Pathogenesis Of CD Research Articles

Seroreactivity to microbial components in Crohnʼs disease is associated with ileal involvement, noninflammatory disease behavior and NOD2/CARD15 genotype, but not with risk for surgery in a Hungarian cohort of IBD patients

Antibodies directed against Saccharomyces cerevisiae (ASCA), perinuclear components of neutrophils (pANCA), and porin protein C of Escherichia coli (anti-OmpC) are reported to be associated with disease phenotype and may be of diagnostic importance in inflammatory bowel disease (IBD). Since limited data are available from Eastern Europe, we assessed the above antibodies in Hungarian IBD patients. In all, 653 well-characterized, unrelated consecutive IBD patients (Crohn's disease [CD]: 558, m/f: 263/295, duration: 8.1 +/- 10.7 years; ulcerative colitis [UC]: 95, m/f: 44/51, duration: 8.9 +/- 9.8 years) and 100 healthy subjects were investigated. Sera were assayed for anti-Omp and ASCA by enzyme-linked immunosorbent assay (ELISA) and ANCA by indirect immunofluorescence assay (IIF). TLR4 and NOD2/CARD15 variants were tested by polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP). Detailed clinical phenotypes were determined by reviewing the medical charts. Anti-Omp, ASCA, and atypical pANCA antibodies were present in 31.2%, 59.3%, and 13.8% of CD, 24.2%, 13.7%, and 48.5% of UC patients, and in 20%, 16%, and 5.6% of controls, respectively. ASCA and anti-Omp positivity were associated with increased risk for CD (odds ratio [OR](ASCA) = 7.65, 95% confidence interval [CI]: 4.37-13.4; OR(Omp) = 1.81, 95% CI: 1.08-3.05). In a logistic regression analysis, anti-Omp and ASCA were independently associated with ileal and noninflammatory disease, but not with a risk for surgery or response to steroids or infliximab. A serology dosage effect was also observed. ASCA and anti-Omp antibodies were associated with NOD2/CARD15, in addition to a gene dosage effect. No associations were found in UC. Serological markers were useful in the differentiation between CD and UC in an Eastern European IBD cohort. Reactivity to microbial components was associated with disease phenotype and NOD2/CARD15 genotype, further supporting the role of altered microbial sensing in the pathogenesis of CD.

Contribution of Various Susceptibility Genes to Pediatric‐onset IBD

Background/aims: Heritability appears greater in early- versus late-onset inflammatory bowel disease (IBD). We evaluated the contribution and phenotypic correlations of a confirmed locus (IBD5) and confirmed (CARD15) or suggested (OCTN1, OCTN2, MDR1, DLG5, TLR4 and NOD1/CARD4) susceptibility genes in a single center population of patients diagnosed at age ≤ 17 years. Methods: 380 probands (60% Male) with IBD (total 251 CD, 107 UC, indeterminate colitis 22), their parents, and 42 affected sibs were genotyped for the IBD5 markers: IGR 2096, IGR 2198, IGR 2230, OCTN1, and OCTN2; the 3 risk alleles of CARD15 (R702W, G908R and 1007fsinsC); MDR1 (rs1045642); NOD1/CARD4 (rs2075820); TLR4 (rs4986790) and DLG5 (1248696, 2289310). Evidence of susceptibility was sought using FBAT (family-based association test); phenotypic correlations were sought using multivariate logistic modeling (MLM). Results: 66% patients were non-Jewish Caucasian; 23% Jewish Caucasian. 24% of CD and 14% of UC probands had affected first degree relative(s). UC was extensive in 77% and 21% had undergone colectomy. CD macroscopically involved small bowel (sb) only in 54% and colon only in 14%. At most recent follow-up, CD was inflammatory in 74% and stricturing in 17%. 30% had undergone resection. FBAT demonstrated no associations with pediatric onset UC. A very strong association was evident between sb CD and 1007fsinsC (p = 0.000001). IBD5 markers demonstrated significant association to colonic CD in non-Jewish families (p=0.004). MDR1 demonstrated significant association with CD (p=0.03) primarily in Jewish patients (p=0.02). A similar association was seen for TLR4 (CD: p=0.06; Jewish: p=0.04). No association was found between CD and the NOD1/CARD4 or DLG5 polymorphisms. MLM confirmed the association between 1007fsincC and isolated sb CD (OR: 5.4, p=0.001). Whilst the risk of stenotic disease was increased in isolated sb disease (OR: 8.2, p=0.001) and Jewish heritage (OR: 3.4, p=0.008), no independent effect of 1007fsinsC was evident (OR: 0.7, p=0.6). TLR4 was strongly associated with isolated colonic disease in both CD (OR: 3.6, p=0.02) and IBD overall (OR: 2.5, p=0.04). Conclusions: In this cohort of exclusively early onset IBD, we confirm the association of CARD15, IBD5 and TLR4 with CD susceptibility and document a novel association with MDR1. Previously described associations with DLG5 are not replicated. We demonstrate that variation in TLR4 predisposes to isolated colonic disease. Our findings reinforce the importance of ethnic stratification in genetic studies, and support the role of barrier function and innate immunity in CD pathogenesis.

