肠道菌群在自身免疫性疾病中的研究进展

自身免疫性疾病(autoimmune disease,AID)通过自身产生抗体,导致免疫耐受失衡,而引起的一系列慢性炎症反应,甚至对机体组织造成损伤。目前AID发病率逐渐升高,而其确切的发病机制尚不明确。肠道菌群作为人体最大的"免疫器官",参与机体代谢,形成肠粘膜屏障,维持免疫功能正常。随着对人体肠道菌群研究的深入,越...     

Cutting edge issues in autoimmune hepatitis

Autoimmune hepatitis (AIH) is a severe liver disease affecting all age groups worldwide. Novel basic and clinical aspects of AIH, addressed at a Monothematic Conference in London in September 2015, are highlighted in this review. The diagnosis of AIH relies upon detection of characteristic autoantibodies, hypergammaglobulinemia, and interface hepatitis on liver histology. The International Autoimmune Hepatitis Group (IAIHG) has devised diagnostic scoring systems to help in comparative studies and clinical practice. AIH arises in a genetically predisposed host, when yet unknown triggers – such an encounter with a pathogen – lead to a T cell-mediated immune response targeting liver autoantigens. This immune response is inadequately controlled because regulatory mechanisms are impaired. The mainstay of treatment for AIH is immunosuppression, which should be instituted as soon as the diagnosis is made. Standard treatment regimens include relatively high doses of predniso(lo)ne, which are tapered gradually as azathioprine is introduced. Recent guidelines have described newer treatment regimens and have tightened the goal of therapy to complete normalization of biochemical, serological and histological parameters. Mycophenolate mofetil, calcineurin inhibitors, mTOR inhibitors and biological agents are potential salvage therapies, but should be reserved for selected non-responsive patients and administered only in experienced centers. Liver transplantation is a life-saving option for those patients who progress to end-stage liver disease. Further dissection of cellular and molecular pathways involved in AIH pathogenesis is likely to lead to the discovery of novel, tailored and better tolerated therapies.     

Strongyloides stercoralis hyperinfection in patient with autoimmune hepatitis and purpura fulminans

Strongyloidiosis is usually an asymptomatic chronic nematodal disease. The term hyperinfection is used to denote autoinfection, a phenomenon in which the number of worms increases enormously. Development or exacerbation of gastrointestinal and pulmonary symptoms is seen, (A) and the detection of increased numbers of larvae in stool and or sputum is the hallmark. It is known to occur with a change in immune status of the host; this can occur due to immunosuppressants. Cytomegalovirus (CMV) is also known to suppress host immunity. Due to the nonspecific presentation, the diagnosis is frequently missed, and the outcome remains poor with 15–87% mortality despite therapy. We report here a case of Strongyloides stercoralis hyperinfection following immunosuppressive therapy for autoimmune hepatitis and concomitant CMV infection with purpura fulminance and frank sepsis, with fatal outcome.     

Occult HBV infection in patients with autoimmune hepatitis: A virological and clinical study

Background/PurposeOccult HBV infection (OBI) could have serious clinical consequences in patients receiving immunosuppressive therapy. We aimed to investigate the prevalence of OBI in Chinese patients with autoimmune hepatitis (AIH) and to analyze its clinical and virological features.Methods103 AIH cases were enrolled. Hepatitis B virus (HBV) serological markers were screened by chemiluminescence. HBV-DNA were detected by nest-PCR and real-time PCR. HBV genotyping and mutation analysis were performed by Sanger sequencing.ResultsTwenty-four out of 103 (23.30%) AIH patients had OBI as evidenced by positive HBV-DNA and negative hepatitis B surface antigen (HBsAg). HBV genotype C is the predominant genotype (57.89%), which had more amino acid (AA) substitutions in S region than that of B-genotype group (P = 0.001). The distribution of AA substitution in the ‘α’ determinant region between genotype C and B were significantly different (P = 0.042). In addition to those already reported OBI-associated AA substitutions (e.g., sG145R and sV184A), some new OBI-associated AA substitutions (e.g., sV106A, sC137* and sL176P) were found in AIH patients in our study. Three out of 24 (12.50%) OBI patients were diagnosed as decompensated cirrhosis, one patient with S deletion mutation and two patients with HBV extensive AA substitutions.ConclusionsThere was a higher proportion of AIH patients with OBI than the general population in China, which can be either seropositive or seronegative-OBI in AIH patients is associated with some specific AA substitutions. The presence of deletion mutations and the extent of AA substitutions in the HBV S region may have predictive clinical implications.     

