Do high serum levels of anti-Saccharomyces cerevisiae antibodies result from a leakiness of the gut barrier in Crohn's disease?

Prevalence of Anti- Saccharomyces Cerevisiae Antibodies (ASCA) in Patients With Irritable Bowel Syndrome (IBS). A Case-control Study

BACKGROUND

Irritable bowel syndrome (IBS) is a disorder of gut-brain interaction that affects patients' quality. Recent research has shown variations in the mycobiome of individuals with IBS, particularly involving Saccharomyces cerevisiae , and its association with dysbiosis and visceral hypersensitivity. However, the role of Anti-Saccharomyces cerevisiae antibodies (ASCA) in IBS remains unclear, despite their significance as markers of disease severity in inflammatory bowel disease.

OBJECTIVE

This study aimed to investigate the role of ASCA in Mexican IBS patients compared with healthy controls (HCs) and determine whether these antibodies could help differentiate between IBS patients and healthy individuals.

METHODS

Serum samples from 400 IBS patients and 400 HC were analyzed. ASCA IgG levels were measured using enzyme-linked immunosorbent assay (ELISA). The IBS patients were further categorized into subtypes: constipation predominant (IBS-C), diarrhea predominant (IBS-D), and mixed (IBS-M).

RESULTS

Among the participants, 66 IBS patients (16.5%) and 63 HC (15.75%) tested positive for ASCA IgG. No significant difference was observed in ASCA IgG levels between the 2 groups ( P value: 0.8451). The prevalence of ASCA IgG positivity was 14.5% in IBS-C, 17.8% in IBS-D, and 15.9% in IBS-M.

CONCLUSION

Surprisingly, a high prevalence of ASCA IgG was found in the HC group in Mexico. Furthermore, there was no significant difference in ASCA IgG levels between IBS patients and controls. These findings suggest that ASCA is not useful as a discriminatory biomarker for distinguishing IBS patients from healthy individuals and cannot serve as a surrogate marker for visceral hypersensitivity.

Pancreatic anti-GP2 and anti-Saccharomyces cerevisiae antibodies in ruminants with paratuberculosis: A better understanding of the immunopathogenesis of Crohn's disease

INTRODUCTION

Ruminants (cattle and sheep) with Mycobacterium avium (MAP)-induced paratuberculosis (ptb), the ruminant model of Crohn's disease (CD), exhibit pancreatic specific autoantibodies (PAB) against GP2 but not against CUZD1. Since anti-Saccharomyces cerevisiae antibodies (ASCAs) is a CD marker, we tested MAP-infected ptb ruminants for ASCA, and compared them with ruminants lacking evidence of anti-MAP serology or with ruminants, which were positive for anti-GP2 antibodies.

MATERIAL AND METHODS

A total of 98 samples from ruminants (48 cattle and 50 sheep) were studied. IgG anti-MAP antibodies, and CD-related ASCA and anti-GP2 antibodies were tested by modified ELISAs.

RESULTS

Nine cattle (18.75%) and 20 sheep (40%) were suffered from ptb. ASCA antibodies were present in 21/48 (43.7%) cattle and 10/50 (20%) sheep while anti-GP2 antibodies were present in 14/48 (29.2%) cattle, and 8/50 (16%) sheep. ASCA antibodies were more prevalent in anti-MAP antibody positive (14/29, 48.3%) than in anti-MAP negative ruminants (17/69, 24.6%, P=0.022) and also in anti-GP2 antibody positive (13/23, 56.5%) than in anti-GP2 negative ruminants (18/75, 24%, P=0.003). No association between ASCA and anti-MAP antibody concentrations were found (r=0.159, P=0.117). A significant association between ASCA and anti-GP2 antibody concentration were observed (r=0.211 and P=0.037).

CONCLUSION

ASCA are present in a significant proportion of ruminants with ptb and correlate with anti-GP2 antibody positivity, a finding further supporting the notion that Crohn's disease and ptb share common immunological mechanisms of antigen-driven loss of self-tolerance.

Microbial Biomarkers in Patients with Nonresponsive Celiac Disease

BACKGROUND AND AIMS

In nonresponsive celiac disease (NRCD), the symptoms and duodenal damage persist despite a gluten-free diet. Celiac disease patients with persistent symptoms are found to have a dysbiotic microbiota. We thus hypothesized that increased seroreactivity to the serum gluten-sensitive microbial antibodies Saccharomyces cerevisiae (ASCA), Pseudomonas fluorescens-associated sequence (I2), and Bacteroides caccae TonB-linked outer membrane protein (OmpW) is associated with NRCD.

METHODS

ASCA, I2 and OmpW were measured in 20 seronegative CD patients with persistent villous damage despite strict dietary treatment (NRCD group). Fifty-eight responsive patients served as CD controls (55 on gluten-free treatment) and 80 blood donors as non-CD controls.

RESULTS

At least one microbial marker was positive in 80% of NRCD patients, in 97% of untreated CD and 87% of treated CD patients, and in 44% of controls. NRCD patients had the highest frequency of ASCA positivity (65% vs 52, 20, and 0%, respectively) and also significantly higher ASCA IgA (median 14.5 U/ml) and IgG (32.5 U/ml) titers than treated CD patients (7.0 U/ml, 13.0 U/ml) and non-CD controls (4.5 U/ml, 5.8 U/ml). The frequencies of I2 and OmpW were lower in NRCD than in untreated CD (65% and 45% vs 86% and 59%, respectively), and I2 titers were higher in NRCD (median absorbance 0.76) and untreated (1.0) and treated (0.83) CD than controls (0.32). OmpW was elevated in untreated (1.1) and treated (0.94) CD patients compared with controls (0.79).