Human inflammatory bowel disease does not associate with Lawsonia intracellularis infection

BackgroundThere is increasing evidence that bacterial infection of the intestinal mucosa may contribute to the pathogenesis of inflammatory bowel diseases (IBD). In pigs, an obligate intracellular bacterium, Lawsonia intracellularis (LI), was shown to cause proliferative enteropathy (PE) of which some forms display histological and clinical similarities to human IBD. Since LI-similar Desulfovibrio spp. may infect human cells, we hypothesized that LI might be associated with the development of human IBD.ResultsIn human intestinal tissue samples, PCR using LLG, 50SL27, LSA and strictly LI-specific 16SII primers, yielded either no amplicons or products with weak homology to human genomic sequences. Sequencing of these amplicons revealed no specificity for LI. However, amplification of DNA with less specific 16SI primers resulted in products bearing homology to certain Streptococcus species. These 16SI-amplified products were present in healthy and diseased specimens, without obvious prevalence.ConclusionLI is not associated with the pathogenesis of UC or CD. Whether an immunologic response to commensal bacteria such as streptococci may contribute to the chronic inflammatory condition in IBD, remained to be determined.

The Critical Role of LIGHT in Promoting Intestinal Inflammation and Crohn’s Disease

Crohn's disease (CD) is a type of inflammatory bowel disease associated with increased Th1 cytokines and unique pathological features. However, its pathogenesis has not been fully understood. Previous studies showed that homologous to lymphotoxin, exhibits inducible expression, competes with herpesvirus glycoprotein D for HVEM on T cells (LIGHT) transgenic (Tg) mice develop autoimmunity including intestinal inflammation with a variable time course. In this study, we establish an experimental model for CD by adoptive transfer of Tg mesenteric lymph node cells into RAG(-/-) mice. The recipients of Tg lymphocytes rapidly develop a disease strikingly similar to the key pathologic features and cytokine characterization observed in CD. We demonstrate that, as a costimulatory molecule, LIGHT preferentially drives Th1 responses. LIGHT-mediated intestinal disease is dependent on both of its identified signaling receptors, lymphotoxin beta receptor and herpes virus entry mediator, because LIGHT Tg mesenteric lymph node cells do not cause intestinal inflammation when transferred into the lymphotoxin beta receptor-deficient mice, and herpes virus entry mediator on donor T cells is required for the full development of disease. Furthermore, we demonstrated that up-regulation of LIGHT is associated with active CD. These data establish a new mouse model resembling CD and suggest that up-regulation of LIGHT may be an important mediator of CD pathogenesis.

Hypogalactosylation of serum IgG in patients with coeliac disease.

