Toward an integrated clinical, molecular and serological classification of inflammatory bowel disease: report of a Working Party of the 2005 Montreal World Congress of Gastroenterology

Incidence of Mycobacterium avium subspecies paratuberculosis in a population-based cohort of patients with Crohn's disease and control subjects

OBJECTIVE

To define the incidence of Mycobacterium avium subspecies paratuberculosis (MAP) in patients with Crohn's disease (CD) and in control subjects.

METHODS

Blood samples from 361 CD patients from a previously described population-based inflammatory bowel disease (IBD) cohort and 200 blood donor controls, of known NOD2 genotype, were screened by PCR for MAP-specific IS900 DNA. These results were correlated with NOD2 genotype.

RESULTS

The PCR assay was capable of detecting 20 fg of purified MAP DNA, equivalent to roughly 100 MAP cells/mL of blood. MAP-specific IS900 DNA was detected in 33.8% of CD cases and 21.5% of controls (OR 1.86, 95% CI 1.247-2.785, P= 0.002). All study participants were genotyped for the NOD2 mutations 2104C>T (R702W), 2722G>C (G908R), and 3020insC (1007fs). Carriage of one or two NOD2 mutations was not associated with a significantly higher risk of CD (OR 0.75, 95% CI 0.465-1.207, P= 0.234). No significant association was seen in the CD cohort for carriage of one or two NOD2 mutations and MAP status (OR 0.883, 95% CI 0.494-1.579, P= 0.675).

CONCLUSIONS

Screening peripheral blood using IS900 PCR indicated that MAP DNA could be detected in a significant proportion of CD cases from a large population-based cohort, and also, in control subjects. The over-representation of MAP DNA in CD suggests either a role or a probable role for MAP in the etiology of CD.

NOD2/CARD15 gene variants are linked to failure of antibiotic treatment in perianal fistulating Crohn's disease

OBJECTIVES

The Crohn's disease (CD) susceptibility gene, nucleotide-binding oligomerizetion domain 2 (NOD2)/caspase recruitment domain 15 (CARD15), is linked to the innate immune response associated with altered epithelial bacterial defense. Its relevance in antibiotic therapy of perianal fistulating CD remains elusive. The aim of the study was to explore systematically the association between NOD2/CARD15 variants and clinical response of perianal fistulas in patients using antibiotic therapy.

METHODS

Fifty-two patients (median age 36 yr) with draining perianal fistulas were treated with ciprofloxacin (N = 49) or metronidazole (N = 3) for a median duration of 7 wk. Complete response was defined as the absence of any draining fistula despite gentle finger compression. Genotyping for NOD2/CARD15 variants and human beta (beta)-defensin 2 (HBD-2) copies was performed by 5' nuclease assays (Applied Biosystems, Foster City, CA). The examiners and laboratory investigators were blinded. The Fisher exact test and Wilcoxon signed rank test were used for statistical analysis.

RESULTS

Ciprofloxacin was discontinued in one patient due to diarrhea after 2 wk. Complete fistula response was observed in 13 of 39 patients with NOD2/CARD15 wild-type (33.3%) compared with none in patients carrying NOD2/CARD15 variants (0%, P= 0.02). The median number of HBD-2 gene copies between responders and partial/nonresponders was similar.

CONCLUSIONS

The study result suggests a substantial contribution of NOD2/CARD15 to the antibiotic treatment outcome of perianal fistulating CD. NOD2/CARD15 variants may predispose to an altered intestinal microflora in perianal fistulas that is less responsive to antibiotic treatment.

Use of infliximab in the prevention and delay of colectomy in severe steroid dependant and refractory ulcerative colitis

AIM: To determine if infliximab can prevent or delay surgery in refractory ulcerative colitis (UC).

METHODS: UC patients who failed to have their disease controlled with conventional therapies and were to undergo colectomy if infliximab failed to induce a clinical improvement were reviewed. Patients were primarily treated with a single 5 mg/kg infliximab dose. The Colitis Activity Index (CAI) was used to determine response and remission. Data of 8 wk response and colectomy rates at 6 mo and 12 mo were collected.

RESULTS: Fifteen patients were included, 7 with UC unresponsive or intolerant to IV hydrocortisone, and 8 with active disease despite oral steroids (all but one with therapeutic dosage and duration of immunomodulation). All the IV hydrocortisone-resistant/intolerant patients had been on azathioprine/6-MP < 8 wk. At 8 wk, infliximab induced a response in 86.7% (13/15) with 40% in remission (6/15). Within 6 mo of treatment 26.7% (4/15) had undergone colectomy and surgery was avoided in 46.6% (7/15) at 12 mo. The colectomy rate at 12 mo in those on immunomodulatory therapy < 8 wk at time of infliximab was 12.5% (1/8) compared with 100% (7/7) in patients who were on long-term maintenance immunomodulators (P < 0.02).

CONCLUSION: Infliximab prevented colectomy due to active disease in immunomodulatory-naïve, refractory UC patients comparable to the use of Cyclosporine. In patients, however, on effective dosage and duration of immunomodulation at time of infliximab therapy colectomy was not avoided.

Traditional corticosteroids for induction of remission in Crohn's disease

BACKGROUND

Historically, corticosteroids have been the most commonly used class of medication for induction of remission in Crohn's disease (CD). Corticosteroids down regulate production of inflammatory cytokines and interfere with NF-kappaB production, thereby blunting inflammatory response.

OBJECTIVES

The primary objective was to systematically review the efficacy and safety of traditional corticosteroids (given orally or intravenously) for induction of remission in CD.

SEARCH STRATEGY

The following electronic databases were searched: MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, the Cochrane Inflammatory Bowel Disease and Functional Bowel Disorders (IBD/FBD) Group Specialized Trial Register, and ClinicalTrials.gov. No language restrictions were applied. Reference lists of trials and review articles, as well as recent proceedings from major gastroenterology meetings were manually searched.

SELECTION CRITERIA

Randomized, controlled clinical trials of traditional, systemic corticosteroids for the induction of remission of active CD were included in this review. Control groups included patients receiving either placebo or 5-aminosalicylates (5-ASA). The study population included patients of any age with active CD (as defined by the study authors or validated clinical activity indices), receiving any formulation of systemically available corticosteroid by any oral or parenteral methods of delivery. The primary outcome was induction of remission of CD. Secondary outcomes included clinical response, change in mean CDAI, adverse events and the proportion of patients withdrawing due to adverse events.

DATA COLLECTION AND ANALYSIS

Two independent investigators reviewed studies for eligibility, extracted the data and assessed study quality using Jadad's criteria. A random or fixed effects model was chosen based on an assessment of heterogeneity, and studies were weighted using the DerSimonian & Laird or the Mantel-Haenszel method accordingly. Meta-analysis was performed using RevMan 4.2.10 software.

MAIN RESULTS

Two studies compared corticosteroids to placebo and six studies compared corticosteroids to 5-ASA. Corticosteroids were found to be significantly more effective than placebo at inducing remission in CD (RR 1.99; 95% CI 1.51 to 2.64; P < 0.00001). Corticosteroids were found to be more effective than 5-ASA at inducing remission in studies with long follow-up duration (i.e. > 15 weeks; RR 1.65; 95% CI 1.33 to 2.03; P < 0.00001). Corticosteroids induced adverse events in a higher proportion of patients than placebo (RR 4.89; 95% CI 1.98 to 12.07; P = 0.0006), or low-dose 5-ASA (RR 2.38; 95% CI 1.34 to 4.25; P = 0.003). No difference existed in the proportion of patients experiencing adverse events when steroids were compared to high-dose 5-ASA. Steroids did not induce more study withdrawals due to adverse events than either placebo or 5-ASA.

AUTHORS' CONCLUSIONS

Corticosteroids are effective for induction of remission in patients with CD, particularly when used for more than 15 weeks. Although corticosteroids cause more adverse events than either placebo or low-dose 5-ASA, these adverse events did not lead to increased study withdrawal in the included studies. Further information is required to determine the optimal duration of treatment and tapering protocol to maximize the efficacy of treatment with corticosteroids. Additionally, further study is required to determine whether corticosteroids are more effective in patients with certain phenotypes or when administered intravenously.

