Antibodies to I2 predict clinical response to fecal diversion in Crohn's disease

ECCO Guidelines on Therapeutics in Crohn's Disease: Surgical Treatment

This article is the second in a series of two publications on the European Crohn's and Colitis Organisation [ECCO] evidence-based consensus on the management of Crohn's disease. The first article covers medical management; the present article addresses surgical management, including preoperative aspects and drug management before surgery. It also provides technical advice for a variety of common clinical situations. Both articles together represent the evidence-based recommendations of the ECCO for Crohn's disease and an update of prior ECCO Guidelines.

Microbiology of Facial Skin Infections-Strains, Susceptibility, and Therapeutic Consequences

BACKGROUND

Skin and soft tissue infections (SSTIs) are common conditions with severe and potentially life-threatening outcomes. However, the use of antibiotics to treat these infections is controversial.

PURPOSE

This study was to identify the microorganisms responsible for facial SSTIs, their antibiotic sensitivities, and the therapeutic outcomes of treatment.

STUDY DESIGN, SETTING, AND SAMPLE

This was a retrospective, observational cohort study conducted at a single oral and maxillofacial plastic surgery department. The study sample included 103 patients with facial SSTIs (61 men, 42 women) with a mean age of 41.8 years (standard deviation ± 20.4).

PREDICTOR/EXPOSURE/INDEPENDENT VARIABLES

The predictor variables included patient characteristics, antibiotic use before the clinic visit, and the infection's site and origin.

MAIN OUTCOME VARIABLE(S)

The primary outcome variable was the presence of antibiotic resistance in the bacterial strains isolated from the infections.

METHODS

The data were collected by reviewing the results of microbiological swabs and patient records obtained from patients with facial SSTIs. Categorical variables were described using absolute and relative frequencies, and continuous variables were described using mean and standard deviation. The association between antibiotic resistance and the predictor variables was analyzed using Pearson's χ² test and student's t test.

RESULTS

The most common cause of SSTI was an infected epidermal cyst (60.1%). Of all the microorganisms identified, 80.6% were Gram-positive, and 55.8% showed antibiotic resistance against one or more of the evaluated antibiotics, including several backup antibiotics. There were no identified risk factors that significantly influenced the probability of resistance, and there were no adverse events observed.

CONCLUSION

The results of this study suggest that surgery should be the primary approach for treating SSTIs, as antibiotic administration may not be effective due to the unknown susceptibility of the causative strains. Antibiotics should be reserved for severe cases and high-risk patients, and if deemed necessary for SSTI management, a broad-spectrum antibiotic should be administered to cover resistant organisms.

Clinical Factors Associated With Response to Fecal Diversion in Crohn's Disease

Up to 80% of Crohn's disease (CD) patients require surgery. Fecal diversion is used selectively in CD proctocolitis refractory to medical treatment or advanced perianal disease. This study examines associations between clinical features in predicting clinical response (CR) to fecal diversion in CD. Charts of CD patients undergoing fecal diversion for medically refractory disease or perianal disease were reviewed. Clinical response was assessed focusing on improvements in urgency, abdominal and perineal pain, decreased anal fistula drainage, and weight gain. Univariate binary logistic regression and multivariate forward-stepwise modeling analysis were used to determine associations with CR. The study cohort comprised 79 patients. After a median follow-up of 36 (3-192) months, 40 (51%) patients achieved a CR. Binary logistic regression analysis revealed both age at diagnosis (hazard ratio [HR] 1.05; confidence interval [CI] 1.01-1.09; P = .007) and disease duration (HR .91; CI .86-.96; P = .001) to be significantly associated with CR. Later age of onset (HR 1.05; CI 1.01-1.10; P = .002) and shorter disease duration (HR .91; CI .86-.97; P = .02) remained significant on multivariate analysis. This largest reported series of fecal diversion for refractory CD in the biologic drug era revealed that young age at diagnosis and long disease duration are associated with a lower CR.

Temporary faecal diversion in ileocolic resection for Crohn's disease: is there an impact on long-term surgical recurrence?

AIM

Temporary faecal diversion after ileocolic resection (ICR) for Crohn's disease reduces postoperative anastomotic complications in high-risk patients. The aim of this study was to assess if this approach also reduces long-term surgical recurrence.

METHOD

This was a multicentre retrospective review of prospectively maintained databases. Patient demographics, medical and surgical details were collected by three specialist centres. All patients had undergone an ICR between 2000 and 2012. The primary end-point was surgical recurrence.

RESULTS

Three hundred and twelve patients (80%) underwent an ICR without covering ileostomy (one stage). Seventy-seven (20%) had undergone an ICR with end ileostomy/double-barrel ileostomy/enterocolostomy followed by closure (two stage). The median follow-up was 105 months [interquartile range (IQR) 76-136 months]. The median time to ileostomy closure was 9 months (IQR 5-12 months). There was no significant difference in surgical recurrence between the one- and two-stage groups (18% vs 16%, P = 0.94). We noted that smokers (20% vs 34%, P = 0.01) and patients with penetrating disease (28% vs 52%, P < 0.01) were more likely to be defunctioned. A reduced recurrence rate was observed in the small high-risk group of patients who were smokers with penetrating disease behaviour treated with a two-stage strategy (0/10 vs 4/7, P = 0.12).

CONCLUSION

Despite having higher baseline risk factors, the results in terms of rate of surgical recurrence over 9 years are similar for patients having a two-stage compared with a one-stage procedure.

ECCO Guidelines on Therapeutics in Crohn's Disease: Surgical Treatment

This article is the second in a series of two publications relating to the European Crohn's and Colitis Organisation [ECCO] evidence-based consensus on the management of Crohn's disease. The first article covers medical management; the present article addresses surgical management, including preoperative aspects and drug management before surgery. It also provides technical advice for a variety of common clinical situations. Both articles together represent the evidence-based recommendations of the ECCO for Crohn's disease and an update of previous guidelines.

