Serological antibodies in inflammatory bowel disease: a systematic review

Serological markers and inflammatory bowel disease: Prevalence of serum markers and their diagnostic value in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic nonspecific disease of the digestive tract that is caused by genetic and environmental factors, including ulcerative colitis, Crohn's disease, and unclassified IBD. At present, the diagnosis of IBD depends mainly on clinical manifestations, imaging changes, colonoscopy, and pathological biopsy, but there exist some limitations. The advantages of serological markers in IBD diagnosis are prominent, and a large number of relevant studies have been reported. This paper reviews the diagnostic and therapeutic value of serological markers in IBD, with an aim to clarify their role in the diagnosis and treatment of IBD.

Molecular diagnosis and classification of inflammatory bowel disease

INTRODUCTION

Traditional diagnosis and classification of inflammatory bowel diseases (IBDs) have been based on clinical evaluation, laboratory testing, endoscopy, imaging, and histological examinations. With the advancement of medical technology, an increasing number of molecular surrogates are playing a key role in diagnosis, differential diagnosis, assessment of disease activity, prediction of clinical course, and therapeutic response of IBD. Areas covered: The authors review roles of both existing and emerging surrogates including genetic, serological, histologic, and fecal markers in diagnosis and classification of IBD. Comparisons in advantages and disadvantages of different markers have also been discussed. In addition, this review underscores controversial and unclear aspects which need further study. Expert commentary: IBD is characteristic of chronicity, relapse-remission and destructiveness. It is of great importance for clinicians to make an accurate diagnosis and classification. Current and new molecular markers perform well with acceptable sensitivity and specificity. The use of molecular markers in clinical practice needs to be further explored and then generalized. More work is warranted to identify novel useful markers and elucidate how to apply them together with current markers in clinical settings.

Expanded TCRβ CDR3 clonotypes distinguish Crohn's disease and ulcerative colitis patients

We aimed to determine whether the TCR repertoires of Crohn's disease (CD) patients contain highly prevalent disease-specific T-cell clonotypes reflective of the characteristic and highly shared aberrant serum antibody reactivity to gut commensal flagellin antigens. The CD4 TCRβ CDR3 sequence repertoires from active CD (n = 20) and ulcerative colitis (UC) (n = 10) patients were significantly more diverse, and individual sequences over-represented, compared to healthy controls (HC) (n = 97). While a very small number of expanded public CDR3 sequences are highly shared between active CD and UC, the majority of significantly expanded TCRβ CDR3 clonotypes are private to CD and UC patients with equivalent prevalence among IBD patients. Further defining TCR clonotypes by Vβ-CDR3 linkage showed significant differences in the TCR repertoires between UC and CD. Flagellin antigen exposure induced expansion of several TCRβ CDR3 sequences in CD4 cells from a flagellin-seropositive subject including sequences highly shared by or relatively private to CD (and UC) patients. These data suggest that flagellin-reactivity contributes to the expansion of a small number of CD4 clonotypes but does not support flagellin antigens as predominantly driving CD4 cell proliferation in CD. Disease-specific expanded TCRβ CDR3 clonotypes characterize CD and UC and the shared exposure to the gamut of gut microbial antigens.

Sulphite oxidase (SO) - a mitochondrial autoantigen as target for humoral and cellular immune reactions in primary sclerosing cholangitis

Background

In a recent study we had evidence that sulphite oxidase (SO) may be a relevant autoantigen in primary sclerosing cholangitis (PSC). Aim of the present study was, therefore, to analyse humoral and cellular immune-reactivity towards SO in these patients in more detail.

Methods

Sera from 53 patients with PSC (30 untreated and 23 treated with ursodeoxycholic acid [UDCA] at time of analysis), from 422 patients with different hepatic and non-hepatic disorders, and from 50 healthy individuals were tested by ELISA for antibodies against full-length-SO (SO-fl) and its three major domains expressed in E.coli (SO-I, SO-II, SO-III). For epitope-mapping, 29 overlapping peptides were used. Peripheral blood mononuclear cells (PBMC) were obtained from 33 PSC-patients and analysed for SO-induced proliferation, production of cytokines, and expression of the activation marker cluster of differentiation (CD) 69.

Results

43% of the 30 untreated and 26% of the 23 treated PSC-patients had IgG anti-SO-antibodies predominantly reacting with SO-fl, SO-I and SO-II. Antibody-reactivity decreased after UDCA-treatment. Prevalence and reactivity of anti-SO-antibodies were significantly higher in PSC than in patients with other hepatic and non-hepatic disorders. Epitope mapping revealed no distinct immuno-dominant regions within SO. Incubation of PBMC from PSC-patients (but not from controls) with SO-antigens revealed an activation of B-cells and a T-helper cell type-2 reaction pattern (production of interleukin [IL]-13, IL-10).

Conclusions

PSC-patients show humoral and cellular immune response towards SO. Antibodies may be predominantly directed against conformational epitopes. SO enhances in vitro especially T-helper cell type-2 immune-reactions, which may be pro-fibrotic. SO is a detoxifying enzyme present also in bacteria; further studies analysing its role in the aetiology and pathogenesis in PSC may, therefore, be important.

Electronic supplementary material

The online version of this article (10.1186/s12876-018-0787-x) contains supplementary material, which is available to authorized users.

Detection of Crohn Disease in Patients with Spondyloarthropathy: The SpACE Capsule Study

OBJECTIVE

Inflammatory bowel disease (IBD) is generally reported to be associated with spondylarthropathies (SpA) in 5%-15% of cases. Systematic colonoscopic assessment by protocol demonstrated mucosal inflammation characteristic of Crohn disease (CD) in up to one-third of patients with SpA. Video capsule endoscopy (CE) is a superior diagnostic tool to detect small bowel mucosal disease. Our study compared the accuracy of CE to standard colonoscopy for detection of inflammatory bowel lesions in patients with SpA, and to describe predictors of small bowel inflammation (SBI) in this cohort.

METHODS

Prospective cross-sectional study of adult patients followed for SpA. Patients were evaluated by CE and standard colonoscopy with biopsies. SBI was quantified using the Lewis Score. Additional screening tests included fecal calprotectin (FCP), C-reactive protein (CRP), and a diagnostic panel of serologic, inflammatory and genetic tests (SGI).

RESULTS

There were 64 patients recruited (53% female, mean age 42 ± 13 yrs). Chronic gastrointestinal (GI) symptoms were present in 57%. CE revealed significant SBI in 27/64 (42.2%), compared to 7/64 (10.9%) by standard colonoscopy (p = 0.035). Elevated FCP was associated with small bowel CD (OR 4.5, 95% CI 1.01-19.9; p = 0.042). No correlation was observed with presence of GI symptoms, CRP, or SGI results. Finding CD led to a change in management in 65.2% of cases.

CONCLUSION

CE uncovered SBI consistent with CD in 42.2% of patients with SpA, with a significant incremental yield over colonoscopy of 31%. FCP levels were significantly correlated with CE results, while GI symptoms and SGI results were poor predictors of SBI.

Significance of serological markers in the disease course of ulcerative colitis in a prospective clinical cohort of patients

Background & aims

To determine the prognostic potential of classic and novel serologic antibodies regarding unfavorable disease course in a prospective ulcerative colitis (UC) patient cohort, since few and conflicting data are available in the literature regarding this matter.

Methods

187 consecutive patients were studied prospectively (median follow-up: 135 months) from a single referral IBD center in Hungary. Sera were tested for different IgA/IgG type autoantibodies (anti-neutrophil cytoplasmic [ANCA], anti-DNA-bound-lactoferrin [anti-LFS], anti-goblet cell [anti-GAB] and anti-pancreatic [PAB: anti-CUZD1 and anti-GP2)]) by indirect immunofluorescence technique and for anti-microbial (anti-Saccharomyces cerevisiae [ASCA] IgG/IgA and anti-OMP Plus^™ IgA) antibodies by enzyme-linked immunosorbent assays.

