Anti-Saccharomyces cerevisiae and antineutrophil cytoplasmic antibodies as predictors of inflammatory bowel disease

Intestinal lysozyme engagement of Salmonella Typhimurium stimulates the release of barrier-impairing InvE and Lpp1

BACKGROUND & AIMS

Lysozyme is a β-1,4-glycosidase that hydrolyzes the polysaccharide backbone of bacterial cell walls. With an additional bactericidal function mediated by a separate protein domain, lysozyme is considered as a uniquely important antimicrobial molecule contributing to the host's innate immune response to infection. Elevated lysozyme production is found in various inflammatory conditions while patients with genetic risks for inflammatory bowel diseases demonstrate abnormal lysozyme expression, granule packaging, and secretion in Paneth cells. However, it remains unclear how a gain- or loss-of-function in host lysozyme may impact the host inflammatory responses to pathogenic infection.

METHODS

We challenged Lyz1-/- and ectopic Lyz1-expressing (Villin-Lyz1TG) mice with S. Typhimurium then comprehensively assessed the inflammatory disease progression. We conducted proteomics analysis to identify molecules derived from human lysozyme-mediated processing of live Salmonella. We examined the barrier-impairing effects of these identified molecules in human intestinal epithelial cell monolayer and enteroids.

RESULTS

Lyz1-/- mice are protected from infection in terms of morbidity, mortality, and barrier integrity, whereas Villin-Lyz1TG mice demonstrate exacerbated infection and inflammation. The growth and invasion of Salmonella in vitro are not affected by human or chicken lysozyme, whereas lysozyme encountering of live Salmonella stimulates the release of barrier-disrupting factors, InvE-sipC and Lpp1, which directly or indirectly impair the tight junctions.

CONCLUSION

The direct engagement of host intestinal lysozyme with an enteric pathogen such as Salmonella promotes the release of virulence factors that are barrier-impairing and pro-inflammatory. Controlling lysozyme function may help alleviate the inflammatory progression.

Investigating the shared genetic architecture between primary sclerosing cholangitis and inflammatory bowel diseases: a Mendelian randomization study

BACKGROUND

Several studies have found that primary sclerosing cholangitis (PSC) and inflammatory bowel disease (IBD) are closely associated. However, the direction and causality of their interactions remain unclear. Thus, this study employs Mendelian Randomization to explore whether there are causal associations of genetically predicted PSC with IBD.

METHODS

Genetic variants associated with the genome-wide association study (GWAS) of PSC were used as instrumental variables. The statistics for IBD, including ulcerative colitis (UC), and Crohn's disease (CD) were derived from GWAS. Then, five methods were used to estimate the effects of genetically predicted PSC on IBD, including MR Egger, Weighted median (WM), Inverse variance weighted (IVW), Simple mode, and Weighted mode. Last, we also evaluated the pleiotropic effects, heterogeneity, and a leave-one-out sensitivity analysis that drives causal associations to confirm the validity of the analysis.

RESULTS

Genetically predicted PSC was significantly associated with an increased risk of UC, according to the study (odds ratio [OR] IVW= 1.0014, P<0.05). However, none of the MR methods found significant causal evidence of genetically predicted PSC in CD (All P>0.05). The sensitivity analysis results showed that the causal effect estimations of genetically predicted PSC on IBD were robust, and there was no horizontal pleiotropy or statistical heterogeneity.

CONCLUSIONS

Our study corroborated a causal association between genetically predicted PSC and UC but did not between genetically predicted PSC and CD. Then, we identification of shared SNPs for PSC and UC, including rs3184504, rs9858213, rs725613, rs10909839, and rs4147359. More animal experiments and clinical observational studies are required to further clarify the underlying mechanisms of PSC and IBD.

Bacteria: Potential Make-or-Break Determinants of Celiac Disease

Celiac disease is an autoimmune disease triggered by dietary gluten in genetically susceptible individuals that primarily affects the small intestinal mucosa. The sole treatment is a gluten-free diet that places a social and economic burden on patients and fails, in some, to lead to symptomatic or mucosal healing. Thus, an alternative treatment has long been sought after. Clinical studies on celiac disease have shown an association between the presence of certain microbes and disease outcomes. However, the mechanisms that underlie the effects of microbes in celiac disease remain unclear. Recent studies have employed disease models that have provided insights into disease mechanisms possibly mediated by bacteria in celiac disease. Here, we have reviewed the bacteria and related mechanisms identified so far that might protect from or incite the development of celiac disease. Evidence indicates bacteria play a role in celiac disease and it is worth continuing to explore this, particularly since few studies, to the best of our knowledge, have focused on establishing a mechanistic link between bacteria and celiac disease. Uncovering host-microbe interactions and their influence on host responses to gluten may enable the discovery of pathogenic targets and development of new therapeutic or preventive approaches.

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.

Deciphering the different phases of preclinical inflammatory bowel disease

Inflammatory bowel disease (IBD) is an immune-mediated inflammatory disease (IMID) of the gastrointestinal tract and includes two subtypes: Crohn's disease and ulcerative colitis. It is well-recognized that IBD is associated with a complex multifactorial aetiology that includes genetic predisposition and environmental exposures, with downstream dysregulation of systemic immune function and host-microbial interactions in the local environment in the gut. Evidence to support the notion of a multistage development of IBD is growing, as has been observed in other IMIDs such as rheumatoid arthritis and systemic lupus erythematosus. With the rising worldwide incidence of IBD, it is increasingly important to understand the complex interplay of pathological events during the different stages of disease development to enable IBD prediction and prevention strategies. In this article, we review comprehensively the current evidence pertaining to the preclinical phase of IBD, including at-risk, initiation and expansion phases. We also discuss the framework of preclinical IBD, expanding on underlying pathways in IBD development, future research directions and IBD development in the context of other IMIDs.

Pomegranate (Punica granatum L.) and Its Rich Ellagitannins as Potential Inhibitors in Ulcerative Colitis

Ulcerative colitis, an immune-mediated inflammatory disease of the gastrointestinal tract, places a significant financial burden on patients and the healthcare system. Recently, reviews of the pomegranate and the abundant medicinal applications of its ellagitannins, as well as its pharmacological action, phytochemicals, metabolism, and pharmacokinetics, have been completed. However, summaries on their anti-ulcerative colitis effects are lacking. Numerous preclinical animal investigations and clinical human trial reports demonstrated the specific therapeutic effects of pomegranate and the effect of its ellagitannins against ulcerative colitis. According to the literature collected by Sci-finder and PubMed databases over the past 20 years, this is the first review that has compiled references regarding how the rich ellagitannins found in pomegranate have altered the ulcerative colitis. It was suggested that the various parts of pomegranates and their rich ellagitannins (especially their primary components, punicalagin, and ellagic acid) can inhibit oxidant and inflammatory processes, regulate the intestinal barrier and flora, and provide an anti-ulcerative colitis resource through dietary management.

Characterizing the pre-clinical phase of inflammatory bowel disease

Understanding the biological changes that precede a diagnosis of inflammatory bowel disease (IBD) could facilitate pre-emptive interventions, including risk factor modification, but this pre-clinical phase of disease remains poorly characterized. Using measurements from 17 hematological and biochemical parameters taken up to 10 years before diagnosis in over 20,000 IBD patients and population controls, we address this at massive scale. We observe widespread significant changes in multiple biochemical and hematological parameters that occur up to 8 years before diagnosis of Crohn's disease (CD) and up to 3 years before diagnosis of ulcerative colitis. These changes far exceed previous expectations regarding the length of this pre-diagnostic phase, revealing an opportunity for earlier intervention, especially in CD. In summary, using a nationwide, case-control dataset-obtained from the Danish registers-we provide a comprehensive characterization of the hematological and biochemical changes that occur in the pre-clinical phase of IBD.

