Utility of fecal and serum anti-Saccharomyces cerevisiae antibodies in the diagnosis of Crohn's disease-like condition of the pouch

Ouch, my pouch! a clinician's guide to pouchitis

Pouchitis is defined as inflammation of the ileal pouch created during a restorative proctocolectomy with ileal pouch-anal anastomosis. Although the incidence of this inflammatory condition is high, the exact etiology often remains unclear and the management challenging. In this review, we summarize the clinical presentation, pathogenesis, diagnosis, and management of this common complication.

Loss of tolerance to glycoprotein 2 isoforms 1 and 4 is associated with Crohn's disease of the pouch

BACKGROUND

Zymogen granule glycoprotein 2 (GP2) is a major autoantigen of Crohn's disease-specific pancreatic autoantibodies.

AIM

To test a link between loss of tolerance to isoforms of GP2 and pouch disorders in a cross-sectional study in ulcerative colitis patients with ileal pouch-anal anastomosis (IPAA).

METHODS

Serum samples of 117 consecutive ulcerative colitis patients after IPAA were tested for presence of Anti-GP2 isoforms 1 (GP2₁ ) & 4 (GP2₄ ) IgG and IgA as well as anti-Saccaromyces cervisiae (ASCA) IgG and IgA antibodies in a blinded fashion via enzyme-linked immunosorbent assay. Pouch disorders were diagnosed based on clinical, endoscopic, histological and radiographic criteria. Crohn's disease of the pouch was defined as involvement of the small bowel mucosa proximal to the ileal pouch with Crohn's disease, development of perianal complications or pouch fistula more than 3 months after ileostomy closure.

RESULTS

Positivity and level of Anti-GP2₁ IgG (AUC 0.77; P < 0.001 & P = 0.02, respectively), Anti-GP2₄ IgG (AUC 0.74; P < 0.001 & P = 0.025, respectively) and Anti-GP2₄ IgA (AUC 0.77; P < 0.001 to P = 0.018, respectively) were specifically associated with Crohn's disease of the pouch. Anti-GP2 was not associated with endoscopic or histological pouch disease activity index. Neither positivity nor levels of ASCA IgG (AUC 0.63; P = 0.12 & P = 0.35, respectively) or ASCA IgA (AUC 0.67; P = 0.38 & P = 0.53) were associated with pouch phenotypes.

CONCLUSIONS

The novel anti-GP2₁ and GP2₄ antibodies are associated with Crohn's disease of the pouch in ulcerative colitis patients after IPAA. Serological anti-GP2 antibodies could aid in diagnosis of Crohn's disease of the pouch.

Review article: the pathogenesis of pouchitis

BACKGROUND

A total proctocolectomy followed by ileal pouch-anal anastomosis is a potentially curative surgery for ulcerative colitis or familial adenomatous polyposis. About 5-35% of patients with ulcerative colitis and 0-11% of patients with familial adenomatous polyposis develop subsequent inflammation of the ileal pouch termed pouchitis.

AIM

To provide a comprehensive analysis of the research studying the possible pathogenesis of pouchitis. The goals were to identify promising areas of investigation, to help focus clinicians, researchers and patients on how to better understand and then potentially manage ileal pouchitis, and to provide avenues for future research investigations.

METHODS

This review examined manuscripts from 1981 to 2015 that discussed and/or proposed hypotheses with supportive evidence for the potential underlying pathogenic mechanism for pouchitis.

RESULTS

The pathogenesis of pouchitis is not definitively understood, but various hypotheses have been proposed, including (i) recurrence of ulcerative colitis, (ii) dysbiosis of the ileal pouch microbiota, (iii) deprivation of nutritional short-chain fatty acids, (iv) mucosal ischaemia and oxygen-free radical injury, (v) host genetic susceptibility and (vi) immune dysregulation. However, none of these alone are able to fully explain pouchitis pathogenesis.

CONCLUSIONS

Pouchitis, similar to inflammatory bowel disease, is a complex disorder that is not caused by any one single factor. More likely, pouchitis occurs through a combination of both dysregulated host inflammatory mechanisms and interaction with luminal microbiota.

Crohn's Disease of the Ileoanal Pouch

Crohn's disease (CD) of the pouch is an increasingly recognized diagnosis after ileal pouch-anal anastomosis. This post-ileal pouch-anal anastomosis diagnosis in conjunction with pouchitis remains the leading reason for pouch excision. Unfortunately, CD of the pouch remains a difficult diagnosis with lack of a uniform definition largely because of its similarity to common postoperative pouch complications, including pouchitis, abscess formation, or stricture at the anastomosis. Once diagnosed, treatment algorithms largely include multimodal therapy including biologics. This review focuses on the definition, etiology, diagnosis, and treatment for CD of the pouch, a postoperative de novo diagnosis of CD.

Diagnostic and Prognostic Microbial Biomarkers in Inflammatory Bowel Diseases

The microbiome plays multifaceted roles in the pathogenesis of inflammatory bowel diseases (IBD). Accordingly, the clinical challenge of patient heterogeneity in disease phenotype and response to treatment should in part be addressed by biomarkers that detect the host response to microbiota, and the levels of microbial taxa and products eliciting the host response in susceptible individuals. Molecular analysis has revealed much evidence for microbial taxonomic membership and microbial products in association with IBD, but their utility as clinical biomarkers is still in its infancy. A rich area of progress has been the development and validation of host serologic microbial biomarkers, which have achieved a distinctive position in the diagnosis and prognosis in IBD, and as a template for defining other categories of microbial biomarkers in disease state and phenotype.

