic hepatitis B (CHB) is a serious health problem in Korea. The natural history of chronic HBV infection has been divided into 4 phases: immune tolerance, immune clearance, inactive HBsAg carrier state and reactivation. During the phases of immune tolerance and inactive HBsAg carrier state, no treatment is required. Patients in the immune clearance or reactivation phases are candidates for therapy. In the last years, treatment effects of CHB have considerably improved. Several agents are currently approved for the treatment of CHB: interferon alpha, pegylated interferon alpha, lamivudine, adefovir, entecavir, telbivudine and clevudine in Korea. The treatment recommendations from the 2004 Korean Association for the Study of the Liver guideline on the management of CHB have been updated to incorporate new therapeutic options. What is uncertain is which agent or combination of agents is most effective, how long therapy should last, and which criteria should be used to start, continue, switch or stop therapy. Issues for consideration include efficacy, safety and incidences of resistance, and method of administration of antiviral therapy in treatment-naive patients.     

Nucleotide sequence analysis of the precore region in patients with spontaneous reactivation of chronic hepatitis B

The role of HBV precore mutations in the spontaneous reactivation of chronic hepatitis B (CHB) is currently unknown. We studied 10 patients with CHB; five were HBeAg⁺ (group I) and five were anti-HBe⁺ (group II). All 10 had spontaneous reactivation of CHB as defined by the appearance of clinical symptoms along with an increase of serum ALT activity at least 5× above baseline values, in the absence of any other known causes of liver disease or CHB reactivation. The precore (87 nt) and proximal core (81 nt) regions were sequenced after PCR amplification. From each patient three serum samples were studied: one 3–12 months before, one during, and one six months after reactivation. Prior to reactivation, none of the group I patients harbored an HBV strain having a mutation that prevented HBeAg synthesis; however, 2/5 developed such a mutation during reactivation (G to A transition at nt 1896). Among the group II patients, three harbored an HBeAg defective mutant both before and during reactivation; after six months, two of these three patients were HBV DNA negative in serum by PCR. Several other sequence polymorphisms, some of which changed the predicted amino acid sequence, were either present initially or developed during reactivation. In conclusion, in this small group of CHB patients who were HBeAg⁺ spontaneous reactivation was accompanied in some cases by a shift to an HBeAg defective mutant, while in patients who were anti-HBe⁺, such mutations were frequently present prior to reactivation. In patients already harboring precore defective mutants, spontaneous reactivation may precede an attenuation of viral replication.     

Molecular characteristics and stages of chronic hepatitis B virus infection

Hepatitis B virus （HBV） is a common viral pathogen that causes a substantial health burden worldwide. Remarkable progress has been made in our under- standing of the natural stages of chronic HBV infection. A dynamic balance between viral replication and host immune response is pivotal to the pathogenesis of liver disease. Knowledge of the HBV genome organization and replication cycle can unravel HBV genotypes and molecular variants, which contribute to the heterogeneity in outcome of chronic HBV infection. Most HBV infections are spontaneously resolved in immunocompetent adults, whereas they become chronic in most neonates and infants at a great risk of developing complications such as cirrhosis and hepatocellular carcinoma （HCC）. Those with chronic HBV infection may present in one of the four phases of infection： immune tolerance, immune clearance [hepatitis B e antigen （HBeAg）-positive chronic hepatitis B （CHB）], inactive carrier state, and reactivation （HBeAg-negative CHB）. Understanding the dynamic nature of chronic HBV infection is crucial in the management of HBV carriers. Long-term monitoring and optimal timing of antiviral therapy for chronic HBV infection help to prevent progression of HBV-related liver disease to its later stage, particularly in patients with higher risk markers of HCC, such as serum DNA concentration, HBeAg status, serum aminotransferase, HBV genotypes, and pre-core or core mutants.     