Traditional corticosteroids for induction of remission in Crohn's disease

BACKGROUND

Historically, corticosteroids have been the most commonly used class of medication for induction of remission in Crohn's disease (CD). Corticosteroids down regulate production of inflammatory cytokines and interfere with NF-kappaB production, thereby blunting inflammatory response.

OBJECTIVES

The primary objective was to systematically review the efficacy and safety of traditional corticosteroids (given orally or intravenously) for induction of remission in CD.

SEARCH STRATEGY

The following electronic databases were searched: MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, the Cochrane Inflammatory Bowel Disease and Functional Bowel Disorders (IBD/FBD) Group Specialized Trial Register, and ClinicalTrials.gov. No language restrictions were applied. Reference lists of trials and review articles, as well as recent proceedings from major gastroenterology meetings were manually searched.

SELECTION CRITERIA

Randomized, controlled clinical trials of traditional, systemic corticosteroids for the induction of remission of active CD were included in this review. Control groups included patients receiving either placebo or 5-aminosalicylates (5-ASA). The study population included patients of any age with active CD (as defined by the study authors or validated clinical activity indices), receiving any formulation of systemically available corticosteroid by any oral or parenteral methods of delivery. The primary outcome was induction of remission of CD. Secondary outcomes included clinical response, change in mean CDAI, adverse events and the proportion of patients withdrawing due to adverse events.

DATA COLLECTION AND ANALYSIS

Two independent investigators reviewed studies for eligibility, extracted the data and assessed study quality using Jadad's criteria. A random or fixed effects model was chosen based on an assessment of heterogeneity, and studies were weighted using the DerSimonian & Laird or the Mantel-Haenszel method accordingly. Meta-analysis was performed using RevMan 4.2.10 software.

MAIN RESULTS

Two studies compared corticosteroids to placebo and six studies compared corticosteroids to 5-ASA. Corticosteroids were found to be significantly more effective than placebo at inducing remission in CD (RR 1.99; 95% CI 1.51 to 2.64; P < 0.00001). Corticosteroids were found to be more effective than 5-ASA at inducing remission in studies with long follow-up duration (i.e. > 15 weeks; RR 1.65; 95% CI 1.33 to 2.03; P < 0.00001). Corticosteroids induced adverse events in a higher proportion of patients than placebo (RR 4.89; 95% CI 1.98 to 12.07; P = 0.0006), or low-dose 5-ASA (RR 2.38; 95% CI 1.34 to 4.25; P = 0.003). No difference existed in the proportion of patients experiencing adverse events when steroids were compared to high-dose 5-ASA. Steroids did not induce more study withdrawals due to adverse events than either placebo or 5-ASA.

AUTHORS' CONCLUSIONS

Corticosteroids are effective for induction of remission in patients with CD, particularly when used for more than 15 weeks. Although corticosteroids cause more adverse events than either placebo or low-dose 5-ASA, these adverse events did not lead to increased study withdrawal in the included studies. Further information is required to determine the optimal duration of treatment and tapering protocol to maximize the efficacy of treatment with corticosteroids. Additionally, further study is required to determine whether corticosteroids are more effective in patients with certain phenotypes or when administered intravenously.

Two-stage candidate gene study of chromosome 3p demonstrates an association between nonsynonymous variants in the MST1R gene and Crohn's disease

BACKGROUND

Genomewide linkage studies identified chromosome 3p21 as an IBD locus. Genomewide association studies have supported this locus and the Wellcome Trust Case Control Consortium (WTCCC) study narrowed it to a 0.6 Mb region. Our objectives were to perform a 2-stage candidate gene association study of the 3p locus and to identify linkage disequilibrium (LD) between significant single-nucleotide polymorphisms (SNPs) and an Oxfordshire subset (n = 282) of the WTCCC as well as the HapMap SNPs.

METHODS

A total of 197 SNPs in 53 genes from the 3p locus were genotyped on the Illumina platform in a screening cohort of 469 Crohn's disease (CD) patients and 461 controls. Significant associations were then genotyped on the iPLEX platform in the original as well as a second cohort of 139 CD patients, 670 ulcerative colitis (UC) patients, and 1131 controls. All cases and controls were Caucasian and from the Oxfordshire region of the UK.

RESULTS

An intronic SNP rs1128535 in the TRAIP gene was associated with CD in the screening and validation cohorts (combined [n = 608] P = 0.0004 [corrected 0.002], odds ratio [OR] 0.77, 95% confidence interval [CI], 0.67-0.89]). No association was seen for UC. Epistasis was seen with the common CARD15 mutations (P = 0.00003 [corrected 0.0006], OR 0.48, 95% CI, 0.34-0.68). No LD was demonstrated with the WTCCC SNPs. Strong LD was demonstrated with 2 nonsynonymous HapMap SNPs in the MST1R gene in an adjacent LD block to the peak WTCCC association, suggesting a distinct association signal.

CONCLUSIONS

The LD with these functional MST1R variants implicate this gene as having a possible role in CD pathogenesis.

Changes in Crohn's disease phenotype over time in the Chinese population: validation of the Montreal classification system

BACKGROUND

Phenotypic evolution of Crohn's disease occurs in whites but has never been described in other populations. The Montreal classification may describe phenotypes more precisely. The aim of this study was to validate the Montreal classification through a longitudinal sensitivity analysis in detecting phenotypic variation compared to the Vienna classification.

METHODS

This was a retrospective longitudinal study of consecutive Chinese Crohn's disease patients. All cases were classified by the Montreal classification and the Vienna classification for behavior and location. The evolution of these characteristics and the need for surgery were evaluated.

RESULTS

A total of 109 patients were recruited (median follow-up: 4 years, range: 6 months-18 years). Crohn's disease behavior changed 3 years after diagnosis (P = 0.025), with an increase in stricturing and penetrating phenotypes, as determined by the Montreal classification, but was only detected by the Vienna classification after 5 years (P = 0.015). Disease location remained stable on follow-up in both classifications. Thirty-four patients (31%) underwent major surgery during the follow-up period with the stricturing [P = 0.002; hazard ratio (HR): 3.3; 95% CI: 1.5-7.0] and penetrating (P = 0.03; HR: 5.8; 95% CI: 1.2-28.2) phenotypes according to the Montreal classification associated with the need for major surgery. In contrast, colonic disease was protective against a major operation (P = 0.02; HR: 0.3; 95% CI: 0.08-0.8).

CONCLUSIONS

This is the first study demonstrating phenotypic evolution of Crohn's disease in a nonwhite population. The Montreal classification is more sensitive to behavior phenotypic changes than is the Vienna classification after excluding perianal disease from the penetrating disease category and was useful in predicting course and the need for surgery.

Low body mass not vitamin D receptor polymorphisms predict osteoporosis in patients with inflammatory bowel disease

BACKGROUND

Osteoporosis is a recognized complication of inflammatory bowel disease (IBD). Aim To investigate the role of environmental factors and vitamin D receptor (VDR) variants on the prevalence of osteoporosis.

METHODS

DEXA scans and case note review were performed on 440 IBD patients from 1997 to 2006. All the IBD patients and 240 healthy controls were genotyped for VDR variants Taq-1 and Apa-1 using PCR-RFLP.

RESULTS

Osteoporosis and osteopenia rates were 15% and 18% for IBD, 16% and 18% for Crohn's disease (CD) and 13% and 19% for ulcerative colitis, respectively. On univariate analysis of the CD patients, low body mass index (BMI, <18.5) and smoking status (P = 0.008 and 0.005 respectively) were associated with osteoporosis and osteopenia. Low BMI was also associated with osteoporosis on multivariate analysis in CD (P = 0.021, OR 5.83, CI 1.31-25.94). No difference was observed between Taq-1 and Apa-1 VDR polymorphisms in IBD, CD, ulcerative colitis and healthy controls. However, CD males were more likely to carry the variant Taq-1 polymorphism than healthy controls males (P = 0.0018, OR 1.94, CI 1.28-2.92) and female CD patients (P = 0.0061, OR 1.60, CI 1.17-2.44).