CONCLUSIONS

Seropositivity and high titers of ASCA are associated with NRCD and might serve as an additional follow-up tool in CD.

Development and Validation of a Novel Prediction Model for Differential Diagnosis Between Crohn's Disease and Intestinal Tuberculosis

BACKGROUND

Although colonoscopy is useful for differentiating between Crohn's disease (CD) and intestinal tuberculosis (ITB), the technique has limitations. We developed a practical prediction model for differentiating between CD and ITB using laboratory and radiologic parameters and colonoscopic characteristics.

METHODS

We prospectively enrolled 80 patients newly diagnosed with CD (n = 40) and ITB (n = 40). We developed a new prediction score by integrating colonoscopic, laboratory, and radiologic parameters. The score's predictive ability was validated on an additional 37 patients.

RESULTS

The accuracy of colonoscopic scoring for differentiation was 81.2% (65/80), with 65.0% sensitivity for CD and 97.5% for ITB. In multivariate analysis, positive IgA and/or IgG anti-Saccharomyces cerevisiae antibody and involvement of the proximal intestine were the independent laboratory and radiologic parameters for CD, and positive QuantiFERON-TB Gold In-Tube Test and typical pulmonary TB findings were the parameters for ITB. A new prediction scoring combining colonoscopic, laboratory, and radiologic factors increased the accuracy of diagnosis from 81.2% to 96.3% (77/80). The CD prediction score (from -2 to 2) estimated the likelihood of CD, from 0.3% for patients scoring -2 to 100% for patients scoring 2. The area under the receiver operating characteristic curve of the score was 0.990 in the development group and 0.981 in the validation group.

CONCLUSIONS

The new prediction model using a CD prediction score can be useful for calculating the probability of either CD or ITB at initial evaluation (NCT01392365).

Anti-Saccharomyces cerevisiae antibodies (ASCA) are associated with body fat mass and systemic inflammation, but not with dietary yeast consumption: a cross-sectional study

BACKGROUND

Baker's/brewer's yeast, Saccharomyces cerevisiae, has been used as an alternative to antibiotic growth promoters to improve growth performance in animals. In humans, Saccharomyces cerevisiae is among the most commonly detected fungi in fecal samples and likely originates from food. Recently, an association between anti-Saccharomyces cerevisiae antibodies (ASCA) and obesity in humans was suggested, but the cause of the elevated ASCA levels is not clear. Our aim was to study ASCA in morbidly obese subjects and explore potential associations with anthropometrics, diet, co-morbidities and biomarkers of inflammation and gut permeability.

METHODS

Subjects with morbid obesity referred to a specialized hospital unit were included. Diet and clinical data were recorded with self-administered questionnaires. Main dietary sources of baker's/brewer's yeast (e.g. bread and beer) were used as a proxy for the intake of yeast. Laboratory analyses included ASCA, serum zonulin (reflecting gut permeability), C-reactive protein and a routine haematological and biochemical screening.

RESULTS

One-hundred-and-forty subjects; 109 (78%) female, 98 with dietary records, mean age 43 years and BMI 42 kg/m2 were included. The number of ASCA positive subjects was 31 (22%) for IgG, 4 (2.9%) for IgA and 3 (2.1%) for IgM. Age, body fat mass and C-reactive protein were significantly higher in IgG-positive compared to IgG-negative subjects (P < 0.05). A borderline significant association was found between elevated zonulin and ASCA IgG-positivity (P = 0.06). No association was found between yeast-containing food and ASCA IgG-positivity, or between yeast-containing food and fat mass.

CONCLUSIONS

The findings indicate that ASCA IgG-positivity may be linked to the generalized inflammation commonly seen with increased adiposity, but not to dietary yeast intake. Other potential causes for the raised ASCA IgG concentrations, such as genetic predisposition, deviations in the gut microbiota and cross-reactivity of ASCA with other antigens, were not explored.

Midkine in vitamin D deficiency and its association with anti-Saccharomyces cerevisiae antibodies

OBJECTIVES AND DESIGN

The growth factor midkine (MK) is a protein that is involved in cancer, inflammation, immunity. Vitamin D is a potent immunomodulator. Anti-Saccharomyces cerevisiae antibody (ASCA) is reported in autoimmune disorders, some of which are among the causes of vitamin D deficiency. The objective of this study was to investigate a possible association of MK and ASCA with vitamin D deficiency.

MATERIALS AND METHODS

208 adults presented to internal medicine outpatient clinic for history and physical examination has been studied. Serum biochemistry, vitamin D, MK, ASCA-IgG and -IgA, IL-1β, IL-6, IL-8, TNF-α, PDGF, VEGF were obtained.

RESULTS

Vitamin D deficiency was 74.2%. Serum MK level was significantly higher in vitamin D-deficient compared to vitamin D-sufficient individuals (1138.1 ± 262.8 vs 958.6 ± 189 pg/mL, respectively; P < 0.009). Serum MK levels were also significantly higher in both ASCA-IgG and -IgA positives compared to negatives (1318.5 ± 160.3 vs 1065.5 ± 256.1, P = 0.008 and 1347.7 ± 229.7 vs 1070.1 ± 250.9 pg/mL, P = 0.011, respectively). Vitamin D was significantly lower in ASCA positives (P = 0.044).Vitamin D showed positive correlation with IL-1β (r 0.338, P < 0.009) and negative correlation with VEGF (r -0.366, P < 0.004).