Alteration of the lung parenchyma associated with autoimmune hepatitis

Summary The clinical history, radiological and histomorphological alterations of the lung parenchyma associated with chronic active autoimmune hepatitis are described. A 6-month-old female infant developed chronic active autoimmune hepatitis associated with autoimmune haemolytic anaemia. She was treated with immunosuppressive drugs, including steroids, for more than 6 years and developed symptoms and radiological signs of interstitial pneumonitis 4 years after onset of the autoimmune hepatitis. Associated bronchiectasis was detected 1 year later. No abnormalities of lung defence mechanisms could be demonstrated. Resection of the sixth left segment and of the basal parts of the left lower lobe revealed honeycombing with changes in the lung parenchyma which included chronic interstitial pneumonitis with multinucleate giant cells, seen predominantly in the distal airways, marked diffuse interstitial mononuclear infiltrates and mild diffuse interstitial fibrosis as well as bronchiectasis and organizing pneumonia. Granulomatous lesions, angiitis and necrotic areas were absent. Immunohistochemistry for immunoglobulins was negative for IgA, IgG and IgM and positive for IgD in the multinucleate giant cells. A strong positive reaction to HLA-DR-specific monoclonal antibody was noted, whereas no specific sugar receptors (endogenous lectins) could be detected by use of biotinylated glyconeoproteins.     

Association between intestinal microbiota and inflammatory bowel disease

Inflammatory bowel disease (IBD), which includes Crohn''s disease (CD) and ulcerative colitis (UC), has emerged as a global disease with high incidence, long duration, devastating clinical symptoms, and low curability (relapsing immune response and barrier function defects). Mounting studies have been performed to investigate its pathogenesis to provide an ever‐expanding arsenal of therapeutic options, while the precise etiology of IBD is not completely understood yet. Recent advances in high‐throughput sequencing methods and animal models have provided new insights into the association between intestinal microbiota and IBD. In general, dysbiosis characterized by an imbalanced microbiota has been widely recognized as a pathology of IBD. However, intestinal microbiota alterations represent the cause or result of IBD process remains unclear. Therefore, more evidences are needed to identify the precise role of intestinal microbiota in the pathogenesis of IBD. Herein, this review aims to outline the current knowledge of commonly used, chemically induced, and infectious mouse models, gut microbiota alteration and how it contributes to IBD, and dysregulated metabolite production links to IBD pathogenesis.     

Recent updates on the management of autoimmune hepatitis

Autoimmune hepatitis (AIH) is an immunoinflammatory chronic liver disease with dynamic and rather heterogeneous disease manifestations. A trend of increasing prevalence of AIH has been observed worldwide, along with a relative increase in the percentage of male patients. AIH is characterized and diagnosed based on serum biochemistry and liver histology: elevated aminotransferases and serum immunoglobulin G (IgG), the presence of serum anti-nuclear antibody or anti-smooth muscle antibody, and interface lympho-plasmacytic hepatitis. Clinical manifestations differ among disease subtypes with distinct time-frames, i.e., AIH with a chronic insidious onset, and acute-onset AIH (the diagnosis of which is often challenging due to the lack of typical serum findings). The absence of disease-specific biomarkers or histological findings may expand the disease phenotype into drug-induced AIH-like liver injury. Corticosteroids and azathioprine are recommended first-line treatments for AIH. The complete normalization of aminotransferases and serum IgG is an essential treatment response to ensure long-term overall survival. An incomplete response or intolerance to these drugs is considered an indication for second-line treatment, especially with mycophenolate mofetil. Life-long maintenance treatment is required for the majority of patients, but the few who achieve prolonged and stringent biochemical remission with lower alanine aminotransferase and IgG within the normal range may be able to discontinue the medications. In the future, the quality of life of AIH patients should be managed by personalized medicine, including the appropriate selection and dosing of first-line therapy and perhaps alternating with potential therapeutics, and the prediction of the success of treatment withdrawal.     

