Anti-Saccharomyces cerevisiae antibodies (ASCA) in Crohn's disease are associated with disease severity but not NOD2/CARD15 mutations

Controlling Candida: immune regulation of commensal fungi in the gut

The intestinal microbiome harbors fungi that pose a significant risk to human health as opportunistic pathogens and drivers of inflammation. Inflammatory and autoimmune diseases are associated with dysbiotic fungal communities and the expansion of potentially pathogenic fungi. The gut is also the main reservoir for disseminated fungal infections. Immune interactions are critical for preventing commensal fungi from becoming pathogenic. Significant strides have been made in defining innate and adaptive immune pathways that regulate intestinal fungi, and these discoveries have coincided with advancements in our understanding of the fungal molecular pathways and effectors involved in both commensal colonization and pathogenesis within the gut. In this review, we will discuss immune interactions important for regulating commensal fungi, with a focus on how specific cell types and effectors interact with fungi to limit their colonization or pathogenic potential. This will include how innate and adaptive immune pathways target fungi and orchestrate antifungal immune responses, in addition to how secreted immune effectors, such as mucus and antimicrobial peptides, regulate fungal colonization and inhibit pathogenic potential. These immune interactions will be framed around our current understanding of the fungal effectors and pathways regulating colonization and pathogenesis within this niche. Finally, we highlight important unexplored mechanisms by which the immune system regulates commensal fungi in the gut.

From ASCA breakthrough in Crohn's disease and Candida albicans research to thirty years of investigations about their meaning in human health

Anti-Saccharomyces cerevisiae antibodies (ASCA) are human antibodies that can be detected using an enzyme-linked immunosorbent assay involving a mannose polymer (mannan) extracted from the cell wall of the yeast S. cerevisiae. The ASCA test was developed in 1993 with the aim of differentiating the serological response in two forms of inflammatory bowel disease (IBD), Crohn's disease and ulcerative colitis. The test, which is based on the detection of anti-oligomannosidic antibodies, has been extensively performed worldwide and there have been hundreds of publications on ASCA. The earlier studies concerned the initial diagnostic indications of ASCA and investigations then extended to many human diseases, generally in association with studies on intestinal microorganisms and the interaction of the micro-mycobiome with the immune system. The more information accumulates, the more the mystery of the meaning of ASCA deepens. Many fundamental questions remain unanswered. These questions concern the heterogeneity of ASCA, the mechanisms of their generation and persistence, the existence of self-antigens, and the relationship between ASCA and inflammation and autoimmunity. This review aims to discuss the gray areas concerning the origin of ASCA from an analysis of the literature. Structured around glycobiology and the mannosylated antigens of S. cerevisiae and Candida albicans, this review will address these questions and will try to clarify some lines of thought. The importance of the questions relating to the pathophysiological significance of ASCA goes far beyond IBD, even though these diseases remain the preferred models for their understanding.

Candida spp. in Human Intestinal Health and Disease: More than a Gut Feeling

Fungi are an essential part of the normal collection of intestinal microorganisms, even though their collective abundance comprises only 0.1-1% of all fecal microbes. The composition and role of the fungal population is often studied in relation to early-life microbial colonization and development of the (mucosal) immune system. The genus Candida is frequently described as one of the most abundant genera, and altered fungal compositions (including elevated abundance of Candida spp.) have been linked with intestinal diseases such as inflammatory bowel disease and irritable bowel syndrome. These studies are performed using both culture-dependent and genomic (metabarcoding) techniques. In this review, we aimed to summarize existing data on intestinal Candida spp. colonization in relation to intestinal disease and provide a brief overview of the biological and technical challenges in this field, including the recently described role of sub-species strain variation of intestinal Candida albicans. Together, the evidence for a contributing role of Candida spp. in pediatric and adult intestinal disease is quickly expanding, even though technical and biological challenges may limit full understanding of host-microbe interactions.

Profiling the inflammatory bowel diseases using genetics, serum biomarkers, and smoking information

Crohn's disease (CD) and ulcerative colitis (UC) are two etiologically related yet distinctive subtypes of the inflammatory bowel diseases (IBD). Differentiating CD from UC can be challenging using conventional clinical approaches in a subset of patients. We designed and evaluated a novel molecular-based prediction model aggregating genetics, serum biomarkers, and tobacco smoking information to assist the diagnosis of CD and UC in over 30,000 samples. A joint model combining genetics, serum biomarkers and smoking explains 46% (42-50%, 95% CI) of phenotypic variation. Despite modest overlaps with serum biomarkers, genetics makes unique contributions to distinguishing IBD subtypes. Smoking status only explains 1% (0-6%, 95% CI) of the phenotypic variance suggesting it may not be an effective biomarker. This study reveals that molecular-based models combining genetics, serum biomarkers, and smoking information could complement current diagnostic strategies and help classify patients based on biologic state rather than imperfect clinical parameters.

The yin and yang of B cells in a constant state of battle: intestinal inflammation and inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract, defined by a clinical relapse-remitting course. Affecting people worldwide, the origin of IBD is still undefined, arising as a consequence of the interaction between genes, environment, and microbiota. Although the root cause is difficult to identify, data clearly indicate that dysbiosis and pathogenic microbial taxa are connected with the establishment and clinical course of IBD. The composition of the microbiota is shaped by plasma cell IgA secretion and binding, while cytokines such as IL10 or IFN-γ are important fine-tuners of the immune response in the gastrointestinal environment. B cells may also influence the course of inflammation by promoting either an anti-inflammatory or a pro-inflammatory milieu. Here, we discuss IgA-producing B regulatory cells as an anti-inflammatory factor in intestinal inflammation. Moreover, we specify the context of IgA and IgG as players that can potentially participate in mucosal inflammation. Finally, we discuss the role of B cells in mouse infection models where IL10, IgA, or IgG contribute to the outcome of the infection.

Association between Taxonomic Composition of Gut Microbiota and Host Single Nucleotide Polymorphisms in Crohn's Disease Patients from Russia

Crohn's disease (CD) is a chronic relapsing inflammatory bowel disease of unknown etiology. Genetic predisposition and dysbiotic gut microbiota are important factors in the pathogenesis of CD. In this study, we analyzed the taxonomic composition of the gut microbiota and genotypes of 24 single nucleotide polymorphisms (SNP) associated with the risk of CD. The studied cohorts included 96 CD patients and 24 healthy volunteers from Russia. Statistically significant differences were found in the allele frequencies for 8 SNPs and taxonomic composition of the gut microbiota in CD patients compared with controls. In addition, two types of gut microbiota communities were identified in CD patients. The main distinguishing driver of bacterial families for the first community type are Bacteroidaceae and unclassified members of the Clostridiales order, and the second type is characterized by increased abundance of Streptococcaceae and Enterobacteriaceae. Differences in the allele frequencies of the rs9858542 (BSN), rs3816769 (STAT3), and rs1793004 (NELL1) were also found between groups of CD patients with different types of microbiota communities. These findings confirm the complex multifactorial nature of CD.

