CARD15 polymorphisms are associated with anti-Saccharomyces cerevisiae antibodies in caucasian Crohn's disease patients

Diagnostic utility of serological biomarkers in patients with Crohn's disease: A case-control study

The aim of this study was to examine the expression of serological markers in patients with inflammatory bowel disease in China, and determine the diagnostic utility of serological markers, individually and in combination, for the diagnosis and differential diagnosis of Crohn's disease (CD).Serum samples were obtained from 160 participants in Eastern China. Among the participants, 98 were diagnosed with CD, 33 had ulcerative colitis (UC), and 29 were healthy controls (HC). The serum samples were tested for the presence of antibodies against outer membrane porin C (anti-OmpC), Pseudomonas fluorescens bacterial sequence I2 (anti-I2), anti-laminarin (anti-L), anti-chitin (anti-C), anti-chitobioside carbohydrate antibody (ACCA), anti-laminaribioside carbohydrate antibody (ALCA), anti-mannobioside carbohydrate antibody (AMCA), and anti-Saccharomyces cerevisiae antibody (ASCA) by indirect enzyme-linked immunosorbent assay (ELISA).Individually, anti-C, anti-L, ASCA-IgG, and ALCA lacked diagnostic value in the differentiation of CD. ASCA-IgA remained the most accurate marker for the diagnosis of CD, with an area under the curve (AUC) of 0.77; however, its sensitivity and specificity were both lower than 75%. Among the combinations of the 5 markers with significant diagnosing ability for CD, combinations with any 2 of the 3 markers, ASCA IgA, AMCA, and ACCA positive, provided the best accuracy in the diagnosis and differential diagnosis of CD (sensitivity and specificity both above 75%) and had the highest Youden index.Serological antibodies, when considered in combination, have remarkable value in the diagnosis and differential diagnosis of CD. Especially, the combination of any 2 of the 3 markers, ASCA-IgA, AMCA, ACCA positive, appears to be optimal.

Serologic microbial associated markers can predict Crohn's disease behaviour years before disease diagnosis

BACKGROUND

Patients with Crohn's disease (CD) have serologic responses to various microbial antigens. Serologic markers are associated with aggressive forms of disease and can be detected before onset of symptoms. Their utility in pre-clinical disease or prediction of complicated disease course before diagnosis is unclear.

AIM

To evaluate the pattern of serologic anti-microbial antibodies long prior to diagnosis and the subsequent risk of complicated Crohn's disease at diagnosis.

METHODS

Sera from 100 US military personnel with Crohn's disease were obtained from the Department of Defense Serum Repository. For each patient, four samples were obtained at different time points before and around diagnosis, and were tested for 6 microbiota-directed antibodies (ASCA-IgA, ASCA-IgG, anti-OmpC, anti-CBir1, anti-A4-Fla2 and anti-FlaX). Associations between the presence and accumulation of Crohn's disease anti-microbial antibodies before diagnosis and with the later development of complications were evaluated.

RESULTS

Overall, 65 patients were positive for at least one Crohn's disease associated anti-microbial antibody in the earliest available sample, at a median of 6 years before Crohn's disease diagnosis (interquartile range, 5.6-8.2). The number of positive anti-microbial antibodies increased up to the time of Crohn's disease diagnosis. Complicated disease developed around the time of diagnosis in 24 patients. The proportion of positive antimicrobial antibodies before diagnosis was higher in patients with complicated vs. noncomplicated Crohn's disease. There was an inverse relationship between the time to first complication and the magnitude of serologic response before diagnosis.

CONCLUSION

The presence and accumulation of circulating anti-microbial antibodies years before Crohn's disease diagnosis was associated with complicated Crohn's disease at or shortly after diagnosis.

A tug-of-war between the host and the pathogen generates strategic hotspots for the development of novel therapeutic interventions against infectious diseases

Microbial pathogens are known to express an array of specific signaling molecules referred as Pathogen Associated Molecular Patterns (PAMPs), which are recognized by Pattern Recognition Receptors (PRRs), present on the surface of the host cells. Interactions between PAMPs and PRRs on the surface of the host cells lead to signaling events which could culminate into either successful infection or clearance of the pathogens. Here, we summarize how these events may generate novel host based as well as pathogen based molecular targets for designing effective therapeutic strategies against infections.