Mucosal Immunity to Gut Fungi in Health and Inflammatory Bowel Disease

The gut microbiome is a diverse microbial community composed of bacteria, viruses, and fungi that plays a major role in human health and disease. Dysregulation of these gut organisms in a genetically susceptible host is fundamental to the pathogenesis of inflammatory bowel disease (IBD). While bacterial dysbiosis has been a predominant focus of research for many years, there is growing recognition that fungal interactions with the host immune system are an important driver of gut inflammation. Candida albicans is likely the most studied fungus in the context of IBD, being a near universal gut commensal in humans and also a major barrier-invasive pathogen. There is emerging evidence that intra-strain variation in C. albicans virulence factors exerts a critical influence on IBD pathophysiology. In this review, we describe the immunological impacts of variations in C. lbicans colonisation, morphology, genetics, and proteomics in IBD, as well as the clinical and therapeutic implications.

Commensal fungi in intestinal health and disease

The microbiota is known to influence several facets of mammalian development, digestion and disease. Most studies of the microbiota have focused on the bacterial component, but the importance of commensal fungi in health and disease is becoming increasingly clear. Although fungi account for a smaller proportion of the microbiota than bacteria by number, they are much larger and therefore account for a substantial proportion of the biomass. Moreover, as fungi are eukaryotes, their metabolic pathways are complex and unique. In this Review, we discuss the evidence for involvement of specific members of the mycobiota in intestinal diseases, including inflammatory bowel disease, colorectal cancer and pancreatic cancer. We also highlight the importance of fungal interactions with intestinal bacteria and with the immune system. Although most studies of commensal fungi have focused on their role in disease, we also consider the beneficial effects of fungal colonies in the gut. The evidence highlights potential opportunities to target fungi and their interactions for therapeutic purposes.

Preclinical Serological Signatures are Associated With Complicated Crohn's Disease Phenotype at Diagnosis

BACKGROUND

At diagnosis, up to one-third of patients with Crohn's disease (CD) have a complicated phenotype with stricturing (B2) or penetrating (B3) behavior or require early surgery. We evaluated protein biomarkers and antimicrobial antibodies in serum archived years before CD diagnosis to assess whether complicated diagnoses were associated with a specific serological signature.

METHODS

Prediagnosis serum was obtained from 201 patients with CD and 201 healthy controls. Samples were evaluated with a comprehensive panel of 1129 proteomic markers (SomaLogic) and antimicrobial antibodies. CD diagnosis and complications were defined by the International Classification of Diseases-Ninth Revision and Current Procedural Terminology codes. Cox regression models were utilized to assess the association between markers and the subsequent risk of being diagnosed with complicated CD. In addition, biological pathway and network analyses were performed.

RESULTS

Forty-seven CD subjects (24%) had a B2 (n = 36) or B3 (n = 9) phenotype or CD-related surgery (n = 2) at diagnosis. Subjects presenting with complicated CD at diagnosis had higher levels of antimicrobial antibodies six years before diagnosis as compared with those diagnosed with noncomplicated CD. Twenty-two protein biomarkers (reflecting inflammatory, fibrosis, and tissue protection markers) were found to be associated with complicated CD. Pathway analysis of the altered protein biomarkers identified higher activation of the innate immune system and complement or coagulation cascades up to six years before diagnosis in complicated CD.

CONCLUSIONS

Proteins and antimicrobial antibodies associated with dysregulated innate immunity, excessive adaptive response to microbial antigens, and fibrosis precede and predict a complicated phenotype at the time of diagnosis in CD patients.

Biomarkers in IBD: What to Utilize for the Diagnosis?

The role of biomarkers in the diagnosis of inflammatory bowel disease is not fully characterized. C-reactive protein has a short half-life and elevates quickly after the onset of an inflammatory process; the performance is better in Crohn's disease than in ulcerative colitis. Erythrocyte sedimentation rate is easy to determine, widely available, and cheap, but the long half-life, the influence of age, anemia, smoking, and drugs limit its usefulness. Fecal markers have good specificity, but suboptimal accuracy. Microbial antibodies and novel immunological markers show promise but need further evidence before entering clinical practice. Proteomic methods could represent the dawn of a new era of stool protein/peptide biomarker panels able to select patients at risk of inflammatory bowel disease.

Ulcerative colitis

Ulcerative colitis is a lifelong inflammatory disease affecting the rectum and colon to a variable extent. In 2023, the prevalence of ulcerative colitis was estimated to be 5 million cases around the world, and the incidence is increasing worldwide. Ulcerative colitis is thought to occur in people with a genetic predisposition following environmental exposures; gut epithelial barrier defects, the microbiota, and a dysregulated immune response are strongly implicated. Patients usually present with bloody diarrhoea, and the diagnosis is based on a combination of clinical, biological, endoscopic, and histological findings. The aim of medical management is, first, to induce a rapid clinical response and normalise biomarkers and, second, to maintain clinical remission and reach endoscopic normalisation to prevent long-term disability. Treatments for inducing remission include 5-aminosalicylic acid drugs and corticosteroids. Maintenance treatments include 5-aminosalicylic acid drugs, thiopurines, biologics (eg, anti-cytokines and anti-integrins), and small molecules (Janus kinase inhibitors and sphingosine-1-phosphate receptor modulators). Although the therapeutic options are expanding, 10-20% of patients still require proctocolectomy for medically refractory disease. The keys to breaking through this therapeutic ceiling might be the combination of therapeutics with precision and personalised medicine.

Phage-display immunoprecipitation sequencing of the antibody epitope repertoire in inflammatory bowel disease reveals distinct antibody signatures

Inflammatory bowel diseases (IBDs), e.g., Crohn's disease (CD) and ulcerative colitis (UC), are chronic immune-mediated inflammatory diseases. A comprehensive overview of an IBD-specific antibody epitope repertoire is, however, lacking. Using high-throughput phage-display immunoprecipitation sequencing (PhIP-Seq), we identified antibodies against 344,000 antimicrobial, immune, and food antigens in 497 individuals with IBD compared with 1,326 controls. IBD was characterized by 373 differentially abundant antibody responses (202 overrepresented and 171 underrepresented), with 17% shared by both IBDs, 55% unique to CD, and 28% unique to UC. Antibody reactivities against bacterial flagellins dominated in CD and were associated with ileal involvement, fibrostenotic disease, and anti-Saccharomyces cerevisiae antibody positivity, but not with fecal microbiome composition. Antibody epitope repertoires accurately discriminated CD from controls (area under the curve [AUC] = 0.89), and similar discrimination was achieved when using only ten antibodies (AUC = 0.87). Individuals with IBD thus show a distinct antibody repertoire against selected peptides, allowing clinical stratification and discovery of immunological targets.

Immunoglobulins at the interface of the gut mycobiota and anti-fungal immunity

The dynamic and complex community of microbes that colonizes the intestines is composed of bacteria, fungi, and viruses. At the mucosal surfaces, immunoglobulins play a key role in protection against bacterial and fungal pathogens, and their toxins. Secretory immunoglobulin A (sIgA) is the most abundantly produced antibody at the mucosal surfaces, while Immunoglobulin G (IgG) isotypes play a critical role in systemic protection. IgA and IgG antibodies with reactivity to commensal fungi play an important role in shaping the mycobiota and host antifungal immunity. In this article, we review the latest evidence that establishes a connection between commensal fungi and B cell-mediated antifungal immunity as an additional layer of protection against fungal infections and inflammation.