Glomerulonephritis and inflammatory bowel disease: A tale of gut-kidney axis dysfunction

The incidence and prevalence of Inflammatory Bowel Disease (IBD) has increased over the past decades, imposing a growing socioeconomic burden on healthcare systems globally. Most of the morbidity and mortality related to IBD is typically attributed to gut inflammation and its complications; yet the disease is characterized by various extraintestinal manifestations that can be severe. Glomerulonephritis (GN) is of particular interest since a significant proportion of patients evolve into end-stage kidney disease, requiring kidney replacement therapy and associated with high morbidity and mortality. Herein, we review the GN landscape in IBD and define the clinical and pathogenic associations reported to date in the literature. Underlying pathogenic mechanisms suggest either the initiation of antigen-specific immune responses in the inflamed gut that cross react with non-intestinal sites, such as the glomerulus, or that extraintestinal manifestations are gut-independent events that occur due to an interaction between common genetic and environmental risk factors. We present data associating GN with IBD either as a bona fide extraintestinal manifestation or reporting it as an extraneous co-existing entity, involving various histological subtypes, such as focal segmental glomerulosclerosis, proliferative GN, minimal change disease, crescentic GN, but most emphatically IgA nephropathy. Supporting the pathogenic interplay between gut inflammation and intrinsic glomerular processes, enteric targeting the intestinal mucosa with budesonide reduced IgA nephropathy-mediated proteinuria. Elucidating the mechanisms at play would provide insight not only into IBD pathogenesis but also into the gut's role in the development of extraintestinal diseases, such as glomerular diseases.

Anti-Saccharomyces cerevisiae Antibodies Are Only Modestly More Common in Subjects Later Developing Crohn's Disease

BACKGROUND

The pathogenic processes in the preclinical phase of inflammatory bowel disease (IBD) are mainly unknown.

AIMS

To study typical antibodies for IBD in the preclinical phase in a cohort of Northern Sweden.

METHODS

Antibodies typical for IBD (ASCA, pANCA, lactoferrin-ANCA, antibodies to goblet cells, and pancreas antigen) were analyzed in 123 subjects with preclinical ulcerative colitis (UC), 54 subjects with preclinical Crohn's disease (CD) and in 390 sex- and age-matched controls. In addition, in a subset of subjects, inflammatory markers (CRP, albumin, calprotectin and ferritin) were measured in plasma.

RESULTS

The mean years between blood samples and IBD diagnosis were for UC 5.1 (SD 3.5) years and CD 5.6 (SD 3.5) years. There was no difference in the proportion of overall positive antibodies between subjects who later developed IBD compared to controls (16.9% vs. 12.3%; p = 0.137). The subjects who later developed CD had a significantly higher proportion of positive ASCA compared to controls (9.3% vs 2.8%; p = 0.034), but for all other antibodies, there were no differences compared to control subjects. Subjects with preclinical IBD and elevated antibodies showed significantly higher plasma calprotectin levels compared to subjects without antibodies (980 μg/L vs 756 μg/L; p = 0.042), but there was no difference in the levels of CRP, albumin and ferritin.

CONCLUSIONS

We found no significant increase in antibodies typical for IBD years before diagnosis except for ASCA, which was slightly more common in subjects who later developed CD. Very few subjects had detectable antibodies to goblet cells and pancreas antigen.

Fungal feelings in the irritable bowel syndrome: the intestinal mycobiome and abdominal pain

Although the gut microbiota consists of bacteria, viruses, and fungi, most publications addressing the microbiota-gut-brain axis in irritable bowel syndrome (IBS) have a sole focus on bacteria. This may relate to the relatively low presence of fungi and viruses as compared to bacteria. Yet, in the field of inflammatory bowel disease research, the publication of several papers addressing the role of the intestinal mycobiome now suggested that these low numbers do not necessarily translate to irrelevance. In this review, we discuss the available clinical and preclinical IBS mycobiome data, and speculate how these recent findings may relate to earlier observations in IBS. By surveying literature from the broader mycobiome research field, we identified questions open to future IBS-oriented investigations.

Beta-Glucan from S. cerevisiae Protected AOM-Induced Colon Cancer in cGAS-Deficient Mice Partly through Dectin-1-Manipulated Macrophage Cell Energy

Although the impacts of Saccharomyces cerevisiae on cancers are mentioned, data on its use in mice with cyclic GMP-AMP synthase deficiency (cGAS-/-) are even rarer. Here, 12 weeks of oral administration of S. cerevisiae protected cGAS-/- mice from azoxymethane (AOM)-induced colon cancers, partly through dysbiosis attenuation (fecal microbiome analysis). In parallel, a daily intralesional injection of a whole glucan particle (WGP; the beta-glucan extracted from S. cerevisiae) attenuated the growth of subcutaneous tumor using MC38 (murine colon cancer cell line) in cGAS-/- mice. Interestingly, the incubation of fluorescent-stained MC38 with several subtypes of macrophages, including M1 (using Lipopolysaccharide; LPS), M2 (IL-4), and tumor-associated macrophages (TAM; using MC38 supernatant activation), could not further reduce the tumor burdens (fluorescent intensity) compared with M0 (control culture media). However, WGP enhanced tumoricidal activities (fluorescent intensity), the genes of M1 pro-inflammatory macrophage polarization (IL-1β and iNOS), and Dectin-1 expression and increased cell energy status (extracellular flux analysis) in M0, M2, and TAM. In M1, WGP could not increase tumoricidal activities, Dectin-1, and glycolysis activity, despite the upregulated IL-1β. In conclusion, S. cerevisiae inhibited the growth of colon cancers through dysbiosis attenuation and macrophage energy activation, partly through Dectin-1 stimulation. Our data support the use of S. cerevisiae for colon cancer protection.

Management of refractory inflammatory bowel disease

PURPOSE OF REVIEW

Nearly one-third of patients with inflammatory bowel disease (IBD) do not achieve remission despite our best therapies. When this happens, it is critical to understand the reason for treatment failure. Once nonresponse is confirmed, these patients should be referred to an IBD centre for multidisciplinary care. This review will discuss the remaining treatment options, including escalation of biologics to unlicensed doses, combination biologics, nonvalidated therapies and surgical options. It will additionally provide updates in the management of acute severe ulcerative colitis (ASUC).

RECENT FINDINGS

There is an increasing interest in combination biologics to treat refractory IBD, although data supporting its safety and effectiveness are limited. The use of hyperbaric oxygen, mesenchymal stem cell therapy and dietary interventions also show early promise in this area. Studies have additionally focused on personalized therapy to identify aggressive phenotypes and predict treatment response in these challenging patients. In ASUC, infliximab and cyclosporine remain mainstays of treatment, and tofacitinib shows promise as a salvage therapy.

SUMMARY

Refractory IBD is common, yet large knowledge gaps remain. Recent and ongoing studies have focused on medical, surgical and dietary approaches with mixed success. Larger prospective studies are desperately needed to address this complex issue.

Primary Sclerosing Cholangitis and Inflammatory Bowel Disease: A Review

Primary sclerosing cholangitis is a disease affecting around 0.006-0.016% of the population. Of these, around 75% have concomitant inflammatory bowel disease (IBD) according to the most recent epidemiological studies. Several theories have been proposed regarding the pathogenesis of primary sclerosing cholangitis (PSC). These include changes in the function of cholangiocytes, effects of the gut microbiome, association with specific human leukocyte antigen haplotypes and dysregulation of the immune system. However, these do not explain the observed association with IBD. Moreover, there are considerable differences in the frequency and outcomes between patients with PSC and ulcerative colitis compared with PSC and Crohn's disease. The aim of this review is to appraise the most recent studies that have contributed to the epidemiology, advances in the pathophysiology, and characterization of important clinical aspects of the association of PSC and IBD.

Tools for the Diagnosis and Management of Crohn's Disease

Numerous tools have emerged over recent decades to aid in the increasingly complex management of patients with Crohn's disease (CD) beyond endoscopy, including video capsule endoscopy, magnetic resonance enterography, computed tomography enterography, a variety of biomarkers, and even wearable biosensors and smartphone applications. These tools have allowed for a more sophisticated and less invasive complementary approach to the evaluation of disease activity and treatment response in patients with CD. This article details the characteristics, practical application, and limitations of these various modalities and discusses how updated guidelines are now incorporating many of them into a treat-to-target strategy.