Role of Fecal Diversion in Complex Crohn's Disease

Crohn's disease (CD) is a chronic inflammatory condition of the gastrointestinal tract resulting in progressive tissue damage, which can result in strictures, fistulae, and abscesses formation. The triggering mechanism is thought to be in the fecal stream, and diversion of this fecal stream is sometimes required to control disease when all other avenues of medical and surgical management have been exhausted. Fecal diversion can be temporary or permanent with the indications being defunctioning a high-risk anastomosis, as a result of a surgical complication, for disease control, or due to severe colonic, rectal, or perianal disease. The incidence of ostomy formation in CD has increased epidemiologically over time. The primary indication for ostomy formation is severe perianal fistulizing disease. However, while 64% of patients have an early clinical response after diversion for refractory perianal CD, restoration of bowel continuity is attempted in only 35% of patients, and is successful in only 17%. The current review discusses the indications for ostomy creation in complex CD, strategies for procedure selection, and patient outcomes.

Increasing experience of ligation of the intersphincteric fistula tract for patients with Crohn's disease: what have we learned?

AIM

Ligation of the intersphincteric fistula tract (LIFT) has been proposed as a treatment of trans-sphincteric fistula in perianal Crohn's disease (CD). The aim of this study was to look at our experience of the LIFT procedure in CD patients on long-term follow-up. Specifically, we aimed to determine the fistula healing rate after the LIFT procedure after more than 12 months follow-up and to identify any prognostic factors.

METHOD

Retrospective study of patients with trans-sphincteric Crohn's fistula tracts treated with the LIFT procedure between January 2011 and October 2015. Complete fistula healing as well as clinical outcomes were analysed.

RESULTS

Data were available for 23 patients. After a median follow-up of 23 months, LIFT site healing was 48%. Patients with healed LIFT had a median follow-up time of 10.5 months, while patients with failed LIFT had a median follow-up time of 31 months (P = 0.04). Median time to failure was 9 months for patients with follow-up > 1 year. Most patients failed within 1 year (9/12; 75%) of the procedure. In multi-site CD, the LIFT procedure was more likely to be successful in those with small bowel disease (P = 0.04) compared with colonic disease (P = 0.02). Other factors such as preoperative use of biological therapies, presence of a seton, previous repair attempts, fistula position, type or number of fistulas, multiple fistula tracts, smoking status and other associated perianal disease did not appear to influence LIFT healing rates.

CONCLUSION

The LIFT procedure offers reasonable long-term success in the treatment of perianal trans-sphincteric fistulas associated with CD. LIFT is more likely to fail in patients with concurrent colonic CD than in patients with small bowel CD.

The role of a defunctioning stoma for colonic and perianal Crohn's disease in the biological era

OBJECTIVE

A defunctioning stoma is a therapeutic option for colonic or perianal Crohn's disease. In the pre-biologic era the response rate to defunctioning in our unit was high (86%), but intestinal continuity was only restored in 11-20%. Few data exist on the outcome of defunctioning since the widespread introduction of biologicals.

MATERIAL AND METHODS

All patients undergoing a defunctioning stoma for colonic/perianal Crohn's disease since 2003-2011 were identified from a prospective database. Indications for surgery, medical therapy, response to defunctioning and long-term clinical outcome were recorded. Successful restoration of continuity was defined as no stoma at last follow up.

RESULTS

Seventy-six patients were defunctioned (57 with biologicals) and at last follow up, 20 (27%) had continuity restored. Early clinical response rate (<3 months) was 15/76 (20%) and overall response 31/76 (41%). Complex anal fistulae/stenosis were associated with a very low chance of restoring continuity (10% and 0%, respectively), while colitis was associated with a higher chance of restoring continuity (48%). Endoscopic or histological improvement in colitis after defunctioning was associated with a higher rate of restoring continuity (10/16, 63%) compared to no such improvement (4/15, 27%, p = 0.05). Those failing biologics had similar chance of restoration as those not receiving biologics, 15/57 (26%) and 5/19 (26%), respectively.

CONCLUSION

Overall response to colonic defunctioning was 41%. Successful restoration of continuity occurred in 27%, but 48% in the absence of perianal disease. Response is appreciably less in the pre-biologic era, so patient and physician expectations need to be managed appropriately.

Noninvasive Testing for Mucosal Inflammation in Inflammatory Bowel Disease

Biomarkers have gained increasing attention for the diagnosis and follow-up of inflammatory bowel disease (IBD). Endoscopy remains the gold standard for assessing disease activity. Biomarkers are rapid, inexpensive, and noninvasive, and can be used in different stages of the disease with high sensitivity and specificity. Calprotectin and tests for C-reactive protein are used to assess the disease activity, predict relapse, and monitor treatment response. New noninvasive tests are being studied. This review discusses current evidence for these surrogate markers, their potential clinical applications, and limitations in disease management. We highlight recent advances in IBD biomarkers and future uses.

Clinical Utility of Biomarkers in IBD

There is no gold standard for the diagnosis and monitoring of inflammatory bowel diseases (IBD). Biomarkers are useful tools for the management of patients suffering from IBD. However, they should be used only when their additional information is useful for clinical decision-making. In principal, four situations during the management of an individual IBD patient can be discriminated from a clinical standpoint in which biomarkers provide useful information. First, biomarkers may be helpful when the diagnosis of IBD is established and aid in the discrimination between ulcerative colitis (UC) and Crohn's disease (CD) is necessary. Second, biomarkers may be helpful in the prognostic evaluation of IBD severity or disease behavior and for early decisions on the best treatment. The third situation in which biomarkers are useful is the evaluation of disease activity during the disease course, for monitoring and for guidance of ongoing treatment. Finally, the fourth typical situation when biomarkers are of value is after surgery to predict or diagnose a relapse of the disease. From a clinical point of view, it may be more useful to discuss specific biomarkers and their individual value and impact in these four prototypic situations than to sum up advantages and disadvantages for each biomarker isolated from the clinical situation. Therefore, this overview is structured in chapters reflecting those four typical situations during the disease course of IBD patents to critically evaluate the potential and value of each of the biomarkers in the specific situation.