Inflammatory bowel disease serology in Asia and the West

AIM: To study serological antibodies in Caucasians and Asians, in health and inflammatory bowel disease (IBD), in Australia and Hong Kong (HK).

METHODS: Anti-glycan antibodies [anti-chitobioside (ACCA), anti-laminaribioside (ALCA)], and anti-mannobioside (AMCA), anti-Saccharomyces cervisiae (gASCA); and atypical perinuclear anti-neutrophil cytoplasmic antibody (pANCA) were tested in IBD patients, their unaffected relatives, and healthy controls in Australia and HK (China). Antibody status (positive or negative) and titre was compared between subjects of different geography, ethnicity and disease state.

RESULTS: Ninety subjects were evaluated: 21 Crohn’s disease (CD), 32 ulcerative colitis (UC), 29 healthy controls, and 8 IBD patient relatives. Forty eight subjects were Australian (29 Caucasian and 19 ethnic Han Chinese) and 42 were from HK (all Han Chinese). Caucasian CD patients had a significantly higher antibody prevalence of gASCA (67% vs 3%, P < 0.001), ALCA (44% vs 6%, P = 0.005), and AMCA (67% vs 15%, P = 0.002), whereas HK CD patients had a higher prevalence of only AMCA (58% vs 25%, P = 0.035), when compared with UC and healthy subjects in both countries. Caucasian CD had significantly higher gASCA prevalence (67% vs 0%, P < 0.001) and titre (median 59 vs 9, P = 0.002) than HK CD patients. Prevalence and titres of ALCA, ACCA and AMCA did not differ between CD in the two countries. Presence of at least one antibody was higher in Caucasian than HK CD patients (100% vs 58%, P = 0.045). pANCA did not differ between countries or ethnicity.

CONCLUSION: Serologic CD responses differ between HK Asian and Australian Caucasian patients. Different genetic, environmental or disease pathogenic factors may account for these differences.

Isolated active ileitis: is it a mild subtype of Crohn's disease?

BACKGROUND

Ileal intubation is being increasingly performed at colonoscopy and has in turn lead to an increasingly recognized subgroup of patients-those with mild terminal ileal inflammation, an entity that we have coined isolated active ileitis (IAI). The aims of this study were to define the natural history of IAI and determine if IAI shares a similar genetic and serologic profile with Crohn's disease (CD).

METHODS

Patients with IAI were identified from our institution's histopathology and endoscopy databases. Cases attended for repeat colonoscopy and blood were analyzed for the expression of antineutrophil cytoplasmic antibody, anti-OmpC, anti-Saccharomyces cerevisiae antigen (ASCA) IgA, ASCA IgG, and anti-CBir antibodies and NOD2 genotyping. Age and sex-matched healthy controls, CD, and UC cases were also recruited.

RESULTS

Sixty-three patients with IAI were recruited. There was no significant difference in the prevalence of antibodies between IAI cases and healthy controls for antineutrophil cytoplasmic antibody, OmpC, ASCA IgA, or ASCA IgG. The presence of all 5 antibodies was significantly higher in the CD group than the IAI group, P < 0.05. There were 28.6% of CD cases that carried one or more NOD2 variants, compared to 26.2% of the IAI cohort and 6.1% of healthy controls. Forty-three cases underwent follow-up ileocolonoscopy. Six of 43 cases (14%) had definite CD.

CONCLUSIONS

A majority of IAI cases developed persistent symptoms and terminal ileal abnormalities; however, only 14% developed classical, histological, or radiological features of CD. Although patients with IAI have a low level of seropositivity, similar to healthy controls, they do share an excess of NOD2 mutations with CD cases.

Granulocyte-macrophage colony-stimulating factor autoantibodies: a marker of aggressive Crohn's disease

BACKGROUND

Neutralizing autoantibodies (Abs) against granulocyte-macrophage colony-stimulating factor (GM-CSF Ab) have been associated with stricturing ileal Crohn's disease (CD) in a largely pediatric patient cohort (total 394, adult CD 57). The aim of this study was to examine this association in 2 independent predominantly adult inflammatory bowel disease patient cohorts.