Biomarkers for the Prediction and Diagnosis of Fibrostenosing Crohn's Disease: A Systematic Review

BACKGROUND AND AIMS

Intestinal strictures are a common complication of Crohn's disease (CD). Biomarkers of intestinal strictures would assist in their prediction, diagnosis, and monitoring. Herein we provide a comprehensive systematic review of studies assessing biomarkers that may predict or diagnose CD-associated strictures.

METHODS

We performed a systematic review of PubMed, EMBASE, ISI Web of Science, Cochrane Library, and Scopus to identify citations pertaining to biomarkers of intestinal fibrosis through July 6, 2020, that used a reference standard of full-thickness histopathology or cross-sectional imaging or endoscopy. Studies were categorized based on the type of biomarker they evaluated (serum, genetic, histopathologic, or fecal).

RESULTS

Thirty-five distinct biomarkers from 3 major groups were identified: serum (20 markers), genetic (9 markers), and histopathology (6 markers). Promising markers include cartilage oligomeric matrix protein, hepatocyte growth factor activator, and lower levels of microRNA-19-3p (area under the curves were 0.805, 0.738, and 0.67, respectively), and multiple anti-flagellin antibodies (A4-Fla2 [odds ratio, 3.41], anti Fla-X [odds ratio, 2.95], and anti-CBir1 [multiple]). Substantial heterogeneity was observed and none of the markers had undergone formal validation. Specific limitations to acceptance of these markers included failure to use a standardized definition of stricturing disease, lack of specificity, and insufficient relevance to the pathogenesis of intestinal strictures or incomplete knowledge regarding their operating properties.

CONCLUSIONS

There is a lack of well-defined studies on biomarkers of intestinal stricture. Development of reliable and accurate biomarkers of stricture is a research priority. Biomarkers can support the clinical management of CD patients and aid in the stratification and monitoring of patients during clinical trials of future antifibrotic drug candidates.

The important role of fungi in inflammatory bowel diseases

Inflammatory bowel disease (IBD) is a life-threatening and chronic inflammatory disease of gastrointestinal tissue, with complex pathogenesis. Current research on IBD has mainly focused on bacteria; however, the role of fungi in IBD is largely unknown due to the incomplete annotation of fungi in current genomic databases. With the development of molecular techniques, the gut mycobiome has been found to have great diversity. In addition, increasing evidence has shown intestinal mycobiome plays an important role in the physiological and pathological processes of IBD. In this review, we will systemically introduce the recent knowledge about multi-dimensional fungal dysbiosis associated with IBD, the interactions between fungus and bacteria, the role of fungi in inflammation in IBD, and highlight recent advances in the potential therapeutic role of fungus in IBD, which may hold the keys to develop new predictive, therapeutic or prognostic approaches in IBD.

Serological markers facilitate the diagnosis of Crohn's disease

Background and aim: The diagnosis of Crohn's disease (CD) is challenging. Ongoing search for biomarkers to facilitate the diagnosis is a worthwhile endeavor. The aim of this study was to explore the role of serological markers in the diagnosis of CD at an inflammatory bowel disease (IBD) referral center.Methods: This was a retrospective study including 196 suspected CD patients. The expression of ASCA-IgG, ASCA-IgA, AYMA-IgG, AYCA-IgA, FI2Y-IgG, and pANCA in the patient's serum was determined by enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence (IF).Results: ASCA was a relatively specific marker for CD (p = 0.0005), but not AYMA-IgG, AYCA-IgA, F12Y-IgG (p = 0.5936, 0.7974, 0.1085, respectively). However, a high sensitivity of 96.77% (95% CI 90.19%-99.83%) was noted for ASCA+/FI2Y+ to identify CD patients among the suspected cases, albeit with low PPV. The more combinations of serological markers, the higher sensitivity, and NPV. No correlation was found between the age of onset or disease location and the expression of ASCA, AYMA, AYCA, FI2Y, or pANCA. There was no significant difference between the expression of ASCA and the disease behavior at diagnosis (p = 0.3307). However, a decreased proportion of AYMA+ CD patients was found in those who received surgery compared with their non-surgical counterparts (p = 0.0488).Conclusions: ASCA was found to be the most accurate serological marker for the differential diagnosis of CD. Combinations of ASCA, AYMA, AYCA, and FI2Y improved diagnostic accuracy of CD.

MICROBIOTA INSIGHTS IN CLOSTRIDIUM DIFFICILE INFECTION AND INFLAMMATORY BOWEL DISEASE

Inflammatory bowel disease (IBD) is characterized by chronic intestinal inflammation that includes Crohn´s disease (CD) and ulcerative colitis (UC). Although the etiology is still unknown, some specific factors have been directly related to IBD, including genetic factors, abnormal intestinal immunity, and/or gut microbiota modifications. Recent findings highlight the primary role of the gut microbiota closely associated with a persistent inappropriate inflammatory response. This gut environment of dysbiosis in a susceptible IBD host can increasingly worsen and lead to colonization and infection with some opportunistic pathogens, especially Clostridium difficile. C. difficile is an intestinal pathogen considered the main cause of antibiotic-associated diarrhea and colitis and an important complication of IBD, which can trigger or worsen an IBD flare. Recent findings have highlighted the loss of bacterial cooperation in the gut ecosystem, as well as the pronounced intestinal dysbiosis, in patients suffering from IBD and concomitant C. difficile infection (CDI). The results of intestinal microbiota studies are still limited and often difficult to compare because of the variety of disease conditions. However, these data provide important clues regarding the main modifications and interrelations in the complicated gut ecosystem to better understand both diseases and to take advantage of the development of new therapeutic strategies. In this review, we analyze in depth the gut microbiota changes associated with both forms of IBD and CDI and their similarity with the dysbiosis that occurs in CDI. We also discuss the metabolic pathways that favor the proliferation or decrease in several important taxa directly related to the disease.

Purification of Bioactive Peptide with Antimicrobial Properties Produced by Saccharomyces cerevisiae

A variety of organisms produce bioactive peptides that express inhibition activity against other organisms. Saccharomyces cerevisiae is considered the best example of a unicellular organism that is useful for studying peptide production. In this study, an antibacterial peptide was produced and isolated from Saccharomycescerevisiae (Baker’s yeast) by an ultrafiltration process (two membranes with cut-offs of 2 and 10 kDa) and purified using the ÄKTA Pure 25 system. Antibacterial peptide activity was characterized and examined against four bacterial strains including Gram-positive and Gram-negative bacteria. The optimum condition for yeast growth and antibacterial peptide production against both Escherichia. coli and Klebsiella aerogenes was 25–30 °C within a 48 h period. The isolated peptide had a molecular weight of 9770 Da, was thermostable at 50–90 °C for 30 min, and tolerated a pH range of 5–7 at 4 °C and 25 °C during the first 24 h, making this isolated antibacterial peptides suitable for use in sterilization and thermal processes, which are very important aspect in food production. The isolated antibacterial peptide caused a rapid and steady decline in the number of viable cells from 2 to 2.3 log units of gram-negative strains and from 1.5 to 1.8 log units of gram-positive strains during 24 h of incubation. The isolated antibacterial peptide from Saccharomyces cerevisiae may present a potential biopreservative compound in the food industry exhibiting inhibition activity against gram-negative and gram-positive bacteria.

