乙型肝炎病毒感染后机体免疫反应的研究进展

机体对乙型肝炎病毒(HBV)的免疫反应是决定疾病预后的重要因素。特异或／和非特异性细胞免疫反应是清除体内HBV的最终途径，而通过细胞因子介导的非溶细胞性抗HBV作用也发挥了重要的作用。HBV感染后疾病发展的不同阶段，机体免疫反应有其各自的特点。本文就HBV感染后机体免疫反应机制作了综述。     

乙型肝炎病毒感染后机体免疫反应的研究进展

机体对乙型肝炎病毒(HBV)的免疫反应是决定疾病预后的重要因素。特异或/和非特异性细胞免疫反应是清除体内HBV的最终途径,而通过细胞因子介导的非溶细胞性抗HBV作用也发挥了重要的作用。HBV感染后疾病发展的不同阶段,机体免疫反应有其各自的特点。本文就HBV感染后机体免疫反应机制作了综述。     

乙型肝炎疫苗佐剂与Th1/Th2细胞平衡调节

日渐增多的证据表明,接种乙型肝炎疫苗后机体保护性免疫应答的产生及感染HBV后机体能否有效清除病毒与Th1/Th2细胞平衡密切相关。一般认为,Th1免疫应答与胞内感染的免疫性和防御性有关,而Th2应答则与感染慢性化有关。因此,在应用乙型肝炎疫苗免疫机体时,若能辅以某种佐剂,调节Th1/Th2细胞平衡,使之诱导机体产生以Th1型应答为主的免疫反应,将有助于有效预防及治疗HBV感染。     

乙型肝炎疫苗佐剂与Th1／Th2细胞平衡调节

日渐增锪证据表明，接种乙型肝炎疫苗后机体保护性免疫应答的产生及感染HBV后机体能否有效清除病毒与Th1/Th2细胞平衡密切相关。一般认为，Th1免疫应答与胞内感染的免疫性和防御性有关，而Th2应答则与感染慢性化有关。因此，在应用乙型肝炎疫苗免疫机体时，若能辅以某种佐剂，调节Th1/Th2细胞平衡，使之诱导机体产生以Th1型应答为主的免疫反应，将有助于有效预防及治疗HBV感染。     

乙型肝炎病毒基因变异与免疫逃逸的研究进展

HBV感染机体后,为了达到长期在宿主体内存在的目的,在机体的免疫压力、药物和其他因素的作用下可发生基因变异,来逃避宿主的免疫监视和清除,不同读码框的不同幕因变异导致免疫逃逸的机制也不相同.此文就HBV不同读码框的基因变异与免疫逃逸的关系进行综述.     

乙型肝炎病毒感染者T细胞介导免疫应答研究进展

对于乙型肝炎病毒感染者来说,机体针对HBV编码抗原的体液及细胞免疫应答,虽有利于病毒的清除,同时也导致对感染肝细胞的损伤。在此过程中,T细胞介导免疫应答起关键作用。本文就近年来这方面的研究进展作一综述。     

肿瘤坏死因子与乙型肝炎

近几年的研究发现,肿瘤坏死因子(TNF)与乙型肝炎病毒(HBV)感染的关系密切,TNF既对HBV具有抑制及清除作用,反过来又可导致多种乙型肝炎的临床表现。抗-TNF或TNF与其它细胞因子联合使用,有利于机体清除HBV。     

辅助性T细胞和乙型肝炎研究进展

辅助性T细胞(简称Th细胞)是根据功能分类的一个T细胞亚群,按分泌的细胞因子不同分为ThO、Th1、Th2、Th3四个亚型,其中研究最多的是Th1和Th2两个亚型。乙型肝炎病毒(HBV)感染机体后,多种因素影响Th细胞增殖并且调节其亚型比例,直接或间接地影响到乙型肝炎发病及其转归,并与肝脏损伤密切相关。近年来在乙型肝炎治疗方面,越来越多的研究集中于激发Th1类免疫反应来清除HBV。本文主要就Th细胞和乙型肝炎在以上几方面的联系进行综述。     

B7家族共刺激分子与机体对乙型肝炎病毒感染的免疫耐受

机体对HBV的免疫耐受是HBV感染慢性化的主要机制.共刺激分子是控制免疫应答的开关.B7家族共刺激分子是最基本的共刺激分子,在HBV感染中可提供细胞活化所需要的第二信号,决定T细胞是活化增殖还是转为无能状态,对机体的免疫耐受起重要作用.了解B7家族共刺激分子在HBV感染免疫应答中的作用,对揭示HBV感染免疫耐受机制有重要的意义.     