CONCLUSIONS

MK was significantly elevated in vitamin D deficiency and associated with ASCA positivity which was significantly increased in vitamin D deficiency. These findings suggested that molecular mechanism of vitamin D deficiency may be related with some inflammatory processes.

Baker's yeast (Saccharomyces cerevisiae) antigen in obese and normal weight subjects

Baker's yeast (Saccharomyces cerevisiae) and its cell wall components have been used as one of the alternatives to antibiotic growth promoters in the feed industry. Antibodies to cell wall mannan of this yeast (ASCA) have been traditionally used in the study of Crohn's disease (CD). We applied ASCA in relation to obesity. This study aims (i) to determine the concentration of ASCA (immunoglobulin A [IgA] and immunoglobulin G [IgG]) in obese compared with normal weight individuals and (ii) to determine if there is a correlation between ASCA concentrations, obesity indices and C-reactive protein. Forty obese individuals (body mass index [BMI] > 35 kg m(-2) ) and 18 healthy (BMI < 25 kg m(-2) ) volunteers participated in this case-control study. Binding activity of serum IgA and IgG to the cell wall mannan of S. cerevisiae was measured by enzyme-linked immunosorbent assay. More than one-third of the obese individual (35%) showed elevated titres of ASCA compared with the control group (5%). This antibody was positively associated with weight (P = 0.01), BMI (P = 0.02) and waist circumference (P = 0.02), but not with C-reactive protein. It seems that ASCA are not only specific for CD but are also associated with obesity. S. cerevisiae or a related antigen may play a role in the matrix of this complex condition.

Increased antibody response to microbial antigens in patients with Crohn's disease and their unaffected first-degree relatives

BACKGROUND

Antibodies directed towards bacterial antigens are considered as serological markers of Crohn's disease. Their role in disease pathogenesis is still under investigation.

AIM

Assess the serologic response towards microbial antigens in Crohn's disease patients, their unaffected first-degree relatives and healthy controls.

METHODS

This retrospective study included 60 Crohn's disease patients, 86 unaffected first-degree relatives and 100 healthy controls. Their sera were tested for anti-chitobioside, anti-laminaribioside, anti-mannobioside, anti-Saccharomyces cerevisiae and anti-outer membrane porin C of Escherichia coli.

RESULTS

The prevalence of anti-chitobioside and anti-laminaribioside was higher in Crohn's disease patients and their first-degree relatives than in healthy controls (51.67%, 61.63% and 8%, respectively, for anti-chitobioside and 76.17%, 88.37% and 23.00% for anti-laminaribioside; p<0.0001). The cumulative semiquantitative immune response against all the tested antibodies was higher in unaffected relatives than in healthy controls (p<0.001). The quantitative analysis revealed that serum levels of anti-chitobioside, anti-laminaribioside and anti-mannobioside were similar in first-degree relatives and Crohn's disease patients and higher than healthy controls (p<0.001).

CONCLUSIONS

Both qualitative and quantitative analysis revealed that unaffected first-degree relatives have increased antibody response to microbial antigens. This impaired immunological response towards enteric microorganisms may result from a genetic predisposition.

Pattern recognition receptor and autophagy gene variants are associated with development of antimicrobial antibodies in Crohn's disease

BACKGROUND

We sought to investigate whether variants in genes involved in bacterial sensing and autophagy (NOD2, TLR5, IRGM, ATG16L1) and the interleukin-23 signaling pathway (IL12B, IL23R, STAT3) were associated with development of antimicrobial antibodies in patients with Crohn's disease (CD).

METHODS

A cohort of 616 CD patients from a tertiary referral hospital (Mount Sinai Hospital, Toronto) was evaluated. DNA was tested for three CD-associated NOD2 variants (3020insC, G908R, R702W), variants in IRGM, ATG16L1, IL12B, IL23R, STAT3, and a TLR5-stop mutation. Serum was analyzed by enzyme-linked immunosorbent assay (ELISA) for anti-Saccharomyces cerevisiae (ASCA) IgG and IgA, anti-outer membrane porin C (anti-ompC), anti-Cbir1 flagellin, and anti-Pseudomonas fluorescens (anti-I2).

RESULTS

NOD2 3020insC was associated with cumulative seroreactivity by quartile sum (P = 0.003) and number of positive antibodies (P = 0.02). NOD2 G908R was also associated with quartile sum (P = 0.05). Increased ASCA seropositivity was associated with NOD2 3020insC (odds ratio [OR] = 1.9, P = 0.02) and G908R (OR = 1.8, P = 0.05), and ATG16L1 T300A (OR = 1.4, P = 0.01) variants; ASCA-positive patients had an increased cumulative number of NOD2 3020insC and ATG16L1 T300A variants (P = 0.007). TLR5-stop mutation abrogated development of anti-flagellin in a dominant-negative fashion (OR = 0.5, P = 0.009). The IRGM CD risk variant was associated with increased anti-flagellin seropositivity (OR = 1.5, P = 0.03). IL12B, IL23R, and STAT3 variants did not contribute to development of antimicrobial antibodies.

CONCLUSIONS

Variants in innate immune genes involved in pattern recognition and autophagy but not the interleukin-23 signaling pathway influence antimicrobial seroreactivity in CD. In particular, the additive effect of NOD2 3020insC and ATG16L1 T300A suggests a role for autophagy in development of ASCA.