Gastrointestinal and Hepatic Disease in Spondyloarthritis

The association of inflammatory arthritis with intestinal pathology extends back more than 100 years. This association is now supported by epidemiologic studies demonstrating an elevated prevalence of inflammatory bowel disease in spondyloarthritis and vice versa, compared with the general population. Genetic and intestinal microbiome studies have further linked these diseases. Although diabetes and nonalcoholic fatty liver disease disproportionately affect individuals with psoriatic arthritis, diseases of the esophagus, stomach, pancreas, and liver are not particularly common in spondyloarthritis. Clinicians should be aware of the differential diagnosis and the appropriate diagnostic tools available when evaluating digestive and hepatic disorders in spondyloarthritis.

The NOD2-Smoking Interaction in Crohn's Disease is likely Specific to the 1007fs Mutation and may be Explained by Age at Diagnosis: A Meta-Analysis and Case-Only Study

Background

NOD2 and smoking are risk factors for Crohn's disease. We meta-analyzed NOD2-smoking interactions in Crohn's disease (Phase 1), then explored the effect of age at diagnosis on NOD2-smoking interactions (Phase 2).

Methods

Phase 1: MEDLINE and EMBASE were searched for studies (n = 18) providing data on NOD2 and smoking in Crohn's disease. NOD2-smoking interactions were estimated using odds ratios (ORs) and 95% confidence intervals (CIs) calculated using random effects models. Phase 2: A case-only study compared the proportion of smokers and carriers of the 1007 fs variant across ages at diagnosis (≤ 16, 17–40, > 40 years).

Findings

Phase 1: Having ever smoked was less common among carriers of the 1007 fs variant of NOD2 (OR 0.74, 95%CI:0.66–0.83). There was no interaction between smoking and the G908R (OR 0.96, 95%CI:0.82–1.13) or the R702W variant (OR 0.89, 95%CI:0.76–1.05). Phase 2: The proportion of patients (n = 627) carrying the 1007 fs variant decreased with age at diagnosis (≤ 16 years: 15%; 17–40: 12%; > 40: 3%; p = 0.003). Smoking was more common in older patients (≤ 16 years: 4%; 17–40: 48%; > 40: 71%; p < 0.001).

Interpretation

The negative NOD2-smoking interaction in Crohn's disease is specific to the 1007 fs variant. However, opposing rates of this variant and smoking across age at diagnosis may explain this negative interaction.

•

There is a negative interaction between NOD2 smoking in Crohn's disease and it is specific to the 1007fs variant.

•

With increasing age, the prevalence of the 1007fs variant decreases and exposure to cigarette smoke increases.

•

Contrasting trends in the 1007fs variant and cigarette smoking may explain the negative NOD2-smoking interaction.

We reviewed 18 studies evaluating NOD2-smoking interactions in Crohn's disease. Only the 1007fs variant interacted with smoking. Smokers with this mutation were less likely to develop Crohn's disease. We then conducted a study of 627 patients with Crohn's disease, which showed that the 1007fs variant was common in young patients and rare in older patients, whereas smoking was more common among older patients. The decreasing prevalence of 1007fs mutation and increasing exposure to smoking as age of diagnosis advances may explain the negative interaction between NOD2 and smoking observed in our meta-analysis. Our study highlights the challenges of identifying gene-environment interactions.

Investigation of the Best Saccharomyces cerevisiae Growth Condition

Introduction

Saccharomyces cerevisiae is known as one of the useful yeasts which are utilized in baking and other industries. It can be easily cultured at an economic price. Today the introduction of safe and efficient carriers is being considered. Due to its generally round shape, and the volume that is enclosed by its membrane and cell wall, it is used to encapsulate active materials to protect them from degradation or to introduce a sustained release drug delivery system. Providing the best conditions in order to achieve the best morphological properties of Saccharomyces cerevisiae as a carrier.

Methods

In this research, the most suitable growth condition of yeast cells which provides the best size for use as drug carriers was found by a bioreactor in a synthetic culture medium. Yeast cell reproduction and growth curves were obtained, based on pour plate colony counting data and UV/Visible sample absorption at 600 nm. Yeast cell growth patterns and growth rates were determined by Matlab mathematical software.

Results

Results showed that pH=4 and dissolving oxygen (DO) 5% was the best condition for yeast cells to grow and reproduce. This condition also provided the largest size (2 × 3 μ) yeast cells.

Conclusion

Owing to the yeast cells’ low-cost production and their structural characteristics, they could be used as potent drug carriers.

Funding

This work was supported by a grant from the Vice Chancellor of Research of Mashhad University of Medical Sciences.

Gut Bacterial DNA Translocation is an Independent Risk Factor of Flare at Short Term in Patients With Crohn's Disease

OBJECTIVES

We aimed at evaluating bacterial DNA (bactDNA) presence in blood of Crohn's disease (CD) patients in remission as an independent risk factor of flare at 6 months.

METHODS

This is a prospective, multicenter study on CD patients with Crohn's disease activity index (CDAI)<150. The primary end point was time-to-relapse as evaluated by CDAI>150 in the following 6 months. BactDNA in blood, the nucleotide-binding oligomerization domain containing 2 (NOD2) genotype, and serum cytokine levels were determined at baseline.

RESULTS

A total of 288 patients were included. BactDNA was detected in 98 patients (34.0%). A variant-NOD2 genotype was identified in 114 patients (39.6%). Forty patients (14%) relapsed during follow-up. Multivariate survival analysis identified bactDNA as an independent risk factor of flare (hazard ratio (HR) 8.75 (4.02-19.06) 95% confidence interval (CI)). Hospitalization, surgery, switch of treatment, initiation and escalation of anti-tumor necrosis factor (TNF) therapy, steroids initiation, and increased fecal calprotectin levels at 6 months were associated with bactDNA at baseline. A logistic regression analysis showed bactDNA as an independent and significant predictive factor of hospitalization (odds ratio (OR) 11.9 (3.4-42.3); P<0.001), steroids startup (OR 8.5 (2.7-27.1); P<0.001), and switch of treatment (OR 3.5 (1.6-7.7); P=0.002) at 6 months. No relationship was observed between bactDNA and mucosal lesions in patients with colonoscopy at admission. Serum pro-inflammatory cytokines were significantly increased in patients with bactDNA or a variant-NOD2 genotype. The combination of both factors induced decreased anti-TNF-α levels and a higher percentage of patients on intensified anti-TNF therapy.

CONCLUSIONS

BactDNA is an independent risk factor of relapse at 6 months in CD patients. BactDNA is also independently associated with an increased risk of hospitalization, switch of treatment, and steroids initiation.

Differential response to microbial antigens by age of diagnosis in patients with Crohn's disease

PURPOSE

Fifteen percent of incident Crohn's disease (CD) cases are diagnosed at older ages and demonstrate colonic location and inflammatory behavior. Serologic responses to gut microbial antigens are associated with specific phenotypes, and may differ by age at diagnosis. Our aim was to identify an association between age at diagnosis of CD and responses to gut microbial antigens.

PATIENTS AND METHODS

Levels of anti-Saccharomyces cerevisiae antibodies (ASCA) immunoglobulins A and G (IgA and IgG), antibodies to Escherichia coli outer membrane porin-C (anti-Omp-C), antibodies to clostridial flagellin (anti-CBir-1), and perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA) were compared in patients by age in three diagnosis groups: patients diagnosed at ages of <40, ≥40-59, and ≥60 years. For each antigen, patients with antibody levels in the first, second, third, and fourth quartile were assigned a score of 1, 2, 3, or 4, respectively. Individual scores were added to create a quartile sum score representing cumulative quantitative immune response.

RESULTS

Eighteen, 17, and 12 patients were diagnosed at ages <40, 40-59, and ≥60 years, respectively. The majority (71%) had ileocolonic disease in the youngest group, compared to 36% in the oldest group (P=0.001). Mean ASCA IgA and IgG titers were increased in the youngest age group compared to the older groups (P=0.19 and P=0.13, respectively). Mean quartile sum scores for antibody levels were 7.2±2.8 in those patients diagnosed at ages <40 years, 4.9±2.9 in the 40-59-year-old age group, and 5.6±2.6 in the ≥60-year-old age group (P=0.06).