免疫系统在乙型、丙型病毒性肝炎发病过程中作用研究进展

乙型病毒性肝炎和丙型病毒性肝炎分别由乙型肝炎病毒和丙型肝炎病毒感染所致。乙型肝炎病毒（HBV）、丙型肝炎病毒（HCV）感染呈全球分布,我国是高流行地区,由于HBV、HCV基因的高变性,容易逃避机体免疫系统的清除。HBV、HCV感染免疫系统细胞,造成机体对HBV、HCV感染的免疫应答异常,并引起组织的损伤,导致肝细胞的慢性持续性感染,并可进一步发展成肝硬化,甚至肝细胞肝癌。HBV、HCV主要经血液传播,包括输血与血制品传播、静脉吸毒、针刺、医源性传播、性接触和母婴垂直传播。     

扶正祛毒法在慢性乙型肝炎病毒携带者中的应用及展望

慢性HBV携带者由于没有明显的临床症状,常隐匿进展为肝硬化或肝癌,因此治疗需求迫切.西医发现其核心机制为免疫耐受但无干预手段,中医认识到其“正虚毒伏”病机关键与免疫耐受机制的相通性,以扶正祛毒立法,为免疫耐受期的慢性HBV携带者带来新的治疗前景.     

High levels of hepatitis B virus DNA in body fluids from chronic carriers

Chronic infection with hepatitis B virus (HBV) is a major global health problem. Transmission is mainly blood-borne, although the route of infection during horizontal transmission in childhood is unclear. Nosocomial outbreaks of HBV have been widely reported, but have mainly focused on blood-borne transmission. There is limited knowledge of the viral load levels in other body fluids. In the present study, chronic HBV carriers were tested for the presence of HBV DNA in serum, saliva, nasopharyngeal fluid, urine and tears by means of qualitative and quantitative polymerase chain reaction (PCR) methods. Twenty-five patients who were positive for HBV DNA with both PCRs were included. Low titres in real-time PCR corresponded with weak bands in the qualitative assay. HBV DNA was found in two urine samples, 10 saliva samples, five nasopharyngeal swabs and in tear fluid from four patients. One highly viraemic HBeAg-positive carrier with serum HBV DNA levels of 7 x 10(9) genome copies had high copy numbers detected in both saliva and nasopharyngeal fluid. These results demonstrate that highly viraemic HBV carriers may have high titres of HBV DNA in other body fluids. This has particular importance for infection control programmes and regulations, underlining the importance of aiming towards regular HBV DNA testing and thus infectivity assessment of chronic carriers in order to prevent transmission.     

HBV感染外周血单个核细胞的临床意义

HBV可感染外周血单个核细胞并在细胞内复制。HBV感染外周血单个核细胞与隐性HBV感染有关 ;与围产期母婴传播相关 ;影响机体体液免疫及细胞免疫状态 ,使HBV持续感染 ;也与病情的轻重及反复有关。     

外周血单个核细胞在乙肝病毒传播中的作用

在急性乙肝和慢性乙肝患者的外周血单个核细胞都有不同程度的乙型肝炎病毒感染。外周血单个核细胞不但可以从外周血摄取乙型肝炎病毒 ,而且乙型肝炎病毒可在其内复制、转录、翻译并能释放病毒颗粒 ,具有一定的感染性。乙型肝炎病毒感染外周血单个核细胞可逃避免疫反应 ,导致病情的隐匿化。当外周血单个核细胞所处的外环境改变时 ,可导致其再次激活 ,引起肝移植术后乙肝复发、乙肝的输血传播及母婴传播     

乙型肝炎病毒携带者妊娠对新生儿的影响探讨

目的 :探讨乙型肝炎病毒慢性携带者妊娠对新生儿的影响。方法 :检测 66例 HBs Ag阳性产妇静脉血、脐血、乳汁中 HBV DNA含量并对其分娩及新生儿指标进行分析。结果 :脐血 HBV DNA阳性率为 59.1% ;产妇血 HBVDNA含量与脐血 HBV DNA含量的相关系数为 0 .3 72 (P<0 .0 5) ,呈正相关 ;产妇血、脐血 HBV DNA含量与新生儿体重无关 ,有新生儿窒息与无新生儿窒息者比较 ,产妇血、脐血 HBV DNA含量均无显著性差异。结论 :乙型肝炎病毒慢性携带者妊娠可造成新生儿乙型肝炎病毒感染 ,孕妇分娩前的感染状况不能反映其对胎儿发育、胎盘功能的影响     