HBeAg negative variants and their role in the natural history of chronic hepatitis B virus infection

Molecular virology methods including polymerase chain reaction,cloning and sequencing have revolutionised our understanding of viral genome variation.In the case of hepatitis B virus(HBV),sequencing studies have identified a number of virus variants normally found during the natural course of chronic infection.The appearance of the precore stop codon(with G-for-A substitution at position 1896)and basal core promoter(BCP)(with A-for-T and G-for-A,at positions 1762 and 1764,respectively)variants which reduce or abrogate hepatitis B e antigen(HBeAg)production,heralds the initiation of the seroconversion phase from HBeAg to antiHBe positivity.The gradual removal of the tolerogenic effect of HBeAg leads to the awakening of the immune response(immune clearance phase).Most patients after HBeAg seroconversion become"inactive HBsAg carriers".However during the course of infection precore and/or BCP variants may emerge and be selected leading to HBeAg negative chronic hepatitis B(CHB)with high viremia levels(reactivation phase).The prevalence of HBeAg negative CHB has been increasing over the last few decades and has become the commonest type of HBV infection in many countries of the world.This probably reflects the aging of existing HBV carriers and the effective prevention measures restricting new HBV infections.Frequent acute exacerbations accompanied by high viral replication,elevated alanine aminotransferase levels and histological activity are a common feature of HBeAg negative CHB leading to cirrhosis much faster than in HBeAg positive CHB patients.     

Assessment of chronic hepatitis B: the importance of hepatitis B virus DNA testing

Background: Chronic hepatitis B (CHB) has an estimated prevalence of 90 000 to 160 000 in Australia. Cirrhosis and hepatocellular carcinoma are important complications of CHB and appropriate evaluation of hepatitis B surface antigen (HBsAg)‐positive individuals is vital to identify treatment candidates. Methods: A review of the database of a tertiary hospital was performed and 348 HBsAg‐positive individuals with baseline demographic, virological, serological and biochemical variables were identified and evaluated cross‐sectionally. A small subgroup of hepatitis B e antigen (HBeAg)‐negative patients with normal alanine aminotransferase (ALT) at baseline were identified and followed longitudinally. Results: 175/348 (50%) of patients were in the HBeAg‐negative, chronic hepatitis phase of disease, 22% in the HBeAg‐positive immune clearance and 6% in the immune tolerant phases. HBeAg‐negative patients were older and more likely to be male than HBeAg‐positive patients. The correlation between hepatitis B virus (HBV) DNA and ALT levels was examined. ALT and HBV DNA levels showed no correlation in HBeAg‐positive CHB and only a weak correlation in HBeAg‐negative patients. Furthermore, 35% of HBeAg‐negative patients with detectable HBV DNA had a normal ALT. Conversely 38% of HBeAg‐negative patients with no detectable HBV DNA had an elevated ALT. A persistently normal ALT over 24 months was seen in five of nine HBeAg‐negative patients with normal initial ALT and detectable HBV DNA. Conclusion: Appropriate evaluation of HBeAg‐negative CHB must include HBV DNA because the ALT is not a reliable guide to underlying viral replication.     

免疫清除期慢性乙型肝炎患者外周血T细胞程序性坏死因子-1表达及其意义

目的 明确程度性坏死因子（PD-1）在免疫清除期慢性乙型肝炎患者外周血T细胞表达状态及其对患者病毒载量水平和生化指标的影响.方法 45例ALT升高的慢性乙型肝炎患者被纳入本研究.应用流式细胞术对所有患者的外周血总CD8+T细胞和CD4+T细胞PD-1表达百分比和表达强度进行检测,其中18例患者接受肝组织活检,并应用免疫...     

Current Management of Hepatitis B in 2016

Chronic hepatitis B infection represents a global public health burden, infecting over 240 million persons worldwide. It is associated with significant morbidity and mortality and represents a leading cause for cirrhosis, liver failure, liver cancer, and liver-related death. Current treatment of hepatitis B is focused on identification of patients with active hepatitis within the immune clearance or reactivation phases of chronic infection, for whom antiviral therapy with peg-interferon or nucleos(t)ide analogs are recommended. Seven antiviral agents are currently approved by the US FDA for treatment of chronic hepatitis B, of which three are recommended as first-line agents by major liver societies. As none are associated with virologic cure, the primary objective of antiviral therapy in 2016 is long-term virologic suppression, which is associated with a decreased risk for cirrhosis and hepatocellular carcinoma, and may reverse liver fibrosis or cirrhosis in some patients. Although biochemical improvement in liver enzymes is common, HBeAg seroconversion occurs in only a minority of patients, and HBsAg seroconversion is rare. Due to ongoing deficits along multiple steps of the care cascade, including screening, diagnosis, linkage to care, and antiviral therapy, many patients with chronic hepatitis B remain undiagnosed, lack access to care by specialists with expertise in the management of CHB, or have not been treated with antiviral agents. Future therapies are currently in development with the aim of functional viral cure, which may transform the treatment of CHB and improve liver outcomes.     

