pANCA represents a cross-reactivity to enteric bacterial antigens

Autoantibodies to beta tubulin in autoimmune liver diseases-Relation to pANCA and clinical relevance

There was evidence that perinuclear antineutrophil cytoplasmic antibodies (pANCA) in autoimmune liver diseases react with human beta-tubulin-5 (TBB5). Here, we reevaluate the specificity and clinical relevance of anti-TBB5 antibodies. Patients with untreated autoimmune hepatitis (AIH; n = 53), AIH under immunosuppressive therapy (AIH-IS; n = 125), primary sclerosing cholangitis (PSC; n = 40), primary biliary cholangitis (PBC; n = 250), nonautoimmune liver diseases (n = 158), inflammatory bowel diseases (IBD; n = 30), and healthy individuals (n = 62) were tested by enzyme-linked immunosorbent assay for IgG- and IgA-antibodies against recombinant human TBB5. pANCA were detected by immunofluorescence test. Sera were absorbed with TBB5 coupled to cyanogen bromide-activated sepharose. Prevalence and reactivity of IgG anti-TBB5 were significantly higher in patients with untreated AIH (68%; arbitrary units [AU] median: 369) than in PSC (28%; AU median: 84, P < 0.001), other liver diseases (14%; AU median: 185, P < 0.0001), IBD (3%; AU median: 111, P < 0.0001), and healthy controls (3%; AU median: 135; P < 0.0001). Anti-TBB5 did not correlate with pANCA, and immunoprecipitation with TBB5 did not abolish pANCA reactivity. In untreated AIH, anti-TBB5-reactivity was significantly higher than in AIH-IS. Transaminases decreased under IS preferentially in anti-TBB5-negative patients. There was no correlation between anti-TBB5-reactivity and histological stages. IgA-anti-TBB5 was mainly found in alcohol-associated liver disease (ALD; 39%). Our data do not support TBB5 as an autoantigenic target of pANCA. However, IgG-anti-TBB5 showed high specificity for (untreated) AIH. While they did not correlate with histological and laboratory parameters, their presence may indicate a poor response to IS.

Human Microbiota Flagellins Drive Adaptive Immune Responses in Crohn's Disease

BACKGROUND AND AIMS

Crohn's disease and ulcerative colitis are characterized by dysregulated adaptive immune responses to the microbiota in genetically susceptible individuals, but the specificity of these responses remains largely undefined. Therefore, we developed a microbiota antigen microarray to characterize microbial antibody reactivity, particularly to human-derived microbiota flagellins, in inflammatory bowel disease.

METHODS

Sera from healthy volunteers (n = 87) at the University of Alabama at Birmingham and from patients recruited from the Kirklin Clinic of University of Alabama at Birmingham Hospital, including patients with Crohn's disease (n = 152) and ulcerative colitis (n = 170), were individually probed against microbiota bacterial flagellins of both mouse and human origin and analyzed for IgG and IgA antibody responses. Circulating flagellin-reactive T effector (CD4⁺CD154⁺) and T regulatory (CD4⁺CD137⁺) cells were isolated and evaluated in selected patients. Resulting adaptive immune responses were compared with corresponding clinical data to determine relevancy to disease behavior.

RESULTS

We show that patients with IBD express selective patterns of antibody reactivity to microbiota flagellins. Patients with Crohn's disease, but not patients with ulcerative colitis, display augmented serum IgG to human ileal-localized Lachnospiraceae flagellins, with a subset of patients having high responses to more than 10 flagellins. Elevated responses to CBir1, a mouse Lachnospiraceae flagellin used clinically to diagnose CD, correlated with multi-Lachnospiraceae flagellin reactivity. In this subset of patients with CD, multi-flagellin reactivity was associated with elevated flagellin-specific CD154⁺CD45RA^- T memory cells, a reduced ratio of flagellin-reactive CD4⁺ T regulatory to T effector cells, and a high frequency of disease complications.

CONCLUSIONS

Patients with Crohn's disease display strong adaptive immune response to human-derived Lachnospiraceae flagellins, which may be targeted for prognosis and future personalized therapies.

Effects of hydroalcoholic extract of Ziziphus jujuba on acetic acid induced ulcerative colitis in male rat (Rattus norvegicus)

Objective To investigate the effects of hydroalcoholic extract of Ziziphus jujuba on the histopathological, tissue oxidative stress and inflammation plus to antioxidant pathways of colon tissue in rat with induced Ulcerative colitis.

Materials and methods Ulcerative colitis was induced in 80 rats those divided into 8 equal groups. Group 1 and 2 were negative controls receiving 1 mL/day of normal saline in enema and oral; group 3 and 4 as positive control 1 and 2 received 10 mg/kg of intra-colonic asacol and oral mesalazine; groups 5 and 6 received 20% and 40% of hydroalcoholic extract of Z. jujuba trans-rectally; group 7 and 8 received 1500 and 3000 mg/kg of hydroalcoholic extract of Z. jujuba orally, respectively. After 7 days, animals were evaluated for colon tissue histopathology, levels of malondialdehyde and IL-1β, and activities of superoxide dismutase, glutathione peroxidase and myeloperoxidase in colon tissue.

Results Hydroalcoholic extract of Z. jujuba in both forms of trans-rectal and oral administration especially in the higher doses could result into a more healing effect in damaged colonic tissue, more reduce glutathione peroxidase and IL-1β level. Also, these two doses (gel 40% and oral 3000 mg/kg) could more decrease the myeloperoxidase activity and stimulate superoxide dismutase and glutathione peroxidase activities. Also, gel 40% in transrectal administration was more potent than administration 3000 mg/kg in oral.

Conclusion The results of the present study indicated that Z. jujube may be considered as a treatment of choice for Ulcerative colitis especially in gel form and also in dose-dependent pattern.

Epidemiology and Pathogenesis of Ulcerative Colitis

Ulcerative colitis (UC) is a complex chronic, immune-mediated inflammatory disorder of the colon. Factors associated with increased risk of UC include diet, particularly Western diet influences in newly industrialized nations, medications, and lifestyle factors that may influence the host's microbiome or immune response to antigens. Although much evidence identifying potential genetic and host-related factors is currently available, there are still many unanswered questions. As the global UC incidence and prevalence continues to increase, there are multiple opportunities for continued investigation to clarify our understanding of UC, identify potential predictors of disease severity, response to therapy, and novel therapeutic targets.

Invited review: Enteric bacteria, lipopolysaccharides and related cytokines in inflammatory bowel disease: biological and clinical significance

Ulcerative colitis (UC) and Crohn's disease (CD) [inflammatory bowel disease (IBD)] are both characterized by an exaggerated immune response at the gut associated lymphoreticular tissue level. Such an abnormal and dysregulated immune response may be directed against luminal and/or enteric bacterial antigens, as also supported by murine models of inflammatory bowel disease (IBD) caused by organisms such as Citrobacter rodentium and Helicobacter hepaticus.

Bacterial endotoxins or lipopolysaccharides (LPS) have been detected in the plasma of IBD patients and an abnormal microflora and/or an increased permeability of the intestinal mucosa have been invoked as cofactors responsible for endotoxemia. At the same time, the evidence that phagocytosis and killing exerted by polymorphonuclear cells and monocytes and the T-cell dependent antibacterial activity are decreased in IBD patients may also explain the origin of LPS in these diseases.