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.

Systematic review with meta-analysis: faecal diversion for management of perianal Crohn's disease

BACKGROUND

Temporary faecal diversion is sometimes used for management of refractory perianal Crohn's disease (CD) with variable success.

AIMS

To perform a systematic review with meta-analysis to evaluate the effectiveness, long-term outcomes and factors associated with success of temporary faecal diversion for perianal CD.

METHODS

Through a systematic literature review through 15 July 2015, we identified 16 cohort studies (556 patients) reporting outcomes after temporary faecal diversion. We estimated pooled rates [with 95% confidence interval (CI)] of early clinical response, attempted and successful restoration of bowel continuity after temporary faecal diversion (without symptomatic relapse), and rates of re-diversion (in patients with attempted restoration) and proctectomy (with or without colectomy and end-ileostomy). We identified factors associated with successful restoration of bowel continuity.

RESULTS

On meta-analysis, 63.8% (95% CI: 54.1-72.5) of patients had early clinical response after faecal diversion for refractory perianal CD. Restoration of bowel continuity was attempted in 34.5% (95% CI: 27.0-42.8) of patients, and was successful in only 16.6% (95% CI: 11.8-22.9). Of those in whom restoration was attempted, 26.5% (95% CI: 14.1-44.2) required re-diversion because of severe relapse. Overall, 41.6% (95% CI: 32.6-51.2) of patients required proctectomy after failure of temporary faecal diversion. There was no difference in the successful restoration of bowel continuity after temporary faecal diversion in the pre-biological or biological era (13.7% vs. 17.6%, P = 0.60), in part due to selection bias. Absence of rectal involvement was the most consistent factor associated with restoration of bowel continuity.

CONCLUSIONS

Temporary faecal diversion may improve symptoms in approximately two-thirds of patients with refractory perianal Crohn's disease, but bowel restoration is successful in only 17% of patients.

Microbiology, genomics, and clinical significance of the Pseudomonas fluorescens species complex, an unappreciated colonizer of humans

Pseudomonas fluorescens is not generally considered a bacterial pathogen in humans; however, multiple culture-based and culture-independent studies have identified it at low levels in the indigenous microbiota of various body sites. With recent advances in comparative genomics, many isolates originally identified as the "species" P. fluorescens are now being reclassified as novel Pseudomonas species within the P. fluorescens "species complex." Although most widely studied for its role in the soil and the rhizosphere, P. fluorescens possesses a number of functional traits that provide it with the capability to grow and thrive in mammalian hosts. While significantly less virulent than P. aeruginosa, P. fluorescens can cause bacteremia in humans, with most reported cases being attributable either to transfusion of contaminated blood products or to use of contaminated equipment associated with intravenous infusions. Although not suspected of being an etiologic agent of pulmonary disease, there are a number of reports identifying it in respiratory samples. There is also an intriguing association between P. fluorescens and human disease, in that approximately 50% of Crohn's disease patients develop serum antibodies to P. fluorescens. Altogether, these reports are beginning to highlight a far more common, intriguing, and potentially complex association between humans and P. fluorescens during health and disease.

Diet in the pathogenesis and treatment of inflammatory bowel diseases

Some of the most common symptoms of the inflammatory bowel diseases (IBD, which include ulcerative colitis and Crohn's disease) are abdominal pain, diarrhea, and weight loss. It is therefore not surprising that clinicians and patients have wondered whether dietary patterns influence the onset or course of IBD. The question of what to eat is among the most commonly asked by patients, and among the most difficult to answer for clinicians. There are substantial variations in dietary behaviors of patients and recommendations for them, although clinicians do not routinely endorse specific diets for patients with IBD. Dietary clinical trials have been limited by their inability to include a placebo control, contamination of study groups, and inclusion of patients receiving medical therapies. Additional challenges include accuracy of information on dietary intake, complex interactions between foods consumed, and differences in food metabolism among individuals. We review the roles of diet in the etiology and management of IBD based on plausible mechanisms and clinical evidence. Researchers have learned much about the effects of diet on the mucosal immune system, epithelial function, and the intestinal microbiome; these findings could have significant practical implications. Controlled studies of patients receiving enteral nutrition and observations made from patients on exclusion diets have shown that components of whole foods can have deleterious effects for patients with IBD. Additionally, studies in animal models suggested that certain nutrients can reduce intestinal inflammation. In the future, engineered diets that restrict deleterious components but supplement beneficial nutrients could be used to modify the luminal intestinal environment of patients with IBD; these might be used alone or in combination with immunosuppressive agents, or as salvage therapy for patients who do not respond or lose responsiveness to medical therapies. Stricter diets might be required to induce remission, and more sustainable exclusion diets could be used to maintain long-term remission.

Temporary fecal diversion in the management of colorectal and perianal Crohn's disease

Aim. To evaluate the results of temporary fecal diversion in colorectal and perianal Crohn's disease. Method. We retrospectively identified 29 consecutive patients (14 females, 15 males; median age: 30.0 years, range: 18–76) undergoing temporary fecal diversion for colorectal (n = 14), ileal (n = 4), and/or perianal Crohn's disease (n = 22). Follow-up was in median 33.0 (3–103) months. Response to fecal diversion, rate of stoma reversal, and relapse rate after stoma reversal were recorded. Results. The response to temporary fecal diversion was complete remission in 4/29 (13.8%), partial remission in 12/29 (41.4%), no change in 7/29 (24.1%), and progress in 6/29 (20.7%). Stoma reversal was performed in 19 out of 25 patients (76%) available for follow-up. Of these, the majority (15/19, 78.9%) needed further surgical therapies for a relapse of the same pathology previously leading to temporary fecal diversion, including colorectal resections (10/19, 52.6%) and creation of a definitive stoma (7/19, 36.8%). At the end of follow-up, only 4/25 patients (16%) had a stable course without the need for further definitive surgery. Conclusion. Temporary fecal diversion can induce remission in otherwise refractory colorectal or perianal Crohn's disease, but the chance of enduring remission after stoma reversal is low.