Coeliac disease (CD) is described as an autoimmune enteropathy associated with the presence of IgG and IgA antigliadin and antitransglutaminase autoantibodies. While of diagnostic significance, the role of these autoantibodies in the immunopathogenesis of CD is elucidated. An inappropriate T cell immune response to gluten is also involved in the pathogenesis of CD, as evidenced by autoantibody switching. The N-glycans released from serum IgG of CD patients and three groups of healthy controls, of differing age ranges, were analysed by NH2-high performance liquid chromatography (HPLC). The fucosylated biantennary N- glycans were the most abundant neutral oligosaccharides; in particular, the agalacto form (G0F) showed a mean value of 42% (s.d. +/- 7.4), 30% (s.d. +/- 5.9), 26% (s.d. +/- 4.2) and 35% (s.d. +/- 6.8) for CD patients, healthy children, healthy adults under 40 and healthy adults over 40 years old, respectively. The ratio of asialo agalacto fucosylated biantenna to asialo monogalacto fucosylated biantenna (G0F)/(G1F) for CD patients showed a significant increase compared to healthy children (P < 0.0002), healthy adults under 40 (P < 0.0002) and healthy adults over 40 years old (P < 0.01). Hypogalactosylation was more pronounced for CD patients than for the patients with other autoimmune diseases such as rheumatoid arthritis or psoriatic arthritis.

Family history of inflammatory bowel disease is uncommon among African Americans

Background: Infectious agents were implicated in the pathogenesis of 1BD. Such infections may be seasonal. However, no information is available regarding the linkage between the month of birth of the patient and the risk to develop CD or UC in Israel. Aim: To determine the risk of developing CD and UC according to the momh of birth. Methods: Birth dates of CD and UC patients in three medical centers were recorded. Data from 576 CD and 268 UC patients born in Israel were available. The risk to develop disease was determined using the standard mortality ratio (SMR). Results: The SMRs for CD and UC according to the month of birth showing significant differences are depicted in the table. Compared to the general population, a sigmficant risk to develop CD but not UC is associated with birth during the winter period, November to February. By contrast, birth during the spnng was found to be protective for onset of CD. Conclusion: These data show that the risk to develop CD, but not UC, vanes significantly by season. These findmgs may support the notion that infectious agents are involved in the pathogenesis of CD,

Microbial factors in inflammatory bowel disease

An unsolved puzzle in IBD research is whether germs, genes, or a combination of the two with excessive immune responses to gut-associated bacteria explains the pathogenesis of UC and CD. Whatever the answer, there is little doubt that microbial factors are involved intimately in IBD pathogenesis. Although a long search has failed to confirm a direct pathogenic role for a specific infectious agent, compelling evidence suggests that commensal enteric bacteria and their products provide a local environmental trigger that initiates and perpetuates IBD, reactivates quiescent disease, results in the frequent septic complications of CD, and contributes to the development of several extraintesinal manifestations. The most compelling evidence for involvement of the enteric flora in the pathogenesis of IBD has been generated from studies of animal models, which collectively support the view that IBD is due to genetically determined dysregulation of the mucosal immune response to luminal antigens derived from the normal bacterial flora. Although removing or dampening the dominant antigenic stimuli with antibiotics or probiotics is conceptually superior to the current array of immunosuppressive and anti-inflammatory agents that nonspecifically block the inflammatory cascade, more definitive, rigorously designed, controlled trials of treatments directed at the microflora are needed. Future research investigating mechanisms of tolerance to luminal bacteria and an understanding of how probiotics can manipulate the intestinal flora beneficially will bring clinicians closer to identifying potential therapeutic targets and unraveling the bacterial connection to IBD pathogenesis.