Results

A total of 73.6%, 62.4% and 11.2% of UC patients were positive for IgA/IgG type of atypical perinuclear-ANCA, anti-LFS and anti-GAB, respectively. Occurrences of PABs were 9.6%, while ASCA IgA/IgG and anti-OMP IgA were 17.6% and 19.8%, respectively. Antibody status was stable over time. IgA type PABs were more prevalent in patients with primary sclerosing cholangitis (37.5% vs. 4.7% for anti-CUZD1 and 12.5% vs. 0% for anti-GP2, p<0.001 for both). IgA type ASCA and anti-CUZD1 antibodies were associated with higher risk of requirement for long-term immunosuppressant therapy in Kaplan-Meier analysis (pLogRank <0.01 for both). However, in multivariate Cox-regression analysis only ASCA IgA (HR: 2.74, 95%CI: 1.46–5.14, p<0.01) remained independent predictor. UC-related hospitalization due to disease activity was only associated with multiple antibody positivity (for 3 or more; HR 2.03 [95% CI: 1.16–3.56]; p = 0.013). None of the individual antibodies or their combination was associated with the risk of development of extensive disease or colectomy.

Conclusion

Even with low prevalence rates, present study gives further evidence to the role of certain antibodies as markers for distinct phenotype and disease outcome in UC. Considering the result of the multivariate analysis the novel antibodies investigated do not seem to be associated with poor clinical outcome in UC, only a classic antibody, IgA subtype ASCA remained an independent predictor of long-term immunosuppressive therapy.

Antibodies against glycoprotein 2 display diagnostic advantages over ASCA in distinguishing CD from intestinal tuberculosis and intestinal Behçet's disease

Objectives:

There is an increasing need to identify reliable biomarkers for distinguishing Crohn’s disease (CD) from other gastrointestinal disorders sharing similar clinical and pathological features. This study aimed at evaluating the diagnostic potential of antibodies to zymogen granule glycoprotein GP2 (aGP2) in a large, well-defined Chinese cohort with a special focus on their role in discriminating CD from intestinal Behçet's disease (BD) and intestinal tubercolosis (ITB).

Methods:

A total of 577 subjects were prospectively enrolled, including 171 patients with CD, 208 patients with ulcerative colitis (UC), 71 with BD, 57 with ITB and 70 healthy controls (HC). aGP2 and anti-Saccharomyces cerevisiae antibodies (ASCA) were determined by ELISA. Perinuclear antineutrophil cytoplasmic antibodies were tested by indirect immunofluorescent assay.

Results:

aGP2 IgG and IgA levels were significantly elevated in patients with CD compared with those in patients with UC, intestinal BD, and ITB and HC. Conversely, ASCA IgG levels were not different between CD and intestinal BD patients, whereas ASCA IgA levels did not discriminate CD from intestinal BD and ITB patients. aGP2 IgA and IgG displayed a better assay performance (larger areas under the curve) over ASCA IgA and IgG in differentiating CD from disease controls (P<0.05). ASCA IgA did not discriminate CD from disease controls. aGP2 IgA and/or IgG was significantly associated with penetrating disease (B3) and ileal CD (L1) (P<0.05), whereas ASCA IgA and/or IgG was not.

Conclusions:

In comparison with ASCA, aGP2 distinguishes CD from intestinal BD or ITB as disease controls more efficiently, aiding in the differential diagnosis of IBD.

IBD Serology and Disease Outcomes in African Americans With Crohn's Disease

BACKGROUNDS

Recent studies have identified the role of serologic markers in characterizing disease phenotype, location, complications, and severity among Northern Europeans (NE) with Crohn's disease (CD). However, very little is known about the role of serology in CD among African Americans (AA). Our study explored the relationship between serology and disease phenotype in AA with CD, while controlling for genetic ancestry.

METHODS

AAs with CD were enrolled as participants through multicenter collaborative efforts. Serological levels of IgA anti-Saccharomyces cervisiae antibody (ASCA), IgG ASCA, E. coli outermembrane porin C, anti-CBir1, and ANCA were measured using enzyme-linked immunosorbent assays. Genotyping was performed using Illumina immunochip technology; an admixture rate was calculated for each subject. Multiple imputation by chained equations was performed to account for data missing at random. Logistic regression was used to calculate adjusted odds ratio (OR) for associations between serological markers and both complicated disease and disease requiring surgery.

RESULTS

A total of 358 patients were included in the analysis. The majority of our patients had inflammatory, noncomplicated disease (58.4%), perianal disease (55.7%), and documented colonic inflammation (86.8%). On multivariable analysis, both IgG ASCA and OmpC were associated with complicated disease (OR, 2.67; 95% CI, 1.67-4.28; OR, 2.23; 95% CI, 1.41-3.53, respectively) and disease requiring surgery (OR, 2.51; 95% CI, 1.49-4.22; OR, 3.57; 95% CI, 2.12-6.00). NE admixture to the African genome did not have any associations or interactions in relation to clinical outcome.

CONCLUSIONS

Our study comprises the largest cohort of AAs with CD. The utility of serological markers for the prognosis of CD in NE applies equally to AA populations.

The value of serum antibodies in differentiating inflammatory bowel disease, predicting disease activity and disease course in the newly diagnosed patient

BACKGROUND

Data on serum antibodies in untreated adult inflammatory bowel disease (IBD) patients at diagnosis are scarcely available, and results on the stability of antibody presence over time are inconsistent. Our aim was to investigate antibodies in newly diagnosed, untreated IBD patients in relation to disease phenotype and course. Furthermore, we analyzed antibody presence over time.

METHODS

Baseline anti-Saccharomyces cerevisiae antibodies (ASCA), anti-chitobioside carbohydrate antibodies (ACCA), anti-laminaribioside carbohydrate antibodies (ALCA) and anti-mannobioside carbohydrate antibodies (AMCA) were measured with enzyme-linked immunosorbent assays and perinuclear anti-neutrophilic cytoplasmic antibodies (pANCA) was measured by indirect immunofluorescence in serum of 120 untreated IBD patients at diagnosis and 19 healthy controls. Antibodies were related to disease outcomes. Serial measurements were available in 71 patients.

RESULTS

The combination of pANCA and ASCA enabled good discrimination between UC and CD (p = .004). Antibody presence was relatively stable over time, even though there were significant changes in concentrations. There was a trend towards larger fluctuations in concentration with immunosuppressive medication. Baseline pANCA in UC patients correlated with calprotectin values (rho = .545, p = .019) and change in pANCA status over time was associated with disease activity at that moment. No associations were found with antibodies at diagnosis and disease outcomes.

CONCLUSION

Antibody profiles at diagnosis support the distinction between CD and UC. Anti-glycan antibodies are reasonably stable over time, but may fluctuate under the influence of immunosuppressive treatment which may explain the inconsistency in findings hitherto. The appearance or disappearance of pANCA antibodies during follow-up correlated with disease activity in UC and may be used in disease monitoring.

Clinical usefulness of serum antibodies as biomarkers of gastrointestinal and liver diseases

The progressively growing knowledge of the pathophysiology of a number of immune-mediated gastrointestinal and liver disorders, including autoimmune atrophic gastritis, coeliac disease, autoimmune enteropathy, inflammatory bowel disease, autoimmune hepatitis, primary sclerosing cholangitis, primary biliary cholangitis and autoimmune pancreatitis, together with the improvement of their detection methods have increased the diagnostic power of serum antibodies. In some cases - coeliac disease and autoimmune atrophic gastritis - they have radically changed gastroenterologists' diagnostic ability, while in others - autoimmune hepatitis, inflammatory bowel disease and autoimmune pancreatitis - their diagnostic performance is still inadequate. Of note, serum antibody misuse in clinical practice has raised a number of controversies, which may generate confusion in the diagnostic management of the aforementioned disorders. In this review, we critically re-evaluate the usefulness of serum antibodies as biomarkers of immune-mediated gastrointestinal and liver disorders, and discuss their pitfalls and merits.