Serological antibodies in inflammatory bowel disease: a systematic review

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

Increased levels of anti-glycan antibodies in patients with cystic fibrosis

Background

The prevalence of Crohn's disease (CD) is increased in patients with cystic fibrosis (CF). Anti-Saccharomyces cerevisiae antibodies (ASCA) have been suggested as a screening tool to detect CD in CF. Recently, several new anti-glycan antibodies have been reported in CD.

Materials and methods

The sera of 119 CF patients of various age groups were prospectively screened for ASCA type IgG (gASCA), anti-laminaribioside carbohydrate IgG antibodies (ALCA), anti-chitobioside carbohydrate IgA antibodies (ACCA), and anti-mannobioside carbohydrate IgG antibodies (AMCA). The frequency of these anti-glycan antibodies was then compared in patients with CD, ulcerative colitis, rheumatoid arthritis and healthy volunteers.

Results

A significant number of CF patients were positive for gASCA (51.3% [41.6-60.6]) and up to three other anti-glycan antibodies concurrently. Serum levels of anti-glycan antibodies in CF and CD were not related to parameters of inflammation. Despite the well-documented difference in clinical course between male and female CF patients no gender difference of anti-glycan antibodies was found. In contrast, there was a significant positive correlation between anti-glycan markers and age in CF patients.

Conclusions

Our findings demonstrate for the first time the increased frequency of a panel of anti-glycan antibodies in CF and provide a link between the presence of these serological biomarkers and patient's age. Anti-glycan antibody profiling may therefore become a valuable tool in the care of patients with CF.

Antibodies anti-Saccharomyces cerevisiae (ASCA) do not differentiate Crohn's disease from celiac disease

CONTEXT

Anti-Saccharomyces cerevisiae antibodies (ASCA), considered serologic markers for Crohn's disease, were described in patients with celiac disease, disappearing after a gluten-free diet.

OBJECTIVES

Evaluation of ASCA positivity in patients with Crohn's disease and celiac disease in relation to healthy individuals.

METHODS

A total of 145 individuals were studied: 36 with Crohn's disease and 52 with celiac disease, that fulfilled the diagnostic criteria for both affections, and 57 healthy individuals for control. The celiac patients were divided as follow: group CeD I at diagnosis (n = 34), group CeD II with gluten-free diet compliance (n = 13) and group CeD III with transgressions to the diet (n = 5). ASCA IgA and IgG were determined by ELISA.

RESULTS

With statistical significance, ASCA IgA were positive in Crohn's disease, celiac disease at diagnosis and celiac disease with diet transgressions; ASCA IgG in Crohn's disease and in all groups with celiac disease.

CONCLUSIONS

The detection of ASCA in patients with celiac disease allows to suggest that ASCA is not a specific marker for Crohn's disease, but was associated with the inflammation of the small intestine. The increased levels of positive ASCA may be due to genetic factors and increased intestinal permeability.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

Intestinal barrier gene variants may not explain the increased levels of antigliadin antibodies, suggesting other mechanisms than altered permeability

Various genes may influence intestinal barrier function, including MAGI2, MYO9B, and PARD3, which are associated with celiac disease. Because direct measurement of intestinal permeability is difficult, antibodies against gliadin (AGA) and Baker's yeast (anti-Saccharomyces cerevisiae antibodies [ASCA]) can be used as an indirect test. The objective of this study was to investigate whether intestinal permeability, represented by AGA, was correlated with MAGI2, MYO9B, and PARD3. Analyses were performed in patients with Down syndrome, a population with suspected increased intestinal permeability. Correlations between AGA and ASCA were investigated. Patients with Down syndrome (n = 126) were genotyped for six single-nucleotide polymorphisms in MAGI2 (rs1496770, rs6962966, rs9640699), MYO9B (rs1457092, rs2305764), and PARD3 (rs10763976). An allele dosage association of these risk genes and AGA levels was performed. The correlation between AGA and ASCA was studied. A strong correlation was found between AGA and ASCA (p < 0.01). The patient group with one or more risk genotypes had lower mean AGA levels (trend test p = 0.007) and consisted of a larger number of patients with normal AGA levels (p = 9.3 x 10(-5)). Celiac-associated risk genotypes are associated with lower AGA values instead of elevated ones. Thus, other immunologic phenomena play a role in the increased prevalence of elevated AGA in patients with Down syndrome, possibly involving altered induction and/or maintenance of tolerance.

Anti-microbial antibodies in celiac disease: Trick or treat?

AIM: To determine the prevalence of a new set of anti-glycan and anti-outer membrane protein (anti-OMP) antibodies in a Hungarian cohort of adult Celiac disease (CD) patients.

METHODS: 190 consecutive CD patients [M/F: 71/119, age:39.9 (SD:14.1) years], 100 healthy, and 48 gastrointestinal controls were tested for glycan anti-Saccharomyces cerevisiae (gASCA), anti-laminaribioside (ALCA), anti-chitobioside, anti-mannobioside, anti-OMP antibodies and major NOD2/CARD15 mutations. Thirty out of 82 CD patients enrolled at the time of diagnosis were re-evaluated for the same antibodies after longstanding gluten-free diet (GFD).