HLA-DRB1 alleles of susceptibility and protection in Iranians with autoimmune hepatitis

Autoimmune hepatitis (AIH) is an uncommon autoimmune liver disease of unknown etiology. The aim of this study was to determine the frequency of HLA-DRB1 alleles in Iranian patients with AIH and investigate the association between HLA alleles and the different types of the disease. Fifty-four AIH patients and 100 age- and sex-matched healthy controls were subjected to low resolution HLA-DRB typing performed by polymerase chain reaction-sequence-specific primers (PCR-SSP) technique. The results revealed higher frequencies of HLA-DRB1¹03, and DRB1¹13 alleles in patients with AIH compared to controls. However, DRB1¹11 was less frequent in AIH patients. In type I AIH patients HLA-DRB1¹03, HLA-DRB1¹04, HLA-DRB1¹08, and HLA-DRB1¹13 were the most frequent alleles. While in type II, the most frequent alleles were HLA-DRB1¹07 and HLA-DRB1¹13. The seronegative patients showed more frequency of HLA-DRB1¹03 and HLA-DRB3. In contrary, the frequency of HLA-DRB1¹11, HLA-DRB1¹15 and HLA-DRB5 in type 1 was less than healthy individuals. These findings indicate the role of HLA-DRB haplotypes in AIH susceptibility and protection, in the Iranian population.     

Acute cytomegalovirus infection modulates the intestinal microbiota and targets intestinal epithelial cells

Primary and recurrent cytomegalovirus (CMV) infections frequently cause CMV colitis in immunocompromised as well as inflammatory bowel disease (IBD) patients. Additionally, colitis occasionally occurs upon primary CMV infection in patients who are apparently immunocompetent. In both cases, the underlying pathophysiologic mechanisms are largely elusive - in part due to the lack of adequate access to specimens. We employed the mouse cytomegalovirus (MCMV) model to assess the association between CMV and colitis. During acute primary MCMV infection of immunocompetent mice, the gut microbial composition was affected as manifested by an altered ratio of the Firmicutes to Bacteroidetes phyla. Interestingly, these microbial changes coincided with high-titer MCMV replication in the colon, crypt hyperplasia, increased colonic pro-inflammatory cytokine levels, and a transient increase in the expression of the antimicrobial protein Regenerating islet-derived protein 3 gamma (Reg3γ). Further analyses revealed that murine and human intestinal epithelial cell lines, as well as primary intestinal crypt cells and organoids represent direct targets of CMV infection causing increased cell death. Accordingly, in vivo MCMV infection disrupted the intestinal epithelial barrier and increased apoptosis of intestinal epithelial cells. In summary, our data show that CMV transiently induces colitis in immunocompetent hosts by altering the intestinal homeostasis.     

Interaction between intestinal microbiota and tumour immunity in the tumour microenvironment

In recent years, an increasing number of studies have reported that intestinal microbiota have an important effect on tumour immunity by affecting the tumour microenvironment (TME). The intestinal microbiota are closely associated with various immune cells, such as T lymphocytes, natural killer cells (NK cells) and macrophages. Some bacteria, such as Akkermansia muciniphila (A. muciniphila) and Lactobacillus reuteri (L. reuteri), have been shown to improve the effect of tumour immunity. Furthermore, microbial imbalance, such as the increased abundance of Fusobacterium nucleatum (F. nucleatum) and Helicobacter hepaticus (H. hepaticus), generally causes tumour formation and progression. In addition, some microbiota also play important roles in tumour immunotherapy, especially PD‐L1‐related therapies. Therefore, what is the relationship between these processes and how do they affect each other? In this review, we summarize the interactions and corresponding mechanisms among the intestinal microbiota, immune system and TME to facilitate the research and development of new targeted drugs and provide new approaches to tumour therapy.     