METHODS

Serum samples from 742 subjects from the NIDDK IBD Genetics Consortium and 736 subjects from Australia were analyzed for GM-CSF Ab and genetic markers. We conducted multiple regression analysis with backward elimination to assess the contribution of GM-CSF Ab levels and established CD risk alleles and smoking on ileal disease location in the 477 combined CD subjects from both cohorts. We also determined associations of GM-CSF Ab levels with complications requiring surgical intervention in combined CD subjects in both cohorts.

RESULTS

Serum samples from patients with CD expressed significantly higher concentrations of GM-CSF Ab when compared with ulcerative colitis or controls in each cohort. Nonsmokers with ileal CD expressed significantly higher GM-CSF Ab concentrations in the Australian cohort (P = 0.002). Elevated GM-CSF Ab, ileal disease location, and disease duration more than 3 years were independently associated with stricturing/penetrating behavior and intestinal resection for CD.

CONCLUSIONS

The expression of high GM-CSF Ab is a risk marker for aggressive CD behavior and complications including surgery. Modifying factors include environmental exposure to smoking and genetic risk markers.

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

BACKGROUND

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Serological antibodies in inflammatory bowel disease: a systematic review

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

OBJECTIVES

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

How expensive is inflammatory bowel disease? A critical analysis

Economic analysis of chronic diseases is required for proper allocation of resources and understanding cost-effectiveness studies of new therapies. Studies on health care cost of ulcerative colitis (UC) and Crohn’s disease (CD) are reviewed here. These studies were carried out in various countries with disparate health care systems. In the United States, data were often modeled or retrieved from large insurance schemes. Surgery and in-patient hospitalization accounted for over half the outlay on UC and CD. Fistulous disease in CD and parenteral nutrition were very costly. In Canada, overall charges were lower than in the United States, but there too, surgical costs were relatively high. In European studies, economic data were abstracted directly from patients’ files. One pan-European study examined the outlay on UC and CD in a community-based prospective inception cohort followed for 10 years. Overall costs in Europe were lower than in the United States. Surgery, hospitalization, year of follow-up, disease phenotype in CD and ASCA-positivity impacted significantly on costs. In all studies, the cost data were right skewed, aminosalicylates were expensive drugs, and biological agents the most expensive; moreover indirect costs were not calculated. Infliximab raised costs considerably in CD, but there were no long-term follow-up studies, so that the cost-benefit of biological agents remains unknown. In conclusion, costs of managing UC and CD vary by country, surgery, genotype and several other factors. The most important question for further research is whether the biological therapies are cost-effective in the long-term.

New biomarkers of Crohn's disease: serum biomarkers and development of diagnostic tools

Crohn's disease (CD) is a complex and heterogeneous inflammatory disorder that is part of inflammatory bowel diseases. Its diagnosis is performed on clinical presentation and results of radiography, endoscopy and histological findings. New noninvasive diagnostic biomarkers are needed to allow rapid and accurate CD discrimination. Blood-derived biomarkers correlating with disease activity, supported by genetic evidences and valid for all CD patients subtypes are still missing. Hence, no biomarkers and no related diagnostic tests are recommended or used alone for CD diagnosis in clinical practice. This review describes diagnosis tests based on the detection/quantification of specific acute-phase reactant proteins, enzymes and derived antibody response developed by inflammatory bowel disease patients for pathogens or symbiotic flora determinant, as well as autoantibodies. Their power as diagnostic tools is discussed, as well as new high-throughput techniques, such as microarrays and proteomics, for the discovery of new CD clinical biomarkers and for the development of specific CD diagnostic tests. Some rapidly evolving nanotechnologies, mathematical analysis and bioinformatics methods are also mentioned to highlight their importance for further accurate CD diagnosis.

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.

Mutations in pattern recognition receptor genes modulate seroreactivity to microbial antigens in patients with inflammatory bowel disease

BACKGROUND AND AIMS

A number of antibodies against microbial epitopes or self-antigens have been associated with Crohn's disease. The development of antibodies reflects a loss of tolerance to intestinal bacteria that underlies Crohn's disease, resulting in an exaggerated adaptive immune response to these bacteria. It was hypothesised that the development of antimicrobial antibodies is influenced by the presence of genetic variants in pattern recognition receptor genes. The aim of this study was therefore to investigate the influence of mutations in these innate immune receptor genes (nucleotide oligomerisation domain (NOD) 2/caspase recruitment domain (CARD) 15, NOD1/CARD4, TUCAN/CARDINAL/CARD8, Toll-like receptor (TLR) 4, TLR2, TLR1 and TLR6) on the development of antimicrobial and antiglycan antibodies in inflammatory bowel disease (IBD).