RESULTS: 65.9% of the CD patients were positive for at least one of the tested antibodies at the time of the diagnosis. Except anti-OMP and ALCA, anti-microbial antibodies were exclusively seen in untreated CD; however, the overall sensitivity was low. Any glycan positivity (LR+: 3.13; 95% CI: 2.08-4.73) was associated with an increased likelihood ratio for diagnosing CD. Significant correlation was found between the levels of anti-glycan and anti-endomysial or anti-transglutaminase antibodies. Anti-glycan positivity was lost after longstanding GFD. Anti-glycan antibody titers were associated with symptoms at presentation, but not the presence of NOD2/CARD15 mutations. Patients with severe malabsorption more frequently had multiple antibodies at diagnosis (P = 0.019).

CONCLUSION: The presence of anti-glycan antibodies in CD seems to be secondary to the impaired small bowel mucosa which can lead to increased antigen presentation. Furthermore, anti-glycan positivity may be considered an additional marker of CD and dietary adherence.

Novel anti-glycan antibodies related to inflammatory bowel disease diagnosis and phenotype

OBJECTIVES

We sought to evaluate whether two novel immunoglobulin A (IgA) cell wall polysaccharide antibodies, anti-laminarin (anti-L) and anti-chitin (anti-C), aid in the diagnosis and phenotype differentiation of Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

A cohort of 818 individuals with inflammatory bowel disease (IBD; 517 CD and 301 UC) from two IBD tertiary referral centers, with median ages of 33 and 39 years, respectively, and disease duration of 8.9 years, were phenotyped using the Montreal classification, and analyzed for seven anti-glycan antibodies (gASCA (anti-Saccharomyces cerevisiae) IgG, gASCA IgA, anti-chitobioside (GlcNAc(beta1,4)GlcNAc(beta)), anti-laminaribioside (Glc(beta1,3)Glb(beta)), anti-mannobioside (Man(alpha1,3)Man(alpha)), anti-L, and anti-C) and perinuclear atypical neutrophil cytoplasmic antibodies (pANCA).

RESULTS

In the CD patient population, 73% were positive for >/=1 anti-glycan antibody. All glycan markers were specific for CD (85.4-97.7%) and more prevalent in CD vs. UC (P<0.0015). gASCA IgG and IgA best differentiated CD from UC followed by anti-L (area under the curve 0.818, 0.815, and 0.702, respectively). The addition of anti-L and anti-C to gASCA IgG and pANCA improved discrimination between CD and UC (P<0.001). Adding anti-L to gASCA and pANCA differentiated colonic CD and UC (P=0.02). An increasing number of positive antibodies was associated with early CD onset, penetrating phenotype, perianal disease, and the need for surgery (P<0.001). Anti-L was associated with ileocolonic CD (odds ratio (OR) 2.28, 95% confidence interval (CI) 1.40-3.69; P=0.001), and anti-C with penetrating (OR 2.75, 95% CI 1.50-5.04; P=0.001) and perianal disease (OR 1.95, 95% CI 1.06-3.59; P=0.03).

CONCLUSIONS

Anti-L and anti-C improve differentiation between CD and UC. Anti-L may also differentiate between isolated colonic CD and UC. Both anti-L and anti-C are independently associated with a more aggressive CD phenotype.

New serological biomarkers of inflammatory bowel disease

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

Antiglycan antibodies as serological markers in the differential diagnosis of inflammatory bowel disease

BACKGROUND

The objective of the study was to evaluate the diagnostic accuracy of recently developed antiglycan serological tests in clinical practice for the diagnosis of Crohn's disease.

METHODS

This study was a cohort analysis of both clinical and biochemical parameters of patients with diagnosed inflammatory bowel disease compared with those in a control population. Antiglycan antibodies were determined using commercially available enzyme immunoassays. The setting was the outpatient unit of the gastroenterology department of a large, tertiary-care referral academic hospital. Participants were 214 consecutive patients, enrolled over a 5-month period, including 116 with Crohn's disease and 53 with ulcerative colitis, as well as 45 with other gastrointestinal diseases and 51 healthy controls.

RESULTS

Anti-Saccharomyces cerevisiae antibodies showed the best performance (54% sensitivity and 88%-95% specificity for Crohn's disease). Among patients with negative anti-Saccharomyces antibodies, 19 (34%) had high titers of at least another tested antiglycan antibody. Anti-Saccharomyces and anti-laminaribioside antibodies were associated with disease involving the small bowel and with penetrating or stricturing phenotype. Anti-laminaribioside was significantly higher in patients with a familial history of inflammatory bowel disease.

CONCLUSIONS

The new proposed serological markers are significantly associated with Crohn's disease, with low sensitivity but good specificity. About one third of anti-Saccharomyces-negative patients may be positive for at least 1 of those markers. Antiglycan antibodies appear to be associated with characteristic localization and phenotype of the disease.

IgG antibodies against common gut bacteria are more diagnostic for Crohn's disease than IgG against mannan or flagellin

INTRODUCTION

Antibodies to baker's yeast (mannan) have been widely used to aid in diagnosis of Crohn's disease. Recently, there has been interest in antibodies against a flagellin from Clostridium coccoides subphylum. We hypothesized that reactivity with these antigens is a surrogate marker for a generalized increased IgG response against intestinal microbiota in Crohn's disease.

METHODS

We compared the diagnostic utility of IgG antibodies against flagellin and mannan with two complex surface antigen preparations, one derived from B. vulgatus (Bv), the other from over 20 common mucosa-associated microbiota, a multibacterial membrane preparation (MBP). IgG antibodies were measured in sera from two age- and sex-matched populations: 120 Crohn's patients (CD) and 160 gastroenterology controls (CON) comprising 40 ulcerative colitis (UC) and 120 non-IBD patients.