A prospective evaluation of the ligation of the intersphincteric tract procedure for complex anal fistula in patients with Crohn's disease

OBJECTIVE

To evaluate 2- and 12-month outcomes after ligation of the intersphincteric fistula tract (LIFT) in Crohn's disease (CD).

BACKGROUND

Surgical approaches to perianal fistulas in CD are frequently ineffective and hampered by concerns over adequate wound healing and sphincter injury. The efficacy of LIFT in CD patients is unknown.

METHODS

Consecutive cases of CD patients with transsphincteric fistulas were prospectively analyzed. Fistula healing and 2 validated quality-of-life indices were assessed.

RESULTS

Fifteen CD patients (9 women; mean age = 34.8 years) were identified. Location of the fistula was lateral (n = 10; 67%) or midline (n = 5; 33%). LIFT site healing was seen in 9 patients (60%) at 2-month follow-up. No patient developed fecal incontinence. LIFT site healing was seen in 8 of the 12 patients (67%) with complete 12-month follow-up. Significant factors for long-term LIFT site healing were lateral versus midline location (P = 0.02) and longer mean fistula length (P = 0.02). Patients who had successful operations significantly improved both their mean Wexner Perianal Crohn's Disease Activity Index and McMaster Perianal Crohn's Disease Activity Index quality-of-life scores at 2-month follow-up (14.0-3.8, P = 0.001, and 10.4-1.8, P = 0.0001, respectively).

CONCLUSIONS

CD-associated anal fistulas may be treated with LIFT. This surgical procedure is a safe, outpatient procedure that minimizes both perianal wound creation and sphincter injury.

Systematic review: new serological markers (anti-glycan, anti-GP2, anti-GM-CSF Ab) in the prediction of IBD patient outcomes

Traditionally, IBD diagnosis is based on clinical, radiological, endoscopic, and histological criteria. Biomarkers are needed in cases of uncertain diagnosis, or to predict disease course and therapeutic response. No guideline recommends the detection of antibodies (including ASCA and ANCA) for diagnosis or prognosis of IBD to date. However, many recent data suggest the potential role of new serological markers (anti-glycan (ACCA, ALCA, AMCA, anti-L and anti-C), anti-GP2 and anti-GM-CSF Ab). This review focuses on clinical utility of these new serological markers in diagnosis, prognosis and therapeutic monitoring of IBD. Literature review of anti-glycan, anti-GP2 and anti-GM-CSF Ab and their impact on diagnosis, prognosis and prediction of therapeutic response was performed in PubMed/MEDLINE up to June 2014. Anti-glycan, anti-GP2 and anti-GM-CSF Ab are especially associated with CD and seem to be correlated with complicated disease phenotypes even if results differ between studies. Although anti-glycan Ab and anti-GP2 Ab have low sensitivity in diagnosis of IBD, they could identify a small number of CD patients not detected by other tests such as ASCA. Anti-glycan Abs are associated with a progression to a more severe disease course and a higher risk for IBD-related surgery. Anti-GP2 Ab could particularly contribute to better stratify cases of pouchitis. Anti-GM-CSF Ab seems to be correlated with disease activity and could help predict relapses. These new promising biomarkers could particularly be useful in stratification of patients according to disease phenotype and risk of complications. They could be a valuable aid in prediction of disease course and therapeutic response but more prospective studies are needed.

IFNG rs1861494 polymorphism is associated with IBD disease severity and functional changes in both IFNG methylation and protein secretion

BACKGROUND

Mucosal expression of interferon (IFN)-γ plays a pivotal role in the pathogenesis of inflammatory bowel disease (IBD) and IBD risk regions flank IFNG. The conserved IFNG rs1861494 T/C introduces a new CpG methylation site, is associated with disease severity and lack of therapeutic response in other infectious and immune-mediated disorders, and is in linkage disequilibrium with a ulcerative colitis (UC) disease severity region. It seems likely that CpG-altering single nucleotide polymorphisms modify methylation and gene expression. This study evaluated the association between rs1861494 and clinical, serologic, and methylation patterns in patients with IBD.

METHODS

Peripheral T cells of UC and Crohn's disease (CD) patients were genotyped for rs1861494 and analyzed for allele-specific and IFNG promoter methylation. Serum antineutrophil cytoplasmic autoantibodies and IFN-γ secretion were measured by enzyme-linked immunosorbent assay and nucleoprotein complex formation by electrophoretic mobility shift assay.

RESULTS

IFNG rs1861494 T allele carriage in patients with IBD was associated with enhanced secretion of IFN-γ. T allele carriage was associated in UC with high levels of antineutrophil cytoplasmic autoantibodies and faster progression to colectomy. In CD, it was associated with complicated disease involving a stricturing/penetrating phenotype. Likewise, IFNG rs1861494 displayed genotype-specific modulation of DNA methylation and transcription factor complex formation.

CONCLUSIONS

This study reports the first association of IFNG rs1861494 T allele with enhanced IFN-γ secretion and known IBD clinical parameters indicative of more aggressive disease and serological markers associated with treatment resistance to anti-tumor necrosis factor therapy in patients with IBD. These data may be useful prognostically as predictors of early response to anti-tumor necrosis factor therapy to identify patients with IBD for improved personalized therapeutics.

Serological markers of inflammatory bowel disease

Inflammatory bowel disease (IBD) is an intestinal inflammatory disease of unknown etiology with two main distinguishable entities, Crohn's disease (CD) and ulcerative colitis (UC). Current diagnosis of IBD relies on the clinical, endoscopic, radiological, histological and biochemical features, but these approaches have shortcomings, especially in cases of overlapping symptoms of CD and UC. The detection of serological markers can improve the diagnosis of IBD, because an aberrant immune response against microbial or endogenous antigens in a genetically susceptible host seems to be implicated in IBD pathogenesis. Current evidence suggests that the detection of serum immunology markers is useful in differential diagnosis of CD versus UC and can be a valuable aid in stratifying patients according to disease phenotype and risk of complications.