In IBD, pro-inflammatory cytokines and chemokines have been detected in elevated amounts in mucosal tissue and/or in peripheral blood, thus suggesting a monocyte/macrophage stimulation by enteric bacteria and/or their constituents ( e.g. LPS).

On these grounds, in experimental models and in human IBD, anti-cytokine monoclonal antibodies and interleukin receptor antagonists are under investigation for their capacity to neutralize the noxious effects of immune mediators. Finally, the administration of lactobacilli is beneficial in human IBD and, in murine colitis, this treatment leads to a normalization of intestinal flora, reducing the number of colonic mucosal adherent and translocated bacteria.

A mouse model for ulcerative colitis based on NOD-scid IL2R γnull mice reconstituted with peripheral blood mononuclear cells from affected individuals

Animal models reflective of ulcerative colitis (UC) remain a major challenge, and yet are crucial to understand mechanisms underlying the onset of disease and inflammatory characteristics of relapses and remission. Mouse models in which colitis-like symptoms are induced through challenge with toxins such as oxazolone, dextran sodium sulfate (DSS) or 2,4,6-trinitrobenzenesulfonic acid (TNBS) have been instrumental in understanding the inflammatory processes of UC. However, these neither reflect the heterogeneous symptoms observed in the UC-affected population nor can they be used to test the efficacy of inhibitors developed against human targets where high sequence and structural similarity of the respective ligands is lacking. In an attempt to overcome these problems, we have developed a mouse model that relies on NOD-scid IL2R γ^null mice reconstituted with peripheral blood mononuclear cells derived from UC-affected individuals. Upon challenge with ethanol, mice developed colitis-like symptoms and changes in the colon architecture, characterized by influx of inflammatory cells, edema, crypt loss, crypt abscesses and epithelial hyperplasia, as previously observed in immune-competent mice. TARC, TGFβ1 and HGF expression increased in distal parts of the colon. Analysis of human leucocytes isolated from mouse spleen revealed an increase in frequencies of CD1a+, CD64+, CD163+ and TSLPR+ CD14+ monocytes, and antigen-experienced CD44+ CD4+ and CD8+ T-cells in response to ethanol. Analysis of human leucocytes from the colon of challenged mice identified CD14+ monocytes and CD11b+ monocytes as the predominant populations. Quantitative real-time PCR (RT-PCR) analysis from distal parts of the colon indicated that IFNγ might be one of the cytokines driving inflammation. Treatment with infliximab ameliorated symptoms and pathological manifestations, whereas pitrakinra had no therapeutic benefit. Thus, this model is partially reflective of the human disease and might help to increase the translation of animal and clinical studies.

Summary: The phenotype and colitis-like symptoms induced in NSG mice reconstituted with PBMCs derived from ulcerative-colitis-affected donors reflect the human disease.

Immune Responses to Intestinal Microbes in Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBDs), including Crohn's disease and ulcerative colitis, are characterized by chronic, T-cell-mediated inflammation of the gastrointestinal tract that can cause significant, lifelong morbidity. Data from both human and animal studies indicate that IBDs are likely caused by dysregulated immune responses to resident intestinal microbes. Certain products from mycobacteria, fungi, and Clostridia stimulate increased effector T cell responses during intestinal inflammation, whereas other bacterial products from Clostridia and Bacteroides promote anti-inflammatory regulatory T cell responses. Antibody responses to bacterial and fungal components may help predict the severity of IBDs. While most currently approved treatments for IBDs generally suppress the patient's immune system, our growing understanding of microbial influences in IBDs will likely lead to the development of new diagnostic tools and therapies that target the intestinal microbiota.

Proinflammatory progranulin antibodies in inflammatory bowel diseases

BACKGROUND

Recently, we identified neutralizing autoantibodies against progranulin (PGRN) in a wide spectrum of rheumatic diseases including cases with enteropathic spondylarthritis. PGRN is a secreted protein with strong anti-inflammatory effects, believed to be mediated by the direct inhibition of TNF receptors 1&2. Given the central role of TNF-α as proinflammatory cytokine, a neutralizing antibody directed against its physiologic antagonist PGRN might entertain a proinflammatory environment.

OBJECTIVE

The aim of the present study was to investigate a possible occurrence of PGRN-antibodies (PGRN-Abs) in inflammatory bowel disease (IBD), and to investigate a possible pathogenic effect.

MATERIALS AND METHODS

Sera samples of 141 patients with Crohn's disease (CD) and of 71 patients with ulcerative colitis (UC) were tested for PGRN-Abs by ELISA. PGRN plasma levels were detected by ELISA. Proinflammatory effects of progranulin-antibodies were analyzed by TNF-α-mediated cytotoxicity assays using HT29 cells and by examination of possible effects of PGRN and of PGRN-antibodies on TNF-α-induced downmodulation of FOXP3 expression in CD4(+)CD25(hi) Tregs.

RESULTS

PGRN-Abs were found in sera of 23/141 (16.31%) patients with CD, and 15/71 (21.13%) patients with UC. PGRN-Abs were more frequent than anti-neutrophil cytoplasmic autoantibodies (ANCAs) in UC, but less frequent than anti-Saccharomyces cerevisiae antibodies (ASCAs) in CD. PGRN-Abs belonged mostly to IgG1 (71.1%) and IgA (26.3%). They occurred in relevant titres and had significant neutralizing effects on PGRN plasma levels. Cytotoxicity assays comparing PGRN-antibody-positive sera with negative sera from matched patients with IBD showed a proinflammatory effect of PGRN-Abs on HT29 cells. Moreover, PGRN-antibodies led to an increase of TNF-α-induced downmodulation of FOXP3 in CD4(+)CD25(hi) Tregs.

CONCLUSION

The results suggest that PGRN-Abs occur frequently in CD and UC, and have a proinflammatory effect.

Suppression of murine colitis and its associated cancer by carcinoembryonic antigen-specific regulatory T cells

The adoptive transfer of regulatory T cells (Tregs) offers a promising strategy to combat pathologies that are characterized by aberrant immune activation, including graft rejection and autoinflammatory diseases. Expression of a chimeric antigen receptor (CAR) gene in Tregs redirects them to the site of autoimmune activity, thereby increasing their suppressive efficiency while avoiding systemic immunosuppression. Since carcinoembryonic antigen (CEA) has been shown to be overexpressed in both human colitis and colorectal cancer, we treated CEA-transgenic mice that were induced to develop colitis with CEA-specific CAR Tregs. Two disease models were employed: T-cell-transfer colitis as well as the azoxymethane-dextran sodium sulfate model for colitis-associated colorectal cancer. Systemically administered CEA-specific (but not control) CAR Tregs accumulated in the colons of diseased mice. In both model systems, CEA-specific CAR Tregs suppressed the severity of colitis compared to control Tregs. Moreover, in the azoxymethane-dextran sodium sulfate model, CEA-specific CAR Tregs significantly decreased the subsequent colorectal tumor burden. Our data demonstrate that CEA-specific CAR Tregs exhibit a promising potential in ameliorating ulcerative colitis and in hindering colorectal cancer development. Collectively, this study provides a proof of concept for the therapeutic potential of CAR Tregs in colitis patients as well as in other autoimmune inflammatory disorders.

