The effect of dietary yeast on the activity of stable chronic Crohn's disease

The yeast-human coevolution: Fungal transition from passengers, colonizers, and invaders

Fungi are the cause of more than a billion infections in humans every year, although their interactions with the host are still neglected compared to bacteria. Major systemic fungal infections are very unusual in the healthy population, due to the long history of coevolution with the human host. Humans are routinely exposed to environmental fungi and can host a commensal mycobiota, which is increasingly considered as a key player in health and disease. Here, we review the current knowledge on host-fungi coevolution and the factors that regulate their interaction. On one hand, fungi have learned to survive and inhabit the host organisms as a natural ecosystem, on the other hand, the host immune system finely tunes the response toward fungi. In turn, recognition of fungi as commensals or pathogens regulates the host immune balance in health and disease. In the human gut ecosystem, yeasts provide a fingerprint of the transient microbiota. Their status as passengers or colonizers is related to the integrity of the gut barrier and the risk of multiple disorders. Thus, the study of this less known component of the microbiota could unravel the rules of the transition from passengers to colonizers and invaders, as well as their dependence on the innate component of the host's immune response. This article is categorized under: Infectious Diseases > Environmental Factors Immune System Diseases > Environmental Factors Infectious Diseases > Molecular and Cellular Physiology.

Dietary triggers of gut inflammation following exclusive enteral nutrition in children with Crohn's disease: a pilot study

Background

The anti-inflammatory effect of exclusive enteral nutrition on the gut of children with Crohn’s disease is rapidly lost after food reintroduction. This study assessed disease dietary triggers following successful treatment with exclusive enteral nutrition.

Methods

Nutrient intake, dietary patterns and dietary biomarkers in faeces (gluten immunogenic peptides, undigestible starch, short chain fatty acids) were assessed in 14 children with Crohn’s disease during early food reintroduction, following exclusive enteral nutrition. Groups above (Group A) and below (Group B) the median levels of faecal calprotectin after food reintroduction were assigned for comparative analysis.

Results

Intakes of fibre, gluten-containing cereals and red and processed meat were significantly higher in Group A than Group B; (median [Q1, Q3], g/day; Fibre: 12.1 [11.2, 19.9] vs. 9.9 [7.6, 12.1], p = 0.03; Red and processed meat: 151 [66.7, 190] vs. 63.3 [21.7, 67], p = 0.02; gluten-containing cereals: 289 [207, 402] vs. 203 [61, 232], p = 0.035). A diet consisting of cereals and meat products was predictive (92% accuracy) of higher faecal calprotectin levels after food reintroduction. In faeces, butyrate levels, expressed as absolute concentration and relative abundance, were higher in Group A than Group B by 28.4 µmol/g (p = 0.015) and 6.4% (p = 0.008), respectively. Levels of gluten immunogenic peptide and starch in faeces did not differ between the two groups.

Conclusions

This pilot study identified potential dietary triggers of gut inflammation in children with Crohn’s disease after food reintroduction following treatment with exclusive enteral nutrition.

Trial registration: Clinical trials.gov registration number: NCT02341248; Clinical trials.gov URL: https://clinicaltrials.gov/ct2/show/NCT02341248 (retrospectively registered).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-02029-4.

Saccharomyces cerevisiae Yeast-Based Supplementation as a Galactagogue in Breastfeeding Women? A Review of Evidence from Animal and Human Studies

Perceived insufficient milk production (PIM) adversely affects breastfeeding duration. Women sometimes use galactagogues with the intent to increase breast milk production and support lactation. Saccharomyces cerevisiae yeast-based supplement (SCYS) is an inactive form of Saccharomyces cerevisiae yeast (SCY) either obtained from the fermentation process or grown on molasses. Anecdotal evidence suggests SCYS is a galactagogue. SCYS is promoted on the internet as a galactagogue in various forms and doses. Dietary supplementation with SCYS during gestation and lactation significantly increases milk yield in ruminants. No human study has evaluated efficacy of SCYS as a galactagogue. SCYS is rich in B vitamins, beta-glucan, mannan oligosaccharides and bioavailable chromium; these may impact breast milk production or composition, thus may alleviate PIM. The safety of taking SCYS during lactation is not well studied. Studies have reported contamination of SCYS with ochratoxin A (OTA) as well as minor side effects from SCYS. Studies are needed to evaluate the efficacy of SCYS on breast milk production and composition and to assess the safety of taking SCYS during lactation in humans.

Dietary Strategies for Maintenance of Clinical Remission in Inflammatory Bowel Diseases: Are We There Yet?

The etiopathogenesis of Inflammatory bowel disease (IBD) is a result of a complex interaction between host immune response, the gut microbiome and environmental factors, such as diet. Although scientific advances, with the use of biological medications, have revolutionized IBD treatment, the challenge for maintaining clinical remission and delaying clinical relapse is still present. As exclusive enteral nutrition has become a well-established treatment for the induction of remission in pediatric Crohn's disease, the scientific interest regarding diet in IBD is now focused on the development of follow-on dietary strategies, which aim to suppress colonic inflammation and delay a disease flare. The objective of this review is to present an extensive overview of the dietary strategies, which have been used in the literature to maintain clinical remission in both Crohn's disease and Ulcerative colitis, and the evidence surrounding the association of dietary components with clinical relapse. We also aim to provide study-related recommendations to be encompassed in future research studies aiming to investigate the role of diet during remission periods in IBD.

Fungal interactions with the human host: exploring the spectrum of symbiosis

Fungi are ubiquitous transient or persistent human colonisers, and form the mycobiome with shifts in niche specific mycobiomes (dysbiosis) being associated with various diseases. These complex interactions of fungal species with the human host can be viewed as a spectrum of symbiotic relationships (i.e. commensal, parasitic, mutualistic, amensalistic). The host relevant outcome of the relationship is the damage to benefit ratio, elegantly described in the damage response framework. This review focuses on Candida albicans, which is the most well studied human fungal symbiont clinically and experimentally, its transition from commensalism to parasitism within the human host, and the factors that influence this relationship.