CONCLUSION

A trend toward decreased cumulative immune responses to CD-associated gut antigens was observed in CD patients diagnosed at older ages compared to younger patients. Host responses to microbial antigens may be less important in older onset IBD and may contribute to the distinct phenotype in this group.

Use of animal models in elucidating disease pathogenesis in IBD

Inflammatory bowel diseases (IBD) are a collection of diseases characterized by chronic gastrointestinal inflammation resulting from an exuberant immune response to commensal flora in genetically susceptible individuals. Rapid advances in the field of genomics have resulted in the identification of at least 163 loci that contribute susceptibility to both Crohn's disease (CD) and ulcerative colitis (UC). Similar to other complex diseases, however, the "curse of missing heritability" remains a significant concern in understanding the mechanisms underlying IBD. While genetic discoveries, to date, only account for 7-14% of disease variance for IBD, studies have increasingly demonstrated a role for environmental factors in disease pathogenesis. Furthermore, the use of animal models of IBD has led to a greater understanding of disease pathogenesis implicating various aspects of the innate immune response including the bacterial, fungal, and viral microbiome and adaptive immune response such as the interleukin (IL)-23/IL-17 pathway.

Mannose-binding lectin deficiency is not associated with anti-Saccharomyces cerevisiae antibody in Korean Crohn's disease patients

BACKGROUND

Mannose-binding lectin (MBL) is a pattern-recognition molecule and an important component of the innate defense system. Anti-Saccharomyces cerevisiae antibody (ASCA) is a well known serologic marker of Crohn's disease (CD). This study aimed to investigate the association between MBL, ASCA, and clinical features in Korean CD patients.

METHOD

Two hundred and eighty-three well-characterized CD patients were included. MBL concentrations, serum IgG and IgA concentrations of ASCA were determined by ELISA. Low MBL concentrations were defined as serum MBL concentrations <500 ng/ml.

RESULT

Low MBL concentrations were observed in 41 CD patients (14.5%). No differences in MBL concentrations were detected according to the age at diagnosis, behavior, or the location of patients with CD. MBL concentrations and the frequency of low MBL concentrations did not differ according to ASCA positivity. The presence of perianal involvement (p=0.043), younger age at diagnosis (p=0.021), and intestinal surgery (p=0.047) were more frequently associated with ASCA positive patients.

CONCLUSION

MBL concentration is not associated with clinical features of CD patients or ASCA positivity. ASCA positivity is associated with a severe clinical course in Korean CD patients.

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.

12-month effects of once-weekly sustained-release growth hormone treatment in adults with GH deficiency

The weekly sustained-release recombinant human GH formulation LB03002, showed beneficial effects in GH-deficient (GHD) adults in a previous 26-week double-blind study. Prior studies of long-acting GH preparations in adults have only been conducted for 6 or 8 months, so the effects of longer-term use are unknown; this is important to address, as replacement is given for many years in GHD adults. This open-label, 26-week study extension evaluated longer-term safety and efficacy of LB03002 over 52 weeks in adults with GHD who had previously been randomized to GH, and provides additional safety and efficacy data over 26 weeks in the cohort who had previously been randomized to placebo. Of 147 adults with GHD who completed a preceding study, 136 patients continued in this open-label study to receive LB03002 over an additional 26 weeks. This represented a continuation of long-acting GH for 26 weeks in the cohort who took this medication in the prior study (LB03002 Throughout group), and describes the first use of long-acting GH in the cohort that was randomized to placebo in the prior study (Switched to LB03002 group). The LB03002 dose was adjusted according to serum insulin-like growth factor-I (IGF-I) levels. LB03002 treatment demonstrated mean significant decreases from baseline in fat mass (FM) for both 26 (Switched group, P = 0.001) and 52 weeks (Throughout group, P = 0.002) of 1.11 (1.95) kg and 1.06 (3.16) kg, respectively. Prolonged GH treatment was effective in sustaining the increase in lean body mass (LBM), serum IGF-I and IGFBP-3 levels achieved during the first 26 weeks. Long-term treatment with the sustained-release weekly GH preparation over both 26 and 52 weeks in adults with GHD demonstrated a sustained reduction of FM with a favorable safety profile. This study extends prior knowledge about long-acting GH because it reports the most prolonged treatment of adults with any long-acting GH preparation, thereby confirming the value and safety of such agents for long-term GH replacement.

Serum antibodies associated with complex inflammatory bowel disease

BACKGROUND

Antibodies to microbial antigens have been associated with specific diagnoses and phenotypes of inflammatory bowel disease. We evaluated the prevalence of pANCA, IgA and IgG anti-Saccharomyces cerevisiae antibodies, anti-OmpC, and anti-flagellin in a large well-defined population of patients with Crohn's disease (CD) and ulcerative colitis (UC) and analyzed for various clinical outcomes.

METHODS

Samples were collected from 391 patients with CD, 207 patients with UC, and 62 healthy controls. Patients were phenotyped using the Montreal classification. Blinded serological analyses were performed for pANCA, IgA and IgG anti-Saccharomyces cerevisiae antibodies, anti-OmpC, and anti-flagellin.

RESULTS

In CD, increasing quantitative levels for antibodies were associated with a younger age of diagnosis, longer disease duration, increased surgeries, ileocolonic and perianal disease, and internal perforating behavior. In UC, they were associated with colectomy. An increasing number of seropositive antibodies in CD was associated with a younger age at diagnosis, increased disease duration, ileocolonic and perianal disease, internal penetrating and stricturing behavior, and increased surgeries. Multivariate analysis confirmed the association of antimicrobial antibodies with features of complicated CD and UC.

CONCLUSIONS

Increased serological markers are associated with a more aggressive CD phenotype and an increased need for colectomy in UC. This raises the possibility for use of these markers in patients at risk of complex disease.

Diagnostic Value of ASCA and Atypical p-ANCA in Differential Diagnosis of Inflammatory Bowel Disease

BACKGROUND

Worldwide, the incidence of inflammatory bowel disease (IBD) is increasing. This study aims to evaluate the diagnostic value of two serological markers, atypical perinuclear anti-neutrophil cytoplasmic antibodies (atypical-P-ANCA) and anti-Saccharomyces cerevisiae antibodies (ASCA), with the intent to determinetheir relationship to ulcerative colitis (UC) and Crohn's disease (CD), in addition to the location and extent of bowel involvement.

METHODS

There were 97 patients enrolled in this study, 72 diagnosed with UC and 25 with CD.The control group consisted of 40 healthy individuals. ASCA was determined by enzyme-linked immunosorbent assay (ELISA) and atypical-P-ANCA by indirect immunofluorescence assay (IIF). For data analyses, we used the chi-square and independent t-tests. Significance was considered to be p<0.05.

RESULTS

For CD, the sensitivityof ASCA was 16% and its specificity was 97%.ASCA had a specifity of 90% in UC patients. The atypical P-ANCA test had a sensitivity of 44% and specificity of 86% for UC. The positive predictive value (PPV) for atypical P-ANCA in UC patients was 78% and for the negative predictive value (NPV), it was 58%.There was no correlation between ASCA and atypical P-ANCA results and the location of gastrointestinal (GI) involvement in CD (p=0.61) and UC (p=0.28) patients.

CONCLUSION

According to the results, ASCA and atypical P-ANCA markers are not useful for IBD screening. Our study suggests that atypical P-ANCA is a useful parameter to differentiate UC from CD. However, ASCA is of limited value for screening and differentiating UC from CD.