RESULTS

IgG was elevated against all antigen preparations in Crohn's but statistical analysis of receiver operator characteristic (ROC) plots showed that IgG against the complex antigen preparations MBP and Bv had better diagnostic accuracy to distinguish the two populations (CD and CON) than IgG against mannan (P < or = 0.01) or flagellin (P < or = 0.04). Concentrations of antibody reactive with distinct individual antigens correlated weakly.

DISCUSSION

The findings support our hypothesis that measurement of IgG reactivity against individual antigens gives an indication of a generalized increased IgG response against individual intestinal microbiota in Crohn's, rather than measuring specific immune responses important for pathogenesis. The data are consistent with either a mucosal defect that facilitates increased exposure to microbial antigens or an altered immune response, both of which could occur due to known genetic and molecular defects in Crohn's disease.

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.

Seroreactivity to microbial components in Crohn's disease is associated with ileal involvement, noninflammatory disease behavior and NOD2/CARD15 genotype, but not with risk for surgery in a Hungarian cohort of IBD patients

BACKGROUND

Antibodies directed against Saccharomyces cerevisiae (ASCA), perinuclear components of neutrophils (pANCA), and porin protein C of Escherichia coli (anti-OmpC) are reported to be associated with disease phenotype and may be of diagnostic importance in inflammatory bowel disease (IBD). Since limited data are available from Eastern Europe, we assessed the above antibodies in Hungarian IBD patients.

METHODS

In all, 653 well-characterized, unrelated consecutive IBD patients (Crohn's disease [CD]: 558, m/f: 263/295, duration: 8.1 +/- 10.7 years; ulcerative colitis [UC]: 95, m/f: 44/51, duration: 8.9 +/- 9.8 years) and 100 healthy subjects were investigated. Sera were assayed for anti-Omp and ASCA by enzyme-linked immunosorbent assay (ELISA) and ANCA by indirect immunofluorescence assay (IIF). TLR4 and NOD2/CARD15 variants were tested by polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP). Detailed clinical phenotypes were determined by reviewing the medical charts.

RESULTS

Anti-Omp, ASCA, and atypical pANCA antibodies were present in 31.2%, 59.3%, and 13.8% of CD, 24.2%, 13.7%, and 48.5% of UC patients, and in 20%, 16%, and 5.6% of controls, respectively. ASCA and anti-Omp positivity were associated with increased risk for CD (odds ratio [OR](ASCA) = 7.65, 95% confidence interval [CI]: 4.37-13.4; OR(Omp) = 1.81, 95% CI: 1.08-3.05). In a logistic regression analysis, anti-Omp and ASCA were independently associated with ileal and noninflammatory disease, but not with a risk for surgery or response to steroids or infliximab. A serology dosage effect was also observed. ASCA and anti-Omp antibodies were associated with NOD2/CARD15, in addition to a gene dosage effect. No associations were found in UC.

CONCLUSIONS

Serological markers were useful in the differentiation between CD and UC in an Eastern European IBD cohort. Reactivity to microbial components was associated with disease phenotype and NOD2/CARD15 genotype, further supporting the role of altered microbial sensing in the pathogenesis of CD.

[Relevance of serologic studies in inflammatory bowel diseases]

The panel of serologic markers for inflammatory bowel diseases (IBDs) is rapidly expanding. Although anti- Saccharomyces cerevisiae antibodies (ASCA) and atypical perinuclear antineutrophil cytoplasmic antibodies (atypical P-ANCA) remain the most widely investigated, an increasing amount of experimental data is available on newly discovered antibodies directed against various microbial antigens. Such antibodies include anti-OmpC (outer membrane porin C), anti- Pseudomonas fluorescens (anti-I2) and antiglycan antibodies (anti-laminaribioside carbohydrate antibody [ALCA]), anti-chitobioside carbohydrate antibody [ACCA]), anti-mannobioside carbohydrate antibody [AMCA]) and anti-CBir1; this latter is the first bacterial antigen to induce colitis in animal models of IBD and also leads to a pathological immune response in IBD patients (anti-flagellin antibody). The role of assessment of various antibodies in the current diagnostic algorithm of IBD is rather questionable due to their limited sensitivity. In contrast, the association of serologic markers with disease behavior and phenotype is getting more into the focus of interest. An increasing number of observations confirm that patients with Crohn's disease expressing multiple serologic markers at high titers are more likely to have complicated small bowel disease (e.g. stricture and/or perforation) and are at higher risk for surgery than those without, or with low titer of antibodies. Creating homogenous disease sub-groups based on serologic response may help develop more standardized therapeutic approaches and may help in a better understanding of the pathomechanism of IBD. Further prospective clinical studies are needed to establish the clinical role of serologic tests in IBD.

Update on Anti-Saccharomyces cerevisiae antibodies, anti-nuclear associated anti-neutrophil antibodies and antibodies to exocrine pancreas detected by indirect immunofluorescence as biomarkers in chronic inflammatory bowel diseases: Results of a multicenter study

AIM: Anti-Saccharomyces cerevisiae antibodies (ASCA), anti-nuclear associated anti-neutrophil antibodies (NANA) and antibodies to exocrine pancreas (PAB), are serological tools for discriminating Crohn’s disease (CrD) and ulcerative colitis (UC). Like CrD, coeliac disease (CoD) is an inflammatory bowel disease (IBD) associated with (auto) antibodies. Performing a multicenter study we primarily aimed to determine the performance of ASCA, NANA and PAB tests for IBD diagnosis in children and adults, and secondarily to evaluate the prevalence of these markers in CoD.