Investigation of faecal volatile organic metabolites as novel diagnostic biomarkers in inflammatory bowel disease

BACKGROUND

The aetiology of inflammatory bowel disease (IBD) remains poorly understood. Recent evidence suggests an important role of gut microbial dysbiosis in IBD, and this may be associated with changes in faecal volatile organic metabolites (VOMs).

AIM

To describe the changes in the faecal VOMs of patients with IBD and establish their diagnostic potential as non-invasive biomarkers.

METHODS

Faecal samples were obtained from 117 people with Crohn's disease (CD), 100 with ulcerative colitis (UC), and 109 healthy controls. Faecal VOMs were extracted using solid-phase micro-extraction and analysed by gas chromatography mass spectrometry. Data analysis was carried out using partial least squares-discriminate analysis (PLS-DA) to determine class membership based on distinct metabolomic profiles.

RESULTS

The PLS-DA model showed clear separation of active CD from inactive disease and healthy controls (P < 0.001). Heptanal, 1-octen-3-ol, 2-piperidinone and 6-methyl-2-heptanone were up-regulated in the active CD group [variable important in projection (VIP) score 2.8, 2.7, 2.6 and 2.4, respectively], while methanethiol, 3-methyl-phenol, short-chain fatty acids and ester derivatives were found to be less abundant (VIP score of 3.5, 2.6, 1.5 and 1.2, respectively). The PLS-DA model also separated patients with small bowel CD from healthy controls and those with colonic CD from UC (P < 0.001). In contrast, less distinct separation was observed between active UC, inactive UC and healthy controls.

CONCLUSIONS

Analysis of faecal volatile organic metabolites can provide an understanding of gut metabolomic changes in IBD. It has the potential to provide a non-invasive means of diagnosing IBD, and can differentiate between UC and CD.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Diet in the pathogenesis and treatment of inflammatory bowel diseases

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

A study evaluating the bidirectional relationship between inflammatory bowel disease and self-reported non-celiac gluten sensitivity

BACKGROUND

Non-celiac gluten sensitivity and the associated use of a gluten-free diet (GFD) are perceived to belong to the spectrum of irritable bowel syndrome (IBS). However, recent reports suggest substantial use of a GFD in inflammatory bowel disease (IBD). We assessed the bidirectional relationship between IBD and self-reported non-celiac gluten sensitivity (SR-NCGS).

METHODS

A cross-sectional questionnaire screened for SR-NCGS and the use of a GFD in 4 groups: ulcerative colitis (n = 75), Crohn's disease (n = 70), IBS (n = 59), and dyspeptic controls (n = 109). We also assessed diagnostic outcomes for IBD in 200 patients presenting with SR-NCGS.

RESULTS

The prevalence of SR-NCGS was 42.4% (n = 25/59) for IBS, followed by 27.6% (n = 40/145) for IBD, and least among dyspeptic controls at 17.4% (n = 19/109); P = 0.015. The current use of a GFD was 11.9% (n = 7/59) for IBS, 6.2% (n = 9/145) for IBD, and 0.9% (1/109) for dyspeptic controls; P = 0.02. No differences were established between ulcerative colitis and Crohn's disease. However, Crohn's disease patients with SR-NCGS were significantly more likely to have stricturing disease (40.9% versus 18.9%, P = 0.046), and higher mean Crohn's Disease Activity Index score (228.1 versus 133.3, P = 0.002), than those without SR-NCGS. Analysis of 200 cases presenting with SR-NCGS suggested that 98.5% (n = 197) could be dietary-related IBS. However, 1.5% (n = 3) were found to have IBD; such patients had associated alarm symptoms, and/or abnormal blood parameters, prompting colonic investigations.

CONCLUSIONS

SR-NCGS is not only exclusive to IBS but also associated with IBD, where its presence may be reflecting severe or stricturing disease. Randomized studies are required to further delineate the nature of this relationship and clarify whether a GFD is a valuable dietetic intervention in selected IBD patients.

Anti-high mobility group box 1 and box 2 non-histone chromosomal proteins (HMGB1/HMGB2) antibodies and anti-Saccharomyces cerevisiae antibodies (ASCA): accuracy in differentially diagnosing UC and CD and correlation with inflammatory bowel disease phenotype

BACKGROUND

The development of a supportive diagnostic method has long been required to differentially diagnose ulcerative colitis (UC) and Crohn's disease (CD). Several antibodies circulate in the sera of patients with inflammatory bowel disease. We previously identified the high mobility group box 1 and box 2 non-histone chromosomal proteins (HMGB1 and HMGB2) as novel antigens of perinuclear type anti-neutrophil cytoplasmic antibodies (pANCA) and discovered anti-HMGB1/HMGB2 antibodies in sera from patients with UC. Here, we evaluated the ability of anti-HMGB1/HMGB2 antibodies combined with anti-Saccharomyces cerevisiae antibodies (ASCA) to differentially diagnose UC and CD.

METHODS

We measured titers of anti-HMGB1/HMGB2 antibodies and ASCA in the sera of 213 patients with UC and 93 with CD, using enzyme-linked immunosorbent assays.

RESULTS

Among the patients with UC, 26.8% were positive for anti-HMGB1/HMGB2 antibodies, with 85.0% specificity towards CD and a positive predictive value of 80.3%. Corticosteroids significantly suppressed the titer of anti-HMGB1/HMGB2 antibodies. Among the patients with CD, 24.7% were positive for ASCA, with 96.2% specificity towards UC and a positive predictive value of 74.2%. Interestingly, the positivity rate of anti-HMGB/HMGB2 antibodies was higher (35.7%) in patients with the ileitis type of CD than in patients with CD in the colon (6.2%; significant difference, P < 0.01). The specificity of anti-HMGB1/HMGB2 antibodies in UC for CD in the colon was 93.8%.

CONCLUSIONS

CD in the colon and UC can be differentially diagnosed using anti-HMGB/HMGB2 antibodies combined with ASCA.