Autoantibodies Against Glycoprotein 2 Isoforms in Pediatric Patients with Inflammatory Bowel Disease

BACKGROUND

Anti-Glycoprotein 2 (GP2) antibodies are associated with a more complicated course of Crohn's disease (CD) in adults. Four different GP2 isoforms with different length and antibody-binding sites have been identified so far but not been explored in serological studies. We aimed to investigate the diagnostic utility of autoantibodies against all 4 isoforms of GP2 in an exclusively pediatric population for the first time.

METHODS

We included 278 children and adolescents with inflammatory bowel disease: 164 with CD, 114 with ulcerative colitis, 83 disease controls (acute gastrointestinal infection, nonspecific gastrointestinal functional disorders), and 219 healthy controls. Sera were tested for anti-GP2 antibodies using 4 different isoforms of GP2 for anti-Saccharomyces cerevisiae antibodies, antineutrophil cytoplasmic antibodies, and pancreatic antibodies.

RESULTS

Anti-GP2 antibodies were significantly more prevalent in patients with CD than in ulcerative colitis and controls. We found a sensitivity of 38% (with a specificity of 95%) for anti-GP2 IgG against isoform 4 in CD. Anti-GP2 IgA against isoform 1 and anti-GP2 IgG against isoform 4 possessed the best diagnostic values for identification of CD. For the differentiation of CD from ulcerative colitis anti-GP2 IgG against isoforms 3 and 4 proved to be most accurate markers. Anti-GP2 antibodies were associated with a more complicated disease behavior and bowel surgery in CD. In a subgroup of patients with CD, anti-GP2 IgG against isoform 4 proved to be a relatively stable marker over time independent of disease activity.

CONCLUSIONS

Anti-GP2 antibodies against different isoforms are specific markers for CD and for different phenotypes in pediatric inflammatory bowel disease.

IBD血清学标志物的临床应用前景

炎症性肠病(inflammatory bowel disease, IBD)是一种病因不明的慢性非特异性肠道炎症性疾病, 包括溃疡性结肠炎(ulcerative colitis, UC)和克罗恩病(Crohn's disease, CD). 目前IBD的诊断及临床过程主要依据其临床表现、常规检验、影像学特征、内镜所见及组织病理综合判断, 但远未满足临床实践. 因此, 寻找一种简单、准确的诊断方法成为目前亟待解决的问题. 迄今, IBD相关血清学标志物的应用对IBD的诊断与鉴别诊断、疾病严重程度界定、疗效判断和预后评估均凸显出其临床优势. 本文就近年来IBD血清学标志物的研究及其临床应用前景作一述评.

Serologic antibodies in relation to outcome in postoperative Crohn's disease

BACKGROUND AND AIM

Disease recurs frequently after Crohn's disease resection. The role of serological antimicrobial antibodies in predicting recurrence or as a marker of recurrence has not been well defined.

METHODS

A total of 169 patients (523 samples) were prospectively studied, with testing peri-operatively, and 6, 12 and 18 months postoperatively. Colonoscopy was performed at 18 months postoperatively. Serologic antibody presence (perinuclear anti-neutrophil cytoplasmic antibody [pANCA], anti-Saccharomyces cerevisiae antibodies [ASCA] IgA/IgG, anti-OmpC, anti-CBir1, anti-A4-Fla2, anti-Fla-X) and titer were tested. Quartile sum score (range 6-24), logistic regression analysis, and correlation with phenotype, smoking status, and endoscopic outcome were assessed.

RESULTS

Patients with ≥ 2 previous resections were more likely to be anti-OmpC positive (94% vs 55%, ≥ 2 vs < 2, P = 0.001). Recurrence at 18 months was associated with anti-Fla-X positivity at baseline (49% vs 29%; positive vs negative, P = 0.033) and 12 months (52% vs 31%, P = 0.04). Patients positive (n = 28) for all four antibacterial antibodies (anti-CBir1, anti-OmpC, anti-A4-Fla2, and anti-Fla-X) at baseline were more likely to experience recurrence at 18 months than patients negative (n = 32) for all four antibodies (82% vs 18%, P = 0.034; odds ratio 6.4, 95% confidence interval 1.16-34.9). The baseline quartile sum score for all six antimicrobial antibodies was higher in patients with severe recurrence (Rutgeert's i3-i4) at 18 months, adjusted for clinical risk factors (odds ratio 1.16, 95% confidence interval 1.01-1.34, P = 0.039). Smoking affected antibody status.

CONCLUSIONS

Anti-Fla-X and presence of all anti-bacterial antibodies identifies patients at higher risk of early postoperative Crohn's disease recurrence. Serologic screening pre-operatively may help identify patients at increased risk of recurrence.

Visceral adiposity predicts post-operative Crohn's disease recurrence

BACKGROUND

Excessive visceral adipose tissue has been associated with poorer outcomes in patients with inflammatory bowel disease.

AIM

To determine whether body composition is associated with outcome in a prospective study of post-operative Crohn's disease patients.

METHODS

The POCER study evaluated management strategies for prevention of post-operative Crohn's disease recurrence; subjects were enrolled after resection of all macroscopic Crohn's disease and were randomised to early endoscopy and possible treatment escalation, or standard care. The primary endpoint was endoscopic recurrence at 18 months. 44 subjects with cross-sectional abdominal imaging were studied, and body composition analysis performed using established techniques to measure visceral adipose tissue area, subcutaneous adipose tissue area, and skeletal muscle area.

RESULTS

The body composition parameter with the greatest variance was visceral adipose tissue. Regardless of treatment, all subjects with visceral adipose tissue/height² >1.5 times the gender-specific mean experienced endoscopic recurrence at 18 months (compared to 47%) [relative risk 2.1, 95% CI 1.5-3.0, P = 0.012]. Waist circumference correlated strongly with visceral adipose tissue area (ρ = 0.840, P < 0.001). Low skeletal muscle was prevalent (41% of patients), but did not predict endoscopic recurrence; however, appendicular skeletal muscle indices correlated inversely with faecal calprotectin (ρ = 0.560, P = 0.046).

CONCLUSIONS

Visceral adiposity is an independent risk factor for endoscopic recurrence of Crohn's disease after surgery. Sarcopenia correlates with inflammatory biomarkers. Measures of visceral adipose tissue may help to stratify risk in post-operative management strategies.

Inflammatory Bowel Disease-Unclassified in Children: Diagnosis and Pharmacological Management

Inflammatory bowel diseases are chronic disorders of the gastrointestinal tract that include Crohn's disease (CD), ulcerative colitis (UC) and inflammatory bowel disease-unclassified (IBDU). The latter defines a subgroup of patients with clinical and endoscopic evidence of chronic colitis, without specific features of either CD or UC. These patients will possibly be re-classified as having UC or CD during the follow-up, although a significant percentage of them will keep the diagnosis of IBDU. IBDU is the rarest subtype of IBD, both in children and in adults, although it is twice as common among the pediatric population, especially in the younger ages. The diagnosis can only be made after a comprehensive diagnostic work-up, combining clinical history, physical and laboratory examination, upper and lower gastrointestinal endoscopy, with histology and imaging of the small bowel. The therapeutic strategy is borrowed from that of UC and CD, although recent data suggest that IBDU has a lower therapeutic burden with a generally mild disease course and a good response to mesalamine. Since there are only few published data on pediatric IBDU, and no guidelines on its management are available, this review aims at summarizing the most recent evidence for the diagnostic work-up with a specific focus on medical and surgical options in the treatment of IBDU.