Colchicine induces enhanced intestinal permeability in the rat

Intestinal permeability was determined in rats receiving colchicine 0.5 ± 0.15 mg day^-1 in drinking water (30 mg L^-1) for periods up to 23 days. The lactulose/mannitol method was used to determine whole gut permeability before and on days 2, 4, 8, 18 and 23 of colchicine administration. The 8-h urinary lactulose excretion following the test meal increased significantly in rats receiving colchicine, compared with the pretreatment value. Increased lactulose permeability was present after 2 days and remained stable throughout the experimental period. Mannitol urinary excretion was not changed. Colchicine increases intestinal tight junction permeability by an as yet undetermined mechanism.     

dsDNA抗体检测对自身免疫性肝炎的临床意义

目的 探讨dsDNA抗体对自身免疫性肝炎(autoimmune hepatitis,AIH)的临床意义.方法 收集临床诊断为AIH的患者血清43例,采用免疫印迹法检测dsDNA抗体.按dsDNA抗体阳性与否,分为抗体阳性组及抗体阴性组,比较dsDNA抗体阳性组与阴性组临床生化指标及预后的差异.结果 43例AIH患者中dsDNA抗体阳性13例(30.23%).13例dsDNA抗体阳性AIH患者平均天冬氨酸转氨酶(AST)为(647.56±529.77)IU/ml,总胆红素(TBIL)为(10.81±8.08)ms/L,明显高于对照组(P<0.05),凝血酶原活动度(PTA)为75.72%4±30.23%,明显低于对照组(P<0.05).dsDNA抗体阳性AIH患者组肝硬化发生率为61.5%(8/13),明显高于对照组(P<0.05).对两组患者出现肝硬化的时间作生存分析,发现dsDNA抗体阳性AIH患者发生肝硬化的时间明显短于对照组(P=0.0074).结论 抗dsDNA阳性的AIH患者肝损伤较重,病情进展较迅速,预后较差.     

MMP-2、MMP-9与溃疡性结肠炎患者肠黏膜通透性的相关性研究

目的：观察血浆基质金属蛋白酶MMP-2、MMP-9表达水平与溃疡性结肠炎(ulcerative colitis,UC)患者肠黏膜通透性的联系,探讨UC的发病机制,为诊断提供较为可靠的参考指标。方法：纳入50例UC患者和30例健康志愿者,分别采集研究对象的外周静脉血,应用酶联免疫吸附法(ELISA)检测血浆MMP-2、MMP-9的表达,高效液相色谱法检测口服乳果糖(L)和甘露醇(M)混合液6 h内尿液L、M的含量,并计算乳果糖/甘露醇比值(LMR)。结果：与健康对照组相比,UC组血浆MMP-2、MMP-9水平显著升高(t=13.843,P<0.001;t=14.165,P<0.001)。UC组血浆MMP-2、MMP-9表达与疾病病变严重程度、病变范围呈正相关;UC组患者尿LMR显著高于健康对照组(t=9.804, P<0.001),UC患者血浆MMP-2、MMP-9表达与肠黏膜通透性呈一定程度的相关性(r=0.832, P<0.001;r=0.847,P<0.001)。结论：UC患者血浆MMP-2、MMP-9表达升高,并能反映UC病变严重程度、病变范围,作用机制可能与肠黏膜通透性增高有关。     

Dynamic efficiency of the human intestinal microbiota

Abstract

The emerging dynamic dimensions of the human intestinal microbiota (IM) are challenging the traditional definition of healthy gut microbiota, principally based on the static concepts of phylogenetic and functional core. On the other hand, recent researches are revealing that the microbiota plasticity is strategic for several aspects of our biology, addressing the different immunological and metabolic needs at various ages, and adjusting the ecosystem services in response to different lifestyle, physiological states or diets. In light of these studies, we propose to revise the traditional concept of healthy human IM, including its degree of plasticity among the fundamental requisites for providing host health. In order to make a model taking into account the relative importance of IM core functions and plasticity for the maintenance of host health, we address to Economics, where the efficiency of a productive system is measured by computing static and dynamic parameters.     

慢性肝病患者血清中4种自身抗体测定及临床意义

目的探讨慢性肝病患者自身免疫状况及其临床意义.方法应用ELISA法与间接免疫荧光法检测不同类型肝病患者血清中类风湿因子(RF),抗核抗体(ANA)、抗甲状腺微粒体抗体(Anti-TM)、抗双链DNA抗体(dsDNA-Ab)4种自身抗体.结果63例慢性乙肝病毒性肝病组检出一种以上自身抗体者12例(19.1%);40例丙肝病毒性肝病组检出一种以上自身抗体者12例(30%),明显高于对照组酒精、药物性肝炎组5.7%,3.3%(P＜0.01).结论自身免疫反应参与慢性肝病的发生发展过程,慢性肝病患者自身抗体测定,对于指导临床治疗具有一定意义.     