Elevated serum anti-flagellin antibodies implicate subclinical bowel inflammation in ankylosing spondylitis: an observational study

INTRODUCTION

Ankylosing spondylitis (AS) and inflammatory bowel disease (IBD) share genetic and clinical features. IBD is associated with the presence of antibodies to a variety of commensal microorganisms including anti-Saccharomyces cerevesiae antibodies (ASCA), antineutrophil cytoplasmic antibodies (ANCA), anti-I2 (associated with anti-Pseudomonas activity), anti-Eschericia coli outer membrane porin C (anti-OmpC) and anti-flagellin antibodies (anti-CBir1). Subclinical intestinal inflammation may be present in up to 65% of patients with AS. This study evaluated the presence of antimicrobial antibodies in patients with AS alone, patients with AS and concomitant IBD (AS-IBD) and a control group of patients with mechanical back pain (MBP).

METHODS

Sera were tested by ELISA for ASCA IgG and IgA, anti-OmpC, anti-CBir1 and ANCA in 76 patients with AS alone, 77 patients with AS-IBD and 48 patients with MBP. Antibody positivity rates, median quantitative antibody levels and the proportion of patients with antibody levels in the 4th quartile of a normal distribution were compared between the three groups of patients.

RESULTS

Patients with AS alone demonstrated higher anti-CBir1 antibody positivity rates and median antibody levels than MBP patients. Anti-CBir1 positivity in AS was associated with elevation of acute phase reactants. AS-IBD patients demonstrated elevated responses when compared to AS alone for ASCA, anti-OmpC and anti-CBir1. Quartile analysis confirmed the findings.

CONCLUSIONS

These data suggest that adaptive immune responses to microbial antigens occur in AS patients without clinical IBD and support the theory of mucosal dysregulation as a mechanism underlying the pathophysiology of AS.

High prevalence of IgA class anti-neutrophil cytoplasmic antibodies (ANCA) is associated with increased risk of bacterial infection in patients with cirrhosis

BACKGROUND & AIMS

Anti-neutrophil cytoplasmic antibodies (ANCA) are a non-uniform family of antibodies recognizing diverse components of neutrophil granulocytes. ANCA formation might be induced by protracted bacterial infections or probably reflect an abnormal immune response to commensal microorganisms. Bacterial infections are common complications in cirrhosis with high incidence of episodes caused by enteric organisms, therefore, we sought to study the presence and clinical importance of ANCA in cirrhosis.

METHODS

Sera of 385 patients with cirrhosis of different etiologies were assayed for ANCA of IgG, IgA, IgA1, IgA2, and secretory IgA subtypes by indirect immunofluorescence and ELISAs. The control group comprised 202 patients with chronic liver diseases without cirrhosis and 100 healthy subjects. In cirrhosis, a 2-year follow-up, observational study was conducted to assess a possible association between the presence of ANCA and clinically significant bacterial infections.

RESULTS

Prevalence of ANCA IgA was significantly higher in cirrhosis (52.2%) compared to chronic liver diseases (18.6%) or healthy controls (0%, p<0.001 for both). ANCA IgA subtyping assays revealed marked increase in the proportion of IgA2 subtype (46% of total ANCA IgA) and presence of the secretory component concurrently. Presence of ANCA IgA was associated with disease-specific clinical characteristics (Child-Pugh stage and presence of ascites, p<0.001). During a 2-year follow-up period, risk of infections was higher among patients with ANCA IgA compared to those without (41.8% vs. 23.4%, p<0.001). ANCA IgA positivity was associated with a shorter time to the first infectious complication (pLogRank <0.001) in Kaplan-Meier analysis and was identified as an independent predictor in multivariate Cox-regression analysis (HR:1.74, 95% CI: 1.18-2.56, p=0.006).

CONCLUSIONS

Presence of IgA type ANCA is common in cirrhosis. Involvement of gut mucosal immune system is in center of their formation and probably reflects sustained exposure to bacterial constituents.

Assessing inflammatory bowel disease-associated antibodies in Caucasian and First Nations cohorts

BACKGROUND

First Nation populations in Canada have a very low incidence of inflammatory bowel disease (IBD). Based on typical infections in this population, it is plausible that the First Nations react differently to microbial antigens with a different antibody response pattern, which may shed some light as to why they experience a low rate of IBD.

OBJECTIVE

To compare the positivity rates of antibodies known to be associated with IBD in Canadian First Nations compared with a Canadian Caucasian population.

METHODS

Subjects with Crohn's disease, ulcerative colitis (UC), rheumatoid arthritis (RA) (as an immune disease control) and healthy controls without a personal or family history of chronic immune diseases, were enrolled in a cohort study aimed to determine differences between First Nations and Caucasians with IBD or RA. Serum from a random sample of these subjects (n=50 for each of First Nations with RA, First Nations controls, Caucasians with RA, Caucasians with Crohn's disease, Caucasians with UC and Caucasians controls, and as many First Nations with either Crohn's disease or UC as could be enrolled) was analyzed in the laboratory for the following antibodies: perinuclear antineutrophil cytoplasmic antibody (pANCA), and four Crohn's disease-associated antibodies including anti-Saccharomyces cerevisiae, the outer membrane porin C of Escherichia coli, I2 - a fragment of bacterial DNA associated with Pseudomonas fluorescens, and the bacterial flagellin CBir-1. The rates of positive antibody responses and mean titres among positive results were compared.

RESULTS

For pANCA, First Nations had a positivity rate of 55% in those with UC, 32% in healthy controls and 48% in those with RA. The pANCA positivity rate was 32% among Caucasians with RA. The rates of the Crohn's disease-associated antibodies for the First Nations and Caucasians were comparable. Among First Nations, up to one in four healthy controls were positive for any one of the Crohn's disease-associated antibodies. First Nations had significantly higher pANCA titres in both the UC and RA groups than Caucasians.

DISCUSSION

Although First Nation populations experience a low rate of IBD, they are relatively responsive to this particular antibody panel.

CONCLUSIONS

The positivity rates of these antibodies in First Nations, despite the low incidence of IBD in this population, suggest that these antibodies are unlikely to be of pathogenetic significance.

Future therapeutic approaches for inflammatory bowel diseases

In this review, we speculate about future therapeutic approaches for inflammatory bowel diseases (IBDs), focusing on the need for better preclinical and clinical models and approaches beyond small molecules and systemically administered biologics. We offer ideas to change clinical trial programs and to use immunologic and genetic biomarkers to personalize medicine. We attempt to reconcile past therapeutic successes and failures to improve future approaches. Some of our ideas might be provocative, but we hope that the examples we provide will stimulate discussion about what will advance the field of IBD therapy.

Ulcerative colitis: immune function, tissue fibrosis and current therapeutic considerations

BACKGROUND

Ulcerative colitis (UC) is a complex disease in which the interaction of genetic, environmental and microbial factors drives chronic intestinal inflammation that finally leads to extensive tissue fibrosis.

DISCUSSION

The present review discusses the current knowledge on genetic susceptibility, especially of the IL-12/IL-23 pathway, the pathophysiologic role of the involved cytokines (e.g. IL-13, IL-23, TGFβ1) and immune cells (e.g. T cells, epithelial cells, fibroblasts) in UC followed by an overview on actual therapeutic considerations. These future therapies will target selectively the involved cell types by blocking their activation and its downstream signalling, by inhibiting their migration to the inflamed site and by anti-cytokine strategies. This may avoid-when initiated in time-the perpetuation of the inflammatory mechanisms thus preventing fibrosis. With respect to animal models that have guided the most productive efforts for understanding human inflammatory bowel disease, these will be shortly discussed in the respective context.