Serologic testing of a panel of five antibodies in inflammatory bowel diseases: Diagnostic value and correlation with disease phenotype

The aim of the present study was to evaluate the diagnostic value of five serological antibodies, perinuclear antineutrophil cytoplasmic antibody (pANCA), anti-Saccharomyces cerevisiae antibodies [ASCA; ASCA-immunoglobulin (IgG)and ASCA-IgA], Escherichia coli outer membrane porin C antibody (anti-OmpC) and CBir1 flagellin antibody for detection in inflammatory bowel diseases. Whether the antibody status correlated with the disease phenotype was also evaluated. Sera from 71 patients with Crohn's disease (CD), 41 patients with ulcerative colitis (UC), 78 patients with other gastrointestinal diseases and 31 healthy control subjects were investigated. Clinical data were gathered at the time of serum sampling and enzyme-linked immunosorbent assay was used to determine titers of the above mentioned five antibodies. The pANCA test exhibited a sensitivity of 53.7% for UC and the ASCA test had a sensitivity of 66.2% for CD. The prevalence of anti-OmpC was significantly higher in CD than in intestinal tuberculosis (TB), indicating that anti-OmpC may be a serologic marker distinguishing CD from TB. The pANCA⁺/ASCA- exhibited the best specificity for differentiating between CD and UC. In UC, the presence of pANCA was greater in the patients with moderate to severe activity than in those with mild activity. ASCA was more positive in ileal CD. Furthermore, positive ASCA-IgG or anti-OmpC implied that complicated CD and pANCA was associated with colonic CD. Seropositivity of anti-CBir1 was lowest in colonic CD.

Assessment of Fecal ASCA Measurement as a Biomarker of Crohn Disease in Pediatric Patients

OBJECTIVES

A simple and reliable biomarker for Crohn disease (CD) would be a valuable clinical tool. We hypothesized that anti-Saccharomyces cerevisiae antibody (ASCA) may be present in the stool of patients with CD. Accordingly, we measured ASCA in the stool and serum of children and adolescents with known or suspected inflammatory bowel disease (IBD).

METHODS

We included 114 patients 19 years or younger (73 boys) with IBD, including 83 patients with CD and 31 subjects without CD (28 with ulcerative colitis, and 3 patients with suspected IBD but without evidence of chronic inflammation at the time of their endoscopy and colonoscopy). Fecal and serum samples were analyzed using semiquantitative ASCA enzyme-linked immunoassays.

RESULTS

Median ASCA levels were significantly elevated in the stool (P = 0.04) and serum (P = 0.0008) of patients with CD, when compared to levels observed in patients without CD. Fecal ASCA levels were similarly more elevated in patients with active CD, relative to levels observed in patients with active ulcerative colitis and acute colitis (P = 0.004). Among patients with CD, fecal and serum ASCA levels were higher (P = 0.01 and 0.01, respectively) in patients with more recently diagnosed disease.

CONCLUSIONS

Fecal ASCA levels are higher in patients with active and newly diagnosed disease. Data from the present study suggest that measurement of fecal ASCA levels could represent a novel noninvasive biomarker for use in evaluating patients with suspected or known IBD. Further studies are necessary to better define the value of fecal ASCA measurements in identifying CD and response to therapy in children and young adults.

Recent advances in clinical practice: a systematic review of isolated colonic Crohn's disease: the third IBD?

The genetics of isolated colonic Crohn's disease place it approximately midway between Crohn's disease with small intestinal involvement and UC, making a case for considering it as a separate condition. We have therefore systematically reviewed its epidemiology, pathophysiology and treatment. Key findings include a higher incidence in females (65%) and older average age at presentation than Crohn's disease at other sites, a mucosa-associated microbiota between that found in ileal Crohn's disease and UC, no response to mesalazine, but possibly better response to antitumour necrosis factor than Crohn's disease at other sites. Diagnostic distinction from UC is often difficult and also needs to exclude other conditions including ischaemic colitis, segmental colitis associated with diverticular disease and tuberculosis. Future studies, particularly clinical trials, but also historical cohorts, should assess isolated colonic Crohn's disease separately.

Roles for Intestinal Bacteria, Viruses, and Fungi in Pathogenesis of Inflammatory Bowel Diseases and Therapeutic Approaches

Intestinal microbiota are involved in the pathogenesis of Crohn's disease, ulcerative colitis, and pouchitis. We review the mechanisms by which these gut bacteria, fungi, and viruses mediate mucosal homeostasis via their composite genes (metagenome) and metabolic products (metabolome). We explain how alterations to their profiles and functions under conditions of dysbiosis contribute to inflammation and effector immune responses that mediate inflammatory bowel diseases (IBD) in humans and enterocolitis in mice. It could be possible to engineer the intestinal environment by modifying the microbiota community structure or function to treat patients with IBD-either with individual agents, via dietary management, or as adjuncts to immunosuppressive drugs. We summarize the latest information on therapeutic use of fecal microbial transplantation and propose improved strategies to selectively normalize the dysbiotic microbiome in personalized approaches to treatment.

Specific members of the predominant gut microbiota predict pouchitis following colectomy and IPAA in UC

OBJECTIVE

Pouchitis is the most common complication after colectomy with ileal pouch-anal anastomosis (IPAA) for UC and the risk is the highest within the 1st year after surgery. The pathogenesis is not completely understood but clinical response to antibiotics suggests a role for gut microbiota. We hypothesised that the risk for pouchitis can be predicted based on the faecal microbial composition before colectomy.

DESIGN

Faecal samples from 21 patients with UC undergoing IPAA were prospectively collected before colectomy and at predefined clinical visits at 1 month, 3 months, 6 months and 12 months after IPAA. The predominant microbiota was analysed using community profiling with denaturing gradient gel electrophoresis followed by quantitative real-time PCR validation.

RESULTS

Cluster analysis before colectomy distinguished patients with pouchitis from those with normal pouch during the 1st year of follow-up. In patients developing pouchitis, an increase of Ruminococcus gnavus (p<0.001), Bacteroides vulgatus (p=0.043), Clostridium perfringens (p=0.011) and a reduction of two Lachnospiraceae genera (Blautia (p=0.04), Roseburia (p=0.008)) was observed. A score combining these five bacterial risk factors was calculated and presence of at least two risk factors showed a sensitivity and specificity of 100% and 63.6%, respectively.

CONCLUSIONS

Presence of R. gnavus, B. vulgatus and C. perfringens and absence of Blautia and Roseburia in faecal samples of patients with UC before surgery is associated with a higher risk of pouchitis after IPAA. Our findings suggest new predictive and therapeutic strategies in patients undergoing colectomy with IPAA.

Genetic and Metabolic Signals during Acute Enteric Bacterial Infection Alter the Microbiota and Drive Progression to Chronic Inflammatory Disease

Chronic inflammatory disorders are thought to arise due to an interplay between predisposing host genetics and environmental factors. For example, the onset of inflammatory bowel disease is associated with enteric proteobacterial infection, yet the mechanistic basis for this association is unclear. We have shown previously that genetic defiency in TLR1 promotes acute enteric infection by the proteobacteria Yersinia enterocolitica. Examining that model further, we uncovered an altered cellular immune response that promotes the recruitment of neutrophils which in turn increases metabolism of the respiratory electron acceptor tetrathionate by Yersinia. These events drive permanent alterations in anti-commensal immunity, microbiota composition, and chronic inflammation, which persist long after Yersinia clearence. Deletion of the bacterial genes involved in tetrathionate respiration or treatment using targeted probiotics could prevent microbiota alterations and inflammation. Thus, acute infection can drive long term immune and microbiota alterations leading to chronic inflammatory disease in genetically predisposed individuals.