Systematic review and meta-analysis of Saccharomyces boulardii in adult patients

This article reviews the evidence for efficacy and safety of Saccharomyces boulardii (S. boulardii) for various disease indications in adults based on the peer-reviewed, randomized clinical trials and pre-clinical studies from the published medical literature (Medline, Clinical Trial websites and meeting abstracts) between 1976 and 2009. For meta-analysis, only randomized, blinded controlled trials unrestricted by language were included. Pre-clinical studies, volunteer studies and uncontrolled studies were excluded from the review of efficacy and meta-analysis, but included in the systematic review. Of 31 randomized, placebo-controlled treatment arms in 27 trials (encompassing 5029 study patients), S. boulardii was found to be significantly efficacious and safe in 84% of those treatment arms. A meta-analysis found a significant therapeutic efficacy for S. boulardii in the prevention of antibiotic-associated diarrhea (AAD) (RR = 0.47, 95% CI: 0.35-0.63, P < 0.001). In adults, S. boulardii can be strongly recommended for the prevention of AAD and the traveler's diarrhea. Randomized trials also support the use of this yeast probiotic for prevention of enteral nutrition-related diarrhea and reduction of Helicobacter pylori treatment-related symptoms. S. boulardii shows promise for the prevention of C. difficile disease recurrences; treatment of irritable bowel syndrome, acute adult diarrhea, Crohn's disease, giardiasis, human immunodeficiency virus-related diarrhea; but more supporting evidence is recommended for these indications. The use of S. boulardii as a therapeutic probiotic is evidence-based for both efficacy and safety for several types of diarrhea.

Does evidence exist to include dietary therapy in the treatment of Crohn's disease?

Prescription drugs and surgery are two common medical therapies for Crohn's disease (CD), an inflammatory bowel disease that affects the GI tract. Unfortunately, certain drugs can cause serious side effects, and surgeries must often be repeated. No diet has been established to alleviate the pain and suffering of CD patients. This is curious given the fact that a higher prevalence of food sensitivities exist in this population of patients, and enteral nutrition is not only the first-line of therapy in Japan, but a known research method used to place the majority of CD patients into remission. Although not all patients respond equally to diet, many simply remove symptom-provoking foods, such as dairy, wheat, corn and certain fruits and vegetables. We suggest assisting these patients in their self-assessment of irritating and symptom-provoking foods by educating them in the use of a food-symptom diary followed by a customized elimination diet trialed for 2-4 weeks to determine if there is any benefit to the individual patient.

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.

Probiotics for induction of remission in Crohn's disease

BACKGROUND

Crohn's disease has a high morbidity and there is no known cure. Current treatments have multiple side effects and an effective treatment with minimal side effects is desired. Probiotics have been proposed as such a treatment but their efficacy is undetermined. There is some evidence that probiotics are effective in other conditions affecting the gastrointestinal tract and they are popular with patients. They are thought to work through competitive action with commensal and pathogenic flora, influencing the immune response.

OBJECTIVES

To determine if there is any evidence for the efficacy of probiotics for the induction of remission in Crohn's disease.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 1, 2007), MEDLINE (1966 to 2007), Excerpta Medica/EMBASE (1974 to 2007), CINAHL (1982-2007) and the Cochrane Inflammatory Bowel Disease and Functional Bowel Disorders Group Specialised Trial Register were searched. Manufacturers of probiotics were also contacted to identify any unpublished trials. References of trials were also searched for any additional trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared probiotics against placebo or any other intervention for the induction of remission in Crohn's disease were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Data extraction and assessment of methodological quality of included studies were independently performed by two authors. The main outcome measure was the occurrence of clinical remission. Odds ratios and 95% confidence intervals were calculated for dichotomous outcomes.

MAIN RESULTS

One small study (n = 11) met the inclusion criteria and was included in the review. There were some methodological concerns with this study. Four of 5 patients in the probiotic group achieved remission compared to 5 of 6 in the placebo group (OR 0.80; 95% CI 0.04 to 17.20).

AUTHORS' CONCLUSIONS

There is insufficient evidence to make any conclusions about the efficacy of probiotics for induction of remission in Crohn's disease. There is a lack of well designed RCTs in this area and further research is needed.

Ingested matter affects intestinal lesions in Crohn's disease

BACKGROUND

Environmental factors of the modern Western lifestyle may trigger Crohn's disease (CD) in susceptible individuals. Because such factors could be part of ingested matter, we intended to improve intestinal Crohn's lesions by exclusion thereof.

METHODS

At first we tested a highly restricted diet (based on spelt bread and red meat, both derived from intensively monitored organic farming) in 5 pilot cases. In a subsequent controlled trial, 18 patients with mild-to-moderate CD were randomly assigned to receive either this active diet or a control diet (low-fiber, low-fat, and high-carbohydrate). Mucosal improvement was assessed by magnetic resonance imaging (MRI) and endoscopy. Secondary endpoints included sonography, the Crohn's Disease Activity Index (CDAI), and the Inflammatory Bowel Disease Questionnaire (IBDQ).

RESULTS

Four of 5 pilot patients showed significant improvement within 4 weeks. From 18 patients in the controlled trial, 8 were randomized to the active and 10 to the control group; 4 decided to quit immediately after dietary counseling, 3 in the active and 1 in the control group (P = 0.183). At 6 weeks MRI and endoscopy showed improvement of intestinal lesions in 3 of 4 assessable patients of the active group and 1 of 9 patients of the control group (P = 0.027). Sonography showed improvement in 4 of 5 patients of the active group and in 1 of 8 assessable patients of the control group (P = 0.016). CDAI and IBDQ improved in both groups to a similar extent.

CONCLUSIONS

Ingested matter as part of the modern Western lifestyle may cause persistence of intestinal Crohn's lesions.