Pfit is a structurally novel Crohn's disease-associated superantigen

T cell responses to enteric bacteria are important in inflammatory bowel disease. I2, encoded by the pfiT gene of Pseudomonas fluorescens, is a T-cell superantigen associated with human Crohn's disease. Here we report the crystal structure of pfiT at 1.7Å resolution and provide a functional analysis of the interaction of pfiT and its homolog, PA2885, with human class II MHC. Both pfiT and PA2885 bound to mammalian cells and stimulated the proliferation of human lymphocytes. This binding was greatly inhibited by anti-class II MHC HLA-DR antibodies, and to a lesser extent, by anti HLA-DQ and DP antibodies, indicating that the binding was class II MHC-specific. GST-pfiT efficiently precipitated both endogenous and in vitro purified recombinant HLA-DR1 molecules, indicating that pfiT directly interacted with HLA-DR1. Competition studies revealed that pfiT and the superantigen Mycoplasma arthritidis mitogen (MAM) competed for binding to HLA-DR, indicating that their binding sites overlap. Structural analyses established that pfiT belongs to the TetR-family of DNA-binding transcription regulators. The distinct structure of pfiT indicates that it represents a new family of T cell superantigens.

Human inflammatory bowel disease (IBD) is a family of chronic inflammatory disorders of the gastrointestinal tract which affect genetically susceptible individuals. IBD is a lifelong disease involving mostly young people, often severely. Crohn's disease (CD) and ulcerative colitis are the two major forms of IBD. Although the exact cause of these diseases remains unknown, both genetic and environmental factors together play significant roles in the disease pathogenesis. Several lines of evidence implicate commensal bacteria as an important pathogenic element in clinical disease, particularly in CD. We recently identified a novel microbial gene, I2, encoded by Pseudomonas fluorescens, a gram-negative commensal, which may be involved in the pathogenesis of CD. Both molecular and immunological approaches were used to identify the human receptor for the microbial antigen encoded by I2, to characterize the ligand-receptor interactions, and to determine the three-dimensional structure of the microbial gene product. In particular, we show that the pfiT is a T cell superantigen, which may help to explain how microbial flora can trigger immune activation in IBD, and may provide the groundwork for novel therapies to treat CD.

Serological antibodies in inflammatory bowel disease: a systematic review

The diagnosis of inflammatory bowel disease (IBD) is traditionally based on a combination of clinical, endoscopic, histological, and radiological criteria. However, further testing is needed in cases of diagnostic uncertainty and in predicting disease course. This systematic review focuses on the potential for 10 serological antibodies to fill these roles: pANCA, ASCA, anti-OmpC, anti-CBir1, anti-I2, ALCA, ACCA, AMCA, anti-L, and anti-C. We discuss their prevalence in IBD and health; their role in disease diagnosis and risk stratification; their stability over time; their presence in unaffected relatives; their association with genetic variants; and differences across ethnic groups. Serological antibodies have some role in primary diagnosis and in differentiating between Crohn's disease and ulcerative colitis. In indeterminate colitis, preoperative measurement of serological antibodies can help to predict the likelihood of complications among patients undergoing pouch surgery. The combined presence and magnitude of a large panel of antibodies appear to be of value in predicting disease progression. There is currently insufficient evidence to recommend the use of antibody testing to predict responses to treatment or surgery in patients with IBD.

The promise and pitfalls of serologic testing in inflammatory bowel disease

The role of IBD serologies is still evolving. However, as that evolution progresses, it will continue to provide important insights into the etiology of IBD and help define individualized treatment strategies for patients. The presence of multiple IBD antimicrobial antibodies and increased reactivity form a useful heuristic model to understand the evolution of CD. The role of ANCAs and autoantibodies in pathogenesis of UC is an area that requires further investigation. Although IBD serologies exhibit considerable diagnostic accuracy, it is unclear whether they will supplant simpler and more direct evaluations in making an initial diagnosis of UC or Crohn (Table 3). The utility of panels of IBD serologies to stratify and predict the course of CD has been an arena of fertile investigation. Developing individual treatment strategies based on the probability of developing complicated aggressive disease would be a significant advance in medical management of CD. However, if major clinical decisions are to be made based on these serologies, we will need more prospective critical studies from the time of diagnosis to define their clinical applicability and to demonstrate a true difference in outcomes.

Characterization of the gastrointestinal microbiota in health and inflammatory bowel disease

The enteric bacterial flora play a key role in maintaining health. Inflammatory bowel disease is associated with quantitative and qualitative alterations in the microbiota. Early characterization of the microbiota involved culture-dependent techniques. The advent of metagenomic techniques, however, allows for structural and functional characterization using culture-independent methods. Changes in diversity, together with quantitative alterations in specific bacterial species, have been identified. The functional significance of these changes, and their pathogenic role, remain to be elucidated.

Scarless single-incision laparoscopic loop ileostomy: a novel technique

BACKGROUND

Laparoscopic surgery has become a favorable alternative to conventional open surgery for the creation of intestinal stomas, and it offers many benefits including reduced postoperative pain, ileus, and hospital stay. Single-incision laparoscopic surgery has been described for many abdominal operations. It may offer better cosmetic outcomes and reduce incisional pain, adhesions, and recovery time.

OBJECTIVE

In this study, we aimed to describe a novel technique of scarless single-incision laparoscopic loop ileostomy for fecal diversion and to report our experience with 8 patients who underwent this procedure within a 1-year period.

DESIGN

This study was designed as a retrospective case series.

SETTINGS

This investigation was conducted at a single-institution, tertiary referral center.

PATIENTS

Eight consecutive patients undergoing scarless single-incision laparoscopic loop ileostomy between August 2009 and August 2010 were included.

INTERVENTION

Scarless single-incision laparoscopic loop ileostomies were performed.

MAIN OUTCOME MEASURES

Among the outcomes measured were operation time, intraoperative blood loss, recovery of intestinal function, length of hospital stay, and surgical complications.