Mining gut microbiome oligopeptides by functional metaproteome display

Pathogen infections, autoimmune diseases, and chronic inflammatory disorders are associated with systemic antibody responses from the host immune system. Disease-specific antibodies can be important serum biomarkers, but the identification of antigens associated with specific immune reactions is challenging, in particular if complex communities of microorganisms are involved in the disease progression. Despite promising new diagnostic opportunities, the discovery of these serological markers becomes more difficult with increasing complexity of microbial communities. In the present work, we used a metagenomic M13 phage display approach to select immunogenic oligopeptides from the gut microbiome of transgenic mice suffering from chronic ileitis. We constructed three individual metaproteome phage display libraries with a library size of approximately 10⁷ clones each. Using serum antibodies, we selected and validated three oligopeptides that induced specific antibody responses in the mouse model. This proof-of-concept study provides the first successful application of functional metaproteome display for the study of protein-protein interactions and the discovery of potential disease biomarkers.

[Biomarkers for chronic inflammatory diseases]

Inflammatory disorders of childhood, such as juvenile idiopathic arthritis (JIA) and inflammatory bowel disease (IBD) are a challenge for laboratory diagnostics. Firstly, the classical inflammatory markers, such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) often inadequately reflect disease activity but on the other hand there are few specific biomarkers that can be helpful in managing these diseases. Acute phase proteins reflect the systemic inflammatory response insufficiently as their increase is only the indirect result of local inflammatory processes. Modern inflammation diagnostics aim to reflect these local processes and to allow precise monitoring of disease activity. Experimental biomarkers, such as S100 proteins can detect subclinical inflammatory activity. In addition, established laboratory parameters exist for JIA [antinuclear antibodies (ANA), rheumatoid factor (RF), antibodies against cyclic citrullinated peptide (anti-CCP)] and for chronic IBD (fecal calprotectin) that are useful in the treatment of these diseases.

pANCA and ASCA in Children with IBD-Unclassified, Crohn's Colitis, and Ulcerative Colitis-A Longitudinal Report from the IBD Porto Group of ESPGHAN

INTRODUCTION

No study to date has evaluated perinuclear antineutrophil cytoplasmic antibody (pANCA) and anti-Saccharomyces cerevisiae antibody (ASCA) in pediatric inflammatory bowel disease-unclassified (IBDU) as compared with Crohn's colitis (CC) and ulcerative colitis (UC), which represent the diagnostic challenge. We aimed to explore the diagnostic utility of serology and to assess whether serology can predict disease severity in these subgroups.

METHODS

This was a multicenter retrospective longitudinal study including 406 children with inflammatory bowel diseases (IBD) from 23 centers affiliated with the Porto group of European Society of Pediatric Gastroenterology, Hepatology and Nutrition (mean age 10.5 ± 3.9, 54% males); 117 (29%) with CC, 143 (35%) with UC, and 146 (36%) with IBDU. Median follow-up period was 2.8 years (interquartile range, 1.6-4.2).

RESULTS

The most prevalent serologic profile in IBDU was pANCA-/ASCA- (41%), followed by pANCA+/ASCA- (34%) and pANCA-/ASCA+ (17%). pANCA-/ASCA+ differentiated well between CC versus IBDU (83% specificity, 96% positive predictive value [PPV]) and UC (97% specificity, 90% PPV) patients, albeit with a low negative predictive value (13% and 40%, respectively). pANCA+/ASCA- did not differentiate as well between IBD subgroups, but UC children with pANCA+/ASCA- had more often severe disease at diagnosis (36 [62%] versus 22 [38%], P = 0.033) and needed more often calcineurin inhibitors, biologics, or colectomy (25 [80%] versus 6 [20%], P = 0.026). In CC, double positivity for ASCA and not pANCA-/ASCA+ profile was associated with disease severity.

CONCLUSIONS

Serology may have some role in predicting disease course and outcomes in colonic IBD, but its routine use needs to be supported by more studies. Serology cannot routinely be recommended for differentiating between IBDU versus CC or UC as a sole diagnostic criterion given its low diagnostic utility.

Concordance in Anti-OmpC and Anti-I2 Indicate the Influence of Genetic Predisposition: Results of a European Study of Twins with Crohn's Disease

BACKGROUND AND AIMS

An adaptive immunological response to microbial antigens has been observed in Crohn's disease (CD). Intriguingly, this serological response precedes the diagnosis in some patients and has also been observed in healthy relatives. We aimed to determine whether genetic factors are implicated in this response in a CD twin cohort.

METHODS

In total, 82 twin pairs (Leuven n = 13, Maastricht n = 8, Örebro n = 61) took part: 81 pairs with CD (concordant monozygotic n = 16, discordant monozygotic n = 22, concordant dizygotic n = 3, discordant dizygotic n = 40) and 1 monozygotic pair with both CD and ulcerative colitis. Serology for Pseudomonas fluorescens-related protein (anti-I2), Escherichia coli outer membrane porin C (anti-OmpC), CBir1flagellin (anti-CBir1) and antibodies to oligomannan (anti-Saccharomyces cerevisiae antibody [ASCA]) was determined by standardized enzyme-linked immunoassay.

RESULTS

All markers were more often present in CD twins than in their healthy twin siblings. Using the intraclass correlation coefficient (ICC), agreements in concentrations of anti-OmpC and anti-I2 were observed in discordant monozygotic but not in discordant dizygotic twin pairs with CD (anti-OmpC, ICC 0.80 and -0.02, respectively) and (anti-I2, ICC 0.56 and 0.05, respectively). In contrast, no agreements were found in anti-CBir, immunoglobulin (Ig) G ASCA and ASCA IgA.

CONCLUSIONS

We show that anti-I2 and anti-CBir1 statuses have specificity for CD and confirm previous reported specificities for anti-OmpC and ASCA. Based on quantitative analyses and observed ICCs, genetics seems to predispose to the anti-OmpC and anti-I2 response but less to ASCA and anti-CBir1 responses.

Microbiome profiling of drinking water in relation to incidence of inflammatory bowel disease

The etiology of inflammatory bowel disease (IBD) is unknown; current research is focused on determining environmental factors. One consideration is drinking water: water systems harbour considerable microbial diversity, with bacterial concentrations estimated at 10(6)-10(8) cells/L. Perhaps differences in microbial ecology of water sources may impact differential incidence rates of IBD. Regions of Manitoba were geographically mapped according to incidence rates of IBD and identified as high (HIA) or low (LIA) incidence areas. Bulk water, filter material, and pipe wall samples were collected from public buildings in different jurisdictions and their population structure analyzed using 16S rDNA sequencing. At the phylum level, Proteobacteria were observed significantly less frequently (P = 0.02) in HIA versus LIA. The abundance of Proteobacteria was also found to vary according to water treatment distribution networks. Gammaproteobacteria was the most abundant class of bacteria and was observed more frequently (P = 0.006) in LIA. At the genus level, microbes found to associate with HIA include Bradyrhizobium (P = 0.02) and Pseudomonas (P = 0.02). Particular microbes were found to associate with LIA or HIA, based on sample location and (or) type. This work lays out a basis for further studies exploring water as a potential environmental source for IBD triggers.

TNFAIP6 is a potential biomarker of disease activity in inflammatory bowel disease

AIM

Ideal biomarkers are needed for evaluating the activity of inflammatory bowel disease (IBD). We aimed to investigate the value of TNFAIP6 as a biomarker.

MATERIALS & METHODS

Inflamed colonic samples and serum samples were collected from patients with Crohn's disease (CD), patients with ulcerative colitis (UC), and normal controls. SPSS 18.0 was used for statistical analysis.

RESULTS

Serum TNFAIP6 was higher in IBD patients than in normal controls and correlated with the inflammatory indicators. Compared with active patients, TNFAIP6 was decreased in both CD and UC patients in remission. Furthermore, TNFAIP6 concentrations consistent with TNF-α level, correlated well with disease location and extent of both CD and UC.