CONCLUSIONS

In this well-phenotyped cohort of IBD patients, a relatively low prevalence of osteoporosis was observed. Low BMI was the only independent risk factor identified to be associated with osteoporosis.

Role of the novel Th17 cytokine IL-17F in inflammatory bowel disease (IBD): upregulated colonic IL-17F expression in active Crohn's disease and analysis of the IL17F p.His161Arg polymorphism in IBD

BACKGROUND

Interleukin (IL)-17F, produced in IL-23R-expressing Th17 cells, is a novel member of the IL-17 cytokine family. Given the association of IL23R with inflammatory bowel disease (IBD), we characterized the role of IL-17F in IBD including its intestinal gene expression and the effect of the IL17F p.His161Arg polymorphism on disease susceptibility and phenotype of Crohn's disease (CD) and ulcerative colitis (UC). In addition, we analyzed the IL17F p.His161Arg polymorphism for potential epistasis with IL23R and NOD2/CARD15 variants.

METHODS

Intestinal IL-17F mRNA expression was measured by quantitative polymerase chain reaction (PCR). Genomic DNA from 1682 individuals (CD: n = 499; UC: n = 216; controls: n = 967) was analyzed for the presence of the IL17F p.His161Arg polymorphism, the 3 NOD2 variants, p.Arg702Trp, p.Gly908Arg, and p.Leu1007fsX1008, and 10 CD-associated IL23R variants.

RESULTS

Intestinal IL-17F mRNA expression was 4.4-fold increased in inflamed colonic lesions compared to uninflamed biopsies in CD (P = 0.016) but not in UC. However, the mean intestinal IL-17F mRNA expression was higher in UC than in CD (P < 0.0001). The IL17F p.His161Arg substitution was observed with similar frequencies in IBD patients and controls and was not associated with a certain disease phenotype, but weakly associated with a low body mass index (BMI; P = 0.009) and an earlier age of disease onset (P = 0.039) in UC. There was no evidence for epistasis between the IL17F p.His161Arg polymorphism and IBD-associated single nucleotide polymorphisms within the IL23R gene.

CONCLUSIONS

Intestinal IL17F gene expression is increased in active CD. The IL17F p.His161Arg polymorphism is not associated with IBD susceptibility and has no epistatic interaction with CD-associated IL23R variants.

Intestinal permeability and its association with the patient and disease characteristics in Crohn’s disease

AIM: To assess the intestinal permeability (IP) in patients with Crohn’s disease (CD) and study the association of IP with the patient and disease characteristics.

METHODS: One hundred and twenty five consecutive patients of CD (Males: 66) were diagnosed on the basis of a combination of standard clinical, endoscopic, imaging and histological features. CD activity index (CDAI) was used to calculate the activity of the disease while the behavior of the disease was assessed by the modified Montreal classification. IP was measured by the ratio of the percentage excretion of ingested doses of lactulose and mannitol in urine (LMR). The upper limit of normality of LMR (0.037) was derived from 22 healthy controls.

RESULTS: Thirty six percent of patients with CD had increased IP. There was no significant difference in mannitol excretion (patients vs controls = 12.5% vs 14.2%, P = 0.4652), but lactulose excretion was significantly higher in patients compared to healthy controls (patients vs controls = 0.326% vs 0.293%, P = 0.0391). The mean LMR was also significantly higher in the patients as compared to healthy controls [0.027 (0.0029-0.278) vs 0.0164 (0.0018-0.0548), P = 0.0044]. Male patients had a higher LMR compared to females [0.036 (95% CI 0.029, 0.046) vs 0.022 (95% CI 0.0178, 0.028) (P = 0.0024), though there was no difference in the number of patients with abnormal IP in both the sexes. Patients with an ileo-colonic disease had a higher LMR than those with only colonic disease [0.045 (95% CI 0.033, 0.06) vs 0.021 (95% CI 0.017, 0.025) (P < 0.001)]. Of patients with ileo-colonic disease, 57.8% had an abnormal IP, compared to 26.7% with colonic and 15.6% with small intestinal disease. Patients with a stricturing disease had significantly higher LMR compared to non-fistulising non-stricturing disease [0.043 (95% CI 0.032, 0.058) vs 0.024 (95% CI 0.019, 0.029) (P = 0.0062)]. There was no correlation of IP with age, disease activity, duration of illness, D-xylose absorption, upper GI involvement, perianal disease, and extra-intestinal manifestations. On multiple regression analysis, male gender and ileo-colonic disease were independent factors associated with increased IP. Gender, location, behavior of the disease and upper GI involvement could explain up to 23% of variability in IP (R² = 0.23).

CONCLUSION: IP was increased in 36% of patients with CD. Male gender and an ileo-colonic disease were the independent factors associated with increased IP.

Aberrant mucin assembly in mice causes endoplasmic reticulum stress and spontaneous inflammation resembling ulcerative colitis

BACKGROUND

MUC2 mucin produced by intestinal goblet cells is the major component of the intestinal mucus barrier. The inflammatory bowel disease ulcerative colitis is characterized by depleted goblet cells and a reduced mucus layer, but the aetiology remains obscure. In this study we used random mutagenesis to produce two murine models of inflammatory bowel disease, characterised the basis and nature of the inflammation in these mice, and compared the pathology with human ulcerative colitis.

METHODS AND FINDINGS

By murine N-ethyl-N-nitrosourea mutagenesis we identified two distinct noncomplementing missense mutations in Muc2 causing an ulcerative colitis-like phenotype. 100% of mice of both strains developed mild spontaneous distal intestinal inflammation by 6 wk (histological colitis scores versus wild-type mice, p < 0.01) and chronic diarrhoea. Monitoring over 300 mice of each strain demonstrated that 25% and 40% of each strain, respectively, developed severe clinical signs of colitis by age 1 y. Mutant mice showed aberrant Muc2 biosynthesis, less stored mucin in goblet cells, a diminished mucus barrier, and increased susceptibility to colitis induced by a luminal toxin. Enhanced local production of IL-1beta, TNF-alpha, and IFN-gamma was seen in the distal colon, and intestinal permeability increased 2-fold. The number of leukocytes within mesenteric lymph nodes increased 5-fold and leukocytes cultured in vitro produced more Th1 and Th2 cytokines (IFN-gamma, TNF-alpha, and IL-13). This pathology was accompanied by accumulation of the Muc2 precursor and ultrastructural and biochemical evidence of endoplasmic reticulum (ER) stress in goblet cells, activation of the unfolded protein response, and altered intestinal expression of genes involved in ER stress, inflammation, apoptosis, and wound repair. Expression of mutated Muc2 oligomerisation domains in vitro demonstrated that aberrant Muc2 oligomerisation underlies the ER stress. In human ulcerative colitis we demonstrate similar accumulation of nonglycosylated MUC2 precursor in goblet cells together with ultrastructural and biochemical evidence of ER stress even in noninflamed intestinal tissue. Although our study demonstrates that mucin misfolding and ER stress initiate colitis in mice, it does not ascertain the genetic or environmental drivers of ER stress in human colitis.

CONCLUSIONS

Characterisation of the mouse models we created and comparison with human disease suggest that ER stress-related mucin depletion could be a fundamental component of the pathogenesis of human colitis and that clinical studies combining genetics, ER stress-related pathology and relevant environmental epidemiology are warranted.

Association between genetic variants in the IL-23R gene and early-onset Crohn's disease: results from a case-control and family-based study among Canadian children

BACKGROUND AND OBJECTIVES

Interleukin (IL)-23 is a key regulator of inflammation and influences the activities of T-helper 17 (Th-17) lymphocytes. Recent reports indicate that variants in the gene coding for its receptor (IL-23R) are strongly associated with Crohn's disease (CD). We investigated whether DNA variants in the IL-23R gene determine susceptibility for CD in Canadian children.

DESIGN AND METHODS

A case-control and case-parent trio design was implemented at three pediatric centers across Canada. Cases of CD (</=20 yr) along with their parents and controls were recruited. DNA samples were collected and genotyped for 10 single nucleotide polymorphisms (SNPs) in the IL-23R gene and three common SNPs in the CARD15 gene. Transmission disequilibrium-based tests were applied to the case-parent data and logistic regression models to the case-control data to study the association between the SNPs and CD.