Anti-Integrin αvβ6 Autoantibodies Are a Novel Biomarker That Antedate Ulcerative Colitis

BACKGROUND & AIMS

Better biomarkers for prediction of ulcerative colitis (UC) development and prognostication are needed. Anti-integrin αvβ6 (anti-αvβ6) autoantibodies have been described in patients with UC. We tested for the presence of anti-αvβ6 antibodies in the preclinical phase of UC and studied their association with disease-related outcomes after diagnosis.

METHODS

Anti-αvβ6 autoantibodies were measured in 4 longitudinal serum samples collected from 82 subjects who later developed UC and 82 matched controls from a Department of Defense preclinical cohort (PREDICTS [Proteomic Evaluation and Discovery in an IBD Cohort of Tri-service Subjects]). In a distinct, external validation cohort (Crohn's and Colitis Canada Genetic Environmental Microbial project cohort), we tested 12 pre-UC subjects and 49 matched controls. Furthermore, anti-αvβ6 autoantibodies were measured in 2 incident UC cohorts (COMPASS [Comprehensive Care for the Recently Diagnosed IBD Patients], n = 55 and OSCCAR [Ocean State Crohn's and Colitis Area Registry], n = 104) and associations between anti-αvβ6 autoantibodies and UC-related outcomes were defined using Cox proportional hazards model.

RESULTS

Anti-αvβ6 autoantibodies were significantly higher among individuals who developed UC compared with controls up to 10 years before diagnosis in PREDICTS. The anti-αvβ6 autoantibody seropositivity was 12.2% 10 years before diagnosis and increased to 52.4% at the time of diagnosis in subjects who developed UC compared with 2.7% in controls across the 4 time points. Anti-αvβ6 autoantibodies predicted UC development with an area under the curve of at least 0.8 up to 10 years before diagnosis. The presence of anti-αvβ6 autoantibodies in preclinical UC samples was validated in the GEM cohort. Finally, high anti-αvβ6 autoantibodies was associated with a composite of adverse UC outcomes, including hospitalization, disease extension, colectomy, systemic steroid use, and/or escalation to biologic therapy in recently diagnosed UC.

CONCLUSIONS

Anti-integrin αvβ6 autoantibodies precede the clinical diagnosis of UC by up to 10 years and are associated with adverse UC-related outcomes.

Trends in Biochemical Parameters, Healthcare Resource and Medication Use in the 5 Years Preceding IBD Diagnosis: A Health Maintenance Organization Cohort Study

BACKGROUND

Few data describing pre-diagnosis changes in patients with inflammatory bowel disease (IBD) exist. We aimed to determine if there is a pattern of change in use of health resources, medications and laboratory results in the years preceding diagnosis.

METHODS

This retrospective study used electronic medical records of Maccabi Health Services (MHS). Patients with IBD ≥ 16 years of age and minimum of 5-years follow-up were identified by entry into the MHS IBD registry and included in the analysis. Demographic, clinical, medication and laboratory data were collected. Generalized estimating equation model was applied to study trends and compare between years.

RESULTS

This study included 5643 patients with IBD. Of these, 3039 (53.8%) had Crohn's disease (CD), 2322 (41.1%) had ulcerative colitis (UC) and 282 (5%) had indeterminate colitis (IC). Laboratory parameters including white blood cells, platelets and C-reactive protein showed significant increases while haemoglobin and mean cell volume showed significant decreases in mean values in the 2 years prior to diagnosis with stable values prior to that (p < 0.0001). Parameters such as creatinine, total protein and albumin showed significant, progressive decreases in mean values starting 5 years prior to diagnosis (p < 0.0001). Patients with CD had distinct laboratory trends when compared with patients with UC.

CONCLUSIONS

Changes in laboratory parameters, healthcare service and medication use occur during the 5-year period before IBD diagnosis. These data can have future clinical applicability by developing a composite score and referral algorithm introducing red flags into primary care visits and appropriate referral for specialist care.

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.

Subclinical bowel inflammation increases healthcare resources utilization and steroid use before diagnosis of inflammatory bowel disease

BACKGROUND

Previous data support that the inflammatory process underlying ulcerative colitis (UC) and Crohn's disease (CD) can start years before the diagnosis. The aim of this study was to determine if patients with an incidental diagnosis of UC or CD demonstrate an increase in healthcare utilization in the years preceding the symptomatic onset of the disease.

METHODS

We performed a multicenter, retrospective, hospital-based, case-control study. Patients with an incidental diagnosis of UC or CD during the colorectal cancer screening program at 9 hospitals were included. Cases were matched 1:3 and compared separately with two control populations: one including healthy non-IBD subjects adjusted by gender, age, and date, excluding those with visits to Gastroenterology; and a second control cohort of UC/CD patients with symptomatic onset.

RESULTS

A total of 124 patients with preclinical inflammatory bowel disease (IBD) were included (87 UC, 30 CD, 7 IBD unclassified; median age 56 years). Patients with preclinical IBD showed an increase in the number of visits to Primary Care up to 3 and 5 years before diagnosis (aIRR 1.59, 95% CI [1.37-1.86], p = 0.001; aIRR 1.43, 95% CI [1.24-1.67], p = 0.01) and more frequent use of steroids (aOR 2.84, 95% CI [1.21-6.69], p = 0.03; aOR 2.25, 95% CI [1.06-4.79], p = 0.04) compared to matched non-IBD healthy controls, respectively. In contrast, patients with a symptomatic onset visited Primary Care less frequently, but they had an increase in the number of visits to Emergency Department, specialist care, sick-leaves, CT/ultrasound examinations, and use of antibiotics or systemic steroids.

CONCLUSIONS

There is an increased need for medical assistance and use of systemic steroids during the presymptomatic phase of IBD. These results will help in establishing new tools for early identification of IBD in the future.

Fecal fungal microbiota alterations associated with clinical phenotypes in Crohn's disease in southwest China

Although previous studies reported that gut fungal microbiota was associated with Crohn's disease (CD), only a few studies have focused on the correlation between gut fungi and clinical phenotypes of CD. Here, we aimed to analyze the association between intestinal fungi and the occurrence of CD, disease activity, biological behaviors, and perianal lesions. Stool samples from subjects meeting the inclusion and exclusion criteria were collected for running internal transcribed spacer 2 (ITS2) high-throughput sequencing. Then, correlation analysis was conducted between intestinal fungi and different clinical groups. There were 45 patients with CD and 17 healthy controls (HCs) enrolled. Results showed that two phyla, Rozellomycota and Mortierellomycota, were not present in patients with CD compared to HCs. At the same time, there was a higher abundance of fungal genera and species belonging to the phylum Ascomycota in patients with CD. SparCC network analysis showed fewer interactions among the fungal communities in patients with CD compared to HCs. Exophiala dermatitidis was positively associated with the clinical active stage and platelet count. The genus Candida was with significantly higher abundance in the non-B1 CD group based on the Montreal classification. Clonostachys, Humicola, and Lophiostoma were significantly enriched in patients with CD with perianal lesions. Our results demonstrated that the composition of the intestinal fungal microbiota in patients with CD and HCs was markedly different, some of which might play a pathogenic role in the occurrence of CD and perianal lesions. Exophiala dermatitidis and genus Candida might be associated with active disease stage and type non-B1 CD (CD with intestinal stenosis or penetrating lesions, or both), respectively.