Detection of hepatitis B virus DNA by in situ tissues hybridization in corneal of HBsAG positive donors

HBV is a hepatotropic virus. The highest concentration found in the blood and liver with lower amount in saliva and semen. The virus was also detected in body fluids. Keratoplasty is an essential operation for the treatment of corneal blindness. At Ain Shams University International Eye Bank 10% of the collected corneas were from donors with HBs antigenemia. These corneas were rejected according to the Eye Bank Association of America. In this study 32 corneal tissues of 16 donors positive HBsAg were examined for,the presence of HBV by in situ DNA hybridization technique to detect HBV DNA in the corneal sections. This marker could not be seen in this work. This preliminary study could be an encouraging step for further researches to evaluate the possibility of the avascular cornea to carry HBV.     

Hepatitis B prevention, diagnosis, treatment and care: a review

Hepatitis B virus (HBV) infection is a major cause of morbidity and mortality worldwide. Chronic hepatitis B (CHB) infection is associated with an increased risk of cirrhosis, hepatic decompensation and hepatocellular carcinoma (HCC). The likelihood of developing CHB is related to the age at which infection is acquired; the risk being lowest in adults and >90% in neonates whose mothers are hepatitis B e antigen positive. Treatment of CHB infection aims to clear HBV DNA and prevent the development of complications. There are currently seven drugs available for the treatment of CHB: five nucleos(t)ide analogues and two interferon-based therapies. Long-term treatment is often required, and the decision to treat is based on clinical assessment including the phase of CHB infection and the presence and extent of liver damage. A safe and effective HBV vaccine has been available since the early 1980s. Vaccination plays a central role in HBV prevention strategies worldwide, and a decline in the incidence and prevalence of HBV infection following the introduction of universal HBV vaccination programmes has been observed in many countries including the USA and parts of South East Asia and Europe. Post-exposure prophylaxis (PEP) with HBV vaccine +/- hepatitis B immunoglobulin is highly effective in preventing mother to child transmission and in preventing transmission following sharps injuries, sexual contact and other exposures to infected blood and body fluids. Transmission of HBV in the health care setting has become an increasingly rare event in developed nations. However, it remains a significant risk in developing countries reflecting the higher prevalence of CHB, limited access to HBV vaccination and PEP and a lack of adherence to standard infection control precautions.     

TNF-α基因多态性与慢性乙肝病毒感染的相关性

慢性乙肝病毒（HBV）感染是一个全球性的卫生问题,但HBV感染的具体机制仍不明确。目前研究证实其主要与病毒本身因素、宿主免疫因素和遗传因素相关。细胞因子在防御病毒感染中发挥重要作用,而肿瘤坏死因子-α（TNF-α）是宿主防御中的关键细胞因子,对固有免疫和适应性免疫系统有广泛影响。本文通过查阅相关文献,探索TNF-α启动子区域的4个位点（-308,-238,-863,-857）的基因多态性与乙肝感染的相关性。结果表明各个研究结论有所不同,但大多数结果支持TNF-α基因多态性影响人体对HBV的易感性。     

Hepatitis B markers in Gloucestershire firemen

Occupational exposure to blood and body fluids and the prevalenceof serological markers of hepatitis B virus (HBV) infectionwere studied in Gloucestershire firemen to assess the occupationalrisk of HBV infection. A high compliance was achieved (472/503,94 per cent). Cumulative occupational exposure to blood or bodyfluids rose progressively to 68 per cent after 24 years' service.No sera were positive for hepatitis B surface antigen (HBsAg).Six sera were positive for hepatitis B surface antibody (anti-HBs)and were tested for hepatitis B core antibody (anti-HBc). Thefour subjects who were positive for anti-HBs alone had all receivedHBV vaccine. Two sera contained both anti-HBs and anti-HBc.Therefore, 2/472 firemen (0.42 per cent) showed evidence ofprevious HBV infection, a similar proportion to that found ina recent study in UK blood donors (0.49 per cent). Despite considerableexposure to blood and body fluids, an occupational risk of hepatitisB infection was not found in Gloucestershire firemen.