MATERIALS AND METHODS

A cohort of 1163 unrelated patients with IBD (874 Crohn's disease, 259 ulcerative colitis, 30 indeterminate colitis) and 312 controls were analysed for anti-Saccharomyces cerevisiae antibodies (gASCA) IgG, anti-laminaribioside antibodies (ALCA) IgG, anti-chitobioside antibodies (ACCA) IgA, anti-mannobioside antibodies (AMCA) IgG and outer membrane porin (Omp) IgA and were genotyped for variants in NOD2/CARD15, TUCAN/CARDINAL/CARD8, NOD1/CARD4, TLR4, TLR1, TLR2 and TLR6.

RESULTS

When compared with Crohn's disease patients without CARD15 mutations, the presence of at least one CARD15 variant in Crohn's disease patients more frequently led to gASCA positivity (66.1% versus 51.5%, p < 0.0001) and ALCA positivity (43.3% versus 34.9%, p = 0.018) and higher gASCA titers (85.7 versus 51.8 ELISA units, p < 0.0001), independent of ileal involvement. A gene dosage effect, with increasing gASCA and ALCA positivity for patients carrying none, one and two CARD15 variants, respectively, was seen for both markers. Similarly, Crohn's disease patients carrying NOD1/CARD4 indel had a higher prevalence of gASCA antibodies than wild-type patients (63.8% versus 55.2%, p = 0.014), also with a gene dosage effect. An opposite effect was observed for the TLR4 D299G and TLR2 P631H variants, with a lower prevalence of ACCA antibodies (23.4% versus 35%, p = 0.013) and Omp antibodies (20.5% versus 34.6%, p = 0.009), respectively.

CONCLUSION

Variants in innate immune receptor genes were found to influence antibody formation against microbial epitopes. In this respect, it is intriguing that an opposite effect of CARD15 and TLR4 variants was observed. These findings may contribute to an understanding of the aetiology of the seroreactivity observed in IBD.

Role of ASCA and the NOD2/CARD15 mutation Gly908Arg in predicting increased surgical costs in Crohn's disease patients: a project of the European Collaborative Study Group on Inflammatory Bowel Disease

BACKGROUND

NOD2/CARD15, the first identified susceptibility gene in Crohn's disease (CD), is associated with ileal stenosis and increased frequency of surgery. Anti-Saccharomyces cerevisiae antibody (ASCA), a serological marker for CD, is associated with ileal location and a high likelihood for surgery. We hypothesized that the presence of ASCA and NOD2/CARD15 mutations could predict increased health care cost in CD.

METHODS

CD patients in a prospectively designed community-based multinational European and Israeli cohort (n = 228) followed for mean 8.3 (SD 2.6) years had blood drawn for measurement of ASCA (IgG, IgA), Arg702Trp, Gly908Arg, and Leu1007fsinsC. Days spent in the hospital and the costs of medical and surgical hospitalizations and medications were calculated.

RESULTS

The median duration of surgical hospitalizations was longer in Gly908Arg-positive than -negative patients, 3.5 and 1.5 days/patient-year (P < 0.01), and in ASCA-positive than -negative patients, 1.1 and 0 days/patient-year (P < 0.001). Median surgical hospitalization cost was 1,580 euro/patient-year in Gly908Arg-positive versus 0 euro/patient-year in -negative patients (P < 0.01), and 663 euro/patient-year in ASCA-positive versus 0 euro/patient-year in -negative patients (P < 0.001). Differences in cost of medications between groups were not significant. The effect of Gly908Arg was expressed in countries with higher Gly908Arg carriage rates. ASCA raised surgical costs independently of the age at diagnosis of disease. Arg702Trp and Leu1007fsinsC did not affect the cost of health care.

CONCLUSIONS

Since CD patients positive for Gly908Arg and ASCA demonstrated higher health care costs, it is possible that measurement of Gly908Arg and ASCA at disease diagnosis can forecast the expensive CD patients.