RESULTS

A total of 259 CD cases, 139 controls, and 232 families (167 trios and 65 dyads) were studied. The mean age at diagnosis was 13.3 yr (range 2.6-20 yr). The majority of the patients were Caucasian. Case-control analysis revealed significant associations with three SNPs (rs1004819, rs7517847, and rs11209026 [R381Q]) and borderline nonsignificant associations with three other SNPs (rs10489629, rs10889697, and rs11465804) in the IL-23R gene. Having any CARD15 variant was associated with a significant risk for CD (P < 0.0001). Analyses of case-parent data confirmed the findings from the case-control analysis including significant associations with the R381Q SNP (P= 0.002). The common variant in this SNP conferred risk for CD. These associations were largely independent of the CARD15 gene.

CONCLUSIONS

Our findings confirm recently reported genome-wide associations between the IL-23R gene and CD. They suggest that the gene is also associated with pediatric-onset CD among Canadian children.

The ATG16L1 gene variants rs2241879 and rs2241880 (T300A) are strongly associated with susceptibility to Crohn's disease in the German population

OBJECTIVES

We analyzed ATG16L1, a recently identified Crohn's disease (CD) susceptibility gene, in a large cohort with inflammatory bowel disease (IBD) including potential interactions with other IBD genes as well as factors regulating its gene expression.

METHODS

Genomic DNA from 2,890 Caucasians including 768 patients with CD, 507 patients with ulcerative colitis (UC), and 1,615 healthy controls was analyzed for 9 different ATG16L1 single nucleotide polymorphisms (SNPs). Genotyping included CARD15/NOD2 variants p.Arg702Trp, p.Gly908Arg, and p.Leu1007fsX1008 and polymorphisms in SLC22A4/OCTN1 (1672 C-->T) and SLC22A5/OCTN2 (-207 G-->C) as well as 10 CD-associated IL23R variants. The transcriptional regulation of ATG16L1 was studied in intestinal epithelial cells following stimulation with Toll-like receptor (TLR) ligands and proinflammatory cytokines and in a murine ileitis model and CD biopsies.

RESULTS

All nine ATG16L1 gene variants analyzed displayed highly significant associations with CD demonstrating a CD-protective effect for the minor allele. The strongest associations were found for rs2241879 and the coding SNP rs2241880 (T300A); P= 3.6 x 10(-6) and 3.7 x 10(-6), respectively (OR 0.74, 95% CI 0.65-0.84 for both variants). The genotype-phenotype analysis revealed no significant associations. In UC, only rs6431660 was weakly disease-associated. There was no evidence for epistasis between the ATG16L1 gene and other susceptibility genes (IL23R, CARD15, SLC22A4/5). ATG16L1 mRNA expression was not upregulated in CD and murine ileitis, and was less than threefold increased in cells stimulated with proinflammatory cytokines and TLR ligands.

CONCLUSION

ATG16L1 is a CD susceptibility gene without epistatic interaction with other CD susceptibility genes and is not upregulated in intestinal inflammation.

Autophagy gene ATG16L1 influences susceptibility and disease location but not childhood-onset in Crohn's disease in Northern Europe

BACKGROUND

The rs2241880A/G variant of the ATG16L1 gene has been associated with susceptibility to ileal Crohn's disease (CD) in adults. Our aim was to assess whether germline variation of ATG16L1 acts as an independent determinant of susceptibility to childhood-onset CD in the high-incidence Scottish population.

METHODS

In all, 2195 subjects (361 children (inflammatory bowel disease [IBD] diagnosis <17 years), their parents (n = 634), 855 adult IBD patients, and 345 controls were genotyped. Case-control analysis was powered to detect effect sizes with an odds ratio (OR) >1.39 in pediatric CD. Case-control analysis, transmission disequilibrium testing (TDT), analysis of variance (ANOVA) of growth parameter z-scores, Kruskal-Wallis test (age at diagnosis), and multifactorial genotype-phenotype analysis (Montreal classification) were performed. 7.8% of pediatric CD patients and 37.2% of adult CD patients had pure ileal disease.

RESULTS

We confirmed the association of the rs2241880G-allele with adult-onset CD (60.7% versus controls 53.9%, P = 0.01, OR 1.32, 95% confidence interval [CI] 1.07-1.63) in contrast to childhood-onset CD (54.1% versus controls, P = 0.95, OR 1.01, 95% CI 0.80-1.26). TDT analysis was negative. Genotype-phenotype analysis demonstrated an association of pure ileal disease with the rs2241880G-allele (P = 0.02, OR 1.34, 95% CI 1.03-1.74). Using binary logistic regression analysis we confirmed the effect of rs2241880 genotype (GG) on ileal disease versus colonic disease (P = 0.03, OR 2.43, 95% CI 1.05-5.65). ATG16L1 genotype did not influence age at CD diagnosis. ANOVA of z-scores of height, weight, and body mass index (BMI) at CD diagnosis in children showed no association with genotype.

CONCLUSIONS

The ATG16L1 variant is associated with susceptibility to adult CD in Scotland, but not early-onset disease. These contrasting effects are primarily driven by differences in disease location between early-onset and adult-onset disease.

No association of the CARD8 (TUCAN) c.30T>A (p.C10X) variant with Crohn's disease: a study in 3 independent European cohorts

BACKGROUND

A recent study reported that the c.30T>A (p.Cys10Ter; rs2043211) variant, in the CARD8 (TUCAN) gene, is associated with Crohn's disease (CD). The aim of this study was to analyze the frequency of p.C10X in 3 independent European (IBD) cohorts from Germany, Hungary, and the Netherlands.

METHODS

We included a European IBD cohort of 921 patients and compared the p.C10X genotype frequency to 832 healthy controls. The 3 study populations analyzed were: (1) Germany [CD, n = 317; ulcerative colitis (UC), n = 180], (2) Hungary (CD, n = 149; UC, n = 119), and (3) the Netherlands (CD, n = 156). Subtyping analysis was performed in respect to NOD2 variants (p.Arg702Trp, p.Gly908Arg, c.3020insC) and to clinical characteristics. Ethnically matched controls were included (German, n = 413; Hungarian, n = 202; Dutch, n = 217).

RESULTS

We observed no significant difference in p.C10X genotype frequency in either patients with CD or patients with UC compared with controls in all 3 cohorts. Conversely to the initial association study, we found a trend toward lower frequencies of the suggestive risk wild type in CD from the Netherlands compared with controls (P = 0.14). We found neither evidence for genetic interactions between p.C10X and NOD2 nor the C10X variant to be associated with a CD or UC phenotype.

CONCLUSIONS

Analyzing 3 independent European IBD cohorts, we found no evidence that the C10X variant in CARD8 confers susceptibility for CD.

New serological markers for inflammatory bowel disease are associated with earlier age at onset, complicated disease behavior, risk for surgery, and NOD2/CARD15 genotype in a Hungarian IBD cohort

BACKGROUND

Antibodies to Saccharomyces cerevisiae (S. cerevisiae) (ASCA) and porin protein-C of Escherichia coli (anti-OmpC) are associated with disease phenotype and may be of diagnostic importance in inflammatory bowel diseases (IBD). Our aim was to determine whether a panel of new antibodies against bacterial proteins and carbohydrates could help differentiate among the various forms of IBD, and whether they were associated with particular clinical manifestations in a Hungarian cohort of IBD patients.

METHODS

Six hundred fifty-two well-characterized, unrelated, consecutive IBD patients (CD [Crohn's disease] 557, men/women 262/295, duration 8.1 +/- 11.3 yr; ulcerative colitis [UC] 95, men/women 44/51, duration 8.9 +/- 9.8 yr) and 100 healthy and 48 non-IBD gastrointestinal (GI) controls were investigated. Sera were assayed for anti-OmpC and antibodies against a mannan epitope of S. cerevisiae (gASCA), laminaribioside (ALCA), chitobioside (ACCA), and mannobioside (AMCA). 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 patients' medical charts.