Serologic markers in inflammatory bowel disease: tools for better diagnosis and disease stratification

In the last decade, new serologic markers have been identified, and attempts to delineate their potential roles in inflammatory bowel disease diagnosis, determination of prognosis and identification of apparently healthy subjects at risk have significantly increased our knowledge. In this review, the major serologic markers will be described, focusing on their common features as a group. It is predicted that within the next 5 years, panels of antibodies will prove to have a significant impact on disease diagnosis and stratification, as well as on the identification of populations at risk and the prediction of response to treatment. Thus, it is expected that they will become useful clinical tools that will enable an improved, 'tailored' approach to inflammatory bowel disease patients.

Anti-Saccharomyces cerevisiae antibodies in coeliac disease

OBJECTIVE

To evaluate, retrospectively, the frequency of anti-Saccharomyces cerevisiae antibodies (ASCA) in patients with coeliac disease.

MATERIAL AND METHODS

ASCA, IgG and IgA were determined by ELISA in sera of 238 coeliac patients. The patients were divided into three groups: group I - 125 untreated patients; group II - 42 patients under a strict gluten-free diet (GFD); and group III - 71 patients who did not comply with a GFD. Sera of 80 healthy blood donors served as controls.

RESULTS

The frequency of ASCA (IgG or IgA) was significantly higher in untreated coeliac patients than in the control group (27.2% versus 3.7%, p=10(-5)). In 238 coeliac patients, the frequency of ASCA was significantly higher in adults than in children (35.4% versus 21.1%, p=0.01). In group III, the frequency of ASCA was significantly higher in adults than in children (60% versus 26.1%, p=0.004). In 238 coeliac patients, ASCA IgG were significantly more frequent than ASCA IgA in both children (19% versus 6.3%, p=0.001) and adults (33.3% versus 12.5%, p=5.10(-4)). In children, ASCA IgG were negative in group II and positive in 20% of group I (p=0.01). In adults, the frequency of ASCA IgG was also significantly lower in group II than in group I (9.5% versus 34%, p=0.03).

CONCLUSIONS

A high frequency of ASCA has been found in coeliac patients. The frequency of ASCA was not statistically different between patients with successful adherence to GFD and healthy controls.

Differences in yeast intolerance between patients with Crohn's disease and ulcerative colitis

PURPOSE

Alimentary factors, especially those modifying the intestinal flora, may influence the course of inflammatory bowel disease. It is known that T and B cells of patients with Crohn's disease can be stimulated with the yeast antigen, mannan. We evaluated the impact of eating habits with special respect to food containing yeast on the course of inflammatory bowel disease.

METHODS

Questionnaires were sent to 180 German-speaking patients of the Inflammatory Bowel Disease Outpatient Clinic at the University Hospital Bern, Switzerland. The following information was obtained by the questionnaires: (1) course of disease, (2) eating habits, (3) environmental data, and (4) inflammatory bowel disease questionnaire. The survey was anonymous.

RESULTS

A total of 145 patients (80.5 percent 95 with Crohn's disease, and 50 with ulcerative colitis) responded. Food items containing yeast were better tolerated by patients with ulcerative colitis than by patients with Crohn's disease. A significant difference between the two groups was observed concerning food containing raw yeast (dough, P = 0.04; and pastry, P = 0.001).

CONCLUSIONS

Food items containing raw yeast led to more frequent problems for patients with Crohn's disease than for patients with ulcerative colitis. This observation supports our previous data, which showed the stimulatory effect of the yeast antigen, mannan, on B and T cells of patients with Crohn's disease but not of controls.

Anti-Saccharomyces cerevisiae antibody in intestinal Behçet's disease patients: relation to clinical course

PURPOSE

This study was designed to assess anti-Saccharomyces cerevisiae antibody positive rate in Behçet's disease and intestinal Behçet's disease and to evaluate whether anti-Saccharomyces cerevisiae antibody expression is associated with clinical findings at diagnosis and clinical course of intestinal Behçet's disease.

METHODS

One hundred six patients with intestinal Behçet's disease, 30 patients with Behçet's disease, and 45 healthy control subjects were included. Anti-Saccharomyces cerevisiae antibody was detected by indirect immunofluorescence assay. According to anti-Saccharomyces cerevisiae antibody expression, the various parameters at diagnosis, cumulative relapse rates, and cumulative probabilities of operation were analyzed.

RESULTS

Anti-Saccharomyces cerevisiae antibody positive rate was 44.3 percent in intestinal Behçet's disease, 3.3 percent in Behçet's disease, and 8.8 percent in healthy control subjects. In patients with intestinal Behçet's disease, age, gender, distribution of Behçet's disease subtype, symptoms, laboratory tests, and colonoscopic findings at diagnosis were not different according to anti-Saccharomyces cerevisiae antibody expression. Cumulative probability of a first operation was significantly higher in anti-Saccharomyces cerevisiae antibody (+) intestinal Behçet's disease than in anti-Saccharomyces cerevisiae antibody (-) intestinal Behçet's disease: 44.8 and 17.2 percent at one year, and 53 and 24.3 percent at two years after diagnosis, respectively (P=0.006). The number of patients who underwent two or more operations was higher in anti-Saccharomyces cerevisiae antibody (+) intestinal Behçet's disease than in anti-Saccharomyces cerevisiae antibody (-) intestinal Behçet's disease (21.3 vs. 8.5 percent). The cumulative relapse rates were not different between the two groups.

CONCLUSIONS

Anti-Saccharomyces cerevisiae antibody positive rate was 44.3 percent in intestinal Behçet's disease. Clinical findings at diagnosis and cumulative relapse rates of intestinal Behçet's disease were not found to be associated with anti-Saccharomyces cerevisiae antibody expression. However, patients with anti-Saccharomyces cerevisiae antibody (+) intestinal Behçet's disease were more likely to receive surgical treatment.

Probiotics for maintenance of remission in Crohn's disease

BACKGROUND

Crohn's disease (CD) is characterised by episodes of disease activity and symptom-free remission. Probiotics are microorganisms that can potentially benefit health, and have been evaluated as an alternate means of preventing relapse in patients with CD.

OBJECTIVES

To assess the effectiveness of probiotics for the maintenance of remission in CD.