Ulcerative colitis: immune function, tissue fibrosis and current therapeutic considerations

BACKGROUND

Ulcerative colitis (UC) is a complex disease in which the interaction of genetic, environmental and microbial factors drives chronic intestinal inflammation that finally leads to extensive tissue fibrosis.

DISCUSSION

The present review discusses the current knowledge on genetic susceptibility, especially of the IL-12/IL-23 pathway, the pathophysiologic role of the involved cytokines (e.g. IL-13, IL-23, TGFβ1) and immune cells (e.g. T cells, epithelial cells, fibroblasts) in UC followed by an overview on actual therapeutic considerations. These future therapies will target selectively the involved cell types by blocking their activation and its downstream signalling, by inhibiting their migration to the inflamed site and by anti-cytokine strategies. This may avoid-when initiated in time-the perpetuation of the inflammatory mechanisms thus preventing fibrosis. With respect to animal models that have guided the most productive efforts for understanding human inflammatory bowel disease, these will be shortly discussed in the respective context.

A prospective analysis of clinical variables, serologic factors, and outcome of ileal pouch-anal anastomosis in patients with backwash ileitis

PURPOSE

The outcome of ileal pouch-anal anastomosis in patients with backwash ileitis is controversial. We prospectively compared the outcomes of ileal pouch-anal anastomosis in colitis patients with backwash ileitis and colitis patients without backwash ileitis.

METHODS

Consecutive colitis patients undergoing ileal pouch-anal anastomosis were reviewed. All patients were classified after surgery as being either backwash ileitis-positive or backwash ileitis-negative. Serum drawn preoperatively was assayed, using enzyme-linked immunosorbent assay, for anti-Saccharomyces cerevisiae, anti-outer membrane of porin C, anti-CBir1, anti-I2, and perinuclear anti-neutrophil cytoplasmic antibody. Outcomes included acute pouchitis (antibiotic responsive), chronic pouchitis (antibiotic dependent or refractory), or de novo Crohn's disease (small inflammation above the pouch inlet or pouch fistula).

RESULTS

Out of 334 patients, 39 (12%) were backwash ileitis-positive. Compared with backwash ileitis-negative patients, backwash ileitis-positive patients had a higher incidence of pancolitis (100% vs 74%; P = .0001), primary sclerosing cholangitis (15% vs 2%; P = .001) and high-level (>100 enzyme-linked immunosorbent assay units/ml) perinuclear anti-neutrophil cytoplasmic antibody expression (29% vs 9%; P = .001). After a median follow-up of 26 months, 53 patients (16%) developed acute pouchitis, 37 (11%) developed chronic pouchitis, and 40 (12%) developed de novo Crohn's disease. There was no significant difference between the backwash ileitis-positive and backwash ileitis-negative patient groups in the incidence of acute pouchitis, chronic pouchitis, or de novo Crohn's disease.

CONCLUSION

There was a significantly higher incidence of pancolitis, primary sclerosing cholangitis, and high-level perinuclear anti-neutrophil cytoplasmic antibody expression in backwash ileitis-positive patients than in backwash ileitis-negative patients. The incidence of acute pouchitis, chronic pouchitis, and de novo Crohn's disease after ileal pouch-anal anastomosis does not differ significantly between backwash ileitis-positive and backwash ileitis-negative patients.

Serologic and laboratory markers in prediction of the disease course in inflammatory bowel disease

The search for biologic markers that can assess the natural history and perhaps predict the course of individual's disease including response to treatments over time has become an important focus of inflammatory bowel disease research. The knowledge of an individual's prognosis can help physicians and patients make important management decisions and aid communication on risk and benefits of disease and treatment.

[Multifactorial etiology and pathogenic factors in inflammatory bowel disease]

All the currently available evidence suggests that the two types of inflammatory bowel disease (IBD), Crohn's disease (CD) and ulcerative colitis (UC), involve a conflict between the immune system of the intestinal mucosa and intraluminal antigens, mainly the intestinal microflora, which are normally tolerated by the immune system. This conflict is modulated by numerous environmental factors and a clear polygenetic predisposition. The present article reviews the behavior of all the etiologic circumstances (microbial, genetic and environmental) and subsequently analyzes the possible pathogenic factors in which the etiologies can be found, namely: dysfunction of the intestinal epithelium, innate immune system alterations, and distortion of the cellular and humoral arms of the acquired immune system. The role of tissue ischemia in CD and expression of "extraintestinal inflammatory metastases", both in CD and UC, are briefly discussed. Finally, the view that IBD may be a spectrum of pathological processes provoked by distinct etiopathogenic factors and the possible biological significance of the growing incidence of this disease in the western world, coinciding with the decline in infectious diseases in this geographical area, are discussed.

Atypical p-ANCA in PSC and AIH: a hint toward a "leaky gut"?

Primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH) are enigmatic chronic inflammatory diseases of the liver, which are frequently associated with chronic inflammatory bowel diseases. Both types of liver disease share various distinct autoantibodies such as atypical perinuclear antineutrophil cytoplasmic antibodies (p-ANCA), and thus are considered autoimmune disorders with atypical features. The discovery that atypical p-ANCA recognize both tubulin beta isoform 5 in human neutrophils and the bacterial cell division protein FtsZ has renewed the discussion on the potential role of microorganisms in the pathogenesis of both diseases. In this paper, we review the evidence for microbial infection in PSC and AIH and discuss new concepts how cross-recognition between microbial antigens in the gut and host components by the immune system along with stimulation of pattern recognition receptors might give rise to chronic hepatic inflammatory disorders with features of autoimmunity.

Recognition of luminal bacterial antigens in inflammatory bowel disease

The incidence of inflammatory bowel disease (IBD) is increasing all over the world. However, it is rather difficult to treat IBD because its etiological factors and pathogenesis are still not clear. In recent years, the researches about the relationship between luminal bacterial antigens and IBD have provided new advances for its etiology and pathogenesis. We, in this paper, describe the present status in the recognition of luminal bacterial antigens in IBD patients which is correlated to the clinical phenotypes, prognosis and familial genetics of this disease, thus contributing to the treatment for IBD.

Autoantibodies in primary sclerosing cholangitis

The aetiology of primary sclerosing cholangitis (PSC) is not known and controversy exists as to whether PSC should be denominated an autoimmune disease. A large number of autoantibodies have been detected in PSC patients, but the specificity of these antibodies is generally low, and the frequencies vary largely between different studies. The presence of autoantibodies in PSC may be the result of a nonspecific dysregulation of the immune system, but the literature in PSC points to the possible presence of specific antibody targets in the biliary epithelium and in neutrophil granulocytes. The present review aims to give an overview of the studies of autoantibodies in PSC, with a particular emphasis on the prevalence, clinical relevance and possible pathogenetic importance of each individual marker.

Interplay of commensal and pathogenic bacteria, genetic mutations, and immunoregulatory defects in the pathogenesis of inflammatory bowel diseases

Enteric microbiota can contribute to Crohn's disease and ulcerative colitis in several ways. Pathogenic or functionally altered commensal bacteria with increased mucosal adherence, invasion and intracellular persistence can activate pathogenic T cells and chronic intestinal inflammation. Compositional changes in intestinal microbiota can lead to decreased protective and increased aggressive species. Genetic polymorphisms resulting in increased mucosal permeability, decreased microbial killing, ineffective clearance of bacteria, biased TH1 and TH17 immune responses and loss of immunological tolerance are probably key contributors to IBD. Future therapies for these heterogeneous diseases should be individualized based on the patient-specific subset.