Ethnic and socio-cultural specificities in Tunisia have no impact on the prevalence of anti-Saccharomyces cerevisiae antibodies in Crohn's disease patients, their relatives or associated clinical factors

BACKGROUND

In Western Europe and the USA, the presence of anti-Saccharomyces cerevisiae antibodies (ASCAs) in Crohn's disease (CD) patients and their healthy relatives suggests that ASCAs may be influenced by genetic and/or environmental factors.

OBJECTIVES

To assess the prevalence of ASCAs in Tunisian patients with CD or ulcerative colitis (UC), and unaffected family members, in relation to clinical phenotype. Patients and methods. Seventy-seven patients (39 CD, 38 UC), 66 healthy relatives of CD patients, 16 relatives of UC patients and 70 healthy controls were studied. ASCAs were quantified with a new isotype-specific ELISA test involving an antigenic extract from S. cerevisiae strain W303 and by the original test which detects total immunoglobulins against S. cerevisiae Su1 mannan.

RESULTS

The specificity of the two tests was identical (91%). The isotype-specific ASCA W303 test was more sensitive than the ASCA Su1 test for immunoglobulin detection, but some CD patients were positive only with this latter test. A high percentage of patients with CD (72%) and their unaffected family members (35%) were ASCA-positive in contrast to UC patients (16%) and their relatives (0%) and controls (8.6%). ASCAs were shown to be independent of rural or urban living, disease activity, but were associated with ileal location. The antigen of S. cerevisiae strain W303 discriminated patients depending on age at onset or location of the disease.

CONCLUSION

This study confirms the antigenic heterogeneity of S. cerevisiae strains in their ability to detect ASCA. It suggests that ASCAs are markers of immunoregulatory disturbance in CD, independently of ethnic/cultural differences between Europe, the USA and North Africa.

CARD15 mutations in Dutch familial and sporadic inflammatory bowel disease and an overview of European studies

OBJECTIVES

The single nucleotide variations R702W, G908R and L1007fs in the CARD15 gene have been found to be independently associated with Crohn's disease. The aim of this study was to evaluate the prevalence of these gene variations in Dutch multiple inflammatory bowel disease-affected families, in sporadic inflammatory bowel disease patients and in healthy controls.

METHODS

Dutch Caucasians from multiple inflammatory bowel disease-affected families were recruited, including 78 probands with Crohn's disease, 34 probands with ulcerative colitis and 71 inflammatory bowel disease-affected and 100 non-affected family members. In addition, 45 sporadic inflammatory bowel disease patients (36 Crohn's disease and nine ulcerative colitis), and 77 unrelated healthy controls were included. Genomic DNA was isolated to determine CARD15 R702W, G908R and L1007fs. For these mutations, we evaluated disease susceptibility and correlation with inflammatory bowel disease phenotypes.

RESULTS

In all included unrelated inflammatory bowel disease-affected probands, the R702W, G908R and L1007fs allele frequencies were 8.8, 6.1 and 11.0%, respectively, for Crohn's disease, and 4.7, 0 and 2.3% for ulcerative colitis. In controls, the allele frequencies were 5.9, 0.7 and 1.9%, respectively. G908R and L1007fs were associated with Crohn's disease (P=0.006 and 0.001, respectively). Compound heterozygotes for any of the three mutations were 11 (9.2%) in Crohn's disease patients, but none in ulcerative colitis patients nor controls. Carriage of CARD15 mutations was not associated with familial disease (P>or=0.38). Inflammatory bowel disease-affected family members of Crohn's disease probands carrying L1007fs, however, were carriers significantly more often than expected (P<0.001). In Crohn's disease patients, a significant trend was found between carriage of at least one CARD15 mutation and between carriage of L1007fs and behaviour of disease, including more carriers with stricturing and even more with penetrating disease (P=0.006 and 0.017, respectively).

CONCLUSION

In the Dutch population, CARD15 G908R and L1007fs are associated with Crohn's disease. Although no difference was found between sporadic and familial cases, in L1007fs-positive multiple affected families the inflammatory bowel disease-affected relatives are more likely than expected to carry this mutation. In Crohn's disease, carriage of at least one CARD15 mutation is associated with a more complicated disease behaviour.