The Development and Validation of Anti-paratuberculosis-nocardia Polypeptide Antibody [Anti-pTNP] for the Diagnosis of Crohn's Disease

BACKGROUND AND AIMS

Non-invasive biomarkers in sera of patients with inflammatory bowel disease [IBD] are not currently available for rapidly and accurately diagnosing the disease. We aimed to investigate and validate the potential roles of anti-paratuberculosis-nocardia polypeptide antibodies [anti-pTNP] in the diagnosis of IBD.

METHODS

Serum samples were collected from 502 patients with diagnosed Crohn's disease [CD], 141 patients with ulcerative colitis [UC], and 109 healthy donors. The levels of anti-pTNPs and anti-Saccharomyces cerevisiae antibodies [ASCAs] were determined by enzyme-linked immunosorbent assay. The effects of each variable on the diagnosis were analysed by receiver operating characteristic [ROC] analysis. We also performed an estimate study by first developing a clinical prediction model, with external validation in CD patients from nine IBD medical centres in China.

RESULTS

The levels of anti-pTNPs in sera of CD patients were higher than those in UC patients and healthy donors. The positive rates of anti-pTNPs were significantly higher in ileal CD patients than in ileocolonic and colonic CD patients, and the levels of anti-pTNP IgG in perianal patients were significantly higher than those in non-perianal CD patients. Of note, anti-pTNPs and perianal diseases were important predictors for active stage of CD patients. Discriminative ability to predict active CD patients was 0.918 (95% confidence interval [CI]:0.886-0.949).

CONCLUSIONS

Anti-pTNP functions as a novel biological marker for diagnosing CD and can be used to assess disease severity, particularly in those with lesion locations in the terminal ileum and stricturing and perianal diseases. A validated prediction model reveals that anti-pTNPs are useful for estimating the likelihood of active CD.

The Correlation between New Serological Markers and Disease Phenotype and Activation in Inflammatory Bowel Disease

Background: The aim of the study is to assess the correlation between a new antibody panel that is developed against glycans on Crohn's disease (CD) and ulcerative colitis (UC) differentiative diagnosis and disease properties. Methods: In the study, 137 CD and 122 UC patients and 90 controls were included. Anti-saccharomyces cerevisiae IgG (ASCA), anti-laminaribioside IgG (ALCA), anti-chitobioside IgA (ACCA), and anti-mannobioside IgG (AMCA) were tested in serum. Results: While at least 1 of the other 3 serological markers was positive in 89% of ASCA-positive patients, at least 1 of the other 3 serological markers was positive in 77% of ASCA-negative patients. Positivity ratio for a single anticarbohydrate was ALCA 18 (22%), ACCA 5 (12%), and AMCA 16 (23%). A significant correlation was found between ASCA positivity (P<0.001) in operated patients and between ASCA, ALCA, and ACCA positivity (P<0.05) in patients with stricturing and fistulizing CD. According to the ROC analysis, ASCA was found to have the highest area under the curve (0.70-0.82) (correlation coefficient interval 95%). A significant correlation was found between ASCA, ALCA, and ACCA positivity and high serum antibody levels and disease activation (P<0.05). Conclusion: ASCA, ALCA, and ACCA were found to be correlated with the disease complication and activation in CD. ASCA and ALCA were determined as the best markers in the differentiation between CD and UC.

Immunosurveillance of Candida albicans commensalism by the adaptive immune system

The fungal microbiota (mycobiota) is an integral part of the microbial community colonizing the body surfaces and is involved in many key aspects of human physiology, while an imbalance of the fungal communities, termed fungal dysbiosis, has been described in pathologies ranging from infections to inflammatory bowel disease. Commensal organisms, such as the fungus Candida albicans, induce antigen-specific immune responses that maintain immune homeostasis. Adaptive immune mechanisms are vital in this process, while deficiencies in adaptive immunity are linked to fungal infections. We start to understand the mechanisms by which a shift in mycobiota composition, in particular in C. albicans abundance, is linked to immunopathological conditions. This review discusses the mechanisms that ensure continuous immunosurveillance of C. albicans during mucosal colonization, how these protective adaptive immune responses can also promote immunopathology, and highlight therapeutic advances against C. albicans-associated disease.

Immune regulation by fungal strain diversity in inflammatory bowel disease

The fungal microbiota (mycobiota) is an integral part of the complex multikingdom microbial community colonizing the mammalian gastrointestinal tract and has an important role in immune regulation^1-6. Although aberrant changes in the mycobiota have been linked to several diseases, including inflammatory bowel disease^3-9, it is currently unknown whether fungal species captured by deep sequencing represent living organisms and whether specific fungi have functional consequences for disease development in affected individuals. Here we developed a translational platform for the functional analysis of the mycobiome at the fungal-strain- and patient-specific level. Combining high-resolution mycobiota sequencing, fungal culturomics and genomics, a CRISPR-Cas9-based fungal strain editing system, in vitro functional immunoreactivity assays and in vivo models, this platform enables the examination of host-fungal crosstalk in the human gut. We discovered a rich genetic diversity of opportunistic Candida albicans strains that dominate the colonic mucosa of patients with inflammatory bowel disease. Among these human-gut-derived isolates, strains with high immune-cell-damaging capacity (HD strains) reflect the disease features of individual patients with ulcerative colitis and aggravated intestinal inflammation in vivo through IL-1β-dependent mechanisms. Niche-specific inflammatory immunity and interleukin-17A-producing T helper cell (T_H17 cell) antifungal responses by HD strains in the gut were dependent on the C. albicans-secreted peptide toxin candidalysin during the transition from a benign commensal to a pathobiont state. These findings reveal the strain-specific nature of host-fungal interactions in the human gut and highlight new diagnostic and therapeutic targets for diseases of inflammatory origin.

Fungal microbiome in inflammatory bowel disease: a critical assessment

The gut microbiome is at the center of inflammatory bowel disease (IBD) pathogenesis and disease activity. While this has mainly been studied in the context of the bacterial microbiome, recent advances have provided tools for the study of host genetics and metagenomics of host-fungal interaction. Through these tools, strong evidence has emerged linking certain fungal taxa, such as Candida and Malassezia, with cellular and molecular pathways of IBD disease biology. Mouse models and human fecal microbial transplant also suggest that some disease-participatory bacteria and fungi may act not via the host directly, but via their fungal-bacterial ecologic interactions. We hope that these insights, and the study design and multi-omics strategies used to develop them, will facilitate the inclusion of the fungal community in basic and translational IBD research.

Detecting Autoantibodies by Multiparametric Assays: Impact on Prevention, Diagnosis, Monitoring, and Personalized Therapy in Autoimmune Diseases

BACKGROUND

The introduction of multiparametric autoantibody tests has been proposed to improve the accuracy of the immunological diagnosis of autoimmune diseases (AID) and to accelerate time for completing the diagnostic process. Multiplex tests are capable of detecting many autoantibodies in a single run whereas a traditional immunoassay uses a single antigen to detect only a single specificity of autoantibodies. The reasons why multiplex tests could replace conventional immunoassays lie in the evidence that they allow for more efficient handling of large numbers of samples by the laboratory, while ensuring greater diagnostic sensitivity in AID screening.

CONTENT

This review aims to highlight the important role that multiparametric tests could assume when designed for defined profiles they are used not only for diagnostic purposes but also to predict the onset of AID to identify clinical phenotypes and to define prognosis. Furthermore, differences in the antibody profile could identify which subjects will be responsive or not to a specific pharmacological treatment.

SUMMARY

The use of autoantibody profiles, when specifically requested and performed with clinically validated technologies, can represent a significant step toward personalized medicine in autoimmunology.