Both preoperative perinuclear antineutrophil cytoplasmic antibody and anti-CBir1 expression in ulcerative colitis patients influence pouchitis development after ileal pouch-anal anastomosis

BACKGROUND & AIMS

Acute pouchitis (AP) and chronic pouchitis (CP) are common after ileal pouch-anal anastomosis (IPAA) for ulcerative colitis. The aim of this study was to assess associations of preoperative perinuclear antineutrophil cytoplasmic antibody (pANCA) and anti-CBir1 flagellin on AP or CP development.

METHODS

Patients were assessed prospectively for clinically and endoscopically proven AP (antibiotic responsive) or CP (antibiotic-dependent or refractory to antibiotic therapy). Sera from 238 patients were analyzed for ANCA and anti-CBir1 using an enzyme-linked immunosorbent assay. pANCA(+) patients were substratified into high-level (>100 EU/mL) and low-level (<100 EU/mL) groups.

RESULTS

After a median follow-up period of 47 months, 72 patients (30%) developed pouchitis. Pouchitis developed in 36% of pANCA(+) patients versus 16% of pANCA(-) patients (P = .005), 46% of anti-CBir1(+) patients versus 26% of anti-CBir1(-) patients (P = .02), and 54% of 35 pANCA(+)/anti-CBir1(+) patients versus 31% of 136 pANCA(+)/anti-CBir1(-) patients (P = .02). AP developed in 37 pANCA(+) patients (22%) versus 6 pANCA(-) patients (9%) (P = .02), and 12 anti-CBir1(+) patients (26%) versus 31 anti-CBir1(-) patients (16%) (P = .1). Although AP was not influenced by pANCA level, AP was seen in 38% of low-level pANCA(+)/anti-CBir1(+) patients versus 18% low-level pANCA(+)/anti-CBir1(-) patients (P = .03). CP was seen in 29% of high-level pANCA(+) patients versus 11% of low-level pANCA(+) patients (P = .03).

CONCLUSIONS

Both pANCA and anti-CBir1 expression are associated with pouchitis after IPAA. Anti-CBir1 increases the incidence of AP only in patients who have low-level pANCA expression, and increases the incidence of CP only in patients who have high-level pANCA expression. Diverse patterns of reactivity to microbial antigens may manifest as different forms of pouchitis after IPAA.

Autoantibodies against ubiquitination factor E4A (UBE4A) are associated with severity of Crohn's disease

BACKGROUND

Identification of a disease- and organ-specific autoantigen can potentially contribute to understanding molecular mechanisms involved in Crohn's disease (CD) and lead to development of clinically useful markers. The aim was to identify potential intestinal autoantigens specific to patients with CD and evaluate their diagnostic value.

METHODS

A cDNA expression library from normal terminal ileum was created and screened with pooled sera from 3 randomly selected patients with CD. For evaluation of the diagnostic value of antibody screening, serum samples obtained from 39 patients with CD, 28 patients with ulcerative colitis (UC), and 60 healthy controls were examined for IgG against the strongest clone.

RESULTS

We identified an intestinal cDNA clone encoding ubiquitination factor E4A (UBE4A), a U-box-type ubiquitin-protein ligase. The prevalence of anti-UBE4A IgG in patients with CD was significantly higher than that in patients with UC or healthy controls (46.2% versus respectively 7.1%, P = 0.0006; 3.3%, P < 0.0001). Anti-UBE4A-positive patients with CD were more likely to require surgery (P = 0.0013). The level of anti-UBE4A IgG was correlated with disease activity (r = 0.777, P < 0.0001) and associated with stricturing or penetrating disease (P = 0.0028). Immunohistochemical studies showed upregulation of UBE4A in enteroendocrine cells of inflamed ileal mucosa with CD.

CONCLUSIONS

Anti-UBE4A antibodies are potentially useful markers for detection and prediction of clinical activity and outcome in patients with CD.

Microbial influences in inflammatory bowel diseases

The predominantly anaerobic microbiota of the distal ileum and colon contain an extraordinarily complex variety of metabolically active bacteria and fungi that intimately interact with the host's epithelial cells and mucosal immune system. Crohn's disease, ulcerative colitis, and pouchitis are the result of continuous microbial antigenic stimulation of pathogenic immune responses as a consequence of host genetic defects in mucosal barrier function, innate bacterial killing, or immunoregulation. Altered microbial composition and function in inflammatory bowel diseases result in increased immune stimulation, epithelial dysfunction, or enhanced mucosal permeability. Although traditional pathogens probably are not responsible for these disorders, increased virulence of commensal bacterial species, particularly Escherichia coli, enhance their mucosal attachment, invasion, and intracellular persistence, thereby stimulating pathogenic immune responses. Host genetic polymorphisms most likely interact with functional bacterial changes to stimulate aggressive immune responses that lead to chronic tissue injury. Identification of these host and microbial alterations in individual patients should lead to selective targeted interventions that correct underlying abnormalities and induce sustained and predictable therapeutic responses.

Immunopathogenesis of inflammatory bowel disease

Crohn’s disease and ulcerative colitis are chronic relapsing immune mediated disorders that results from an aberrant response to gut luminal antigen in genetically susceptible host. The adaptive immune response that is then triggered was widely considered to be a T-helper-1 mediated condition in Crohn’s disease and T-helper-2 mediated condition in ulcerative colitis. Recent studies in animal models, genome wide association, and basic science has provided important insights in in the immunopathogenesis of inflammatory bowel disease, one of which was the characterization of the interleukin-23/Th-17 axis.

Serologic markers in inflammatory bowel disease: tools for better diagnosis and disease stratification

In the last decade, new serologic markers have been identified, and attempts to delineate their potential roles in inflammatory bowel disease diagnosis, determination of prognosis and identification of apparently healthy subjects at risk have significantly increased our knowledge. In this review, the major serologic markers will be described, focusing on their common features as a group. It is predicted that within the next 5 years, panels of antibodies will prove to have a significant impact on disease diagnosis and stratification, as well as on the identification of populations at risk and the prediction of response to treatment. Thus, it is expected that they will become useful clinical tools that will enable an improved, 'tailored' approach to inflammatory bowel disease patients.

Anti-Saccharomyces cerevisiae antibody in intestinal Behçet's disease patients: relation to clinical course

PURPOSE

This study was designed to assess anti-Saccharomyces cerevisiae antibody positive rate in Behçet's disease and intestinal Behçet's disease and to evaluate whether anti-Saccharomyces cerevisiae antibody expression is associated with clinical findings at diagnosis and clinical course of intestinal Behçet's disease.

METHODS

One hundred six patients with intestinal Behçet's disease, 30 patients with Behçet's disease, and 45 healthy control subjects were included. Anti-Saccharomyces cerevisiae antibody was detected by indirect immunofluorescence assay. According to anti-Saccharomyces cerevisiae antibody expression, the various parameters at diagnosis, cumulative relapse rates, and cumulative probabilities of operation were analyzed.