RESULTS

Sixty-six percent of the CD patients had at least one of the investigated antibodies. Among glycan antibodies, gASCA or the combination of gASCA and atypical perinuclear antineutrophil cytoplasmic antibodies (pANCA) was most accurate for differentiating between CD and UC. ASCA and gASCA assays performed similarly. Increasing amount and level of antibody responses toward gASCA, ALCA, ACCA, AMCA, and OmpC were associated with more complicated disease behavior (P < 0.0001) and need for surgery in CD (P= 0.023). A serological dosage effect was also observed. gASCA and AMCA antibodies were associated with NOD2/CARD15, in addition to a gene-dosage effect. No serotype-phenotype associations were found in UC.

CONCLUSIONS

Antibody response to this new panel of serological markers was associated with complicated disease phenotype, NOD2/CARD15 genotype, and a need for surgery in this eastern European IBD cohort.

[Optimization of immunomodulatory treatment with azathioprine or 6-mercaptopurine in inflammatory bowel disease]

BACKGROUND

There is limited information on the optimal use of thiopurinic immunomodulators in inflammatory bowel disease (IBD) and the dosage, efficacy and toxicity of these drugs has not been clearly established.

AIM

To evaluate clinical outcomes and the toxicity of thiopurinic immunomodulators in clinical practice (effectiveness), as well as possible associated variables.

METHODS

Data were obtained from a database of patients with ulcerative colitis and Crohn's disease who started treatment with azathioprine or 6-mercaptopurine with an identical predetermined schedule and follow-up. Remission, relapse and toxicity were defined and analyzed and their relationship with clinical, biologic and demographic variables was evaluated with multivariate analysis.

RESULTS

We evaluated 150 courses of treatment in 126 patients. Treatment was given to induce clinical remission in 118 courses and 62% of the patients reached this outcome, which was maintained for a mean of 52 months. The only variable associated with poor response was perianal disease. Adverse events were detected in 34% of the courses and were the main cause of treatment withdrawal. Factors significantly associated with withdrawal due to adverse events were starting with full doses of thiopurinic drugs (OR, 4.26; 95% CI, 1.12-16.32) and cotreatment with infliximab (OR, 5.6; 95% CI, 1.17-27.1).

CONCLUSIONS

Some clinical variables such as disease phenotype, the use of full doses of thiopurinic drugs from the start of treatment, and co-treatments can have a notable influence on adverse effects and thus on the effectiveness of this therapy in IBD.

The incidence of Crohn's disease in Cardiff over the last 75 years: an update for 1996-2005

BACKGROUND

The incidence of Crohn's disease rose rapidly in industralized countries over the past 50 years, but it is unclear whether the incidence is still rising or has reached a plateau.

AIMS

To update the long-term incidence study of Crohn's disease in Cardiff for 1996-2005, to investigate whether incidence is still rising and to study changes in disease characteristics over time.

METHOD

Crohn's cases identified by retrospective analysis of hospital records as in previous studies in Cardiff.

RESULTS

Two hundred and twelve cases were identified. Corrected incidence for this decade was 66 x 10(6) per year (95% confidence interval: 58-76), showing a continuing rise compared to previous decades. The proportion with colonic disease at presentation continues to rise (43%) with a corresponding fall in those with terminal ileal disease. There remains a strong female preponderance (F:M 1.6:1) as in previous studies. The incidence in children under age 16 continues to rise, and the median age at diagnosis has fallen slightly.

CONCLUSION

Crohn's disease incidence continues to rise slowly in Cardiff with a continuing increase in those presenting with colonic disease, which is now the commonest disease pattern.

Tumor necrosis factor-alpha polymorphisms in ulcerative colitis-associated colorectal cancer

OBJECTIVES

Ulcerative colitis (UC) is characterized by chronic recurrent mucosal inflammation. Genetic studies in UC have indicated linkage to chromosome 6 in the region of the tumor necrosis factor-alpha (TNF-alpha) gene, a potent proinflammatory cytokine. TNF-alpha production is influenced by multiple factors including the type of immune cell and its level of activation. However, several single nucleotide polymorphisms (SNP) in the promoter region of TNF-alpha have been correlated with either increased or decreased production, indicating that regulation of TNF-alpha is in part genetic. Because UC patients are at increased risk for developing colorectal cancer (CRC), we investigated if there was an association between SNPs in the promoter of the TNF-alpha gene and UC-CRC.

METHODS

DNA was extracted from formalin-fixed, paraffin-embedded tissue from 114 UC-CRC cases and 114 UC-no CRC controls. Controls were frequency matched on duration and extent of colitis, age, ethnicity, and gender. All 228 tissue samples were analyzed for five TNF-alpha promoter polymorphisms (-238[G-->A], -308[G-->A], -857[C-->T], -863[C-->A], and -1031[T-->C]) using PCR and sequencing.

RESULTS

The -308(G-->A) SNP was significantly associated with UC-CRC cases at both the allele and genotype level (P < 0.0001). No other SNPs were significantly associated with UC-CRC.

CONCLUSION

We report a novel finding of a strong association between the -308(G-->A) SNP and UC-CRC. Complete elucidation of the mechanism of UC-CRC carcinogenesis will require investigation of other genes involved in modulating inflammation, but our results suggest that some UC patients may have additional genetic predispositions toward developing UC-CRC.

Crohn's disease: a review of current treatment with a focus on biologics

Crohn's disease is a debilitating and expensive disease that is growing in incidence in both developing and developed countries. While conventional therapies, such as corticosteroids and immunosuppressants, continue to play a vital role in treating this condition, it is evident that many affected individuals do not respond to therapy or develop intolerable adverse effects. The addition of modern biological therapies to the Crohn's disease armamentarium is providing a change in expectations for disease outcome. Infliximab and adalimumab are currently the only biological agents approved for induction and maintenance treatment in adults (infliximab and adalimumab) and children (infliximab) with Crohn's disease. Furthermore, infliximab has a beneficial effect on perianal fistulas. Other tumour necrosis factor (TNF)-alpha inhibitors, such as certolizumab pegol, also demonstrate promising results in adults with moderate to severe active disease. In addition, adalimumab and certolizumab pegol have shown clinical efficacy in patients who are intolerant to or lose response to infliximab, suggesting that switching between agents may allow response to be maintained over time. The primary safety concerns with TNFalpha inhibitors include increased risk of serious infection (including reactivation of tuberculosis), malignancy (particularly lymphoma) and demyelinating disease. Other agents in development include recombinant human anti-inflammatory cytokines, agents that target pro-inflammatory cytokines and granulocyte-macrophage colony-stimulating factors. Further prospective studies will provide interesting insight into different mechanisms by which factors involved in the pathophysiology of Crohn's disease can be modulated.

Linking genetic susceptibility to Crohn's disease with Th17 cell function: IL-22 serum levels are increased in Crohn's disease and correlate with disease activity and IL23R genotype status

BACKGROUND

We analyzed the influence of Crohn's disease (CD)-associated IL23R gene variants on IL-22 that is expressed in IL-23R+ Th17 cells.

METHODS

IL-22 serum levels were measured in 242 CD patients and in 31 healthy controls. Subanalyses included serum levels of IL-6, TNF-alpha, IL-17A, IL-17F, C-reactive protein (CRP), and leukocyte count. In all patients, genotyping for 10 CD-associated IL23R single nucleotide polymorphisms (SNPs) and the 3 main CD-associated CARD15 variants was performed.

RESULTS

There was a highly significant increase in IL-22 serum expression in CD patients compared to healthy controls (P = 2.53 x 10(-9)). IL-22 serum levels correlated with disease activity: IL-22 levels in patients with a Crohn's disease activity index (CDAI) >150 were significantly higher than in patients with a CDAI <150 (P = 0.001), while TNF-alpha and IL-6 were not significantly different between these 2 groups. Analyzing the effect of 10 IL23R variants on IL-22 serum levels, we demonstrated that the quotients of mean IL-22 serum levels of carriers of the minor allele to the mean serum IL-22 in wildtype carriers correlated highly with the corresponding CD susceptibility risk for each gene variant (r = 0.807). The IL-22 levels in carriers of CD risk-increasing IL23R variants were significantly higher than in carriers of CD risk-decreasing IL23R variants (P = 0.008).