The CARD8 p.C10X mutation associates with a low anti-glycans antibody response in patients with Crohn's disease

BACKGROUND

Crohn's disease (CD) is associated with elevated anti-glycans antibody response in 60% of CD patients, and 25% of healthy first-degree relatives (HFDRs), suggesting a genetic influence for this humoral response. In mice, anti-glucan antibody response depends on the NLRP3 inflammasome. Here, we explored the effect of mutated CARD8, a component of the inflammasome, on anti-glycans antibody response in human.

METHODS

The association between p.C10X mutation (rs2043211) of the CARD8 gene and the levels of anti-glycans antibody response was examined in 39 CD families. The family-based QTDT association test was used to test for the genetic association between CARD8 p.C10X mutation and anti-glycan antibodies in the pedigrees. The difference in antibody responses determined by ELISA was tested in a subgroup of CD probands (one per family) and in a subgroup of HFDRs using the Wilcoxon Kruskal Wallis non-parametric test.

RESULTS

The QTDT familial transmission tests showed that the p.C10X mutation of CARD8 was significantly associated with lower levels of antibody to mannans and glucans but not chitin (p=0.024, p=0.0028 and p=0.577, for ASCA, ALCA and ACCA, respectively). These associations were independent of NOD2 and NOD1 genetic backgrounds. The p.C10X mutation significantly associated or displayed a trend toward lower ASCA and ALCA levels (p=0.038 and p=0.08, respectively) only in the subgroup of CD probands. Such associations were not significant for ACCA levels in both subgroups of CD probands and of HFDRs.

CONCLUSION

Our results show that ASCA and ALCA but not ACCA levels are under the influence of CARD8 genotype. Alteration of CARD8, a component of inflammasome, is associated with lower levels of antibodies directed to mannans and glucans at least in CD patients.

Anti-Saccharomyces cerevisiae antibodies associate with phenotypes and higher risk for surgery in Crohn's disease: a meta-analysis

BACKGROUND

Recent studies suggested that anti-Saccharomyces cerevisiae antibody (ASCA) status was associated with diagnostic findings, stratified classification phenotypes, disease activity and clinical course of Crohn's disease (CD). However, the relationship between ASCA status and phenotypes of CD remains controversial in these studies.

AIMS

The purpose of this study was to evaluate whether ASCA status is associated with the phenotypes and the risk of surgery in diverse populations in CD.

METHODS

We conducted a meta-analysis of studies assessing the association of ASCA status with phenotypes and risk of surgery in CD. Three independent reviewers undertook data extraction. We pooled odds ratios separately for the cohort and case-control studies.

RESULTS

We identified ten cohort studies (n = 2,365) and 14 case-control studies (n = 1,887) that investigated the association of ASCA status with phenotypes and risk of surgery in CD. The meta-analysis of the cohort studies showed significant association between the ASCA-positive status and higher risk of early-onset age (OR 2.25, 95 % CI 1.41-3.57, P < 0.001), ileal involvement disease (1.70, 1.05-2.77, P = 0.03), complicated disease behavior (2.09, 1.71-2.57, P < 0.001), perianal disease (1.49, 1.14-1.94, P = 0.004), and risk for surgery (1.61, 1.29-2.01, P < 0.001). Meta-analysis of the case-control studies also showed a significantly higher risk in ileal involvement disease (1.77, 1.25-2.49, P = 0.001), complicated disease behavior (2.13, 1.70-2.68, P < 0.001), perianal disease (1.96, 1.38-2.78, P < 0.001), and risk for surgery (1.71, 1.17-2.49, P = 0.005), except for the early-onset age (1.16, 0.80-1.69, P = 0.44).

CONCLUSIONS

This meta-analysis indicated that positive ASCA status is a risk factor for early-onset age, ileal involvement, complicated behavior, perianal disease and requirement for surgery in 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 role of autoantibodies in inflammatory bowel disease

The search for the underlying trigger of an inappropriate inflammatory reaction characteristic of inflammatory bowel diseases (IBD) has led to the discovery of several antibodies. The panel of serologic markers for IBD is rapidly expanding. Serologic markers hold the promise of helping researchers and clinicians to better understand IBD heterogeneity and natural history. The real importance of the antibodies produced against various microbial and autoantigens is still uncertain. Whether these antibodies play a primary role in the pathogenesis of IBD, or their presence is only a consequence of the inflamed mucosa is a fundamental question that remains to be clarified. The impact of the routine evaluation of these serologic markers in the everyday clinical IBD diagnostic algorithm is questionable due to their limited sensitivity. Despite their great potential, the routine use of serologic markers for diagnosis and follow-up is currently not justified. However, their correlation with disease phenotype and behavior is more established. A combination of serum markers has been shown to be of more value compared to using single markers alone. The ongoing challenge is how to best utilize these serologic markers to provide clinically relevant information in a cost-effective manner. Further prospective clinical trials are needed to determine their exact role in pathogenesis and practical clinical importance. We review the current standpoint of the clinical impact of various established and newly suggested markers in Crohn's disease and ulcerative colitis.

Genetic deletion of dectin-1 does not affect the course of murine experimental colitis

Background

It is believed that inflammatory bowel diseases (IBD) result from an imbalance in the intestinal immune response towards the luminal microbiome. Dectin-1 is a widely expressed pattern recognition receptor that recognizes fungi and upon recognition it mediates cytokine responses and skewing of the adaptive immune system. Hence, dectin-1 may be involved in the pathogenesis of IBD.

Methods

We assessed the responses of dectin-1 deficient macrophages to the intestinal microbiota and determined the course of acute DSS and chronic Helicobacter hepaticus induced colitis in dectin-1 deficient mice.

Results

We show that the mouse intestinal microbiota contains fungi and the cytokine responses towards this microbiota were significantly reduced in dectin-1 deficient macrophages. However, in two different colitis models no significant differences in the course of inflammation were found in dectin-1 deficient mice compared to wild type mice.

Conclusions

Together our data suggest that, although at the immune cell level there is a difference in response towards the intestinal flora in dectin-1 deficient macrophages, during intestinal inflammation this response seems to be redundant since dectin-1 deficiency in mice does not affect intestinal inflammation in experimental colitis.

The impact of intestinal resection on serum levels of anti-Saccharomyces cerevisiae antibodies (ASCA) in patients with Crohn's disease

BACKGROUND

Antibodies to Saccharomyces cerevisiae (ASCA) are highly prevalent in sera of patients with Crohn's disease and have been proposed to identify subgroups of patients with a disabling disease course.

AIM

To investigate the impact of intestinal resection on serum levels of ASCA in patients with Crohn's disease and the predictive value of ASCA levels on surgical recurrence.

METHODS

Sera from 60 patients who underwent 'curative' intestinal resection due to stricturing and/or penetrating complications were collected preoperatively and during post-operative follow-up (week 2, months 4, 8 and 11 ± 1). Measurement of ASCA IgG and IgA isotypes were performed using ELISA. Re-operation rate was associated with ASCA status and serum levels.

RESULTS

At baseline 44/60 (73%) of patients were rated as positive for ASCA IgG, 45/60 (75%) for ASCA IgA and 52/60 (87%) as positive for at least one of both. ASCA serum levels remained stable during first year from resection. After a median of 106 months 10 of 40 (25%) patients with long-term follow-up underwent one or more intestinal re-operations. Neither ASCA positivity nor absolute ASCA serum levels were predictive of surgical recurrence.