METHODS: Sera of 109 patients with CrD, 78 with UC, 45 with CoD and 50 healthy blood donors were retrospectively included. ASCA, NANA and PAB were detected by indirect immunofluorescence (IIF).

RESULTS: ASCA+/NANA- profile displayed a positive predictive value of 94.2% for CrD. Detection of ASCA was correlated with a more severe clinical profile of CrD and treatment of the disease did not influence their serum levels. ASCA positivity was found in 37.9% of active CoD. PAB were found in 36.7% CrD and 13.3% CoD patients and were not correlated with clinical features of CrD, except with an early onset of the disease. Fifteen CrD patients were ASCA negative and PAB positive.

CONCLUSION: ASCA and PAB detected by IIF are specific markers for CrD although their presence does not rule out a possible active CoD. The combination of ASCA, NANA and PAB tests improves the sensitivity of immunological markers for CrD. Repeating ASCA, NANA, and PAB testing during the course of CrD has no clinical value.

Utility of serological markers in inflammatory bowel diseases: Gadget or magic?

The panel of serologic markers for inflammatory bowel diseases (IBD) is rapidly expanding. Although anti-Saccharomyces cerevisiae antibodies (ASCA) and atypical perinuclear antineutrophil cytoplasmic antibodies (P-ANCA) remain the most widely investigated, an increasing amount of experimental data is available on newly discovered antibodies directed against various microbial antigens. The role of the assessment of various antibodies in the current IBD diagnostic algorithm is often questionable due to their limited sensitivity. In contrast, the association of serologic markers with disease behavior and phenotype is becoming increasingly well-established. An increasing number of observations confirms that patients with Crohn’s disease expressing multiple serologic markers at high titers are more likely to have complicated small bowel disease (e.g. stricture and/or perforation) and are at higher risk for surgery than those without, or with low titers of antibodies. Creating homogenous disease sub-groups based on serologic response may help develop more standardized therapeutic approaches and may help in a better understanding of the pathomechanism of IBD. Further prospective clinical studies are needed to establish the clinical role of serologic tests in IBD.

Anti-Saccharomyces cerevisiae antibody does not differentiate between Crohn's disease and intestinal tuberculosis

The clinical, morphological, and histological features of intestinal tuberculosis (IT) and Crohn's disease (CD) mimic so much, that it becomes difficult to differentiate between them. The sensitivity of anti-Saccharomyces cerevisiae antibody (ASCA) IgG and ASCA IgA in CD is 60%-80%, whereas the specificity is almost 90%. There are no reports of study of ASCA in patients with IT, nor has it ever been used to differentiate CD from IT. Patients with ulcerative colitis (UC; n=25), CD (n=59), and IT (n=30) and 21 healthy controls were included in this study. The location and behavior of CD were classified according to the Modified Montreal classification. Five milliliters of blood was taken from them and serum was stored at -70 degrees C. ASCA antibodies (both IgG and IgA) were estimated using commercially available ELISA kits (AESKU Diagnostics, Germany). Anti-neutrophilic cytoplasmic antibody was measured by indirect immunofluorescence test. ASCA IgA was positive in 4.7%, 28%, 33.9%, and 43.3% and ASCA IgG was positive in 4.7%, 24%, 50.8%, and 46.6% of healthy controls and patients with UC, CD, and IT, respectively. Either ASCA IgG or ASCA IgA was positive in 9.5%, 40%, 61% and 66.6% of healthy controls, UC, CD, and IT, respectively. ANCA was positive in 0%, 32%, 10.1%, and 6.6% of healthy controls, UC, CD, and IT, respectively. ASCA IgG was positive in a significantly higher number of patients with CD (P<0.0001) and IT (P<0.0001) in comparison to healthy controls. ASCA IgA was positive in a significantly higher number of patients with UC (P<0.04), CD (P<0.013), and IT (P<0.006) in comparison to healthy controls. In comparisons between diseases, ASCA IgG was positive in significantly more patients with CD (P<0.001) and IT (P<0.001) in comparison to UC. There was no significant difference in ASCA IgA (33.9% vs. 43.3%), ASCA IgG (50.86% vs. 46.6%), or ANCA (10.7%, 7.4%) in patients with CD and IT, respectively. There was no correlation between ASCA and duration, location and behavior of CD, and IT. We conclude that ASCA IgG and ASCA IgA do not help to differentiate between IT and CD.

Antibodies against laminaribioside and chitobioside are novel serologic markers in Crohn's disease

BACKGROUND & AIMS

New serologic markers of inflammatory bowel disease may be useful for differentiating between Crohn's disease and ulcerative colitis and for disease stratification. We profiled sugar-binding antibodies to identify novel antiglycan antibodies that may be associated with inflammatory bowel disease.

METHODS

Serum samples were obtained from patients with diagnosed Crohn's disease or ulcerative colitis and from control patients. The presence of antiglycan antibodies was evaluated using either a glycan array (GlycoChip; Glycominds, Ltd, Lod, Israel) in patients with Crohn's disease (n = 72) or ulcerative colitis (n = 56) and in healthy controls (n = 41) or using an enzyme-linked immunosorbent assay in patients with Crohn's disease (n = 124), ulcerative colitis (n = 106), and in control patients (n = 101).