637例慢性HBV感染者自然史各期肝组织纤维化演变规律研究

目的研究慢性HBV感染者自然史各期中肝组织纤维化演变规律。方法按照《慢性乙型肝炎防治指南(2010年版)》描述的CHB自然史分期的血清学特征作为纳入标准,将慢性HBV感染者分为免疫耐受期、免疫清除期、非活动或低(非)复制期以及再活动期,统计和分析各组患者的性别、年龄、ALT水平、血清HBV DNA、肝组织炎症(G)的变化特点,以及各组肝组织纤维化(S)的演变规律。结果共637例患者,其中男性501例(78.6%),女性136例(21.4%)。免疫耐受期患者101例,免疫清除期患者248例,低(非)复制期患者119例,再活动期患者169例。各期患者的相应肝组织炎症分级比较均有统计学意义,其中免疫清除期和再活动期肝组织炎症较为活跃(χ2=150.424,P0.0001)。各期患者肝纤维化分期亦有统计学差异,其纤维化程度呈渐次加重的趋势(χ2=141.682,P0.0001)。结论慢性HBV感染者自然史表现为肝组织炎症反复活跃、肝组织纤维化程度进行性加重的过程。     

Chronic hepatitis B virus infection acquired in childhood: special emphasis on prognostic and therapeutic implication of delayed HBeAg seroconversion

In high endemic areas of hepatitis B virus (HBV) infection, the vast majority of infection is acquired perinatally or during early childhood. The age of the patient is, therefore, almost equivalent to the duration of HBV infection. The natural history of chronic HBV infection consists of three chronological phases: immune tolerance, immune clearance and low replicative phases. The prevalence of hepatitis B e antigen (HBeAg) in asymptomatic HBV carriers is around 90% before 15 years of age, and decreases remarkably to less than 10% after 40 years of age. The immune clearance phase is characterized by a series of hepatitis flares and remissions. These will be followed eventually by HBeAg seroconversion, which is usually accompanied by remission of liver disease and confers favourable outcome. However, patients with persistent HBeAg seropositivity over 40 years of age are associated with a significantly higher risk for progression to cirrhosis than those with HBeAg seroconversion before 40 years of age, and thus should be considered as patients with 'delayed' HBeAg seroconversion. Antiviral or immunomodulatory therapy should be considered seriously for these patients.     

Antibody to Hepatitis B Core Antigen Levels in the Natural History of Chronic Hepatitis B: A Prospective Observational Study

Previous studies have revealed antibody to hepatitis B core antigen (anti-HBc) levels as a predictor of treatment response in hepatitis B early antigen (HBeAg)-positive chronic hepatitis B (CHB) patients in both interferon and nucleos(t)ide analog therapy cohorts. However, there is no information about anti-HBc levels in the natural history of CHB.This study aimed to define anti-HBc levels of different phases in the natural history of CHB.Two hundred eleven treatment-naive CHB patients were included in the study. They were classified into 4 phases: immune tolerance (IT) phase (n = 39), immune clearance (IC) phase (n = 48), low or no-replicative (LR) phase (n = 55), and HBeAg-negative hepatitis (ENH, n = 69). Fifty patients who were HBsAg negative and anti-HBc positive were also recruited as past HBV infection (PBI) control group. Anti-HBc levels were measured by a newly developed double-sandwich immunoassay. Correlation of anti-HBc levels with alanine aminotransferase (ALT) and other HBV-related markers within each phase was performed.Serum anti-HBc levels were statistically significant between patients in different phases of CHB (P < 0.001). The median anti-HBc levels were: IT (3.17 log₁₀ IU/mL), IC (4.39 log₁₀ IU/mL), LR (3.29 log₁₀ IU/mL), ENH (4.12 log₁₀ IU/mL), and PBI (0.61 log₁₀ IU/mL). There existed a strong correlation in IC (r = 0.489, P < 0.001), a poor correlation in ENH (r = 0.275, P = 0.042), and no correlation in patients with ALT reached 5 times upper limit of normal (r = 0.120, P = 0.616).Anti-HBc levels show significant differences during the natural course of CHB. These results may provide some potentially useful insights into hepatitis B pathogenesis and immune activation against hepatitis B virus.