Food Habit Associated Mycobiota Composition and Their Impact on Human Health

Mycobiota is not only associated with healthy homeostasis in the human gut but also helps to adapt to the environment. Food habits, alcohol consumption, intake of probiotics, and contaminated food with a mycotoxin, often lead to the alteration in the mycobiota composition. Impaired immunity of the host may affect fungal symbiosis leading to mycosis. The human gut adapts to the commensalism fungi belonging to the phylum Ascomycota and Basidiomycota. Diet habits such as plant-or animal-based, phytoestrogens enriched plant products, fat-rich diets also influence the colonization of certain fungal species in the mammalian gut. Food habits or mycotoxin-contaminated food or fungal peptides have an impact on bacterial-fungal interaction and human health. The mycobiota population such as Fusarium, Humicola, Aspergillus, and Candida are altered due to alcohol intake in alcoholic liver disease. The role of associated gut mycobiota due to irregular bowel habits or lifestyle change has been observed in inflammatory bowel disease. In this review, it has been observed that Saccharomyces, Aspergillus, Fusarium, Cladosporium, Candida, and Malassezia were the common genus in the human mycobiota. Therefore, this study focused on how diet habits and alcohol intake, among others., influence mycobiota composition that may affect the human immune system or overall health.

Exploring the Early Phase of Crohn's Disease

The development of Crohn's disease (CD) is characterized by a breakdown of homeostatic immune-bacterial communication, which takes place at the intestinal mucosa when environmental triggers impact genetically predisposed individuals. Converging lines of evidence support the hypothesis that this pathogenetic model develops through sequential, although inter-related, steps that indicate failure of mucosal defense mechanisms at various stages. In this context, immunologic phenomena that mediate the initial appearance of inflammatory lesions across the intestinal tissue may differ substantially from those that mediate and perpetuate chronic inflammatory responses. A compromise in the integrity of the epithelial barrier is among the earliest events and leads to accelerated influx of intraluminal antigens and intact microorganisms within the immunologically rich lamina propria. Inadequate clearance of invading microorganisms also may occur as a result of defects in innate immunity, preventing the timely and complete resolution of acute inflammatory responses. The final step is the development of persistent adaptive responses, which also differ between early and late Crohn's disease. Current progress in our ability to delineate single-cell transcriptomics and proteomics has allowed the discovery of cellular and molecular mechanisms that participate in each sequential step of CD development. This not only will advance our understanding of CD pathogenesis, but also facilitate the design of targeted therapeutic approaches.

Mycobiota-induced IgA antibodies regulate fungal commensalism in the gut and are dysregulated in Crohn's disease

Secretory immunoglobulin A (sIgA) plays an important role in gut barrier protection by shaping the resident microbiota community, restricting the growth of bacterial pathogens and enhancing host protective immunity via immunological exclusion. Here, we found that a portion of the microbiota-driven sIgA response is induced by and directed towards intestinal fungi. Analysis of the human gut mycobiota bound by sIgA revealed a preference for hyphae, a fungal morphotype associated with virulence. Candida albicans was a potent inducer of IgA class-switch recombination among plasma cells, via an interaction dependent on intestinal phagocytes and hyphal programming. Characterization of sIgA affinity and polyreactivity showed that hyphae-associated virulence factors were bound by these antibodies and that sIgA influenced C. albicans morphotypes in the murine gut. Furthermore, an increase in granular hyphal morphologies in patients with Crohn's disease compared with healthy controls correlated with a decrease in antifungal sIgA antibody titre with affinity to two hyphae-associated virulence factors. Thus, in addition to its importance in gut bacterial regulation, sIgA targets the uniquely fungal phenomenon of hyphal formation. Our findings indicate that antifungal sIgA produced in the gut can play a role in regulating intestinal fungal commensalism by coating fungal morphotypes linked to virulence, thereby providing a protective mechanism that might be dysregulated in patients with Crohn's disease.

Systemic Inflammation in Preclinical Ulcerative Colitis

BACKGROUND & AIMS

Preclinical ulcerative colitis is poorly defined. We aimed to characterize the preclinical systemic inflammation in ulcerative colitis, using a comprehensive set of proteins.

METHODS

We obtained plasma samples biobanked from individuals who developed ulcerative colitis later in life (n = 72) and matched healthy controls (n = 140) within a population-based screening cohort. We measured 92 proteins related to inflammation using a proximity extension assay. The biologic relevance of these findings was validated in an inception cohort of patients with ulcerative colitis (n = 101) and healthy controls (n = 50). To examine the influence of genetic and environmental factors on these markers, a cohort of healthy twin siblings of patients with ulcerative colitis (n = 41) and matched healthy controls (n = 37) were explored.

RESULTS

Six proteins (MMP10, CXCL9, CCL11, SLAMF1, CXCL11 and MCP-1) were up-regulated (P < .05) in preclinical ulcerative colitis compared with controls based on both univariate and multivariable models. Ingenuity Pathway Analyses identified several potential key regulators, including interleukin-1β, tumor necrosis factor, interferon-gamma, oncostatin M, nuclear factor-κB, interleukin-6, and interleukin-4. For validation, we built a multivariable model to predict disease in the inception cohort. The model discriminated treatment-naïve patients with ulcerative colitis from controls with leave-one-out cross-validation (area under the curve = 0.92). Consistently, MMP10, CXCL9, CXCL11, and MCP-1, but not CCL11 and SLAMF1, were significantly up-regulated among the healthy twin siblings, even though their relative abundances seemed higher in incident ulcerative colitis.

CONCLUSIONS

A set of inflammatory proteins are up-regulated several years before a diagnosis of ulcerative colitis. These proteins were highly predictive of an ulcerative colitis diagnosis, and some seemed to be up-regulated already at exposure to genetic and environmental risk factors.

Anti-Microbial Antibody Response is Associated With Future Onset of Crohn's Disease Independent of Biomarkers of Altered Gut Barrier Function, Subclinical Inflammation, and Genetic Risk

BACKGROUND AND AIMS

Altered host immune reactivity to microbial antigens is hypothesized to trigger the onset of Crohn's disease (CD). We aimed to assess whether increased serum anti-microbial antibody response in asymptomatic first-degree relatives (FDRs) of CD patients is an independent risk factor for future CD development.

METHODS

We measured host serum antibody response to 6 microbial antigens at enrollment (Prometheus enzyme-linked immunosorbent assay test: anti-Saccharomyces cerevisiae antibodies immunoglobulin A/immunoglobulin G, anti-OmpC, anti-A4-Fla2, anti-FlaX, anti-CBir1) and derived the sum of positive antibodies (AS). We used samples at enrollment of prospectively followed healthy FDRs from a nested case-control cohort of the Crohn's and Colitis Canada Genetics Environment Microbial Project. Those who later developed CD (n = 77) were matched 1:4 by age, sex, follow-up duration, and geographic location with control FDRs remaining healthy (n = 307). To address our research aims, we fitted a multivariable conditional logistic regression model and performed causal mediation analysis.

RESULTS

High baseline AS (≥2) (43% of cases, 11% of controls) was associated with higher risk of developing CD (adjusted odds ratio, 6.5; 95% confidence interval, 3.4-12.7; P < .001). Importantly, this association remained significant when adjusted for markers of gut barrier function, fecal calprotectin, C-reactive protein, and CD-polygenic risk score, and in subjects recruited more than 3 years before diagnosis. Causal mediation analysis showed that the effect of high AS on future CD development is partially mediated (42%) via preclinical gut inflammation.

CONCLUSIONS

Our results suggest that increased anti-microbial antibody responses are associated with risk of future development of CD, independent of biomarkers of abnormal gut barrier function, subclinical inflammation, and CD-related genetic risks. This suggests that anti-microbial antibody responses are an early predisease event in the development of CD.