RESULTS

Seven patients underwent surgery for active Crohn's disease refractory to medical therapy. One patient underwent surgery for radiation-induced rectovesical fistula. Median surgery time was 76 minutes, and median intraoperative blood loss was 10 mL. Median length of postoperative hospitalization was 7 days. Of the 8 patients included in our series, 2 patients (25%) required reoperation for stoma ischemia because of vascular congestion that we attribute to a tight fascial opening or extensive bowel manipulation. Other surgical complications included nonoperative readmission for ileus and partial small-bowel obstruction (n = 2), anal dilation to evacuate an obstructed distal colon (n = 1), and peristomal cellulitis (n = 1).

LIMITATIONS

This study was limited by its small sample size and its retrospective nature.

CONCLUSION

Scarless single-incision laparoscopic loop ileostomy is a feasible alternative to standard laparoscopy for fecal diversion. Surgeons attempting this technique should do so with caution, given the high stoma ischemia rate in our small case series.

Predicting, treating and preventing postoperative recurrence of Crohn's disease: the state of the field

The majority of patients diagnosed with Crohn's disease eventually require surgical intervention. Unfortunately, postsurgical remission tends to be short lived; a significant number of patients experience clinical relapse and many require additional operations. The pathogenesis of this postoperative recurrence is poorly understood and, currently, there are no reliable tools to predict when and in whom the disease will recur. Furthermore, the postoperative prophylaxis profiles of available Crohn's disease therapeutic agents such as 5-aminosalicylates, immunomodulators, steroids and probiotics have been disappointing. Recently, the combination of antibiotics and azathioprine in selected high-risk patients has demonstrated some potential for benefit. The goal of the present article is to provide a coherent summary of previous and new research to guide clinicians in managing the challenging and complex problem of postoperative Crohn's disease recurrence.

Characterization of changes in serum anti-glycan antibodies in Crohn's disease--a longitudinal analysis

Introduction

Anti-glycan antibodies are a promising tool for differential diagnosis and disease stratification of patients with Crohn's disease (CD). We longitudinally assessed level and status changes of anti-glycan antibodies over time in individual CD patients as well as determinants of this phenomenon.

Methods

859 serum samples derived from a cohort of 253 inflammatory bowel disease (IBD) patients (207 CD, 46 ulcerative colitis (UC)) were tested for the presence of anti-laminarin (Anti-L), anti-chitin (Anti-C), anti-chitobioside (ACCA), anti-laminaribioside (ALCA), anti-mannobioside (AMCA) and anti-Saccharomyces cerevisiae (gASCA) antibodies by ELISA. All patients had at least two and up to eleven serum samples taken during the disease course.

Results

Median follow-up time for CD was 17.4 months (Interquartile range (IQR) 8.0, 31.6 months) and for UC 10.9 months (IQR 4.9, 21.0 months). In a subgroup of CD subjects marked changes in the overall immune response (quartile sum score) and levels of individual markers were observed over time. The marker status (positive versus negative) remained widely stable. Neither clinical phenotype nor NOD2 genotype was associated with the observed fluctuations. In a longitudinal analysis neither changes in disease activity nor CD behavior led to alterations in the levels of the glycan markers. The ability of the panel to discriminate CD from UC or its association with CD phenotypes remained stable during follow-up. In the serum of UC patients neither significant level nor status changes were observed.

Conclusions

While the levels of anti-glycan antibodies fluctuate in a subgroup of CD patients the antibody status is widely stable over time.

The utility of biomarkers in the diagnosis and therapy of inflammatory bowel disease

Fecal and serologic biomarkers can be used in the diagnosis and management of inflammatory bowel disease (IBD). Fecal markers such as calprotectin and lactoferrin have been studied for their ability to identify patients with IBD, assess disease activity, and predict relapse. Antibodies against Saccharomyces cerevisiae and perinuclear antineutrophil cytoplasmic proteins have been used in diagnosis of IBD, to distinguish Crohn's disease (CD) from ulcerative colitis, and to predict the risk of complications of CD. Tests for C-reactive protein and erythrocyte sedimentation rate have been used to assess inflammatory processes and predict the course of IBD progression. Levels of drug metabolites and antibodies against therapeutic agents might be measured to determine why patients do not respond to therapy and to select alternative treatments. This review addresses the potential for biomarker assays to improve treatment strategies and challenges to their use and development.

The role of bacteria and pattern-recognition receptors in Crohn's disease

Crohn's disease is widely regarded as a multifactorial disease, and evidence from human and animal studies suggests that bacteria have an instrumental role in its pathogenesis. Comparison of the intestinal microbiota of patients with Crohn's disease to that of healthy controls has revealed compositional changes. In most studies these changes are characterized by an increase in the abundance of Bacteroidetes and Proteobacteria and a decrease in that of Firmicutes. In addition, a number of specific mucosa-associated bacteria have been postulated to have a role in Crohn's disease, including Mycobacterium avium subspecies paratuberculosis, adherent and invasive Escherichia coli, Campylobacter and Helicobacter species. The association between mutations in pattern-recognition receptors (Toll-like receptors and Nod-like receptors) and autophagy proteins and Crohn's disease provides further evidence to suggest that defective sensing and killing of bacteria may drive the onset of disease. In this Review, we present recent advances in understanding the role of bacteria and the contribution of pattern-recognition receptors and autophagy in the pathogenesis of Crohn's disease.

Distinct IFNG methylation in a subset of ulcerative colitis patients based on reactivity to microbial antigens

BACKGROUND

High antibody reactivity toward microbial antigens in Crohn's disease (CD) patients is predictive of a more aggressive disease course. However, few ulcerative colitis (UC) patients exhibit serologic reactivity toward microbial antigens. Mucosal expression of IFN-γ plays a pivotal role in inflammatory bowel disease (IBD) pathogenesis. Recent genome-wide association studies (GWAS) surprisingly link UC, but not CD, risk loci to IFNG. We recently demonstrated that mucosal T cells from IBD patients exhibit distinct patterns of IFNG methylation compared to controls. This study evaluated the relationship between IFNG methylation and serologic and clinical profiles in peripheral T cells from IBD patients.