SEARCH STRATEGY

The following databases were searched: the Cochrane Database of Systematic Reviews (2005, Issue 3); the Cochrane Central Register of Controlled Trials (2005, Issue 3); the Cochrane IBD/FBD Group Trials Register (2005), MEDLINE (1966-2005); EMBASE (1980-2005); ISI Web of Knowledge (BIDS) 1981-2005; On-line clinical trials databases (2005); and review articles. Experts in the field were contacted for unpublished data.

SELECTION CRITERIA

Randomised controlled trials of probiotic therapy.

DATA COLLECTION AND ANALYSIS

Two independent reviewers performed data extraction and assessment of methodological quality. The primary outcome was the relative risk (RR) of relapse after maintenance treatment (and 95% confidence intervals [CI]).

MAIN RESULTS

Seven small studies were identified and varied according to probiotics tested, methodological quality and medication regimen. No studies were pooled for statistical analysis. There was no statistically significant benefit of E. coli Nissle for reducing the risk of relapse compared to placebo (RR 0.43, 95% CI 0.15 to 1.20), or Lactobacillus GG after surgically-induced remission (RR 1.58, 95% CI 0.30 to 8.40) or medically-induced remission (RR 0.83, 95% CI 0.25 to 2.80). There was no statistically significant benefit of probiotics for reducing the risk of relapse compared to maintenance therapy employing aminosalicylates or azathioprine (RR 0.67, 95% CI 0.13 to 3.30), and in this study the probiotic Lactobacillus GG was associated with adverse events. In children, there was there was no statistically significant difference between Lactobacillus GG and placebo for reducing the risk of relapse (RR 1.85, 95% CI 0.77 to 4.40). A small study using the yeast Saccharomyces boulardii demonstrated a difference that was not statistically significant in favour of probiotic combined with a reduced level of maintenance therapy over standard maintenance treatment alone (RR 0.17, 95% CI 0.02 to 1.23).

AUTHORS' CONCLUSIONS

There is no evidence to suggest that probiotics are beneficial for the maintenance of remission in CD. All of the included studies enrolled small numbers of patients and may have lacked statistical power to show differences should they exist. Larger trials are required to determine if probiotics are of benefit in Crohn's disease.

Candida albicans is an immunogen for anti-Saccharomyces cerevisiae antibody markers of Crohn's disease

BACKGROUND AND AIMS

Antibodies directed against oligomannose sequences alpha-1,3 Man (alpha-1,2 Man alpha-1,2 Man)(n) (n = 1 or 2), termed anti-Saccharomyces cerevisiae antibodies (ASCAs) are markers of Crohn's disease (CD). S. cerevisiae mannan, which expresses these haptens, is used to detect ASCA, but the exact immunogen for ASCA is unknown. Structural and genetic studies have shown that Candida albicans produces mannosyltransferase enzymes that can synthesize S cerevisiae oligomannose sequences depending on growth conditions. This study investigated whether C. albicans could act as an immunogen for ASCA.

METHODS

Sequential sera were collected from patients with CD, systemic candidiasis, and rabbits infected with C. albicans. Antibodies were purified by using chemically synthesized (Sigma) ASCA major epitopes. These affinity-purified antibodies and lectins were then used to analyze the expression of ASCA epitopes on molecular extracts and cell walls of C. albicans and S cerevisiae grown in various conditions.

RESULTS

In humans and rabbits, generation of ASCA was shown to be associated with the generation of anti-C. albicans antibodies resulting specifically from infection. By using affinity-purified antibodies, C. albicans was shown to express ASCA epitopes on mannoproteins similar to those of S. cerevisiae. By changing the growth conditions, C. albicans mannan was also able to mimic S. cerevisiae mannan in its ability to detect ASCA associated with CD. This overexpression of ASCA epitopes was achieved when C. albicans grew in human tissues.

CONCLUSIONS

C. albicans is one of several immunogens for ASCA and may be at the origin of an aberrant immune response in CD.

Probiotics used in human studies

GOAL

To investigate the literature from 1980 to 2004 for the types of studies and organisms used as probiotics in human studies and diseases.

METHODS

PubMed search for probiotic organisms used in studies from 1980 to August 2004. The data from those papers were evaluated for organisms used, dose, vehicle, frequency, and investigator's report of positive or negative results.

RESULTS

A total of 185 manuscripts were identified. Investigators reported results of both single and multiple organisms in the same manuscript. A single organism was used in 125 reports, and multiple organisms, ranging from 2 to 9, were used in 60 reports. Positive results were reported in 239 clinical situations and negative results reported in 49 in a total of 288 clinical conclusions drawn by the respective investigators. The studies are tabulated in this review.

CONCLUSION

There is a large literature available in credible journals that report benefit of probiotic administration using a wide range of doses, organisms, and clinical situations. Most of the studies are simple reports of a clinical situation and require additional evaluation.

Yeast metabolic products, yeast antigens and yeasts as possible triggers for irritable bowel syndrome

Many patients with irritable bowel syndrome (IBS) are disillusioned by the lack of efficacy of treatments and suffer from numerous symptoms not covered by the Rome criteria for IBS, as the current empirical treatment regimens fail to address these persistent debilitating 'IBS associated symptoms'. These symptoms are similar to other symptom complexes like chronic fatigue and the so-called 'candida syndrome', and many seek help from alternative medicine. The possible role of Candida and yeasts in non-immune compromised individuals is disputed and is the subject of this review. Even if the involvement of yeasts in the aetiology of IBS still remains unclear, there is increasing evidence for yeasts being able to cause IBS-symptoms in sensitized patients via Candida products, antigens and cross-antigens. But more research is needed before antifungal treatment can be recommended as a first line treatment for IBS.