NOD2 variants and antibody response to microbial antigens in Crohn's disease patients and their unaffected relatives

BACKGROUND & AIMS

The Cdcs1 locus of the C3Bir mouse confers severe colitis associated with a decrease in innate immune function and an increase in adaptive T-cell responses to commensal bacterial products. The aim of our study was to determine if defects in innate immunity are similarly associated with increased adaptive immune responses to microbial antigens in Crohn's disease patients.

METHODS

Sera from 732 patients, 220 unaffected relatives, and 200 healthy controls were tested for antibodies to oligomannan, the Pseudomonas fluorescens-related protein, Escherichia coli outer membrane porin C, CBir1 flagellin, and DNA from the same subjects was tested for 3 Crohn's disease-associated variants of the NOD2 gene, and 5 toll-like receptor (TLR) 2, 2 TLR4, and 2 TLR9 variants. The magnitude of responses to microbial antigens was examined according to variant status.

RESULTS

NOD2 variant carriage increased in frequency with increasing number of positive antibodies and increasing cumulative quantitative response as measured by quartile sum (P for trend, .0008 and .0003, respectively). Mean antibody and quartile sums were higher for patients carrying any NOD2 variant versus those carrying none (2.24 vs 1.92 and 10.60 vs 9.72; P = .0008 and P = 0.0003, respectively). The mean quartile sum was higher for unaffected relatives carrying any NOD2 variant versus those carrying none (10.67 vs 9.75, respectively; P = .02). No association was found between any TLR variant and the magnitude of response.

CONCLUSIONS

Patients with Crohn's disease and unaffected relatives carrying variants of the NOD2 gene have increased adaptive immune responses to microbial antigens.

Ankylosing spondylitis and bowel disease

Between 5 and 10% of cases of ankylosing spondylitis (AS) are associated with inflammatory bowel disease (IBD), either Crohn's disease or ulcerative colitis. A much larger percentage of AS patients have subclinical gut inflammation manifested either by endoscopic findings or by histology. The association with HLA-B27 is less strong in IBD-associated AS than in idiopathic AS, and there is evidence for an association between gut inflammation in AS with the Crohn's-disease-related CARD15 mutations. Despite the different genetics, the immunopathology suggests common inflammatory pathways in gut and joint inflammation in AS, and in gut inflammation in AS and IBD. Although this observation is of interest to unravel the pathophysiology of the disease, systematic screening of AS patients by ileocolonoscopy is not indicated in the absence of gut symptomatology as only a small proportion of AS patients with subclinical gut inflammation will develop overt IBD over time. Treatment of AS associated with IBD with non-steroidal anti-inflammatory drugs (NSAIDs) is problematic because of concerns of potential re-activation of IBD by NSAIDs. Major advances have been made in recent years with the establishment of anti-tumour necrosis factor (TNF) therapy in AS, the other spondyloarthritides and IBD. Anti-TNF agents are of particular relevance to AS patients with concomitant IBD who are at risk of exacerbation of the underlying bowel disease when treated with NSAIDs. In IBD, infliximab, unlike etanercept, is effective in treating clinical symptoms, inducing and maintaining remission, and mucosal healing. Adalimumab appears to be effective in treating both AS and IBD; however, official approval is pending. Currently, infliximab is the drug of choice for the treatment of patients with active AS associated with IBD.

TNFalpha genotype influences development of IgA-ASCA antibodies in Crohn's disease patients with CARD15 wild type

A typical feature of Crohn's disease (CD) patients is the development of antibodies against self- (PAB) or exogenous (ASCA) antigens, a process in which mucosal cytokine expression pattern might be involved. On the other hand, mutations in CARD15, a genetic risk factor for CD, alter cytokine production in response to bacterial infection. In the present study, we evaluated the role of functionally relevant IL-10 and TNFalpha gene polymorphisms in the synthesis of these antibodies and their relationship with CARD15 mutations. In CARD15 wild type patients, high TNFalpha producer genotypes protect against IgA-ASCA development, whereas an inverse association was observed in autoantibody synthesis (PAB). These associations were not observed in patients with CARD15 mutations, probably due to the lack of TNFalpha release as a consequence of the failure of CARD15 protein to recognize the peptidoglycan. Thus, we proposed a CARD15-TNFalpha circuit that might play a role in mucosal immune surveillance.