METHODS

DNA from peripheral T cells of 163 IBD patients (91 CD and 64 UC) and 42 controls was analyzed for methylation of eight IFNG sites. Serum markers ASCA, OmpC, I2, CBir, and pANCA were measured by enzyme-linked immunosorbent assay (ELISA). IFN-γ secretion was measured by ELISA.

RESULTS

IBD patients requiring surgery exhibited reduced IFNG methylation compared to nonsurgical patients (P < 0.02). Enhancement of IFN-γ secretion (P < 0.003), along with high antibody responses toward multiple microbial antigens (P < 0.017) in UC, but not CD, patients was correlated with decreased IFNG methylation. pANCA levels were not correlated with IFNG methylation.

CONCLUSIONS

Levels of IFNG methylation were correlated with immune response to microbial components and expression of IFN-γ in UC patients. Serological and epigenetic markers identify a subset of UC patients with an expression profile of a key TH1 pathogenic cytokine. These data may provide a useful tool to classify a more homogeneous subset of UC patients, allowing for improved diagnostics and targeted therapeutics.

The prevalence and diagnostic value of perinuclear antineutrophil cytoplasmic antibodies and anti-Saccharomyces cerevisiae antibodies in patients with inflammatory bowel disease in mainland China

BACKGROUND

Perinuclear anti-neutrophil cytoplasmic (pANCA) and anti-Saccharomyces cerevisiae antibodies (ASCA) have been studied extensively in Western countries. We determined the prevalence of pANCA and ASCA in the mainland Chinese population and the ability of pANCA and ASCA to discriminate between ulcerative colitis (UC) and Crohn's disease (CD).

METHODS

Two hundred-six unrelated patients with IBD (UC, n=152; CD, n=54), 60 patients with other gastrointestinal diseases, and 80 healthy controls were included. Sera pANCA and ASCA titers were determined by a standardized indirect immunofluorescence technique.

RESULTS

The sensitivity, specificity, positive and negative predictive values, and positive likelihood ratio of pANCA were calculated for differentiating UC from healthy controls (43.4%, 96.3%, 95.7%, 47.2%, and 11.7, respectively) and ASCA for differentiating CD from healthy controls and (46.3%, 96.3%, 89.3%, 72.6%, and 12.5, respectively). The combination of pANCA and ASCA did not result in greater diagnostic efficiency than either test alone. pANCA was more frequent in UC with extensive or severe phenotype than others. ASCA was associated with severe CD disease activity.

CONCLUSIONS

pANCA and ASCA are useful in confirming the diagnosis of IBD and differentiating between UC and CD in an IBD cohort in central China.

Value of mucosal assessment and biomarkers in inflammatory bowel disease

Clinical remission at a single point in time provides surprisingly little predictive value for future inflammatory bowel disease (IBD) activity owing to the waxing and waning nature of the disease course. Furthermore, patients often present with complications of IBD despite apparent clinical remission, suggesting that undetected subclinical inflammation is driving these complications. This has led to research on a variety of surrogate markers of biologically significant asymptomatic inflammatory disease activity, including endoscopic healing, histologic normalization and biomarkers of inflammation in the blood and stool. If these have strong predictive value, they could be used to risk-stratify patients and justify the early use of immunomodulators and anti-TNF agents. Mucosal healing has been associated with positive outcomes in IBD, but the supporting data are largely retrospective and subject to channeling bias, and it is not clear whether complete mucosal healing produces better outcomes than partial healing. Stool and blood biomarkers correlate well with mucosal inflammation, but are imperfect surrogates for mucosal healing. Before using surrogate markers of intestinal inflammation to justify long-term, potentially toxic and costly therapy, prospective longitudinal studies are needed to identify surrogate end points with cut points that justify changes in therapy, and which therapies provide cost-effective benefits for mild, moderate or severe inflammation.

Role of the innate immune system in the pathogenesis of inflammatory bowel disease

Crohn disease and ulcerative colitis are chronic inflammatory diseases of the intestinal tract commonly denoted as inflammatory bowel diseases. It has been proposed that these diseases result from aberrant mucosal immune responses to nonpathogenic microbial residents of the intestines. Recently, it was established that continuous interactions between the innate and the adaptive intestinal immune cells and the microbiota are directly involved in maintaining the physiological noninflammatory state of the intestinal mucosa. In light of the complexity of this mucosal homeostasis, it is astonishing that the inflammatory bowel diseases are relatively rare. Recently, altered functions of the innate immune system have been identified. As such, both hyperresponsiveness and hyporesponsiveness of innate cells have been implicated in the pathogenesis of inflammatory bowel diseases.

New serological biomarkers of inflammatory bowel disease

Serological biomarkers in inflammatory bowel disease (IBD) are a rapidly expanding list of non-invasive tests for objective assessments of disease activity, early diagnosis, prognosis evaluation and surveillance. This review summarizes both old and new biomarkers in IBD, but focuses on the development and characterization of new serological biomarkers (identified since 2007). These include five new anti-glycan antibodies, anti-chitobioside IgA (ACCA), anti-laminaribioside IgG (ALCA), anti-manobioside IgG (AMCA), and antibodies against chemically synthesized (Σ) two major oligomannose epitopes, Man α-1,3 Man α-1,2 Man (ΣMan3) and Man α-1,3 Man α-1,2 Man α-1,2 Man (ΣMan4). These new biomarkers serve as valuable complementary tools to existing biomarkers not only in differentiating Crohn’s disease (CD), ulcerative colitis (UC), normal and other non-IBD gut diseases, but also in predicting disease involvement (ileum vs colon), IBD risk (as subclinical biomarkers), and disease course (risk of complication and surgery). Interestingly, the prevalence of the antiglycan antibodies, including anti-Saccharomyces cerevisiae antibodies (ASCA), ALCA and AMCA, was found to be associated with single nucleotide polymorphisms (SNPs) of IBD susceptible genes such as NOD2/CARD15, NOD1/CARD4, toll-like receptors (TLR) 2 and 4, and β-defensin-1. Furthermore, a gene dosage effect was observed: anti-glycan positivity became more frequent as the number of NOD2/CARD15 SNPS increased. Other new serum/plasma IBD biomarkers reviewed include ubiquitination factor E4A (UBE4A), CXCL16 (a chemokine), resistin, and apolipoprotein A-IV. This review also discusses the most recent studies in IBD biomarker discovery by the application of new technologies such as proteomics, fourier transform near-infrared spectroscopy, and multiplex enzyme-linked immunosorbent assay (ELISA)’s (with an emphasis on cytokine/chemokine profiling). Finally, the prospects of developing more clinically useful novel diagnostic algorithms by incorporating new technologies in serological biomarker profiling and integrating multiple biomarkers with bioinformatics analysis/modeling are also discussed.