Environmental risk factors (excluding tobacco and microorganisms): critical analysis of old and new hypotheses

The increase in incidence in both ulcerative colitis and Crohn's disease during the 20th century has led to an abundance of different hypotheses on what sort of exposures are responsible. There has been a special focus on dietary factors, as well as on other exposures introduced on a population-based level, including fast food, cola drinks, toothpaste, antibiotics and oral contraceptives. The aim of this review is to critically assess the results from the different observational studies that have investigated these hypotheses, and also to propose research agendas that should be pursued in the future. The conclusion is that infectious exposures and early bacterial colonization, which are associated with better hygiene early in life and that influence immune function, and possibly oral contraceptives, remain the only exposures of interest for future research into the aetiology of ulcerative colitis and Crohn's disease.

Seroreactivity against Saccharomyces cerevisiae in patients with Crohn’s disease and celiac disease

AIM: To explore whether there was anti-Saccharomyces cerevisiae antibodies (ASCA) positivity in our patients with biopsy-confirmed celiac disease.

METHODS: A cohort of patients with inflammatory bowel diseases (42 patients with Crohn’s disease and 10 patients with ulcerative colitis) and gluten sensitive enteropathy (16 patients) from Debrecen, Hungary were enrolled in the study. The diagnosis was made using the formally accepted criteria. Perinuclear antineutrophil cytoplasmic antibodies (pANCA) and anti-Saccharomyces cerevisiae antibodies (ASCA), antiendomysium antibodies (EMA), antigliadin antibodies (AGA) and anti human tissue transglutaminase antibodies (tTGA) were investigated.

RESULTS: The results showed that ASCA positivity occurred not only in Crohn’s disease but also in Celiac disease and in these cases both the IgG and IgA type antibodies were proved.

CONCLUSION: It is conceivable that ASCA positivity correlates with the (auto-) immune inflammation of small intestines and it is a specific marker of Crohn’s disease.

Distinct elevation of levels of anti-Caenorhabditis elegans antibody in sera of patients with inflammatory bowel disease

Dysregulation of immune responses to intestinal exogenous antigens contributes to the pathogenesis of inflammatory bowel disease, but the specific antigen responsible for the pathogenesis of inflammatory bowel disease is unknown. We measured serum antibody titers against Caenorhabditis elegans antigens. Immunoglobulin G (IgG) and IgG subclass anti-C. elegans antibodies in serum samples from 29 patients with ulcerative colitis, 30 patients with Crohn's disease, 7 patients with intestinal Behçet's disease, and 11 healthy controls were measured by enzyme-linked immunosorbent assay. Serum IgG and IgG2 antibody titers against C. elegans were significantly higher in patients with inflammatory bowel disease than in controls. Antibody levels were not affected by age, gender, disease activity, extent of disease, or small bowel involvement. The anti-C. elegans antibody titer was significantly lower in patients with Crohn's disease taking mesalazine or sulfasalazine than in patients not taking these drugs. The increased immune responses to C. elegans found in patients with inflammatory bowel disease reflect dysregulated immune responses to enteric antigens, which might play a role in the pathogenesis of inflammatory bowel disease.

Cross-reactivity of yeast antigens in human colon and peripheral leukocytes

Elevation of the serum anti-Saccharomyces cerevisiae antibody (ASCA) level has been reported in patients with Crohn's disease. This study investigated the antigenic distribution of S. cerevisiae in human colon and peripheral leukocytes. ASCA was isolated from sera from patients with Crohn's disease using immuno-affinity chromatography and then biotinylated and assayed immunohistologically and immunocytologically to determine the distribution of antigens recognized by ASCA in human colon and peripheral leukocytes. Immunoblot analysis of yeast extract and human peripheral leukocytes was performed. Immunohistological study using biotinylated ASCA revealed the presence of yeast-like particles in the granulation tissue of inflamed colonic mucosa. Biotinylated ASCA also stained lymphocytes and polymorphonuclear cells infiltrating inflamed intestine. Monocytes in epithelioid granulomas of colon with Crohn's disease were also stained. Polymorphonuclear leukocytes in peripheral blood were also stained with biotinylated ASCA. The antigens reactive to ASCA among heat-extracted, non-heat-extracted yeast antigens, and human leukocyte extract differed. The findings of cross-reactivity of polymorphonuclear leukocytes with S. cerevisiae antigen and the presence of S. cerevisiae antigen in Crohn's disease granulomas suggest the possibility of involvement of S. cerevisiae in the pathogenesis of Crohn's disease.

Gut mucosal response to food antigens in Crohn's disease

BACKGROUND

Food antigens may contribute to gut inflammation in Crohn's disease.

AIM

To assess in vivo sensitization to food antigens, ascertain whether sensitivity is gut specific, assess food sensitization in vitro, and correlate in vivo changes with histological and blood changes.

METHODS

Skin testing and rectal exposure to six food antigens (cereal, cabbage, citrus, milk, yeast and peanut) and control saline were assessed double-blind by immediate and 3.5-h laser Doppler blood flowmetry, and rectal biopsies were taken. Peripheral blood lymphocyte proliferation was measured in response to the same antigens.

RESULTS

Ten patients with Crohn's disease and 10 healthy controls were studied. Blood flow increased in 24 of 60 antigen sites in Crohn's disease patients and six of 60 antigen sites in controls (P < 0.0001) after 3.5 h. The Crohn's disease group demonstrated higher rectal blood flow than controls in response to all food antigens, and this was significantly different for the responses to yeast (P = 0.036) and citrus fruits (P = 0.038). Lymphocyte proliferation occurred in 32 of 60 tests in Crohn's disease patients and eight of 60 tests in controls (P < 0.0001). There were no skin responses. Submucosal oedema corresponded to increased mucosal flow.

CONCLUSIONS

Crohn's disease patients demonstrate in vivo and in vitro sensitization to food antigens, which is gut specific. Mucosal flowmetry allows the identification of sensitization to gut antigens.

Serological markers in inflammatory bowel disease: the pros and cons

Accurate serological assays are desirable for the diagnosis of inflammatory bowel disease. Among several serological markers anti-Saccharomyces cerevisiae mannan antibodies and perinuclear antineutrophil cytoplasmic autoantibodies are highly disease specific for Crohn's disease and ulcerative colitis, respectively. Combining the two improves their specificity. Sensitivity, however, is still low. Due to lack of standardization and vast interobserver variability, they cannot be used as the only diagnostic criteria but can assist clinicians in diagnosing and categorizing patients with inflammatory bowel disease as well as in helping them to take therapeutic decisions.