Human Leukocyte Antigen Class II Alleles in White Brazilian Patients With Celiac Disease

ABSTRACTBackgroundCeliac disease (CD) is a permanent gluten intolerance disorder characterized by malabsorption, intestinal mucosa villus atrophy, and crypt hyperplasia. Clinical and histologic features improve in persons consuming a gluten free diet. The pathogenesis of CD involves environmental, genetic, and immunologic factors.MethodsThe frequencies of human leukocyte antigen (HLA) class II alleles were evaluated in white Brazilian patients who had CD and compared with those observed in healthy individuals from the same geographical area (Ribeirão Preto, São Paulo) and of similar ethnic background. Twenty‐five patients with CD, 11 females and 14 males, and 91 control individuals were studied. The HLA class II alleles were typed using amplified DNA hybridized with sequence‐specific primers. Statistical analysis was performed using the two‐tailed Fisher exact test. The relative risk (RR), etiologic fraction (EF), and preventive fraction (PF) were also estimated. The EF represents the attributable risk for the development of CD at the population level, whereas PF represents the protective risk.ResultsThe frequency of the HLA‐DRB1*03, HLA‐DRB1*07, and HLA‐DQB1*02 alleles was significantly increased in patients. The RR conferred by these alleles was 5.35, 7.15, and 10.6, respectively, and the EF was 48.7%, 44.7%, and 76%, respectively. The frequency of HLADQB1*06 alleles was significantly decreased in CD patients, conferring an RR of 0.08 and a PF of 48%.ConclusionsThe results show that HLA‐DRB1*03, HLA‐DRB1*07, and HLA‐DQB1*02 alleles conferred susceptibility to CD in Brazilian patients. In contrast, HLADQB1*06 alleles conferred protection against development of the disease.

CURRENT THEORIES ON THE CAUSES OF INFLAMMATORY BOWEL DISEASE

The understanding of the pathogenesis of CD and UC has greatly expanded over the last decade. The combination of abnormalities in the immune system, the contribution of nonimmune cells in the intestinal mucosa, a variety of genetic risk determinants, and random environmental factors may all be necessary to induce what clinically presents as IBD. It is likely that several agents can initiate an immune response that in the intestinal microenvironment and the genetic background of the patient finally leads to pathology.

Measles vaccination and inflammatory bowel disease.

Measles vaccination and inflammatory bowel disease.

PREVALENCE OF COELIAC DIESASE IN FIRST DEGREE RELATIVES OF NON-COELIAC INSULIN DEPENDENT DIABETES MELLITUS SUBJECTS.

93 Autoimmune diseases are known to be clustred not only in the same individual, but also in different members of the same family. An increased prevalence of autoimmune disorders have been found in first degree relatives(FDR) of patients with insulin-dependent diabetes mellitus (IDDM). Recent data support the hypothesis that autoimmune mechanisms might be operative in the pathogenesis of CD and this prompted as to screen for CD the FDR of IDDM subjects. Methods The study population comprised 252 IDDM patients, 562 FDR and 2000 healthy blood donors. The subject sera were screened for IgA-endomysium antibody (AEA) by IFA using the human umbilical cord vein(HUCV) tissue as antigenic substrate. Duodenal biopsy was performed in all subjects tested positive for AEA. The FDR sera were also screened for the related IDDM autoantibodies: antiglutamic acid decarboxylase (GAD) and anti-IA2. Results The results are summarized in thetable. 19(7.5%) of the IDDM patients have CD. 4 (9.5%) of the FDR of coeliac diabetics have CD. 11 (2%) of the FDR of AEA-negative diabetics have CD. 6 (0.3%) of the 2000 blood donors have CD. 2 (4.7%) of the FDR of coeliac diabetics had positive GAD antibodies. 19 (3.6%) of the FDR of AEA-negative dibetics had positive GAD antibodies and 10 (1.9%) of the FDR of the same group had IA2 positive antibodies.Conclusions Our data demonstrate an increased prevalence of CD in FDR of IDDM subjects with negative AEA test. The prevalence of AEA in the FDR of diabetics with negative AEA test are slightly lower of the related IDDM autoantibodies.

Mucosal substance P receptor expression in HIV infection and inflammatory bowel disease.