Microbial host interactions in IBD: implications for pathogenesis and therapy

Crohn's disease (CD), ulcerative colitis (UC), and pouchitis appear to be caused by pathogenic T-cell responses to discrete antigens from the complex luminal microbiota, with susceptibility conferred by genetic polymorphisms that regulate bacterial killing, mucosal barrier function, or immune responses. Environmental triggers initiate or reactivate inflammation and modulate genetic susceptibility. New pathogenesis concepts include defective bacterial killing by innate immune cells in CD, colonization of the ileum in CD with functionally abnormal Escherichia coli that adhere to and invade epithelial cells and resist bacterial killing, and alterations in enteric microbiota composition in CD, UC, and pouchitis detected by molecular probes. The considerable therapeutic potential of manipulating the enteric microbiota in inflammatory bowel disease patients has not been realized, probably due to failure to recognize heterogenic disease mechanisms that require individualized use of antibiotics, probiotics, prebiotics, combination therapies, and genetically engineered bacteria to restore mucosal homeostasis.

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.

Host-bacteria interaction in inflammatory bowel disease

INTRODUCTION/BACKGROUND

Inflammatory bowel disease (IBD) results from complex interactions between: host genome, immune system, mucosa, bacteria, and environment.

SOURCES OF DATA

Review of PubMed database using search terms 'bacteria and inflammatory bowel disease' and 'genetics and inflammatory bowel disease'. PubMed 'related reference' feature and references from retrieved articles were examined.

AREAS OF AGREEMENT

IBD results from interaction between the microbiota of the gut and the immune system. Key gene defects associated with IBD are involved in bacterial recognition and processing. The environment at least modifies and may determine pathogenesis.

AREAS OF CONTROVERSY

It has been disputed whether the primary defect in IBD is immunological or bacterial, and which bacteria are key. GROWING POINTS/AREAS FOR RESEARCH: 'M cells', the specialized epithelial cells that overlie Peyer's patches, are a major interface between gut bacteria and the immune system. Improved understanding is needed of the bacteria involved in IBD pathogenesis, their genotypes and phenotypes, their portal of entry and their mechanism for escaping attack from the immune system. Bacterial ligands involved in bacteria-epithelial adhesion are emerging, and molecular techniques are rapidly increasing our knowledge of the human intestinal microbiota.

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.

IBD serological panels: facts and perspectives

Beyond a defective innate immune response in inflammatory bowel disease (IBD), an increased immunological response toward microbial and self antigens has been intrinsically linked to the pathogenesis of such common immunopathologies of the gut. Mounting evidence indicates that increased seroreactivity toward certain antigens are a predictive and quantitative heritable trait, including the anti-Saccharomyces cerevisiae antibody (ASCA). Consistently, Candida albicans and Crohn's disease-associated NOD2 mutations have been recently identified as immunogen and genetic determinants for ASCA, respectively. In clinical practice, current panels of serological markers are not recommended for diagnosis, stratifying, and monitoring IBD. Therefore, prospective studies and highly sensitive serological panels of markers are eagerly awaited before guiding clinical decisions. Better understanding of the serological response in IBD might also provide new insights into their epidemiology and pathophysiology.

Mucosal antibody responses of colonized cattle to Escherichia coli O157-secreted proteins, flagellin, outer membrane proteins and lipopolysaccharide

The aim of this work was to characterize adaptive mucosal immune responses to Escherichia coli O157:H7 at the principal site of colonization in the bovine species. Following experimental infection, extracts from terminal rectum mucosal samples were tested for IgA antibodies by immunoblotting against different bacterial antigens including: whole-cell E. coli O157:H7 with and without proteinase treatment, outer membrane and cytoplasmic preparations, secreted protein supernatants and purified E. coli O157 lipopolysaccharide and H7 flagellin. Lipopolysaccharide and H7 flagellin preparations were also used to coat enzyme-linked immunosorbent assay plates to determine mucosal IgG1 and IgA antibody titers. In this work, evidence is presented of strong local IgA immune responses induced following infection at the bovine terminal rectal mucosa directed against multiple antigens including type III secretion-dependent proteins, O157 lipopolysaccharide, H7 flagellin and OmpC.

In vivo imaging and genetic analysis link bacterial motility and symbiosis in the zebrafish gut

Complex microbial communities reside within the intestines of humans and other vertebrates. Remarkably little is known about how these microbial consortia are established in various locations within the gut, how members of these consortia behave within their dynamic ecosystems, or what microbial factors mediate mutually beneficial host-microbial interactions. Using a gnotobiotic zebrafish-Pseudomonas aeruginosa model, we show that the transparency of this vertebrate species, coupled with methods for raising these animals under germ-free conditions can be used to monitor microbial movement and localization within the intestine in vivo and in real time. Germ-free zebrafish colonized with isogenic P. aeruginosa strains containing deletions of genes related to motility and pathogenesis revealed that loss of flagellar function results in attenuation of evolutionarily conserved host innate immune responses but not conserved nutrient responses. These results demonstrate the utility of gnotobiotic zebrafish in defining the behavior and localization of bacteria within the living vertebrate gut, identifying bacterial genes that affect these processes, and assessing the impact of these genes on host-microbial interactions.