Occurrence of Colorectal Cancer and the Influence of Medical Treatment in Patients With Inflammatory Bowel Disease: A Danish Nationwide Cohort Study, 1997 to 2015

BACKGROUND

The risk of colorectal cancer (CRC) for patients with inflammatory bowel disease (IBD) has previously been investigated with conflicting results. We aimed to investigate the incidence and risk of CRC in IBD, focusing on its modification by treatment.

METHODS

All patients with incident IBD (n = 35,908) recorded in the Danish National Patient Register between 1997 and 2015 (ulcerative colitis: n = 24,102; Crohn's disease: n = 9739; IBD unclassified: n = 2067) were matched to approximately 50 reference individuals (n = 1,688,877). CRC occurring after the index date was captured from the Danish Cancer Registry. Exposure to medical treatment was divided into categories including none, systemic 5-aminosalicylates, immunomodulators, and biologic treatment. The association between IBD and subsequent CRC was investigated by Cox regression and Kaplan-Meier estimates.

RESULTS

Of the IBD patients, 330 were diagnosed with CRC, resulting in a hazard ratio (HR) of 1.15 (95% confidence interval [CI], 1.03-1.28) as compared with the reference individuals. However, when excluding patients diagnosed with CRC within 6 months of their IBD diagnosis, the HR decreased to 0.80 (95% CI, 0.71-0.92). Patients with ulcerative colitis receiving any medical treatment were at significantly higher risk of developing CRC than patients with ulcerative colitis who were not given medical treatment (HR, 1.35; 95% CI, 1.01-1.81), whereas a similar effect of medical treatment was not observed in patients with Crohn's disease or IBD unclassified.

CONCLUSIONS

Medical treatment does not appear to affect the risk of CRC in patients with IBD. The overall risk of developing CRC is significantly increased in patients with IBD as compared with the general population. However, when excluding patients diagnosed with CRC within 6 months of their IBD diagnosis, the elevated risk disappears.

Preclinical Markers in Inflammatory Bowel Disease. A Nested Case-Control Study

Background

Our objective was to determine if patients who later develop inflammatory bowel disease (IBD) show signs of increased inflammatory activity in plasma measured with high sensitivity C-reactive protein (CRP), calprotectin, and albumin before the clinical onset of IBD.

Methods

We identified 96 subjects who later developed IBD (70 ulcerative colitis [UC] and 26 Crohn's disease [CD]). High sensitivity CRP, calprotectin, and albumin were analyzed in frozen plasma, donated from cases and sex-age matched controls 1-15 years before diagnosis.

Results

We found that subjects who later developed UC had lower albumin levels, and subjects who later developed CD had higher CRP levels than controls. Multivariable conditional logistic regression with albumin, calprotectin, and CRP showed a lower risk for developing IBD and UC with higher albumin levels (odds ratio [OR] 0.79, confidence interval [CI] 0.69-0.90; respective OR 0.77, CI 0.66-0.91). Higher CRP levels were associated with an increased risk of developing CD (OR 1.314, CI 1.060-1.630). When adjusting for body mass index or smoking in the logistic regression model, similar results were found. Plasma calprotectin levels in the preclinical period among patients with IBD did not differ from controls.

Conclusions

In this nested case-control study, subjects who later developed IBD had signs of low-grade systemic inflammation, indicated by significantly higher CRP plasma levels in CD and lower albumin plasma levels in UC, before the onset of clinical disease.

Results of the Seventh Scientific Workshop of ECCO: Precision Medicine in IBD-Prediction and Prevention of Inflammatory Bowel Disease

Inflammatory bowel disease [IBD] is a complex chronic disorder with no clear aetiology and no known cure. Despite recent advances in overall disease management and improved therapeutics, patients with IBD still experience a substantial burden. Furthermore, as the incidence continues to increase in developing areas of the world, it is expected that the burden of IBD to society will increase and exert tremendous pressure on health care systems worldwide. Therefore, new strategies to prevent the global increase of IBD are urgently required. Data are being progressively acquired on the period preceding disease diagnosis, which support the concept that IBD has a preclinical period that may reveal the triggers of disease and may be amenable to early intervention. Having a better knowledge of this preclinical period will increase the potential not only for improved understanding of disease pathogenesis and improved therapeutics, but also for disease prediction and prevention.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A Pilot Clinical Study on Post-Operative Recurrence Provides Biological Clues for a Role of Candida Yeasts and Fluconazole in Crohn's Disease

Background and aims: This study prompted by growing evidence of the relationship between the yeast Candida albicans and Crohn’s disease (CD) was intended to assess the effect of a 6-month course of the antifungal fluconazole (FCZ) on post-operative recurrence of CD. Methods: Mycological samples (mouth swabs and stools) and serum samples were collected from 28 CD patients randomized to receive either FCZ (n = 14) or placebo (n = 14) before surgical resection. Serological analysis focused on levels of calprotectin, anti-glycan antibodies, and antibody markers of C. albicans pathogenic transition. Levels of galectin-3 and mannose binding lectin (MBL) involved in C. albicans sensing and inflammation were also measured. Results: 1, 2, 3, and 6 months after surgery, endoscopy revealed recurrence in 5/12 (41.7%) patients in the FCZ group and 5/9 (55.6%) in the placebo group, the small cohort preventing any clinical conclusions. In both groups, surgery was followed by a marked decrease in C. albicans colonization and biomarkers of C. albicans pathogenic transition decreased to non-significant levels. Anti-glycan antibodies also decreased but remained significant for CD. Galectin-3 and calprotectin also decreased. Conversely, MBL levels, which inversely correlated with anti-C. albicans antibodies before surgery, remained stable. Building biostatistical multivariate models to analyze he changes in antibody and lectin levels revealed a significant relationship between C. albicans and CD. Conclusion: Several combinations of biomarkers of adaptive and innate immunity targeting C. albicans were predictive of CD recurrence after surgery, with area under the curves (AUCs) as high as 0.86. FCZ had a positive effect on biomarkers evolution. ClinicalTrials.gov ID: NCT02997059, 19 December 2016. University Hospital Lille, Ministry of Health, France. Effect of Fluconazole on the Levels of Anti-Saccharomyces cerevisiae Antibodies (ASCA) After Surgical Resection for Crohn’s Disease. Multicenter, Randomized, and Controlled in Two Parallel Groups Versus Placebo.

Clinical value of antibodies in inflammatory bowel diseases

Inflammatory bowel disease IBD (Crohns disease CD, ulcerative colitis UC) immune-mediated diseases of the digestive tract of unknown etiology. The basis of the pathogenesis of IBD is a violation of the protective mechanisms of the intestinal barrier as a result of a complex interaction of environmental factors, a genetic predisposition and defects in the activation of the immune response in the lymphoid tissue of the intestinal mucosa. Three groups of antibodies are detected in the sera of IBD patients: autoantibodies, antimicrobial antibodies and antibodies to peptide antigens. In CD, the most useful diagnostic markers are ASCA; in UC patients pANCA. Antibodies are not among the diagnostic criteria for CD and UC, the diagnosis of which is traditionally made on the basis of a complex of clinical, radiological, endoscopic and histological signs, but can be used as useful additional non-invasive markers for early diagnosis, assessment of clinical phenotypes, prognosis and effectiveness of treatment of these diseases.

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.

Early microscopic findings in preclinical inflammatory bowel disease

BACKGROUND

The immune response involved in the pathogenesis of Inflammatory Bowel Disease (IBD) may be present years before the diagnosis, but the characteristics of the disease during the preclinical period have been scarcely investigated.

AIM

To describe the microscopic findings of preclinical IBD and its relationship with the natural history of the disease.