CONCLUSION

Serum TNFAIP6 may be a promising biomarker for evaluating the disease activity of IBD, demonstrating the diagnostic value in disease location differentiation.

Intestinal tuberculosis and Crohn's disease: challenging differential diagnosis

Along with epidemiological changes in tuberculosis (TB) and an increased incidence of Crohn's disease (CD), the differential diagnosis of intestinal TB (ITB) and CD is of vital importance and has become a clinical challenge because treatment based on misdiagnosis may lead to fatal outcomes. In this study, we reviewed the similarities and differences in clinical, endoscopic, radiological and histological features of these two diseases. Concomitant pulmonary TB, ascites, night sweats, involvement of fewer than four segments of the bowel, patulous ileocecal valve, transverse ulcers, scars or pseudopolyps strongly indicate ITB. Bloody stools, perianal signs, chronic diarrhea, extraintestinal manifestations, anorectal lesions, longitudinal ulcers and a cobblestone appearance are all suggestive of CD. Significant differences in the size, number, location and patterns of granulomas in ITB and CD with regard to their histopathologic features have been noted. Immune stain of cell surface markers is also helpful. Interferon-γ release assay and polymerase chain reaction analysis have achieved satisfactory sensitivity and specificity in the diagnosis of ITB. Computed tomography enterographic findings of segmental small bowel or left colon involvement, mural stratification, the comb sign and fibrofatty proliferation are significantly more common in CD, whereas mesenteric lymph node changes (calcification or central necrosis) and focal ileocecal lesions are more frequently seen in ITB. A diagnosis should be carefully established before the initiation of the therapy. In suspicious cases, short-term empirical anti-TB therapy is quite efficient to further confirm the diagnosis.

Anticommensal Responses Are Associated with Regulatory T Cell Defect in Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy Patients

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a monogenic autoimmune disease caused by mutations in the AIRE gene. Although mainly an endocrine disease, a substantial fraction of patients have gastrointestinal manifestations. In this study, we have examined the role of anticommensal responses and their regulation. APECED patients had increased levels of Abs against Saccharomyces cerevisiae (p < 0.0001) and against several species of commensal gut bacteria, but not against species predominantly associated with other locations. The anticommensal Ab levels did not correlate with gastrointestinal autoantibodies, neutralizing anti-IL-17 or -IL-22 Abs, or gastrointestinal symptoms, although scarcity of the available clinical data suggests that further study is required. However, the anti-S. cerevisiae Ab levels showed a significant inverse correlation with FOXP3 expression levels in regulatory T cells (Treg), previously shown to be dysfunctional in APECED. The correlation was strongest in the activated CD45RO(+) population (ρ = -0.706; p < 0.01). APECED patients also had decreased numbers of FOXP3(+) cells in gut biopsies. These results show that APECED patients develop early and sustained responses to gut microbial Ags in a pattern reminiscent of Crohn's disease. This abnormal immune recognition of gut commensals is linked to a systemic Treg defect, which is also reflected as a local decrease of gut-associated Treg. To our knowledge, these data are the first to show dysregulated responses to non-self commensal Ags in APECED and indicate that AIRE contributes to the regulation of gut homeostasis, at least indirectly. The data also raise the possibility of persistent microbial stimulation as a contributing factor in the pathogenesis of APECED.

Current application of proteomics in biomarker discovery for inflammatory bowel disease

Recently, the field of proteomics has rapidly expanded in its application towards clinical research with objectives ranging from elucidating disease pathogenesis to discovering clinical biomarkers. As proteins govern and/or reflect underlying cellular processes, the study of proteomics provides an attractive avenue for research as it allows for the rapid identification of protein profiles in a biological sample. Inflammatory bowel disease (IBD) encompasses several heterogeneous and chronic conditions of the gastrointestinal tract. Proteomic technology provides a powerful means of addressing major challenges in IBD today, especially for identifying biomarkers to improve its diagnosis and management. This review will examine the current state of IBD proteomics research and its use in biomarker research. Furthermore, we also discuss the challenges of translating proteomic research into clinically relevant tools. The potential application of this growing field is enormous and is likely to provide significant insights towards improving our future understanding and management of IBD.

Emerging role of novel biomarkers in the diagnosis of inflammatory bowel disease

There is currently no gold standard test for the diagnosis of inflammatory bowel disease (IBD). Physicians must rely on a number of diagnostic tools including clinical and endoscopic evaluation as well as histologic, serologic and radiologic assessment. The real difficulty for physicians in both primary and secondary care is differentiating between patients suffering from functional symptoms and those with true underlying IBD. Alongside this, there is always concern regarding the possibility of a missed, or delayed diagnosis of ulcerative colitis (UC) or Crohn’s disease. Even once the diagnosis of IBD has been made, there is often uncertainty in distinguishing between cases of UC or Crohn’s. As a consequence, in cases of incorrect diagnosis, optimal treatment and management may be adversely affected. Endoscopic evaluation can be uncomfortable and inconvenient for patients. It carries significant risks including perforation and in terms of monetary cost, is expensive. The use of biomarkers to help in the diagnosis and differentiation of IBD has been increasing over time. However, there is not yet one biomarker, which is sensitive of specific enough to be used alone in diagnosing IBD. Current serum testing includes C-reactive protein and erythrocyte sedimentation rate, which are cheap, reliable but non-specific and thus not ideal. Stool based testing such as faecal calprotectin is a much more specific tool and is currently in widespread clinical use. Non-invasive sampling is of the greatest clinical value and with the recent advances in metabolomics, genetics and proteomics, there are now more tools available to develop sensitive and specific biomarkers to diagnose and differentiate between IBD. Many of these new advances are only in early stages of development but show great promise for future clinical use.

Systematic review: predicting and optimising response to anti-TNF therapy in Crohn's disease - algorithm for practical management

BACKGROUND

Nonresponse and loss of response to anti-TNF therapies in Crohn's disease represent significant clinical problems for which clear management guidelines are lacking.

AIM

To review the incidence, mechanisms and predictors of primary nonresponse and secondary loss of response to formulate practical clinical algorithms to guide management.

METHODS

Through a systematic literature review, 503 articles were identified which fit the inclusion criteria.

RESULTS

Primary nonresponse to anti-TNF treatment affects 13-40% of patients. Secondary loss of response to anti-TNF occurs in 23-46% of patients when determined according to dose intensification, and 5-13% of patients when gauged by drug discontinuation rates. Recent evidence suggests that the mechanisms underlying primary nonresponse and secondary loss of response are multifactorial and include disease characteristics (phenotype, location, severity); drug (pharmacokinetic, pharmacodynamic or immunogenicity) and treatment strategy (dosing regimen) related factors. Clinical algorithms that employ therapeutic drug monitoring (using anti-TNF tough levels and anti-drug antibody levels) may be used to determine the underlying cause of primary nonresponse and secondary loss of response respectively and guide clinicians as to which patients are most likely to respond to anti-TNF therapy and help optimise drug therapy for those who are losing response to anti-TNF therapy.

CONCLUSIONS

Nonresponse or loss of response to anti-TNF occurs commonly in Crohn's disease. Clinical algorithms utilising therapeutic drug monitoring may establish the mechanisms for treatment failure and help guide the subsequent therapeutic approach.

Trimethylamine-N-oxide: A Novel Biomarker for the Identification of Inflammatory Bowel Disease

BACKGROUND

The gastrointestinal (GI) microbiome is recognized for potential clinical relevance in inflammatory bowel disease (IBD). Data suggest that there is a disease-dependent loss of microbial diversity in IBD. Trimethylamine-N-oxide (TMAO) is generated by GI anaerobes through the digestion of dietary phosphatidylcholine and carnitine in a microbial-mammalian co-metabolic pathway. IBD-related changes in the gut microbiome may result in disease-specific changes in TMAO plasma concentrations.