RESULTS

Anti-Saccharomyces cerevisiae antibody positive rate was 44.3 percent in intestinal Behçet's disease, 3.3 percent in Behçet's disease, and 8.8 percent in healthy control subjects. In patients with intestinal Behçet's disease, age, gender, distribution of Behçet's disease subtype, symptoms, laboratory tests, and colonoscopic findings at diagnosis were not different according to anti-Saccharomyces cerevisiae antibody expression. Cumulative probability of a first operation was significantly higher in anti-Saccharomyces cerevisiae antibody (+) intestinal Behçet's disease than in anti-Saccharomyces cerevisiae antibody (-) intestinal Behçet's disease: 44.8 and 17.2 percent at one year, and 53 and 24.3 percent at two years after diagnosis, respectively (P=0.006). The number of patients who underwent two or more operations was higher in anti-Saccharomyces cerevisiae antibody (+) intestinal Behçet's disease than in anti-Saccharomyces cerevisiae antibody (-) intestinal Behçet's disease (21.3 vs. 8.5 percent). The cumulative relapse rates were not different between the two groups.

CONCLUSIONS

Anti-Saccharomyces cerevisiae antibody positive rate was 44.3 percent in intestinal Behçet's disease. Clinical findings at diagnosis and cumulative relapse rates of intestinal Behçet's disease were not found to be associated with anti-Saccharomyces cerevisiae antibody expression. However, patients with anti-Saccharomyces cerevisiae antibody (+) intestinal Behçet's disease were more likely to receive surgical treatment.

Association of IL-10 and TNFalpha genotypes with ANCA appearance in ulcerative colitis

The appearance of autoantibodies is a common characteristic of ulcerative colitis (UC). Specifically, anti-neutrophil cytoplasmic antibodies (ANCA) are the most prevalent in this disease and their synthesis may be genetically conditioned. The aim of the present study was to test the influence on appearance of autoantibodies of IL-10 and TNFalpha genes promoter polymorphisms, which control cytokine levels. Genetic polymorphisms of TNFalpha (-308 G/A) and IL-10 (-1082 G/A) and ANCA and anti-goblet cells antibodies (GAB) presence were determined in 99 UC patients. The -308A* allele and -308AA/AGTNFalpha genotypes (high producer), clearly correlated with ANCA positivity (p = 0.004 and p = 0.007, respectively). Additionally, homozygous carriage of the -1082A*IL-10 allele (low producer) significantly associated with ANCA presence (p = 0.007). Furthermore, combination of both genotypes (low IL-10/high TNFalpha producer genotype) had a greater influence on ANCA positivity than each individual genotype (p = 0.008). ANCA production in UC thus appears to be conditioned by IL-10 and TNFalpha genotypes.

Immunogenetic phenotypes in inflammatory bowel disease

The currently accepted etiopathogenic hypothesis suggests that the chronic intestinal inflammation and related systemic manifestations characteristic of inflammatory bowel disease (IBD) are due to an overly aggressive or pathologic immune response to resident luminal bacterial constituents. Predisposing factors are genetic dysregulation of mucosal immune responses and/or barrier function, with onset triggered by environmental stimuli. These factors and their interactions may also be important determinants of disease phenotype and disease progression. The emergence of immunogenetic phenotypes lends support to the proposed hypothesis that susceptibility genes regulate distinct immune processes, driven by luminal antigens, expressed as specific immune phenotypes which in turn influence clinical phenotypes in IBD patients.

Defects in mucosal immunity leading to ulcerative colitis

Evidence accumulated over the last decade demonstrates that what we call 'ulcerative colitis' is actually a heterogeneous group of diseases resulting from different pathogenic mechanisms with a common symptomatic expression. Subgroups of patients with ulcerative colitis can be stratified by presence or absence of serum autoantibodies, which are thought not to be pathogenic but to mark for a distinct disease phenotype. In recent years, animal-based experimental systems have emerged that reflect human ulcerative colitis and have potential to accelerate our understanding of its pathogenesis. Genetic and immunological data from human studies in combination with results from animal model systems are the foundation of a hypothesis, which includes a role for microbial antigen exposure in the initiation, perpetuation, and amplification of the disease. In ulcerative colitis, it appears as though the T-cell response to the antigens is not T-helper (Th) 1 dominant as in the case of Crohn's disease but rather is either Th2 [interleukin (IL)-4, IL-13] or is mediated by specialized cells such as natural killer (NK) T cells (IL-13). Lamina propria T cells from ulcerative colitis patients produce significantly greater amounts of IL-13. Ulcerative colitis is associated with an atypical Th2 response mediated by a distinct subset of NK T cells that produce IL-13 and are cytotoxic for epithelial cells. The way in which this response affects the ultimate cascade of inflammatory events has yet to be determined.

Antibodies to CBir1 flagellin define a unique response that is associated independently with complicated Crohn's disease

BACKGROUND & AIMS

Antibody responses to certain microbial antigens define heterogeneous groups of Crohn's patients; multiple and high-level responses to these antigens are associated with aggressive clinical phenotypes. The flagellin, CBir1, identified by investigations in the C3H/HeJBir mouse model, has been identified as a dominant antigen capable of inducing colitis in mice and eliciting antibody responses in a subpopulation of patients with Crohn's disease (CD). The aim of this study was to evaluate serum response to CBir1 flagellin in CD patients and to compare this response to responses defined previously to oligomannan (anti-Saccharomyces cerevisiae antibody), I2, OmpC, and neutrophil nuclear autoantigens (pANCA), and to determine anti-CBir1-associated phenotypes.

METHODS

A total of 484 sera from the Cedars Sinai Medical Center repository, previously typed for anti-Saccharomyces cerevisiae antibody, anti-I2, anti-OmpC, and pANCA were tested for anti-CBir1 by enzyme-linked immunosorbent assay, and results were assessed for clinical phenotype associations.

RESULTS

The presence and level of immunoglobulin G anti-CBir1 were associated with CD independently. Anti-CBir1 was present in all antibody subgroups and expression increased in parallel with increases in the number of antibody responses. pANCA+ CD patients were more reactive to CBir1 than were pANCA+ ulcerative colitis patients. Anti-CBir1 expression is associated independently with small-bowel, internal-penetrating, and fibrostenosing disease features.

CONCLUSIONS

Serum responses to CBir1 independently identify a unique subset of patients with complicated CD. This bacterial antigen was identified in a murine model and has a similar pattern of aberrant reactivity in a subset of CD patients.

Evaluation of assays for perinuclear antineutrophilic cytoplasmic antibodies and antibodies to Saccharomyces cerevisiae in dogs with inflammatory bowel disease

OBJECTIVE

To evaluate the use of immunofluorescence asssays for perinuclear antineutrophilic cytoplasmic antibodies (pANCAs) and antibodies to Saccharomyces cerevisiae (ASCAs) in dogs with inflammatory bowel disease (IBD) and assess the clinical value of these serologic markers of the disease.

ANIMALS

39 dogs with IBD, 18 dogs with acute diarrhea, 19 dogs with chronic non-IBD-associated diarrhea, 26 healthy dogs of various breeds and age, and 22 healthy young working dogs.

PROCEDURE

Sera obtained from the dogs in each group were added to canine granulocyte- and Saccharomyces cerevisiae-mounted slides for detection of pANCAs and ASCAs via immunofluorescence techniques. Sensitivity and specificity (with 95% confidence intervals [CIs]) were calculated for the group of dogs with IBD versus each of the 2 groups of healthy dogs, the group of dogs with acute diarrhea, and the group of dogs with chronic non-IBD-associated diarrhea.

RESULTS

Among the 39 dogs with IBD, 20 yielded positive results via the pANCA assay (sensitivity, 0.51 [95% CI, 0.35 to 0.67]) and 17 yielded positive results via the ASCA assay (sensitivity, 0.44 [95% CI, 0.22 to 0.69]). The specificity of the pANCA assay in the 4 groups of non-IBD-affected dogs ranged from 0.83 (95% CI, 0.85 to 0.96) to 0.95 (95% CI, 0.72 to 1.00).