METHODS

Medical records from all patients with an incidental diagnosis of IBD during a screening colonoscopy were included in this multicentric and retrospective study. We assessed 15 histologic items in the biopsy samples at diagnosis, and the Geboes score was calculated in patients with Ulcerative Colitis (UC). The main outcome was the development of gastrointestinal symptoms during follow-up.

RESULTS

We included 110 patients (79 UC, 24 Crohn's Disease (CD) and 7 with unclassified disease). In UC the most common histologic findings were acute or chronic inflammatory infiltrate and crypt epithelial polymorphs, while in CD we observed acute or chronic neutrophilic infiltrate and epithelial irregularity. Granuloma were only observed in 4% of CD patients. Crypt distortion and the infiltration of neutrophils in the epithelium were associated with a higher risk of developing symptomatic disease.

CONCLUSIONS

Preclinical IBD shows specific microscopic findings and they are associated with the progression to symptomatic disease.

Increased Intestinal Permeability Is Associated With Later Development of Crohn's Disease

BACKGROUND & AIMS

Increased intestinal permeability has been associated with Crohn's disease (CD), but it is not clear whether it is a cause or result of the disease. We performed a prospective study to determine whether increased intestinal permeability is associated with future development of CD.

METHODS

We assessed the intestinal permeability, measured by the urinary fractional excretion of lactulose-to-mannitol ratio (LMR) at recruitment in 1420 asymptomatic first-degree relatives (6-35 years old) of patients with CD (collected from 2008 through 2015). Participants were then followed up for a diagnosis of CD from 2008 to 2017, with a median follow-up time of 7.8 years. We analyzed data from 50 participants who developed CD after a median of 2.7 years during the study period, along with 1370 individuals who remained asymptomatic until October 2017. We used the Cox proportional hazards model to evaluate time-related risk of CD based on the baseline LMR.

RESULTS

An abnormal LMR (>0.03) was associated with a diagnosis of CD during the follow-up period (hazard ratio, 3.03; 95% CI, 1.64-5.63; P = 3.97 × 10^-4). This association remained significant even when the test was performed more than 3 years before the diagnosis of CD (hazard ratio, 1.62; 95% CI, 1.051-2.50; P = .029).

CONCLUSIONS

Increased intestinal permeability is associated with later development of CD; these findings support a model in which altered intestinal barrier function contributes to pathogenesis. Abnormal gut barrier function might serve as a biomarker for risk of CD onset.

Preclinical disease and preventive strategies in IBD

There is growing evidence that inflammatory bowel disease has a preclinical phase that precedes disease symptoms, during which immune system activation has already occurred and inflammatory pathways have been primed, setting the stage for disease to expand and leading up to clinical diagnosis. Gaining insight to this pre-diagnosis period could improve our knowledge about disease pathogenesis and potentially result in the detection of biomarkers that could predict disease development. The ultimate goal of such research is to identify a population at risk for developing IBD, so preventive strategies could be implemented and disease prevention be achieved.

Growth and Puberty in Children with Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) are gastrointestinal tract pathologies of unknown etiology; they have an alternating trend, with active and silent phases. IBD are classified in two main forms: ulcerative colitis (UC) and Crohn’s disease (CD). Both have chronic and recurrent course, gastrointestinal symptoms, and extraintestinal manifestations. The altered immune response role seems to be important both in UC and CD. In the majority of cases, CD begins with abdominal pain, diarrhea, decrease in appetite, and weight loss; there can be also perianal fistulas, rhagades, and perianal recurrent abscesses. In addition, retarded growth and delayed puberty can precede the development of the disease or can even be predominant at onset. Growth retardation is found in 40% of IBD patients, but the underlying mechanism of this and other extra-intestinal manifestations are partially known: the main hypotheses are represented by malnutrition and inflammatory response during the active phase of the disease. The increased level of pro-inflammatory cytokines can influence growth, but also the onset of puberty and its progression. In addition, it could be essential to clarify the role and the possible effects of all the currently used treatments concerning growth failure and delayed puberty.

The Gut Microbial Profile of Preclinical Crohn's Disease Is Similar to That of Healthy Controls

BACKGROUND AND AIMS

It is unclear whether microbial dysbiosis plays an etiologic role in Crohn's disease (CD) or is the result of protracted inflammation. Here, we test the hypothesis that dysbiosis predates clinical CD in asymptomatic first-degree relatives (FDRs) of CD patients: normal (FDR1), with borderline inflammation (FDR2), and with frank, very early inflammation (FDR3).

METHODS

The gut microbial diversity was tested in ileocecal biopsies through next generation sequencing of the 16S rRNA gene in 10 healthy controls (HCs), 22 patients with active, untreated CD, and 25 FDRs (9 FDR1; 12 FDR2; 4 FDR3). The metagenomic functions of 41 microbiome-related processes were inferred by Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis.

RESULTS

Compared with HCs, alpha diversity in CD patients was decreased, with an observed decrease in Faecalibacterium prausnitzii and increase in Bacteroides fragilis. In FDRs, microbial diversity was unchanged compared with HCs. In Operational Taxonomic Units and PICRUSt Principal coordinates and component analyses, the ellipse centroid of FDRs was diagonally opposed to that of CD patients, but close to the HC centroid. In both analyses, statistically significant differences in terms of beta diversity were found between CD and HC but not between FDR and HC.

CONCLUSIONS

In FDRs (including FDR3-who bear preclinical/biologic onset disease), we found that the microbial profile is remarkably similar to HC. If confirmed in larger studies, this finding suggests that clinical CD-associated dysbiosis could result from the changed microenvironment due to disease evolution over time.

Meta-analysis of anti-Saccharomyces cerevisiae antibodies as diagnostic markers of Behçet's disease with gastrointestinal involvement

OBJECTIVE

Due to common exposure to yeast in the alcoholic and baking industry, positive rate of anti-Saccharomyces cerevisiae antibodies (ASCA) is reportedly high in patients with Behçet's disease (BD) who have gastrointestinal symptoms (gastrointestinal BD (GIBD)). We performed a meta-analysis to assess the diagnostic value of ASCA in differentiating patients with BD from those with other chronic inflammatory bowel diseases.

METHODS

The meta-analysis is presented with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Meta-analysis of Observational Studies in Epidemiology checklist. Relevant studies that investigated ASCA levels in patients with BD were retrieved from PubMed, EMBASE, Web of Science, SCOPUS and the Cochrane Library on 12 July 2019; the search was rerun on 12 February 2020. Stata/SE V.12.0 and Meta-DiSc V.1.4 were used to perform the meta-analysis and sensitivity analysis, disaggregated by isotypes of ASCA.

RESULTS

Nine studies were included in the meta-analysis. The results revealed a strong association between ASCA and GIBD, especially ASCA-IgG (OR=5.50 (95% CI 2.58 to 11.55), p=0.000) and ASCA-IgG+IgA (OR=5.36 (95% CI 1.40 to 20.45), p=0.014). The positivity rate of ASCA in GIBD was significantly higher than that in ulcerative colitis (UC): IgA (OR=2.13 (95% CI 1.30 to 3.50), p=0.003); IgG+IgA (OR=2.19 (95% CI 1.03 to 4.66), p=0.042); IgG/IgA ((=2.03 (95% CI 1.30 to 3.17), p=0.002). However, the frequency of ASCA-IgG was significantly higher in patients with Crohn's disease than GIBD (OR=0.48 (95% CI 0.28 to 0.83), p=0.009). There was no significant difference in ASCA positivity between BD without gastrointestinal involvement and healthy controls and between GIBD and intestinal tuberculosis (iTB) (p>0.05).