CONCLUSIONS

The Th17 cytokine IL-22 is expressed at high levels in CD and correlates with disease activity, offering a better separation between active and inactive CD than IL-6 and TNF-alpha. IL23R genotypes influence IL-22 serum expression, linking genetic CD susceptibility to Th17 cell function for the first time.

The association of MYO9B gene in Italian patients with inflammatory bowel diseases

BACKGROUND

Variants of myosin IXB (MYO9B) gene, encoding for a motor protein implicated in epithelial permeability, have been recently associated with inflammatory bowel disease.

AIMS

To investigate the contribution of three polymorphisms of MYO9B gene for predisposition to Crohn's disease and ulcerative colitis, their association with clinical phenotypes, particularly intestinal permeability, and possible interaction with the CARD15 gene.

METHODS

549 Crohn's disease patients, 658 ulcerative colitis patients and 674 controls were genotyped for the rs962917, rs1545620 and rs2305764 single nucleotide polymorphisms.

RESULTS

Highly significant genotypic association with Crohn's disease and ulcerative colitis was shown for all three single nucleotide polymorphisms, with odds ratio ranging from 1.5 to 1.7 (P-value: <0.01 to <0.002). A significant difference in allele frequencies was also observed in inflammatory bowel disease patients, with the single most significant association for rs1545620, detected in 47% of Crohn's disease, 47% of ulcerative colitis patients and 42% of controls (P < 0.005). No association with specific sub-phenotypes was found, with the exception of a trend towards an abnormal intestinal permeability (P = 0.043) in Crohn's disease carrying the rs1545620 risk allele.

CONCLUSIONS

Our findings confirm the association between the MYO9B polymorphisms and susceptibility to both ulcerative colitis and Crohn's disease, with a weak influence on sub-phenotypic expression.

Tolerability and safety of mercaptopurine in azathioprine-intolerant patients with inflammatory bowel disease

BACKGROUND

Azathioprine intolerance is a common clinical problem, requiring drug withdrawal in up to 30% of patients. The successful use of mercaptopurine is described, but data to support this strategy are needed.

AIMS

To assess the tolerability of mercaptopurine in inflammatory bowel disease patients previously intolerant of azathioprine, and identify predictive factors.

METHODS

Sixty-one azathioprine-intolerant patients (31 males, median age at diagnosis 32 years, 31 with Crohn's disease, 30 with ulcerative colitis) who had been treated with mercaptopurine were identified. Intolerances included nausea and vomiting, flu-like illness, neutropenia, hepatotoxicity and pancreatitis.

RESULTS

Mercaptopurine was tolerated by 59% (36 of 61) of azathioprine-intolerant patients (median dose 1.0 mg/kg), 61% (17 of 28) in patients with azathioprine-related nausea and vomiting, 61% (11 of 18) with flu-like illness, 33% (three of nine) with hepatotoxicity, 100% (one of one) with neutropenia, 100% (three of three) with rash and 0% (zero of one) with pancreatitis. Mercaptopurine intolerance was frequently for a different adverse event. Those intolerant of mercaptopurine were younger (28.4 years vs. 37.0 years; P = 0.014) and more frequently female (14/30 vs. 2/29, P = 0.027). Mercaptopurine tolerability was not affected by diagnosis, location, behaviour, surgery, smoking, family history or extra-intestinal manifestations.

CONCLUSION

Mercaptopurine may be tolerated in up to 60% of azathioprine-intolerant patients, and treatment should be considered, particularly if intolerance was due to nausea, vomiting, flu-like illness or rash.

A proposed classification of ileal pouch disorders and associated complications after restorative proctocolectomy

Both medical and surgical therapies for ulcerative colitis have inherent advantages and disadvantages that must be balanced for patients with moderate to severe disease. Restorative proctocolectomy with ileal pouch-anal anastomosis has become the surgical treatment of choice for the majority of patients with ulcerative colitis who require proctocolectomy. However, adverse sequelae of mechanical, inflammatory, functional, neoplastic, and metabolic conditions related to the pouch can occur postoperatively. Recognition and familiarization of the disease conditions related to the ileal pouch can be challenging for practicing gastroenterologists. Accurate diagnosis and classification of the disease conditions are imperative for proper management and prognosis.

Inflammatory bowel disease: Genetic and epidemiologic considerations

Genome-wide association studies have firmly established that many genomic loci contribute to inflammatory bowel disease, especially in Crohn’s disease. These studies have newly-established the importance of the interleukin 23 and autophagy pathways in disease pathogenesis. Future challenges include: (1) the establishment of precisely causal alleles, (2) definition of altered functional outcomes of associated and causal alleles and (3) integration of genetic findings with environmental factors.

C-reactive protein levels during a relapse of Crohn’s disease are associated with the clinical course of the disease

AIM: To explore if C-reactive protein (CRP) levels might serve as a prognostic factor with respect to the clinical course of Crohn’s disease and might be useful for classification.

METHODS: In this retrospective cohort study we enrolled 94 patients from the inflammatory bowel disease (IBD) database of the University Medical Centre Utrecht. CRP levels during relapse were correlated with the number of relapses per year. Severity of relapses was based on endoscopic reports and prednisone use. Furthermore, patients were categorized in a low or high CRP group based on their CRP response during relapse and demographic and clinical features were compared.

RESULTS: Overall, a positive correlation between CRP levels, number of relapses, and severity of relapse was found (respectively r_s = 0.31, P < 0.01 and r_s = 0.50, P < 0.001). Employing a cut-off level of 15 mg/L, the index CRP level was found to discriminate patients with respect to the number of relapses per year, as well as for severity of relapses (respectively 0.25 ± 0.16 vs 0.36 ± 0.24, P < 0.05 and 4.4 ± 1.2 vs 3.2 ± 1.1 on a 10-point visual analogue scale, P < 0.001 for the high CRP and low CRP groups respectively). In addition, the high CRP group showed more cumulative days of prednisone use per year (107 ± 95 vs 58 ± 48, P < 0.05), as well as a better response to infliximab (93 % vs 33 %, P = 0.06).

CONCLUSION: A higher CRP level during relapse seems to be associated with a more severe clinical course of disease.

Family history and serology predict Crohn's disease after ileal pouch-anal anastomosis for ulcerative colitis

PURPOSE

Approximately 5 to 10 percent of patients undergoing ileal pouch-anal anastomosis with a diagnosis of ulcerative colitis are subsequently diagnosed with Crohn's disease. Preoperative predictors for Crohn's disease post-ileal pouch-anal anastomosis have not been prospectively defined.

METHODS

A total of 238 consecutive patients with ulcerative colitis or indeterminate colitis undergoing ileal pouch-anal anastomosis were prospectively enrolled into a longitudinal database. Clinical factors were assessed perioperatively. Serum drawn preoperatively was assayed for anti-Saccharomyces cerevisiae, antiouter membrane porin-C, anti-CBir1, and perinuclear antineutrophil cytoplasmic antibody using enzyme-linked immunosorbent assay. Crohn's disease was defined by small bowel inflammation proximal to the ileal pouch or a perianal fistula identified at least three months after ileostomy closure. Predictors were assessed in a multivariate Cox proportional hazards model to predict the rate of Crohn's disease after ileostomy closure.

RESULTS

Sixteen patients (7 percent) were diagnosed with Crohn's disease; median time to Crohn's disease was 19 (range, 1-41) months. Significant factors for postoperative Crohn's disease after ileal pouch-anal anastomosis included family history of Crohn's disease (hazard ratio, 8.4; 95 percent confidence interval, 2.96-24.1; P < 0.0001) and anti-Saccharomyces cerevisiae immunoglobulin-A seropositivity (hazard ratio, 3.14; 95 percent confidence interval, 1.1-9.81; P = 0.04). Crohn's disease developed in only 8 of 198 patients (4 percent) without these predictors vs. 8 of 40 patients (20 percent) in those with at least one of these factors (P = 0.002). The cumulative risk of Crohn's disease among patients with two risk factors (67 percent) was higher than in patients with either risk factor (18 percent) or neither risk factor (4 percent, P < 0.001).

CONCLUSIONS

Patients with ulcerative colitis and indeterminate colitis with a family history of Crohn's disease or preoperative anti-Saccharomyces cerevisiae immunoglobulin-A seropositivity are more likely to be diagnosed with Crohn's disease after ileal pouch-anal anastomosis.