Increased intestinal sugar permeability after challenge in children with cow's milk allergy or intolerance

The diagnosis of cow's milk allergy or intolerance (CMAI) is based on clinical improvement on exclusion diet and relapse after challenge with milk. The aim of this work was to investigate the value of the cellobiose/mannitol (C/M) sugar permeability test, performed before and after cow's milk challenge, as a tool for the diagnosis of CMAI. Thirty-two patients underwent milk challenge at a median age of 13 months (range 3–84 months). A dual sugar (C/M) permeability test with an iso-osmolar solution was performed before and 24 h after challenge. Of the 10 patients who developed symptoms after challenge, nine showed increased postchallenge C/M ratio, whereas such an increase was observed in only one of the 22 nonrelapsed subjects. The postchallenge C/M ratio increase in relapsed subjects is to be attributed to both higher cellobiose and lower mannitol urinary excretion. These results suggest the use of the sugar permeability test, in addition to clinical observation, as an aid in the evaluation of provocation tests in infants with suspected CMAI.     

Effects of luminal antigen on intestinal albumin and hyaluronan permeability and ion transport in atopic patients

BACKGROUND: Increased luminal transport of proteins and fluid is part of the inflammatory reaction in inflammatory disease of the bowel and of the airways in allergic diseases and asthma. The objective of this study was to determine intestinal appearance rates of albumin and hyaluronan in vivo in atopic patients allergic to birch, as well as changes in net jejunal transport of monovalent ions and water induced by the antigen. METHODS: Secretion studies were performed with the use of a segmental jejunal perfusion system with a small two-balloon, six-channel tube. The intestinal mucosa was challenged with birch allergen in patients allergic to birch and in matched control subjects (n = 12 in both groups). RESULTS: In patients, but not in control subjects, the luminal antigen induced a net increase in albumin of 2689 ± 567 μg/cm/hr and in hyaluronan of 2609 ± 737 ng/cm/hr (p < 0.01 vs control subjects in both cases). Furthermore, basal net absorption of Cl^- ions, Na⁺ ions, and water was converted to a net secretion after antigen challenge. CONCLUSION: Exposure to antigen normally acting on the respiratory tract induced increased permeability of the gastrointestinal mucosa. This would suggest less organ specificity and more general allergic recognition shared by several immunocompetent tissues in the body, probably mediated by circulating IgE antibodies. (J ALLERGY CLIN IMMUNOL 1996;97:1225-32.)     

Relationship between plasma cells and hepatic stellate cells in autoimmune hepatitis

Autoimmune hepatitis is an inflammatory chronic disease of the liver, which frequently results in cirrhosis. The present study aimed to verify the relationship between plasma cells and stellate cells in autoimmune hepatitis. Thirty-three pre-treatment, 11 post-treatment, and 10 normal liver biopsies were reviewed. Sirius Red staining (for semi-quantitative analysis of hepatic fibrosis) and immunohistochemistry were carried out: double staining for smooth muscle α-actin and plasma cell marker (for detection and localization of activated hepatic stellate cells and plasma cells, respectively); and single staining for glial fibrillary acid protein (for detection of hepatic stellate cells). We found an increase in the stellate cell population, mainly with an activated phenotype in autoimmune hepatitis, compared to the control group (liver specimens with no histological evidence of liver disease, obtained from patients undergoing hepatic resection for benign liver mass). A positive significant correlation was observed between stellate cells and scores of fibrosis (measured by Sirius Red) and the number of plasma cells. Additionally, there was a co-localization of plasma cells and activated stellate cells. We also observed a reduction in the number of plasma cells, hepatic stellate cells, and fibrosis in patients who had successfully been treated and had a second liver biopsy post-treatment. Our findings support that the number of plasma cells can be a surrogate marker for the severity of liver disease, reflecting the number of hepatic stellate cells and the amount of fibrosis. It remains to be seen if this is a result of a direct interaction between the plasma cells and hepatic stellate cells or the response to the same stimulus that affects both cellular types.