CONCLUSIONS

Serum ASCA levels remain stable after curative intestinal resection in Crohn's disease. This indicates the persistence of both stimulus and immunological mechanism operative in the production of ASCA even after complete surgical resection of macroscopically inflamed intestinal tissue. After intestinal resection, neither ASCA positivity nor ASCA serum levels predict the risk of surgical recurrence during long-term follow-up.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

DISCUSSION

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

CONCLUSIONS

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

Current and future role of biomarkers in Crohn's disease risk assessment and treatment

BACKGROUND

Crohn's disease (CD), a chronic inflammatory bowel disease (IBD), occurs in genetically susceptible individuals who develop aberrant immune responses to endoluminal bacteria. Recurrent inflammation increases the risk of several complications. Despite use of a traditional "step-up" therapy with corticosteroids and immunomodulators, most CD patients eventually require surgery at some time in their disease course. Newer biologic agents have been remarkably effective in controlling severe disease. Thus, "top-down," early aggressive therapy has been proposed to yield better outcomes, especially in complicated disease. However, safety and cost issues mandate the need for careful patient selection. Identification of high-risk candidates who may benefit from aggressive therapy is becoming increasingly relevant. Serologic and genetic markers of CD have great potential in this regard. The aim of this review is to highlight the clinical relevance of these markers for diagnostics and prognostication.

METHODS

A current PubMed literature search identified articles regarding the role of biomarkers in IBD diagnosis, severity prediction, and stratification. Studies were also reviewed on the presence of IBD markers in non-IBD diseases.

RESULTS

Several IBD seromarkers and genetic markers appear to be associated with complex CD phenotypes. Qualitative and quantitative serum immune reactivity to microbial antigens may be predictive of disease progression and complications.

CONCLUSION

The cumulative evidence provided by serologic and genetic testing has the potential to enhance clinical decision-making when formulating individualized IBD therapeutic plans.

Diagnostic utility of anti-Saccharomyces cerevisiae antibody (ASCA) and Interferon-γ assay in the differential diagnosis of Crohn's disease and intestinal tuberculosis

BACKGROUND

Differential diagnosis of Crohn's disease (CD) from intestinal tuberculosis (ITB) is challenging. Anti-Saccharomyces cerevisiae antibody (ASCA) is a specific serological marker for CD and INF-gamma assay (QuantiFERON-TB gold test, QFT) is a good supplementary diagnostic tool for ITB. We evaluated the clinical usefulness of ASCA and QFT for differential diagnosis of CD from ITB in Korean adults.

METHODS

A total of 147 patients suspected to have ITB or CD were prospectively enrolled from 13 hospitals. ASCA IgG and IgA serum titers were measured by ELISA, and the QFT test was also performed.

RESULTS

Thirty-two of 72 (44.4%) patients with CD were ASCA positive (titer >25U) compared to 10 of 75 ITB patients (13.3%) and 3 of 20 healthy controls (15%) (p<0.01). The QFT test was positive in 7 patients with CD (9.7%) and 50 patients with ITB (66.6%) (p<0.01). In cases which ASCA positive/QFT negative, the sensitivity, specificity, positive predictive value, and negative predictive value for the diagnosis of CD were 44.4%, 96.0%, 91.4%, and 64.3%, respectively.

CONCLUSION

ASCA is a useful diagnostic tool for CD in Korea, where ITB is prevalent. In particular, when ASCA is combined with QFT, effective differential diagnosis of CD from ITB is possible.

NOD2 mutations and anti-Saccharomyces cerevisiae antibodies are risk factors for Crohn's disease in African Americans

OBJECTIVES

NOD2 mutations and anti-Saccharomyces cerevisiae antibodies (ASCAs) are established risk factors of Crohn's disease (CD) in whites but have not been assessed in African-American (AA) adults with CD.

METHODS

AAs with CD and controls were recruited by the Mid-Atlantic African-American IBD Study as part of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) IBD Genetics Consortium. Genotyping for the three common CD NOD2 mutations (Leu1007fsinsC, G908R/2722g>c, and R702W/2104c>t) and ASCA enzyme-linked immunosorbent assays were performed in 183 AA CD patients and in 143 controls. Logistic regression was used to calculate adjusted odds ratios (ORs) for the association between ASCA and disease phenotype.

RESULTS

ASCA sensitivity and specificity values were 70.5 and 70.4%, respectively. On univariate analysis, ASCA was significantly associated with younger age at diagnosis, ileal involvement, and complicated (stricturing/penetrating) behavior. On multivariate analysis, ASCA titer (per 25 Units) was associated with ileal involvement (OR 1.18, 95% confidence interval (CI): 1.04-1.34), complicated behavior (OR 1.13, 95% CI: 1.01-1.28), and surgery (hazard ratio: 1.11, 95% CI: 1.02-1.21). Cigarette smoking and CD family history were also significantly associated with surgery. NOD2 carriers (all heterozygotes) were more common among CD cases than controls (8.2 vs. 2.1%; OR 4.17%, 95% CI: 1.18-14.69). The NOD2 mutation population attributable risk was 6.2%.

CONCLUSIONS

In comparison with whites, ASCA in AAs has a similar sensitivity but a lower specificity for CD. ASCA is associated with ileal involvement, complicated behavior, and surgery in AAs with CD. NOD2 is a risk gene for AA CD, although mutation frequency and population attributable risk are much lower than in whites.

Novel diagnostic and prognostic modalities in inflammatory bowel disease

Inflammatory bowel disease remains a complex disease with variable clinical presentations and often nonspecific symptoms. Physicians must rely on diagnostic tools for clarification of disease diagnosis and for guiding management of patients with established disease. Advances in radiologic imaging modalities facilitate early and accurate detection of luminal disease and extraluminal complications. The introduction and dissemination of small bowel capsule endoscopy and double-balloon enteroscopy permit detailed visualization and sampling of the mucosa throughout the entire bowel. Serologic biomarkers are evolving as a valuable tool to clarify diagnosis and stratify patients by disease phenotypes and patterns of behavior. Neutrophil-derived fecal biomarkers are emerging as useful surrogate markers of intestinal inflammation with the potential for a variety of clinical applications, but their application to clinical management has not yet been clarified.

Novel diagnostic and prognostic modalities in inflammatory bowel disease

Inflammatory bowel disease remains a complex disease with variable clinical presentations and often nonspecific symptoms. Physicians must rely on diagnostic tools for clarification of disease diagnosis and for guiding management of patients with established disease. Advances in radiologic imaging modalities facilitate early and accurate detection of luminal disease and extraluminal complications. The introduction and dissemination of small bowel capsule endoscopy and double-balloon enteroscopy permit detailed visualization and sampling of the mucosa throughout the entire bowel. Serologic biomarkers are evolving as a valuable tool to clarify diagnosis and stratify patients by disease phenotypes and patterns of behavior. Neutrophil-derived fecal biomarkers are emerging as useful surrogate markers of intestinal inflammation with the potential for a variety of clinical applications, but their application to clinical management has not yet been clarified.

Genetic risk profiling and prediction of disease course in Crohn's disease patients

BACKGROUND & AIMS

Clinical presentation at diagnosis and disease course of Crohn's disease (CD) are heterogeneous and variable over time. Early introduction of immunomodulators and/or biologicals might be justified in patients at risk for disease progression, so it is important to identify these patients as soon as possible. We examined the influence of recently discovered CD-associated susceptibility loci on changes in disease behavior and evaluated whether a genetic risk model for disease progression could be generated.

METHODS

Complete medical data were available for 875 CD patients (median follow-up time, 14 years; interquartile range, 7-22). Fifty CD-associated polymorphisms were genotyped. Kaplan-Meier survival analyses, multiple logistic regression, and generalized multifactor dimensionality reduction analyses (GMDR) were performed, correcting for follow-up time.