Diverse effects of the CARD15 and IBD5 loci on clinical phenotype in 630 patients with Crohn's disease

OBJECTIVES

Genetic variants at the CARD15 and IBD5 loci are strongly associated with Crohn's disease (CD), but evidence of the effect of these variants on the clinical expression of CD is conflicting and has often been hampered by small sample sizes. We studied 630 well-characterized patients to clarify the genotype/phenotype relationship in CD.

METHODS

Patients and healthy controls were genotyped for three common mutations in CARD15 and a marker of the IBD5 risk haplotype. Allele frequencies were compared between phenotypic subgroups using chi2 or Fisher's exact tests. Genotype/phenotype analysis was carried out using multinomial logistic regression modelling allowing for adjustment for correlated or confounding factors.

RESULTS

The mean age at diagnosis was significantly lower in carriers of the CARD15 or IBD5 risk alleles. After correction for age and smoking, CARD15 mutations were strongly associated with both ileal disease (P=8.8 x 10(-6)) and stenotic disease (P=0.003), but the association with stenotic disease appeared to be due to a confounding effect with ileal disease. CARD15 mutations were also associated with the presence of granulomas (P=5.7 x 10(-5)), which remained significant after adjustment for age at diagnosis and disease location (P=0.0047). The IBD5 risk haplotype frequency was significantly elevated in cases with perianal disease (P=0.028) and axial spondyloarthropathy (P=0.012).

CONCLUSION

Genetic variants at the CARD15 and IBD5 loci have diverse effects on clinical expression in CD. CARD15 mutations are significantly correlated with the presence of granulomas.

Local and systemic interleukin-18 and interleukin-18-binding protein in children with inflammatory bowel disease

BACKGROUND

Interleukin-18 (IL-18) is increased in the inflamed mucosa of patients with Crohn's disease (CD). The balance between this pleiotropic proinflammatory cytokine and its natural inhibitor, IL-18-binding protein (IL-18BP), may contribute to the pathogenesis of inflammatory bowel disease (IBD).

METHODS

Serum and mucosal biopsies were collected from children with IBD, from children with celiac disease, and from controls. Biopsies were maintained in culture for 24 hours, and supernatant was collected. Serum and supernatant IL-18 and IL-18BPa concentrations were measured by immunoassay. Disease activity score (PCDAI) and standard serum inflammatory markers (albumin, platelets, ESR, and CRP) were recorded.

RESULTS

Serum IL-18 was greater in children with CD (537 pg/mL) than in controls (335 pg/mL; P < 0.05) but not in children with ulcerative colitis (UC) or IBD type unclassified (IBDU). Mucosal IL-18 was greater in children with CD and UC/IBDU than in controls (P < 0.01). Serum IL-18BPa was increased in children with CD compared with that in controls (3.9 versus 2.6 ng/mL; P < 0.05), but was not elevated in children with UC/IBDU. Furthermore, calculated free-serum IL-18 was elevated in CD, but not UC/IBDU, compared with that in controls (P = 0.001). Total and free-serum IL-18 were elevated in severe CD relative to in mild/moderate disease.

CONCLUSIONS

IL-18, produced in the colons of children with IBD, may contribute to local inflammatory changes. Systemic IL-18 level may be a useful indicator of gut inflammation. Furthermore, free IL-18 is greatly elevated in children with CD, suggesting that compensatory increases in IL-18BPa are insufficient. Further exploration of the role of this cytokine in the pathogenesis of IBD is now required.

Outcome after proctocolectomy with ileal pouch-anal anastomosis for ulcerative colitis

BACKGROUND

During the course of their disease, about 30% of patients with ulcerative colitis (UC) will undergo proctocolectomy with ileal pouch-anal anastomosis (IPAA). We evaluated the outcome of IPAA in a Belgian referral center.

METHODS

Clinical charts were reviewed for pre- and postoperative disease course, functional outcome, and complications in all patients with UC (n = 182) and indeterminate colitis (n = 2) who underwent IPAA in 1990-2004.

RESULTS

Follow-up data were available in 173 out of 184 patients (67 female, median age at proctocolectomy 39.0 years). Median functional Oresland score 1 year after IPAA was 3 (range 0-11). Early postoperative complications were seen in 27% of patients. After a median (interquartile range) follow-up of 6.5 (3.4-9.9) years, 35% of patients developed septic and/or obstructive complications. Forty-six percent of patients developed at least 1 episode of pouchitis. Risk factors for pouchitis were the presence of extraintestinal manifestations (odds ratio [OR] 1.92 (1.23-3.01), P = 0.004) and younger age at proctocolectomy (P = 0.004). Chronic pouchitis was present in 33 patients and associated with extraintestinal manifestations (OR 2.93 (1.13-7.62), P = 0.027), backwash ileitis (OR 9.28 (1.71-50.49), P = 0.010), and length of follow-up (P = 0.004). Pouch failure occurred in 5% of patients.

CONCLUSIONS

Although proctocolectomy with IPAA surgery has a good functional outcome, postoperative complications, especially pouchitis, remain considerable in patients with UC.

Review article: Inflammatory bowel disease and genetics

INTRODUCTION

Inflammatory bowel disease (IBD) comprising ulcerative colitis (UC) and Crohn's disease (CD) is multigenic disorder. Tremendous progress has been achieved in unravelling the genetic background of IBD. It has led to the discovery of mutations in NOD2 associated with ileal CD and numerous other genes have been found to be associated with IBD susceptibility.

METHODS

A review of the literature on the genetic background of IBD was performed.

RESULTS

It is only partially understood how mutations in NOD2 lead to CD. Mouse models, in vitro data and studies in humans offer conflicting data as regards whether there is a loss or gain of function of NOD2 in CD. Several additional genes have been identified of which only a few are currently being recognized as potential disease causing or disease modifying genes. Promising candidate genes include TLR4, MDR1, NOD1 (CARD4), DLG5 as well as the IBD5 locus including SLC22A4/5.

CONCLUSIONS

Although genetic research has not yet led to a better prediction of the disease course or patient selection for medical therapy, remarkable progress has been made in the understanding of the pathogenesis of IBD. For future genetic research, accurate phenotyping of patients is very important and large population-based cohorts are needed. Eventually, genetic research may be able to classify different disease phenotypes on a more detailed molecular basis and may provide important contributions in the development of new therapeutic approaches.

Phenotype classification in IBD: Is there an impact on therapy?

This review summarizes the current phenotypic classifications of inflammatory bowel disease (IBD) and outlines their implications for diagnosis, therapy, prognosis, clinical trial design, and genotype-phenotype correlations.

IL23R R381Q and ATG16L1 T300A are strongly associated with Crohn's disease in a study of New Zealand Caucasians with inflammatory bowel disease

OBJECTIVE

Recently, separate genome-wide association analyses have identified nonsynonymous SNPs in IL23R and ATG16L1 (rs11209026; c1142G>A, R381Q, and rs2241880; c1338A>G, T300A, respectively) as strong candidate susceptibility factors for Crohn's disease (CD) in whites. The aim of our study was to test whether these SNPs are associated with CD in a population-based cohort of New Zealand Caucasian inflammatory bowel disease (IBD) patients.

METHODS

Allele frequencies of rs11209026 and rs2241880 were determined in 496 CD patients, 466 ulcerative colitis (UC) patients, and 591 controls. Distribution of the relevant alleles was compared between controls and IBD patients. rs11209026 and rs2241880 genotype distributions were examined both within IBD clinical subphenotypes and CARD15 genotypes.

RESULTS

rs11209026 and rs2241880 were both associated with CD (P valuers11209026=0.0026, OR 0.54, 95% CI 0.36-0.81; P valuers2241880=0.0001, OR 1.41, 95% CI 1.18-1.67). In addition, there was evidence for association of rs11209026 with UC (P value=0.037, OR 0.66, 95% CI 0.45-0.98). No significant association was observed between IL23R genotype or ATG16L1 genotype and IBD subphenotypes. IL23R was associated with CD and UC only in the absence of CARD15 mutations, whereas ATG16L1 was associated with CD in the presence and absence of CARD15 mutations.