Immune sensitization to food, yeast and bacteria in Crohn's disease

BACKGROUND

Complex food proteins and enteric flora may act as antigenic stimuli in Crohn's disease. This study assessed the prevalence and magnitude of lymphocyte priming to these antigens in Crohn's disease.

METHODS

A total of 31 Crohn's disease patients (median age 42 years, range 25-72 years) and 22 healthy controls (median 29 years, 23-43 years) were studied. Peripheral blood lymphocytes were collected and incubated with antigens in hanging drop culture for 4 days. The antigens tested were cow's milk, cereals, cabbage group, citrus group, peanut group, Saccharomyces (yeast), Bacteroides, E. coli and Klebsiella. On the 4th day 3H-thymidine incorporation was measured after a 4-h pulse. Responses to antigens were considered positive if mean proliferative values were above the 99% confidence interval for background proliferation.

RESULTS

The mean background and mitogen-stimulated proliferation did not differ between patients and controls. The mean proliferation to antigens was not above background in controls, but in Crohn's patients proliferative responses to all food and bacterial antigens were significantly higher than background values. Twenty-three out of 31 Crohn's patients and five out of 22 controls (P=0.0003) responded to one or more antigens. Sixteen Crohn's patients and two controls responded to four or more antigens (P=0.001, Fisher's exact test).

CONCLUSION

The reactivity of peripheral lymphocytes to food, yeast and bacterial antigens, especially multiple antigens, is common in Crohn's disease. These sensitized lymphocytes may contribute to the inflammatory process.

Infliximab for refractory ulcerative colitis

Eight patients with active ulcerative colitis (UC), refractory to usual combination medical therapy, were treated with a single i.v. dose of chimeric monoclonal antibody to recombinant human tumor necrosis factor alpha; many of these patients were scheduled for surgical colectomy because of their active disease. All patients responded extremely well to a single 5 mg/kg infusion of infliximab, with marked improvement after the infusion clinically, colonoscopically, and histologically on colonic biopsy. There were no significant complications or side effects; mean duration of remission has not been determined because none of the patients have relapsed. Infliximab appears to be a potent agent for inducing remission in refractory patients with ulcerative colitis.

Anti-Saccharomyces cerevisiae antibodies in inflammatory bowel disease: a family study

BACKGROUND

Antibodies to Saccharomyces cerevisiae (ASCA) have been described as specific markers for Crohn disease (CD). The reason for this disease specific generation of antibodies is not clear. Therefore, a family study was performed to evaluate whether the antibody production was due to genetic or environmental factors.

METHODS

Seventy-one patients with CD, 25 patients with ulcerative colitis (UC), their 282 first-degree relatives, and 32 spouses were included. As controls, 43 sera from healthy persons and 69 sera from patients with various autoimmune disorders were tested for ASCA by indirect immunofluorescence and ELISA.

RESULTS

ASCA were detected in 68% of the patients with CD and in none of the controls, UC patients included. Forty-eight (25%) first-degree relatives of patients with CD were ASCA-positive. ASCA status of relatives was not related to the fact whether these persons lived in the same household with the patients or not. However, one of the spouses of CD patients (4%) was found to be ASCA-positive and the antibody was also found in 5 (6%) of the relatives of UC patients.

CONCLUSIONS

ASCA are specific markers for CD. Since these antibodies are found in 25% of first-degree relatives, the generation of ASCA may be mainly related to genetic influences although environmental factors may also play a certain role.

IgG subclasses of anti Saccharomyces cerevisiae antibody in inflammatory bowel disease

Elevation of serum anti Saccharomyces cerevisiae antibody (ASCA) has been reported in patients with Crohn's disease. We analysed the subclasses of Immunoglobulin (Ig) G reaction in ASCA in sera from patients with inflammatory bowel disease, healthy controls, and patients with intestinal Behçet's disease. Serum samples were obtained from 29 patients with Crohn's disease, 30 patients with ulcerative colitis, 7 patients with intestinal Behçet's disease, and 12 healthy controls. Serum IgG subclasses IgG1, IgG2, IgG3, and IgG4 of ASCA were analysed using ELISA. IgG4 ASCA was significantly increased in patients with inflammatory bowel disease. In patients with intestinal Behçet's disease, IgG1, IgG3, and IgG4 ASCA were increased. Differential responses, in terms of subclasses in ASCA, were found in patients with inflammatory bowel disease and patients with intestinal Behçet's disease, which may represent different pathophysiologies of these intestinal inflammatory diseases.

Decreased anti-Saccharomyces cerevisiae antibody titer by mesalazine in patients with Crohn's disease

BACKGROUND

Saccharomyces cerevisiae may contribute to the pathophysiology of Crohn's disease. We determined serum anti-Saccharomyces cerevisiae antibody (ASCA) levels in patients with inflammatory bowel disease.

METHODS AND RESULTS

Immunoglobulin G (IgG) ASCA was measured by using an ELISA in serum samples from 19 patients with ulcerative colitis, 18 patients with Crohn's disease and 7 healthy controls. The ASCA level was significantly higher in patients with ulcerative colitis and patients with Crohn's disease than in controls, and was significantly higher in patients with Crohn's disease compared with patients with ulcerative colitis. Age, gender, disease activity, extent of disease and small bowel involvement each did not affect ASCA levels. The use of elemental or polymeric diet therapy for Crohn's disease and administration of corticosteroids to patients with inflammatory bowel disease also did not affect ASCA levels. The ASCA titer was significantly lower in patients with Crohn's disease taking mesalazine than in those not taking it, although, serum IgG levels did not differ between these two groups, which might imply a suppression of IgG production by mesalazine at the intestinal level.

CONCLUSIONS

The finding of increased serum ASCA titers in patients with inflammatory bowel disease suggests that Saccharomyces cerevisiae may play a role in the pathophysiology of this condition.