CONCLUSIONS AND CLINICAL RELEVANCE

Immunofluorescence assays for pANCA and ASCA appear to be useful for the detection of IBD in dogs. The pANCA immunofluorescence assay had high specificity for canine IBD, and pANCAs appear to be accurate markers of intestinal inflammation.

Pancreatic autoantibodies in Crohn's disease: a feasible diagnostic tool?

Potential implications of antibody markers in Crohn's disease: Diagnostic markers, alone or in conjunction with other antibodies? Delineation of clinical phenotypes? Markers of disease behaviour? Markers of (genetic) susceptibility? Identification of genetically homogenous subgroups? Bridge between basic science and clinic? The exact role of serum antibodies in inflammatory bowel disease remains a matter of ongoing debate. Although a direct implication in the disease pathogenesis is unlikely, their diagnostic potential in cases of an undetermined colitis or in defining clinical phenotypes in Crohn's disease has been shown in several studies. Serum antibodies might also be helpful in predicting the disease behaviour and are thus valuable tools in the choice of medical or surgical therapy.

Autoantibodies against the bactericidal/permeability-increasing protein from inflammatory bowel disease patients can impair the antibiotic activity of bactericidal/permeability-increasing protein

Bactericidal/permeability-increasing protein (BPI) is an antineutrophil cytoplasmic autoantibody (ANCA) target antigen in inflammatory bowel disease (IBD). The aim of this study was to characterize binding regions of BPI-autoantibodies and to analyze their ability to block the antibiotic effect of BPI. Sera of 24 ulcerative colitis and Crohn's disease patients were examined in indirect immuno-fluorescence, ANCA enzyme-linked immunosorbent assay (ELISA), and by epitope mapping with 13mer peptides and Western blot for presence of BPI-autoantibodies. IgG preparations were used to determine inhibition of BPI's antimicrobial function by BPI-autoantibodies in a bacterial growth inhibition assay. BPI-autoantibodies were detected by ELISA in 18/24 patients. Epitope mapping and western blotting revealed an additional 3 patients with BPI-autoantibodies. IgG preparations of all patients with Crohn's disease and 9 of 12 ulcerative colitis patients could inhibit the antibiotic function of BPI in vitro as compared with healthy control subjects. Inhibiting BPI-autoantibodies correlated with extraintestinal manifestations, peripheral blood leukocyte counts, and anemia. BPI-autoantibodies recognizing the N-terminal portion were associated with greater mucosal damage and intestinal extent of disease. BPI is a frequent target antigen of autoantibodies in ulcerative colitis and Crohn's disease. Inhibition of the antibiotic function mediated by the N-terminal region of BPI by these autoantibodies may contribute to a proinflammatory environment in IBD patients.

Genetic variants of the mannan-binding lectin are associated with immune reactivity to mannans in Crohn's disease

BACKGROUND & AIMS

Some patients with Crohn's disease (CD) develop antibodies against mannan, a component of the yeast Saccharomyces cerevisiae cell wall. Mannan-binding lectin (MBL), a component of the innate immune system, can bind to S. cerevisiae . MBL concentration depends on genetic polymorphisms. The aim of this study was to evaluate whether low MBL contributes to anti-S. cerevisiae antibody (ASCA) production.

METHODS

ASCA and MBL concentrations in sera from patients with CD (n = 74), ulcerative colitis (UC) (n = 22), and healthy controls (n = 32) were measured by an enzyme-linked immunosorbent assay (ELISA). Genetic MBL variants were determined from 58 CD patients, 18 UC patients, and 47 controls by DNA sequencing. Lymphocytes were tested for proliferative response after stimulation with mannan.

RESULTS

ASCA were found in 47% of the patients with CD and in 0% of the controls. More ASCA-positive patients (52%) had low serum MBL concentrations compared with ASCA-negative patients (4%) (P < 0.0001). T-cell proliferation in response to mannan stimulation was observed in ASCA-positive patients and could be inhibited by the addition of MBL. These patients had significantly lower MBL serum concentrations than patients whose lymphocytes did not proliferate on mannan stimulation (P < 0.0001). Homozygous or compound heterozygous MBL mutations in the exon 1 and promoter occurred in 12 patients with cellular or humoral immune reactivity to mannan as compared with only 1 nonreactive patient (P < 0.0001).

CONCLUSIONS

A subgroup of CD patients is characterized by ASCA positivity, T-cell proliferation on mannan stimulation, and mutations in the MBL gene that result in MBL deficiency. Thus, we propose that enhanced mannan exposure stimulates specific immune responses in a subgroup of CD patients with genetically determined low MBL concentrations. This enhanced exposure contributes to the generation of ASCA.

Do serological markers and cytokines determine the indeterminate?

There is a general sense that indeterminate colitis (IC) runs an aggressive clinical course, is medically refractory, and is associated with higher pouch failure rates following restorative proctocolectomy. The question has been raised whether IC can be assigned to a diagnosis of Crohn's disease or ulcerative colitis through the characterization of immunogenetic similarities, or whether IC may represent a distinct subgroup within these heterogeneous disorders. In this article, the use of serologic markers, genetics, and immune responses to understand the pathogenesis of inflammatory bowel disease (IBD) and define clinically important subgroups of patients will be discussed. Then, how these scientific advances have been applied to the entity of IC will be reviewed. Importantly, a recent prospective study suggests that the absence of IBD-associated serologic markers defines the majority of IC as a separate entity within the spectrum of IBD. The development of serologic, genetic, and immune response markers will allow for rational description of clinically important subgroups, redefine natural history, and predict responses to therapy in IBD.

BPI-ANCA of pediatric cystic fibrosis patients can impair BPI-mediated killing of E. coli DH5alpha in vitro

Gram-negative bacterial lung infections and chronic bacterial colonization are major threats for pediatric cystic fibrosis (CF) patients. Besides impeded mucociliary clearance, other mechanisms that contribute to increased susceptibility to infections are presumed. The bactericidal/permeability-increasing protein (BPI), which is delivered by neutrophil granulocytes and mucosal epithelial cells, is one of the most potent innate antibiotics against Gram-negative bacteria and endotoxin. Antineutrophil cytoplasmic autoantibodies against BPI (BPI-ANCA) have been found in up to 90% of CF patients, and titers correlated inversely with lung function parameters. As major pulmonary damage is mediated by Gram-negative bacteria and their products, the question was raised as to whether BPI-ANCA can inhibit the antibiotic function of BPI in these patients. Sera of 23 pediatric CF patients were analyzed for the presence of BPI-ANCA by indirect immunofluorescence, ELISA, epitope mapping, and Western blotting. Patients' IgG were tested in a bacterial growth inhibition assay with recombinant BPI (rBPI) and an amino-terminal fragment of BPI (rBPI(21)) that retains antibiotic activity for inhibition of the antibiotic function of BPI against E. coli DH5alpha in vitro. BPI was recognized by 21 of 23 patients' sera in our detection assays. Thirteen of 23 patients' BPI-ANCA (56%) could inhibit the antibiotic function in vitro. Moreover, epitope mapping over the whole BPI sequence revealed that more patients' BPI-ANCA recognize the amino-terminal part of BPI than can be detected by ELISA. Thus, in pediatric CF patients, BPI-ANCA may contribute to diminished bacterial clearance by inhibiting the antibiotic function of BPI.