CONCLUSION

ASCA may play a role in the pathogenesis of gastrointestinal involvement. Negative result of IgG favours the diagnosis of GIBD/BD when differentiated from Crohn's disease. ASCA-IgA showed moderate diagnostic performance in distinguishing GIBD and UC and the diagnostic performance was better in combination with IgG. However, ASCA may not be a useful serologic marker distinguishing GIBD and iTB.

PROSPERO REGISTRATION NUMBER

CRD42020115245.

Diagnosis and natural history of preclinical and early inflammatory bowel disease

Inflammatory bowel disease is a chronic and progressive disorder of the gastrointestinal tract. A relevant proportion of patients develop complicated lesions, defined as strictures, fistulas and/or abscesses already at diagnosis, and this proportion increases over time. The preclinical phase defines the period of time from the appearance of the first immune disturbances until the development of overt disease, and it may be present months to years before the diagnosis. Multiple biomarkers (e.g., C-reactive protein, interleukin-6, fecal calprotectin) and cellular mechanisms (e.g., complement cascade, lysosomes, innate immunity, and glycosaminoglycan metabolism) are already altered during this period. Research in this area allows the description of the initial immune disturbances that may identify potential targets and lead to the development of new drug therapies. During this period, different interventions in high-risk individuals, including drugs or environmental factors, will open the possibility of innovative strategies focused on the reduction of complications, or even prevention trials for inflammatory bowel disease. Here, we review the most relevant findings regarding the characteristics, prevalence and biomarkers associated with preclinical disease, along with their possible use in our future clinical practice.

Serum Biomarkers Identify Patients Who Will Develop Inflammatory Bowel Diseases Up to 5 Years Before Diagnosis

BACKGROUND & AIMS

Biomarkers are needed to identify patients at risk for development of inflammatory bowel diseases. We aimed to identify serum biomarkers of Crohn's disease and ulcerative colitis that can be detected and quantified before diagnosis.

METHODS

We obtained serum samples from patients archived before a diagnosis of Crohn's disease (n = 200) or ulcerative colitis (n = 199), as well as from 200 healthy individuals (controls), collected from 1998 through 2013 as part of the US Defense Medical Surveillance System. We measured levels of antibodies against microbes (anti-Saccharomyces cerevisiae IgA or IgG, anti-Escherichiacoli outer membrane porin C, anti-CBir1, anti-flagellin 2, anti-flagellin X, and perinuclear anti-neutrophil cytoplasmic antibodies) and 1129 proteins in each sample. We then used functional principal component analysis to derive the time-varying trajectory for each marker, which then was used in a multivariate model to predict disease status. Predictive performances at different prediagnosis timepoints were evaluated using area under the receiver operating characteristic curves (AUROCs). Biological pathways that were up-regulated in serum from patients with Crohn's disease were identified based on changes in protein abundance at different time periods preceding diagnosis.

RESULTS

We identified a panel of 51 protein biomarkers that were predictive of Crohn's disease within 5 years with an AUROC of 0.76 and a diagnosis within 1 year with an AUROC of 0.87. Based on the proteins included in the panel, imminent development of CD was associated with changes in the complement cascade, lysosomes, innate immune response, and glycosaminoglycan metabolism. Serum antibodies and proteins identified patients who received a diagnosis of ulcerative colitis within 5 years with an AUROC of only 0.56 and within 1 year with an AUROC of 0.72.

CONCLUSIONS

We identified a panel of serum antibodies and proteins that were predictive of patients who will receive a diagnosis of Crohn's disease within 5 years with high accuracy. By contrast we did not identify biomarkers associated with future diagnosis of ulcerative colitis.

New-Onset of Crohn's Disease Is Associated with Antistreptolysin O Positive Titers

Objective

Different infectious agents have been presumed to be candidates acting as an etiologic factor or trigger of Crohn’s disease (CD). Group A Streptococcus (GAS) is a common human infection agent that can also trigger post-infectious immune-mediated conditions. The current study aimed to examine whether the immunogenic activity induced by GAS may trigger new-onset of CD.

Methods

Data for antistreptolysin O (ASO) level, throat culture for GAS, and history of streptococcal infection were collected from 91 patients with CD that were divided into three groups including; new-onset CD, CD in remission and active CD. The data were compared with the control group.

Results

All participants had negative results of throat culture for GAS and had no history of documented streptococcal infection in the past year. Our results indicate that new-onset CD, but not CD in remission or active CD, is associated with significantly increased positive ASO compared to controls. Half of the patients in the new-onset CD group were ASO positive, which was significantly higher compared to the control group in a univariant (OR: 4.00; 95% CI 1.27–12.58; P=0.02) and multivariant analysis (OR: 4.41; 95% CI 1.35–14.37; P=0.014).

Conclusion

Our study is the first to focus on ASO levels in patients with CD and to demonstrate a significant association between ASO and new-onset of CD. Large prospective randomized controlled studies are needed to confirm the validity of this data and to further clarify the clinical significance of our findings.

Gut Microbiota beyond Bacteria-Mycobiome, Virome, Archaeome, and Eukaryotic Parasites in IBD

The human microbiota is a diverse microbial ecosystem associated with many beneficial physiological functions as well as numerous disease etiologies. Dominated by bacteria, the microbiota also includes commensal populations of fungi, viruses, archaea, and protists. Unlike bacterial microbiota, which was extensively studied in the past two decades, these non-bacterial microorganisms, their functional roles, and their interaction with one another or with host immune system have not been as widely explored. This review covers the recent findings on the non-bacterial communities of the human gastrointestinal microbiota and their involvement in health and disease, with particular focus on the pathophysiology of inflammatory bowel disease.

Fungal Dysbiosis and Intestinal Inflammation in Children With Beta-Cell Autoimmunity

Although gut bacterial dysbiosis is recognized as a regulator of beta-cell autoimmunity, no data is available on fungal dysbiosis in the children at the risk of type 1 diabetes (T1D). We hypothesized that the co-occurrence of fungal and bacterial dysbiosis contributes to the intestinal inflammation and autoimmune destruction of insulin-producing beta-cells in T1D. Fecal and blood samples were collected from 26 children tested positive for at least one diabetes-associated autoantibody (IAA, GADA, IA-2A or ICA) and matched autoantibody-negative children with HLA-conferred susceptibility to T1D (matched for HLA-DQB1 haplotype, age, gender and early childhood nutrition). Bacterial 16S and fungal ITS2 sequencing, and analyses of the markers of intestinal inflammation, namely fecal human beta-defensin-2 (HBD2), calprotectin and secretory total IgA, were performed. Anti-Saccharomyces cerevisiae antibodies (ASCA) and circulating cytokines, IFNG, IL-17 and IL-22, were studied. After these analyses, the children were followed for development of clinical T1D (median 8 years and 8 months). Nine autoantibody positive children were diagnosed with T1D, whereas none of the autoantibody negative children developed T1D during the follow-up. Fungal dysbiosis, characterized by high abundance of fecal Saccharomyces and Candida, was found in the progressors, i.e., children with beta-cell autoimmunity who during the follow-up progressed to clinical T1D. These children showed also bacterial dysbiosis, i.e., increased Bacteroidales and Clostridiales ratio, which was, however, found also in the non-progressors, and is thus a common nominator in the children with beta-cell autoimmunity. Furthermore, the progressors showed markers of intestinal inflammation detected as increased levels of fecal HBD2 and ASCA IgG to fungal antigens. We conclude that the fungal and bacterial dysbiosis, and intestinal inflammation are associated with the development of T1D in children with beta-cell autoimmunity.