AIM

To determine whether TMAO plasma levels in IBD are altered compared to controls and whether they correlate with disease presence or activity.

METHODS

Liquid chromatography-tandem mass spectrometry was used to measure TMAO, choline, and carnitine plasma levels in 479 subjects (373 non-IBD controls, 106 IBD). Subjects were also genotyped for the flavin monooxygenase (FMO)3 variants, E158K and E308G.

RESULTS

Plasma TMAO levels were 2.27 µM lower in the IBD population compared to the control population (p = 0.0001). Lower TMAO levels were similarly seen in active ulcerative colitis (UC) (1.56 µM) versus inactive disease (3.40 µM) (p = 0.002). No difference was seen in active Crohn's disease (CD) versus inactive CD. No intergroup variation existed in plasma TMAO levels based on FMO3 genotype. Choline levels were higher in IBD, while carnitine levels were similar between the two groups, suggesting that lower TMAO levels in IBD were not due to dietary differences.

CONCLUSIONS

Decreased TMAO levels are seen in IBD compared to a non-IBD population. These data suggest that TMAO may have potential as a biomarker to support IBD diagnosis as well as to assess disease activity in UC.

Crohn's disease: a clinical update

Crohn's disease is increasing in prevalence worldwide. It arises from a complex interplay between both genetic predisposition and environmental influence. A search of databases and clinical practice guidelines was performed to provide the most up-to-date evidence-based approach for diagnosing and managing patients with Crohn's disease. No single gold standard investigation exists. Whilst full ileocolonoscopy with biopsies remains the mainstay for diagnosis, other less invasive imaging modalities are being actively considered in the workup, as well as the use of serological markers. Management should incorporate dietary and lifestyle modifications where necessary, the use of medications in induction and remission of disease, and consideration of surgical intervention where medical therapy has failed.

Inflammation, Antibiotics, and Diet as Environmental Stressors of the Gut Microbiome in Pediatric Crohn's Disease

Abnormal composition of intestinal bacteria--"dysbiosis"-is characteristic of Crohn's disease. Disease treatments include dietary changes and immunosuppressive anti-TNFα antibodies as well as ancillary antibiotic therapy, but their effects on microbiota composition are undetermined. Using shotgun metagenomic sequencing, we analyzed fecal samples from a prospective cohort of pediatric Crohn's disease patients starting therapy with enteral nutrition or anti-TNFα antibodies and reveal the full complement and dynamics of bacteria, fungi, archaea, and viruses during treatment. Bacterial community membership was associated independently with intestinal inflammation, antibiotic use, and therapy. Antibiotic exposure was associated with increased dysbiosis, whereas dysbiosis decreased with reduced intestinal inflammation. Fungal proportions increased with disease and antibiotic use. Dietary therapy had independent and rapid effects on microbiota composition distinct from other stressor-induced changes and effectively reduced inflammation. These findings reveal that dysbiosis results from independent effects of inflammation, diet, and antibiotics and shed light on Crohn disease treatments.

Overcoming difficulty in diagnosis and differential diagnosis of Crohn's disease: the potential role of serological and genetic tests

Crohn's disease (CD) represents a heterogeneous group of chronic inflammatory disorders with various phenotypes. Establishing a definite diagnosis of CD should be based upon a combined assessment of clinical, endoscopic, radiological and pathological features. Although segmental disease distribution, transmural inflammation and non-caseating epithelioid granulomas have been considered as a 'hallmarks' for CD, clear diagnosis of CD in some patients has been challenging, due to overlapping endoscopic, radiographic and histologic features with other inflammatory bowel disease-like conditions. Laboratory markers (serological and genetic tests) may provide additional clues for the diagnosis and differential diagnosis of CD. This review focuses on the application of the currently available serological and genomic markers and in diagnosis and differential diagnosis of CD.

Fungal Signature in the Gut Microbiota of Pediatric Patients With Inflammatory Bowel Disease

BACKGROUND

Inflammatory bowel disease (IBD) involves dysregulation of mucosal immunity in response to environmental factors such as the gut microbiota. The bacterial microbiota is often altered in IBD, but the connection to disease is not fully clarified and gut fungi have recently been suggested to play a role as well. In this study, we compared microbes from all 3 domains of life-bacteria, archaea, and eukaryota-in pediatric patients with IBD and healthy controls.

METHODS

A stool sample was collected from patients with IBD (n = 32) or healthy control subjects (n = 90), and bacterial, archaeal, and fungal communities were characterized by deep sequencing of rRNA gene segments specific to each domain.

RESULTS

Patients with IBD (Crohn's disease or ulcerative colitis) had lower bacterial diversity and distinctive fungal communities. Two lineages annotating as Candida were significantly more abundant in patients with IBD (P = 0.0034 and P = 0.00038, respectively), whereas a lineage annotating as Cladosporium was more abundant in healthy subjects (P = 0.0025). There were no statistically significant differences in archaea, which were rare in pediatric samples compared with those from adults.

CONCLUSIONS

Pediatric IBD is associated with reduced diversity in both fungal and bacterial gut microbiota. Specific Candida taxa were found to be increased in abundance in the IBD samples. These data emphasize the potential importance of fungal microbiota signatures as biomarkers of pediatric IBD, supporting their possible role in disease pathogenesis.

Association of Anti-glycan Antibodies and Inflammatory Bowel Disease Course

BACKGROUND AND AIMS

The usefulness of anti-glycan antibodies alone or combined with anti-Saccharomyces cerevisiae [ASCA] or perinuclear antineutrophil cytoplasmic [pANCA] antibodies for diagnosis of inflammatory bowel disease [IBD], differentiation between Crohn's disease [CD] and ulcerative colitis [UC], disease stratification including IBD phenotype, and also for determination of the course of the disease, remain unclear.

METHODS

A large panel of serological anti-glycan carbohydrate antibodies, including anti-mannobioside IgG antibodies [AMCA], anti-chitobioside IgA [ACCA], anti-laminaribioside IgG antibodies [ALCA], anti-laminarin [anti-L] and anti-chitine [anti-C] were measured in the serum from a cohort of 195 patients with IBD] [107 CD and 88 UC]. The respective accuracy of isolated or combined markers for diagnosis, disease differentiation, stratification disease phenotype, and severity of the disease course, defined by a wide panel of criteria obtained from the past medical history, was assessed.

RESULTS

The positivity of at least one anti-glycan antibody was detected in a significant higher proportion of CD and UC compared with healthy controls [p < 0.0001 and p < 0.0007, respectively]. Whereas ASCA and ANCA antibody status had the highest efficacy to be associated with CD in comparison with UC (area under receiver operating characteristic curve [AUROC] = 0.70 for each], the adjunction of anti-laminarin antibody substantially improved the differentiation between CD and UC [AUROC = 0.77]. Titres of ACCA [> 51U/ml] and anti-laminarin [> 31U/ml] were significantly linked with a higher association with steroid dependency (odds ratio [OR] =2.0 [1.0-4.0], p = 0.03 and OR = 2.4 [1.1-5.2], p = 0.02, respectively]. We further defined the respective performance of anti-glycan antibodies to discriminate between patients with severe or not severe CD and UC course and determined the associated optimal cut-off values: severe CD course was significantly more likely in case of AMCA > 77U/ml [OR = 4.3; p = 0.002], ASCA > 63U/ml [OR = 3.5; p < 0.009] and at a lesser degree ACCA > 50U/ml [OR = 2.8; p < 0.02] and severe UC course was significantly associated with AMCA > 52U/ml [OR = 3.4; p = 0.04] and ACCA > 25U/ml [OR = 3.0; p < 0.04].

CONCLUSIONS

Anti-glycan antibodies are valuable serological markers, especially AMCA antibodies that may help clinicians to promptly classify patients into high risk for severe disease.