RESULTS

Inaddition to antibodies against mannan, antibodies to laminaribioside (Glc[beta1,3]Glc[beta]) and chitobioside (GlcNAc[beta1,4]GlcNAc[beta]) had the highest discriminative capability between Crohn's disease and ulcerative colitis (P < .001 and P < .05, respectively). Importantly, 44% (12/27) of anti-Saccharomyces cerevisiae antibody-negative Crohn's disease patients were positive for antilaminaribioside or antichitobioside. In patients with inflammatory bowel disease positive for antibodies against either laminaribioside, chitobioside, or mannan, the diagnosis of Crohn's disease was suggested with a sensitivity of 77.4% and specificity of 90.6%. Having at least 2 of these antibodies increased the specificity to 99.1%. In Crohn's disease, higher levels of antibodies against laminaribioside or mannan were significantly associated with small intestinal disease (P = .03 and P < .0001, respectively).

CONCLUSIONS

Antilaminaribioside and antichitobioside carbohydrate antibodies are novel serologic markers associated with Crohn's disease. These antibodies may contribute to the diagnosis and improved stratification of Crohn's disease.

Correlation between Saccharomyces cerevisiae DNA in intestinal mucosal samples and anti-Saccharomyces cerevisiae antibodies in serum of patients with IBD

AIM: To investigate the correlation between ASCA and presence of mucosal S. cerevisiae DNA in a population of CD, ulcerative colitis (UC) patients and controls.

METHODS: S. cerevisiae-specific primers and a fluorescent probe were designed for a 5’ exonuclease real time PCR (TaqMan^TM) assay, which is a homogenous system using a fluorescent-labelled probe for the detection of PCR product in real time. We analyzed the relation of the PCR results with the ASCA findings in a group of 76 inflammatory bowel disease (IBD) patients (31 CD, 45 UC) and 22 healthy controls (HC).

RESULTS: ASCA (IgA or IgG) were positive in 19 (61%) patients with CD, 12 (27%) with UC and none of the HC. PCR amplification was inhibited and excluded from the final results in 10 (22%) UC patients, 7 (22%) CD patients, and 6 (30%) HC. In only 15 of the mucosal samples, S. cerevisiae DNA was detected by real time PCR, including 7 (29%) in CD, 7 (19%) in UC, 1 (6%) in HC. In 4 CD and in 4 UC patients, ASCA and mucosal S. cerevisiae were positive. Mucosal S. cerevisiae was present in combination with negative ASCA IgA and IgG in 3 UC, and 3 CD patients.

CONCLUSION: We conclude that since the presence of S. cerevisiae in colonic mucosal biopsy specimens is very rare, ASCA is unlikely to be explained by continuous exposure to S. cerevisiae in the mucosa. Therefore, ASCA formation must occur earlier in life and levels remain relatively stable thereafter in immunological susceptible persons.

Disappearance of anti-Saccharomyces cerevisiae antibodies in coeliac disease during a gluten-free diet

BACKGROUND

Anti-Saccharomyces cerevisiae antibodies (ASCAs) are known to be positive in about 65% of Crohn's disease patients, in up to 43% of coeliac disease patients and in 0-5% of healthy controls. Coeliac disease might be an in-vivo model for unravelling the role of mucosal integrity in the formation of ASCAs since mucosal abnormalities normalize during a gluten-free diet (GFD).

AIMS

Firstly, to evaluate, retrospectively, the frequency of ASCA positivity in coeliac patients both at diagnosis and during follow-up on a GFD. Secondly, to study the correlation between ASCA positivity and mucosal damage.

METHODS

One hundred and eleven patients with histologically proven coeliac disease, positive endomysium antibodies on diagnosis and normalization of trans-glutaminase antibodies (t-TGAs) after successful adherence to a GFD were included. ASCAs, IgA and IgG were tested by enzyme-linked immunosorbent assays both at diagnosis and after the GFD.

RESULTS

Eighty-three children and 28 adults were included in this study. The mean age at diagnosis was 4.6 years for children and 48 years for adults. At diagnosis 15/83 (18%) of children were ASCA positive (either IgG or IgA), compared to 17/28 (61%) of adults. After successful adherence to a GFD and normalization of t-TGAs only one child remained ASCA positive (1%) compared to eight adults (29%). Two out of 28 (7%) adults remained positive for both IgA and IgG ASCAs.

CONCLUSION

In the majority of patients ASCAs disappeared during a GFD. In children this disappearance of ASCA positivity was more pronounced. This can be explained by the well-known fact that gut permeability normalizes much better in children than in adults. Also, the adults had higher levels of ASCAs at diagnosis. This was probably because they had been exposed to gluten for longer and therefore had more long-lasting damage.

Relevance of serologic studies in inflammatory bowel disease

The serologic panel for inflammatory bowel disease (IBD) is rapidly expanding. Antineutrophil cytoplasmic antibodies (ANCA) and anti-Saccharomyces cerevisiae mannan antibodies (ASCA) have remained the most widely studied markers, but immune reactivity against a new group of bacterial antigens such as I2, OmpC (outer membrane porin C), and flagellin, has been described in Crohn's disease. Several clinical avenues have been explored, such as the usefulness of serologic markers as screening tools for IBD and in accelerating a diagnosis in patients with indeterminate colitis. Another area of interest is disease stratification. Emerging data suggest there is a diversity of qualitative and quantitative responses to environmental antigens that differs among groups of IBD patients and may be associated with different clinical behaviors. As a result, it may be possible to tailor therapy on the basis of serologic responses. Prospective studies are needed before translating this concept into clinical practice. Clustering of IBD patients into more homogeneous subgroups based on antibody responses may help to unravel the pathophysiology of subsets of IBD.