Gastrointestinal (GI) disease is a common manifestation of HIV infection. Symptoms may result from the acquisition of intestinal infection, but in certain cases functional and mucosal abnormality may result from mucosal HIV infection. The pathogenesis of HIV enteropathy is poorly understood, but a range of neuroenteric disturbances has been described including a reduction in mucosal substance P (SP). Inflammatory bowel disease (IBD) is a generic term used to describe two major clinical entities; Crohn's disease (CD) and ulcerative colitis (UC). Dysregulation of mucosal neuropeptide expression has been implicated in the pathogenesis of CD and UC. Mucosal SP expression has been variously described as increased, normal or reduced in intestinal tissue from patients with IBD. In contrast, uniform increases in mucosal SP receptor (SPR) have been described in patients with IBD using quantitative autoradiography. The purpose of this study was to characterize intestinal mucosal SPR mRNA expression in control, HIV and IBD patients using semiquantitative reverse transcription PCR. Intestinal tissue was obtained during diagnostic colonoscopy from 7 control, 9 HIV-infected and 28 (12 CD and 16 UC) IBD patients. RNA was isolated from the tissue biopsies, reverse transcribed and amplified with primers specific for SPR. SPR mRNA expression was detected in 7/7 (100%) of control, 2/9 (22%) of HIV-infected, 12/12 (100%) of CD and 11/16 (69%) of UC intestinal biopsies. These data demonstrate that SPR mRNA expression is significantly reduced in patients with HIV infection. Reduced mucosal SPR expression may contribute to the mucosal abnormality, altered intestinal motility and GI symptoms associated with HIV infection.

Eicosanoids Content in Small Intestinal Mucosa of Children with Celiac Disease

SummaryCeliac disease (CD) is characterized by diarrhea, growth retardation, and weight loss in genetically susceptible subjects on a gluten‐containing diet. The exact pathogenesis of CD is still obscure, but it is considered to be immunologically mediated. We have previously shown elevated prostaglandin E2 (PGE2) and thromboxane B2 (TxB2) content in small intestinal mucosa obtained from active celiac children. In the present study, we found significantly elevated PGE2, leukotriene B4 (LTB4), and leukotrienes C4,D4, and E4 (LTC4D4E4) content in small bowel mucosa from children suffering from CD on a gluten‐containing diet in comparison to control subjects. PGE2 was 25,278 ± 7,761 vs. 4,478 ± 426 pg/mg of protein (mean ± SEM), respectively. LTB4 was 8,807 ± 3,706 vs. 403 ± 63 pg/mg of protein (mean ± SEM), respectively. LTC4D4E4 was 15,369 ± 4,085 vs. 2,998 ± 279 pg/mg of protein (mean ± SEM), respectively. We conclude that the elevated content of arachidonic acid metabolic products via cyclooxygenase and lipoxygenase pathways may contribute to the diarrhea and may be involved in the pathogenesis of mucosal injury.

ADENOVIRUS 12 INFECTION AND COLLIAC DISEASE

It is noteworthy the region of amino acid sequence homology between A gliadin and the early region E1b protein of human adenovirus 12 /Ad 12/. The encounter of immune system with E1b protein produced during viral infection may be important in the pathogenesis of coeliac disease /CD/ because of immunological cross reactivity. We have investigated the prevalance of neutralising antibody to Ad 12 among children with treated CD /16 girls, 7 boys, moan age: 8, 7 years, range: 4.0 - 13.9 years/. 23 age-matched children served as controls. Serial two fold dilution of sera were incubated with the same volume of 20 TCIO50 of Ad 12 at 37°C for two hours, then the mixtures were added to the test tubes containing of HEp2 cell culture. The cytopathic effects were examined after five to six days incubation. Reciprocal neutralising antibody titres greater than 4 arbitrarily were regarded as positive. 12 of 23 treated coeliac children had neutralising antibody to determinants on the structural hexon protein of Ad 12. In contrast such antibody was present in only 5 of 23 controls /p -0.05/. No correlation was found between the neutralising antibody titres and the time elapsed from diagnosis of CD. The role of Ad 12 in the pathogenesis of CD may be possible on the basis of our results.