Risk factors for Crohn’s disease of the neo-small intestine in ulcerative colitis patients with total proctocolectomy and primary or secondary ileostomies

BACKGROUND

De novo Crohn’s disease (CD) of the neo-small intestine in ulcerative colitis (UC) patients after total proctocolectomy (TPC) is a new disease entity, which may persist even after a secondary diverting permanent ileostomy for pouch failure. We sought to compare outcomes of primary ileostomy (PI, i.e., stoma created after colectomy without trying of ileal pouch) and secondary ileostomy (SI, i.e., stoma created after pouch failure) and to evaluate factors associated with the development of CD of the neo-small intestine proximal to ileostomy.

METHODS

A total of 123 eligible patients were identified from our Pouch Center Registry (PI group, n = 57 and SI group, n = 66). Demographics, clinical features and outcomes (CD of theneo-small intestine, non-CD related strictures, requirement of CD-related medications use, ileostomy-associated hospitalization, ileostomy failure with stoma revision/relocation, and shortgut syndrome) were compared. Step-wise logistic regression models were performed.

RESULTS

The median follow-up for the whole cohort was 5.0 (2.0–12.0) years. Younger age at diagnosis and surgery, family history of IBD, toxic megacolon/fulminant colitis, pre-diversion severe diarrhea, prediversion anti-TNF biological therapy, arthralgia/arthropathy and staged surgery were more common in the SI group (p < 0.05). In multivariate analysis, the presence of SI [odds ratio (OR), 8.23; 95% confidence interval (CI), 2.43–27.85], family history of IBD (OR, 9.14; 95% CI, 3.13–26.69), and pre-diversion of weight loss (OR, 3.72; 95% CI, 1.23–11.21) were contributing factors for developing CD of the neo-small intestine.

CONCLUSIONS

CD of the neo-small intestine in stoma patients was associated with the presence of SI, family history of IBD, and pre-diversion poor nutrition status. Patients with secondary ileostomy due to pouch failure should be carefully monitored. Aggressive medical, endoscopic or surgical therapy may be needed in patients at risk, before permanent diversion.

Antibodies against glycoprotein 2 are novel markers of intestinal inflammation in patients with an ileal pouch

BACKGROUND AND AIMS

The Crohn's disease (CD)-specific pancreatic auto-antibodies (PAB), have been recently identified to target glycoprotein 2 (GP2). Pouchitis is an inflammation of the small bowel developing in up to 60% of ulcerative colitis patients undergoing proctocolectomy and ileal pouch anal anastomosis. Occurrence of CD-specific antibodies was reported to be a predictor of pouchitis. We aimed to assess the prevalence of anti-GP2 antibodies (anti-GP2) in the serum and feces of pouch patients and to correlate them with clinical parameters. Furthermore, we examined mucosal expression of the GP2 protein in the pouch.

METHODS

Pouch patients were prospectively recruited and checked for clinical, endoscopic, and laboratory markers of inflammation. IgG and IgA anti-GP2 levels in serum and fecal samples were determined using ELISA. GP2 protein was assessed by immunohistochemistry.

RESULTS

Anti-GP2 was elevated in both serum and fecal samples of patients with inflamed compared to those with non-inflamed pouches and patients with familial-adenomatous polyposis after surgery (p<0.05, respectively). Moreover, patients with CD-like complications exhibited significantly higher anti-GP2 titers than those without CD-like complications (p≤0.01). High levels of anti-GP2 correlated with more frequent bowel movements per day and with the presence of at least one anti-glycan antibody (p≤0.05). GP2 itself was more abundant in the mucosa of patients with chronic pouchitis.

CONCLUSIONS

Anti-GP2 exists in the serum and feces of pouch patients and correlates with pouch inflammation, and presence of other serological markers. Thus, anti-GP2 may contribute to better stratification of pouchitis, more-so when the inflammation exhibits CD-like complications.

Targeting tissular immune response improves diagnostic performance of anti-Saccharomyces cerevisiae antibodies (ASCA) in Crohn's disease

Antibodies against Saccharomyces cerevisiae (ASCA) and Escherichia coli outer membrane porin C (anti-OmpC) are known to be detectable in the serum of patients with Crohn’s disease (CD) but display a very poor sensitivity for the disease especially in forms with isolated colonic involvement. In this study we aimed at evaluating performances of these markers in supernatant of cultured colonic biopsies.

Patients with colonic CD (n =  67), ulcerative colitis (UC) (n = 35) and control individuals (n = 37) were prospectively recruited for colonoscopy pinch biopsies and blood sampling. Serum and supernatant of culture tissues were analyzed for ASCA and anti-OmpC. Direct immunofluorescence was also performed on colonic tissues for total IgA detection.

We detected for the first time ASCA IgA/IgG and anti-OmpC IgA in cultured colonic tissue supernatants. For both markers, sensitivities for diagnosing CD were better in supernatants (ASCA: 53.7%, anti-OmpC: 28.4%) than in serum (ASCA: 31.3%, anti-OmpC: 22.4%). Combination of results from a panel of these tests gave the greatest sensitivity ever described for CD diagnosis in colonic forms (70.2%).

In this study, we described, for the first time, ASCA in supernatant of colonic tissue cultures. This assaying approach in CD diagnosis should be taken into consideration in the future especially in CD forms with isolated colonic involvement.

Considerations and complications in patients undergoing ileal pouch anal anastomosis

Total proctocolectomy with ileal pouch anal anastomosis (IPAA) preserves fecal continence as an alternative to permanent end ileostomy in select patients with ulcerative colitis and familial adenomatous polyposis. The procedure is technically demanding, and surgical complications may arise. This article outlines both the early and late complications that can occur after IPAA, as well as the workup and management of these potentially morbid conditions.