Circulating antibodies to Saccharomyces cerevisiae (bakers'/brewers' yeast) in gastrointestinal disease

AIM

To measure circulating antibodies to yeast organisms that could be used to characterise the yeast specific immune response in gastrointestinal disease.

METHODS

A quantitative, isotype specific enzyme linked immunosorbent assay was developed to measure circulating antibodies to an aqueous extract of Saccharomyces cerevisiae (sacc). Comparisons of specific antibody concentrations were made between 224 healthy controls and 51 patients with Crohn's disease, 41 with ulcerative colitis, 24 with indeterminate colitis, 23 with chronic liver disease, 17 with coeliac disease, and seven with irritable bowel syndrome. Additional comparisons were made between Crohn's disease and ulcerative colitis patients. Within the Crohn's disease group, the dependence of antibody levels on several clinical variables was assessed.

RESULTS

IgG and IgA anti-sacc antibodies were significantly raised in Crohn's disease. IgG antibodies were also raised in patients with chronic liver disease. Among patients with Crohn's disease, IgG antibody concentrations were higher in those with serum alpha 1 acid glycoprotein (AAG) above the normal range and there was a strong trend towards increased IgG anti-sacc in the presence of small bowel disease, whereas IgA anti-sacc correlated positively with disease duration. No differences were detected according to whether patients were taking steroids. Neither the Crohn's disease nor the chronic liver disease group differed from normal subjects in respect of IgG antibodies to bovine milk casein. On linear regression analysis of complete data from 39 Crohn's disease patients, AAG was found to be a significant predictor of both IgG and IgA antibodies, and male sex and disease duration to be additional predictors of IgA antibodies. There was a significant difference in IgG antibodies between Crohn's disease and ulcerative colitis.

CONCLUSIONS

Raised antibodies to yeast, although not completely specific for Crohn's disease, may have a future role in diagnosis. The assays described here could be used to address this question in the context of a prospective study.

Nutrition in inflammatory bowel disease

Nutrition is clearly disturbed by active intestinal inflammation. Appetite is reduced, yet energy substrates are diverted into the inflammatory process, and thus weight loss is characteristic. The nutritional disturbance represents part of a profound defect of somatic function. Linear growth and pubertal development in children are notably retarded, body composition is altered, and there may be significant psychosocial disturbance. Macrophage products such as tumour necrosis factor-alpha and interleukins-1 and 6 may be the central molecules that link the inflammatory process to this derangement of homeostasis. Intriguingly, there is also increasing evidence that an aggressive nutritional programme may in itself be sufficient to reduce the mucosal inflammatory response. Recent evidence suggests that enteral nutrition alone may reduce many pro-inflammatory cytokines to normal and allow mucosal healing. In addition, specific nutritional components, such as n-3 polyunsaturated fatty acids, may have an anti-inflammatory effect as they may alter the pattern of leukotrienes generated during the immune response. The recent discovery of the specific molecular mediators of appetite and body composition, such as leptin and myostatin, may allow increased therapeutic specificity and further improvement in the nutritional treatment of the inflammatory bowel diseases.

Specific antibody response to oligomannosidic epitopes in Crohn's disease

Elevated antibody levels against the yeast Saccharomyces cerevisiae have been reported in sera from patients with Crohn's disease and not with ulcerative colitis. The aim of the study was to identify the nature of the epitopes supporting this antibody response. Whole cells from different S. cerevisiae strains were selected in immunofluorescence assay for their ability to differentiate the antibody responses of patients with Crohn's disease and ulcerative colitis. Their cell wall phosphopeptidomannans were then tested as antigen in enzyme-linked immunosorbent assay (ELISA) against sera from 42 patients with Crohn's disease, 20 patients with ulcerative colitis, and 34 healthy controls. Graded chemical degradations were performed on the most reactive strain phosphopeptidomannan. The discriminating epitope was determined through gas-liquid chromatography-mass spectrometry. The greatest discrimination among patients with Crohn's disease, ulcerative colitis, and controls was obtained with Su1, a S. cerevisiae strain used in brewing of beer. ELISA directed against phosphopeptidomannan of this strain was 64% sensitive and 77% specific for discriminating Crohn's disease versus ulcerative colitis and 71% sensitive and 89% specific for Crohn's disease versus controls. Periodate oxidation and selective degradation demonstrated that the most important polysaccharide epitope was shared by both the acid-stable and the alkali-labile domains of the phosphopeptidomannan. The determination of oligomannose sequences of S. cerevisiae Su1 phosphopeptidomannans suggested that a mannotetraose, Man (1 --> 3)Man(1 --> 2)Man(1 --> 2)Man, supported the serological response seen in Crohn's disease. Further identification of the immunogen eliciting this antibody response as a marker of the disease may help to understand its etiology.

Aetiology and pathogenesis of chronic inflammatory bowel disease

While Crohn's disease and ulcerative colitis are both conditions characterized by intestinal inflammation, with some overlap in their clinical and histological features, they are essentially different in pathogenesis. Crohn's disease appears to be primarily a condition of chronic T-lymphocyte activation, with tissue damage induced by secondary macrophage activation. What activates the T-cells is unknown. In this chapter we look at the evidence for and against cell-wall deficient mycobacteria species, viral infection of vascular endothelium and luminal contents as potential mechanisms of chronic activation. In ulcerative colitis, by contrast, there is no strong evidence for T-cell activation, and humoral mechanisms predominate. While the finding of atypical anti-neutrophil cytoplasmic antibodies (P-ANCAs) may be useful in screening, the only novel pathogenetic discovery is the co-localization of a 40 kD colonic autoantibody with immunoglobulins and complement on the apical enterocyte surface. Despite the fundamental differences in initiating mechanisms, the two conditions have many 'downstream' inflammatory processes in common. We discuss the evidence for local production of cytokines, arachidonic acid metabolites and reactive oxygen and nitrogen radicals, highlighting the potential adverse consequences for intestinal vascular integrity.