New Trends in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic idiopathic inflammatory disease of the gastrointestinal (GI) tract. In the past decade a shift in the treatment paradigm of IBD has ensued. The availability of drugs capable of inducing mucosal healing, combined with the recognition that IBD is not an intermittent disease, but rather a progressive one causing bowel damage and disability, led us to a more stringent strategy. Tailored therapy with more aggressive treatment in high-risk patients, treating beyond symptoms, intervening early before damage occurs, optimizing therapeutic regimens, and actively pursuing sustained remission and sustained control of inflammation are strategies that are slowly being incorporated in our clinical practice. Furthermore, new drugs targeting different immunological pathways, such as vedolizumab, have recently been approved and therefore more therapeutic resources for patients failing anti-tumour necrosis factor alpha (anti-TNFα) agents will be available. The future years look promising for IBD. Hopefully the new trends in IBD management, combined with new drugs, will make possible to change the course of disease and provide better therapy and quality of life for patients suffering from this disabling disease.

Clinical aspects of indirect immunofluorescence for autoimmune diseases

Because the most common term used in conversations considering autoimmunity is autoantibodies, it is well-expected that the indirect immunofluorescence assay, which detects antibodies directed against various antigens, is one of our most impressive techniques for investigating autoimmune diseases (AIDs). Roughly speaking, the current literature corroborates that this immunopathologic investigation means that autoantibodies detection makes a considerable contribution to both diagnostic and prognostic aspects of AIDs in the clinical setting. However, it varies between different AIDs, autoantibodies, ethnicities or detection methodologies. Directly focusing on the indirect immunofluorescence assay, we present evidence to support this multidimensional variation regarding the subject via reviewing briefly the best-investigated autoantibodies in the well-documented AIDs, including vasculitis, inflammatory bowel disease, scleroderma, autoimmune hepatitis, primary biliary cirrhosis, systemic lupus erythematosus and Sjögren's syndrome.

Differential diagnosis in inflammatory bowel disease colitis: State of the art and future perspectives

Distinction between Crohn’s disease of the colon-rectum and ulcerative colitis or inflammatory bowel disease (IBD) type unclassified can be of pivotal importance for a tailored clinical management, as each entity often involves specific therapeutic strategies and prognosis. Nonetheless, no gold standard is available and the uncertainty of diagnosis may frequently lead to misclassification or repeated examinations. Hence, we have performed a literature search to address the problem of differential diagnosis in IBD colitis, revised current and emerging diagnostic tools and refined disease classification strategies. Nowadays, the differential diagnosis is an untangled issue, and the proper diagnosis cannot be reached in up to 10% of patients presenting with IBD colitis. This topic is receiving emerging attention, as medical therapies, surgical approaches and leading prognostic outcomes require more and more disease-specific strategies in IBD patients. The optimization of standard diagnostic approaches based on clinical features, biomarkers, radiology, endoscopy and histopathology appears to provide only marginal benefits. Conversely, emerging diagnostic techniques in the field of gastrointestinal endoscopy, molecular pathology, genetics, epigenetics, metabolomics and proteomics have already shown promising results. Novel advanced endoscopic imaging techniques and biomarkers can shed new light for the differential diagnosis of IBD, better reflecting diverse disease behaviors based on specific pathogenic pathways.

Indian Society of Gastroenterology consensus statements on Crohn's disease in India

In 2012, the Indian Society of Gastroenterology's Task Force on Inflammatory Bowel Diseases undertook an exercise to produce consensus statements on Crohn's disease (CD). This consensus, produced through a modified Delphi process, reflects our current recommendations for the diagnosis and management of CD in India. The consensus statements are intended to serve as a reference point for teaching, clinical practice, and research in India.

The emerging role of miRNAs in inflammatory bowel disease: a review

Inflammatory bowel disease (IBD), comprised of ulcerative colitis and Crohn's disease, is believed to develop as a result of a deregulated inflammatory response to environmental factors in genetically susceptible individuals. Despite advances in understanding the genetic risks of IBD, associated single nucleotide polymorphisms have low penetrance, monozygotic twin studies suggest a low concordance rate, and increasing worldwide IBD incidence leave gaps in our understanding of IBD heritability and highlight the importance of environmental influences. Operating at the interface between environment and heritable molecular and cellular phenotypes, microRNAs (miRNAs) are a class of endogenous, small noncoding RNAs that regulate gene expression. Studies to date have identified unique miRNA expression profile signatures in IBD and preliminary functional analyses associate these deregulated miRNAs to canonical pathways associated with IBD pathogenesis. In this review, we summarize and discuss the miRNA expression signatures associated with IBD in tissue and peripheral blood, highlight miRNAs with potential future clinical applications as diagnostic and therapeutic targets, and provide an outlook on how to develop miRNA based therapies.

Food antigen-induced immune responses in Crohn's disease patients and experimental colitis mice

BACKGROUND

In Crohn's disease (CD), the involvement of food antigens in immune responses remains unclear. The objective of this study was to detect immune responses against food antigens in CD patients and examine the mechanism in a mouse model of colitis.

METHODS

We enrolled 98 CD patients, 50 ulcerative colitis patients, and 52 healthy controls (HCs) to compare the levels of serum immunoglobulin (Ig)Gs against 88 foods. The presence of serum IgGs against foods was also examined in interleukin (IL)-10 knockout (KO) mice in which CD4(+) T cell activation by antigenic food protein was assessed. Mice transferred with IL-10 KO cells received diets with or without food antigens, and the development of colitis was evaluated.

RESULTS

The prevalence of IgGs against various foods, especially vegetables, grains, and nuts, was significantly higher in CD patients than in HCs. Similarly, the prevalence of IgGs against food proteins was higher in IL-10 KO mice than in BALB/c mice. Beta-conglycinin, identified as an antigenic food proteins in IL-10 KO mice, induced CD4(+) T cell production of interferon-γ and IL-17 through dendritic cell antigen presentation. Elimination of the food antigens ameliorated the development of colitis in mice without altering the composition of their intestinal microbiota.

CONCLUSIONS

In CD colitis mice, intestinal inflammation via CD4(+) T cell hyperactivation was induced by food antigens associated with high serum IgG levels and was ameliorated by the elimination of food antigens. This disrupted immunological tolerance to food antigen, which might act as an exacerbating factor, remains to be elucidated in CD patients.

The immunologic effects of mesalamine in treated HIV-infected individuals with incomplete CD4+ T cell recovery: a randomized crossover trial

The anti-inflammatory agent, mesalamine (5-aminosalicylic acid) has been shown to decrease mucosal inflammation in ulcerative colitis. The effect of mesalamine in HIV-infected individuals, who exhibit abnormal mucosal immune activation and microbial translocation (MT), has not been established in a placebo-controlled trial. We randomized 33 HIV-infected subjects with CD4 counts <350 cells/mm3 and plasma HIV RNA levels <40 copies/ml on antiretroviral therapy (ART) to add mesalamine vs. placebo to their existing regimen for 12 weeks followed by a 12 week crossover to the other arm. Compared to placebo-treated subjects, mesalamine-treated subjects did not experience any significant change in the percent CD38+HLA-DR+ peripheral blood CD4+ and CD8+ T cells at week 12 (P = 0.38 and P = 0.63, respectively), or in the CD4+ T cell count at week 12 (P = 0.83). The percent CD38+HLA-DR+ CD4+ and CD8+ T cells also did not change significantly in rectal tissue (P = 0.86, P = 0.84, respectively). During the period of mesalamine administration, plasma sCD14, IL-6, D-dimer, and kynurenine to tryptophan ratio were not changed significantly at week 12 and were similarly unchanged at week 24. This study suggests that, at least under the conditions studied, the persistent immune activation associated with HIV infection is not impacted by the anti-inflammatory effects of mesalamine.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01090102.