RESULTS

Homozygosity for the rs1363670 G-allele in a gene encoding a hypothetical protein near the IL12B gene was independently associated with stricturing disease behavior (odds ratio [OR], 5.48; 95% confidence interval [CI], 1.60-18.83; P = .007) and with shorter time to strictures (P = .01), especially in patients with ileal involvement (P = .0002). Male patients carrying at least one rs12704036 T-allele in a gene desert had the shortest time to non-perianal fistula (P < .0001). The presence of a C-allele at the CDKAL1 single nucleotide polymorphism rs6908425 and the absence of NOD2 variants were independently associated with development of perianal fistula (OR, 8.86; 95% CI, 1.13-69.78; P = .04 and OR, 0.56; 95% CI, 0.38-0.83; P = .004, respectively), particularly when colonic involvement and active smoking were present.

CONCLUSIONS

CD-associated polymorphisms play a role in disease progression and might be useful in identifying patients who could benefit from an early top-down treatment approach.

Clustering of (auto)immune diseases with early-onset and complicated inflammatory bowel disease

Studies in adult inflammatory bowel disease (IBD) patients have highlighted associations with genetic and serologic markers and suggest an association with disease location, behaviour and natural history. Data on patients with Crohn's disease (CD, n=80), ulcerative colitis (UC, n=15) and indeterminate colitis (n=4) were collected. All individuals were analysed for CARD15 R702W, G908R and L1007fs for toll-like receptor 4 (TLR4) Asp299Gly and for anti-Saccharomyces cerevisiae antibodies (ASCA) and atypical perinuclear antineutrophil cytoplasmatic antibodies (pANCA). After a mean of 10.7 years of follow up, the disease behaviour changed in 45% of CD patients, in contrast to disease location, where only 12.5% had a change (p<0.001). The younger the age at diagnosis, the more patients presented with colonic disease (p=0.021). Also, more TLR4 Asp299 Gly variants were found when the age at onset was younger (p=0.018). A large number of concomitant diseases were observed. There was no difference in the prevalence of TLR4 variants nor ASCA or pANCA between the patients with or without concomitant diseases. Patients who progressed more often needed surgery as compared to patients who remained free of stenosing or fistulising disease (27/32 or 84% versus 3/35 or 8.6%, respectively, p<0.0001) and more often had concomitant immune-mediated diseases and a trend for more seroreactivity towards ASCA.

Predictive value of serologic markers in a population-based Norwegian cohort with inflammatory bowel disease

BACKGROUND

Perinuclear antineutrophil cytoplasmic antibodies (pANCA) and anti-Saccharomyces cerevisiae antibodies (ASCA) are proposed to be specific markers for ulcerative colitis (UC) and Crohn's disease (CD). Their prevalence and relationship to disease phenotype and outcome in unselected cohorts of patients with inflammatory bowel disease (IBD), however, is largely unclear. We studied the prevalence of these serologic markers in a population-based IBD cohort 10 years after diagnosis, and examined whether their presence could be related to distinct subgroups and outcome of disease.

METHODS

Of 685 living IBD patients, 620 met for a 10-year follow-up, of whom 526 (UC, n = 357 and CD, n = 169) participated in this study.

RESULTS

Twenty-seven percent (n = 46) of CD patients were ASCA-positive and 31% (n = 109) of UC patients were pANCA-positive. Positive ASCA was more frequent in CD patients with stricturing (P = 0.003) or penetrating (P = 0.012) complications than in those with inflammatory behavior at diagnosis. Moreover, the presence of ASCA was associated with an at least twice higher risk of evolving more severe disease behavior during follow-up (P < 0.001). In UC, pANCA expression was related to female gender (P = 0.005) and the use of azathioprine (P < 0.001), and in CD, to colon-limited disease and age >/=40 years at diagnosis (P = 0.009 and P = 0.001, respectively).

CONCLUSIONS

The prevalence of ASCA in CD and pANCA in UC appears markedly lower than in referral-based populations. Even with the low prevalence, our study gives further support to the role of ASCA and pANCA as markers for distinct phenotype and outcome of disease.

Anti-Saccharomyces cerevisiae antibodies status is associated with oral involvement and disease severity in Crohn disease

OBJECTIVES

To determine anti-Saccharomyces cerevisiae antibodies (ASCA) status and its relation to disease phenotype in patients with inflammatory bowel disease (IBD).

PATIENTS AND METHODS

A total of 301 Scottish patients with early-onset IBD-197 Crohn disease (CD), 76 ulcerative colitis (UC), 28 indeterminate colitis (IC)-and 78 healthy control individuals were studied. ASCA status (IgA, IgG) was determined by enzyme-linked immunosorbent assay. ASCA status was then analyzed in relation to CD phenotype.

RESULTS

Patients with CD had a higher prevalence of ASCA than patients with UC and healthy controls: 82/197 versus 12/76, odds ratio (OR) 3.80 (1.93-7.50) and 82/197 versus 6/78, OR 8.56 (3.55-20.62), respectively. Univariate analysis showed that positive ASCA status was associated with oral CD (17/25 vs 59/153, OR 3.39 [1.38-8.34]), perianal CD (39/77 vs 38/108, OR 1.89 [1.04-3.44]) and the presence of granulomata (63/132 vs 15/52, OR 2.25 [1.13-4.48]) and also with markers of disease severity: raised C-reactive protein (44/90 vs 12/49, OR 2.95[1.36-6.37]), hypoalbuminemia (44/85 vs 20/74, OR 2.28[1.19-4.37]), and surgery (27/49 vs 54/147, OR 2.11 [1.10-4.06]). From multivariate analysis, the presence of oral disease (adjusted P = 0.001, OR 22.22 [3.41-142.86]) and hypoalbuminemia (adjusted P = 0.01, OR 4.78 [1.40-16.39]) was found to be independently associated with ASCA status. No association was demonstrated between ASCA and IBD candidate genes.

CONCLUSIONS

Patients with CD had a higher prevalence of ASCA than did other patients with IBD. ASCA status described patients with CD who had a specific phenotype, showing an association with markers of disease severity and oral CD involvement.

Fungi and inflammatory bowel diseases: Alterations of composition and diversity

OBJECTIVE

Altered bacterial diversity of the intestinal mucosa-associated microbiota may reflect the net influence of lifestyle factors associated with the development of chronic inflammatory bowel diseases (IBD). While a reduced bacterial diversity has been reported in IBD, little is known about the fungal microbiota. The aim of this study was to carry out a systematic analysis of intestinal fungal microbiota in IBD.

MATERIAL AND METHODS

The mucosa-associated fungal microbiota of 104 colonic biopsy tissues from 47 controls and 57 IBD patients was investigated using metagenomic 18S rDNA-based denaturing gradient gel electrophoresis (DGGE), clone libraries, sequencing, and in situ hybridization techniques.

RESULTS

Fungi-specific 18S rDNA signatures could be detected in all 104 patients, accounting for only a small proportion of the intestinal microbiota (0.02% of the mucosal and 0.03% of the fecal microbiota). An overall fungal biodiversity of 43 different operational taxonomic units (OTUs) was found in the clone libraries. The qualitative composition of fungal microbiota was different between patients with IBD and controls. The DGGE profiles showed a higher mean fungal diversity in patients with Crohn's disease (CD) in comparison with controls (10.8+/-3.1 versus 6.2+/-2.4 for CD, p <or= 0.001). No disease-specific fungal species were found in the CD and ulcerative colitis (UC) group.

CONCLUSIONS

Diverse fungal species are part of the normal enteric microbiota, but diversity is increased and composition of the fungal communities varies in IBD. Further work is needed to investigate whether the alteration of the fungal flora in IBD is secondary to an imbalanced bacterial microbiota or an independent etiologic factor.