Genetic and serological markers to identify phenotypic subgroups in a Dutch Crohn' s disease population

BACKGROUND AND AIMS

Both genetic and microbial factors seem to play a pivotal role in the aetiopathogenesis of Crohn's disease. The CARD15 frameshift mutation might link host genetic factors and the indigenous microbial flora, since CARD15 expression is stimulated by peptidoglycan, thereby activating NF-kappaB. It is hypothesised that CARD15 mutation carriers have defective anti-microbial reactions, resulting in more penetrating lesions and antibody responses, which are now being used as highly specific markers for Crohn's disease. The serological marker anti-Saccharomyces cerevisiae antibody directed against cell wall oligomannosidic epitopes has high specificity for Crohn's disease. Perinuclear anti-neutrophil cytoplasmic antibodies have been found in a subgroup of Crohn's disease patients, mostly with colonic involvement.

METHODS

We investigated the incidence of two CARD15 mutations (3020insC and 2722G>C), anti-S. cerevisiae antibody, and perinuclear anti-neutrophil cytoplasmic antibody in 108 (73F/35M) patients with Crohn's disease with a mean duration of disease since diagnosis of 16 (1-41) years in relation to their phenotype, according to the Vienna classification.

RESULTS

The prevalence of CARD15 frameshift mutation was 21%. Of all patients, 62% were anti-S. cerevisiae antibody positive, and 9% had perinuclear anti-neutrophil cytoplasmic antibodies. The prevalence of both anti-S. cerevisiae antibodies and perinuclear anti-neutrophil cytoplasmic antibodies was higher in the mutation carriers compared to non-carriers. Remarkably, all patients with a CARD15 mutation and positive anti-S. cerevisiae antibody had ileal disease. Carriership of the mutation was significantly associated with penetrating behaviour of the disease and weakly associated with stricturing behaviour. Furthermore, anti-S. cerevisiae antibody was associated with ileal disease involvement. Finally, most perinuclear anti-neutrophil cytoplasmic antibody positive patients showed ulcerative-like behaviour of disease (by means of colonic localisation).

CONCLUSIONS

Genetic and serologic markers might be useful in defining patient subgroups. This may result in a more accurate prediction of disease behaviour, prognosis and therapeutic approach.

Evaluation of serological markers to differentiate between ulcerative colitis and Crohn's disease: pANCA, ASCA and agglutinating antibodies to anaerobic coccoid rods

BACKGROUND

Accurate diagnosis of inflammatory bowel disease, in particular the differentiation between ulcerative colitis and Crohn's disease, is important for treatment and prognosis. Several serological markers have been used as non-invasive diagnostic tools in inflammatory bowel disease patients both to differentiate ulcerative colitis from Crohn's disease and to define patient subgroups.

AIM

To evaluate the diagnostic accuracy of three serological tests in differentiating ulcerative colitis from Crohn's disease by single or combined use.

METHODS

Sera from 51 patients with clinically well-defined ulcerative colitis and 50 patients with clinically well-defined Crohn's disease were analysed. Detection assays for the presence of perinuclear anti-neutrophil cytoplasmatic antibodies (pANCA), antibodies against (ASCA) and serum agglutinating antibodies to anaerobic coccoid rods were studied. Sensitivity, specificity, predictive values and likelihood ratios of each of these serological tests were determined.

RESULTS

In supporting the diagnosis of ulcerative colitis, the sensitivity and specificity of the pANCA test were 63% and 86%, respectively. The ASCA test (immunoglobulin A or immunoglobulin G positive) for diagnosing Crohn's disease had a sensitivity of 72% and a specificity of 82%. The sensitivity of antibodies to anaerobic coccoid rods in diagnosing Crohn's disease was 52%, whereas specificity was 90%. A combination of pANCA-positive and ASCA-negative results in the case of ulcerative colitis showed a sensitivity and specificity of 51% and 94%, respectively. However, for ASCA-positive and pANCA-negative results in the case of Crohn's disease, sensitivity was 64% and specificity was 94%. The combination of all three tests increased positive predictive value and specificity to 100% for both ulcerative colitis and Crohn's disease. In Crohn's disease patients, positive pANCA was correlated with colonic involvement. No correlation was found between the presence of any of these antibodies and disease activity, duration and behaviour or medical treatment.

CONCLUSIONS

The value of these serological tests in differentiating ulcerative colitis from Crohn's disease is limited when used separately but, by combining two or more tests, the positive predictive value and specificity can be improved substantially. These tests might be of help in studying disease heterogeneity, and may contribute to defining various subgroups of patients with different pathogeneses.

Antibody response to dietary and autoantigens in G alpha i2-deficient mice

BACKGROUND

Mice with a targeted mutation in the G protein subunit G alpha i2 gene develop a colonic mucosal inflammation, with a highly activated B-cell response. We wanted to investigate whether this increased B-cell activity was directed against dietary antigens and/or various self tissues.

METHODS

The level of antibodies specific for dietary (gliadin, soya and fish meal) antigens was measured by ELISA. Reactivity against self antigens was measured by immunohistochemistry on cryo-sectioned mouse and rat tissue. Sera and intestinal lavages were analysed from G alpha i2-/- mice before and after development of colitis and in age-matched wild type litter mates.

RESULTS

Titres of antibodies against dietary antigens were significantly enhanced both in serum and in large intestinal lavages from G alpha i2-/- mice with ongoing colitis but not prior to disease, as compared to wild type mice. The autoreactivity to self tissues was significantly increased in G alpha i2-/- mice both before and after development of colitis as compared to litter mate control animals. Self tissue reactivity was directed not only against epithelial cells of the colon, small intestine and gastric glands, but also against smooth muscle cells, hepatocytes, bile duct cells, renal tubule and collecting tubule cells of the kidney. In analogy to human ulcerative colitis, autoantibodies against epithelial cells, bile duct epithelium and neutrophil granulocytes were found.

CONCLUSIONS

Earlier increase in levels of autoantibodies (before onset of colitis) than of food antibodies (after onset of colitis) suggests the latter response to be a secondary phenomenon to e.g. a destroyed barrier function.

Diagnostic methodologies: serology, endoscopy, and radiology

The two major inflammatory bowel diseases, Crohn's disease (CD) and ulcerative colitis (UC), represent clinicopathologic entities that traditionally have been diagnosed on the basis of a combination of clinical, radiologic, endoscopic, and histologic features. Serum perinuclear antineutrophil cytoplasmic antibodies (pANCA) and anti-Saccharomyces cerevisiae antibodies (ASCA) have recently been added to our diagnostic armamentarium. Several studies have demonstrated that UC-associated pANCAs recognize nuclear antigens. Additional studies have demonstrated that the pANCA human monoclonal antibody (mAb) Fab 5-3 reacts with histone H1 and with bacterial and mycobacterial antigens. Several reports have suggested that, in CD, pANCA and ASCA are correlated with colonic and small bowel disease respectively. One study found that higher ASCA levels were correlated with more aggressive CD. Serology may prove to be useful in predicting the evolution of indeterminate colitis. Magnetic resonance imaging (MRI) and leukocyte scintigraphy hold promise in identifying inflammatory CD. MRI enteroclysis is useful in identifying both luminal small bowel disease and extraluminal complications. A recent study of surveillance colonoscopy in extensive Crohn's colitis showed a high risk of dysplasia and cancer.