CONCLUSIONS

We replicated the previously reported associations between CD and rs11209026 and rs2241880, confirming that IL23R and ATG16L1 are susceptibility loci for CD in the New Zealand population. We also provide further evidence for association of rs11209026 with UC and a report of an additive effect between IL23R and CARD15 genotypes in CD.

Longitudinal concordance for clinical characteristics in a Swedish-Danish twin population with inflammatory bowel disease

BACKGROUND

The genetic influence on disease course in inflammatory bowel disease (IBD) remains unknown. We therefore aimed to study longitudinal concordance for clinical characteristics and longitudinal stability using the Montreal Classification in an IBD twin population.

METHODS

A total of 158 twins with ulcerative colitis (UC) (18 belonging to 9 concordant monozygotic pairs) and 141 twins with Crohn's disease (CD) (34 belonging to 17 concordant monozygotic pairs) were enrolled. Medical notes were scrutinized for clinical characteristics at diagnosis and after 10 years. Using the binominal distribution, we tested the hypothesis that clinical characteristics were independent within individuals in disease concordant monozygotic pairs.

RESULTS

In CD, location was identical in 11/17 monozygotic concordant pairs at diagnosis (P = 0.008) and in 11/16 pairs after 10 years (P = 0.02). Behavior at diagnosis was identical in 13/17 pairs (P = 0.03) and in 11/16 pairs after 10 years (P = 0.01). Monozygotic UC twins were concordant (within 5 years) for age at diagnosis (6/9 pairs; P < 0.001) and symptomatic onset (4/9 pairs; P = 0.02) but not for extent of disease at diagnosis or after 10 years. The Montreal Classification did not demonstrate longitudinal stability, either regarding location or behavior of CD or extent of UC.

CONCLUSIONS

The high phenotypic concordance, both at diagnosis and longitudinally, in monozygotic twins with CD supports a genetic influence not only on disease occurrence but also on disease course. This contrasts with UC, where the genetic impact appears less. Montreal Classification characteristics changed over time and should be used cautiously.

Effect of phenotype on health care costs in Crohn's disease: A European study using the Montreal classification

BACKGROUND

Crohn's disease (CD) is a chronic inflammation of the gastrointestinal tract associated with life-long high health care costs. We aimed to determine the effect of disease phenotype on cost.

METHODS

Clinical and economic data of a community-based CD cohort with 10-year follow-up were analyzed retrospectively in relation to Montreal classification phenotypes.

RESULTS

In 418 patients, mean total costs of health care for the behavior phenotypes were: nonstricturing-nonpenetrating 1690, stricturing 2081, penetrating 3133 and penetrating-with-perianal-fistula 3356 €/patient-phenotype-year (P<0.001), and mean costs of surgical hospitalization 215, 751, 1293 and 1275 €/patient-phenotype-year respectively (P<0.001). Penetrating-with-perianal-fistula patients incurred significantly greater expenses than penetrating patients for total care, diagnosis and drugs, but not surgical hospitalization. Total costs were similar in the location phenotypes: ileum 1893, colon 1748, ileo-colonic 2010 and upper gastrointestinal tract 1758 €/patient-phenotype-year, but surgical hospitalization costs differed significantly, 558, 209, 492 and 542 €/patient-phenotype-year respectively (P<0.001). By multivariate analysis, the behavior phenotype significantly impacted total, medical and surgical hospitalization costs, whereas the location phenotype affected only surgical costs. Younger age at diagnosis predicted greater surgical expenses.

CONCLUSIONS

Behavior is the dominant phenotype driving health care cost. Use of the Montreal classification permits detection of cost differences caused by perianal fistula.

A study in three European IBD cohorts confirms that the ATG16L1 c.898A>G (p.Thr300Ala) variant is a susceptibility factor for Crohn's disease

BACKGROUND AND AIMS

A recent study reported that a nonsynonymous SNP rs2241880 (c.898A>G, p.Thr300Ala) within ATG16L1 confers susceptibility to Crohn's disease (CD). We analyzed ATG16L1 c.898A>G in three independent European inflammatory bowel disease (IBD) cohorts from Germany, Hungary and the Netherlands.

METHODS

In total, we included 910 European IBD patients and compared the ATG16L1 c.898A>G genotype frequency with 707 ethnically matched healthy controls. We included patients from 3 populations originating from Germany (CD n=310; ulcerative colitis [UC] n=179), Hungary (CD n=147; UC n=117), and the Netherlands (CD n=157). Subtyping analysis was performed in respect to CARD15 alterations and clinical characteristics.

RESULTS

We found a highly significant association of c.898A>G to CD. The association was significant (p=0.0005) for the total CD cohort but also for the individual populations from Germany (p=0.02) and Netherlands (p=0.02) whereas in the Hungarian CD patients a clear trend was observed (p=0.19; OR 1.227, 95% CI 0.910; 1.654). No association was found between c.898A>G and UC. No statistical interactions were observed between ATG16L1 c.898A>G and CARD15 variants. Furthermore no association to a CD subphenotype was detected.

CONCLUSIONS

We confirm that ATG16L1 variant c898A>G confers a risk variant for CD but is not associated with a distinct CD phenotype.

Granuloma-positive Crohn's disease

BACKGROUND

The epithelioid granuloma is a characteristic histological feature of Crohn's disease. In some pathological classification schemes, the criteria for a definite, probable or possible diagnosis have been listed, with the epithelioid granuloma indicating definite Crohn's disease.

METHODS

In the present evaluation, 247 prospectively evaluated Crohn's disease patients (24.3%), from a consecutively accumulated population database of 1015 patients, were found to have an epithelioid granuloma. The recently devised Montreal classification for Crohn's disease was then applied to this granuloma-positive cohort of Crohn's disease patients to define age at diagnosis for men and women, disease site and disease behaviour.

RESULTS

The investigation showed that patients with Crohn's disease and granulomas were most often diagnosed early in the course of their disease, particularly women. Their disease was often extensive, with ileocolonic and upper gastrointestinal tract involvement. Finally, disease behaviour was most often complex, especially with penetrating disease complications.

CONCLUSION

Using homogeneous (ie, 'reagent-grade') patient cohorts defined by a recently devised classification method for Crohn's disease, the study demonstrated that an epithelioid granuloma may represent a histopathological marker for an early biological event in the etiopathogenesis of Crohn's disease, and this may have predictive significance with respect to the location and clinical behaviour of Crohn's disease.

Resource use in patients with Crohn's disease treated with infliximab

AIM

To estimate the impact of infliximab (IFX) on hospital resources for patients with Crohn's disease.

METHODS

Resource use data for at least 1 year before (B-IFX) and after (A-IFX) infliximab administration were retrospectively collected for all patients treated with IFX at the Hospital Cabueñes (Spain). Direct costs calculated were: hospital-stays, surgeries, out-patient visits, diagnostic and laboratory tests, pharmacological treatments, and day-care hospitalization for IFX administration.

RESULTS

Patients (n = 34; mean age at treatment: 43.6 years) with 9.8 and 4.3 years (B-IFX and A-IFX, respectively) had their costs estimated. Partial or complete response was achieved in 82% of patients. Total annual B-IFX costs per patient were Euro 4,464, of which 62.4% was for hospitalization, 3.1% for surgery, 8.7% for consultation visits, 16.2% for diagnostic and laboratory tests, and 9.6% for other treatments. Total annual A-IFX costs per patient were Euro 10,594; of which 6.4% was for hospitalization, 0.8% for surgery, 4.2% for consultation visits, 7.6% for diagnostic and laboratory tests, 5.5% for other treatments, and 75.5% for IFX and its administration. The primary cost item was hospitalization (Euro 2,783) during the B-IFX period as opposed to IFX itself (Euro 7,996) during the subsequent A-IFX period.

CONCLUSIONS

In routine practice, IFX appears to be an effective treatment by reducing hospital-stays, but increases overall budgetary cost for patients with Crohn's disease.

Serum and mucosal S100 proteins, calprotectin (S100A8/S100A9) and S100A12, are elevated at diagnosis in children with inflammatory bowel disease

OBJECTIVE

Various markers characterize the complex inflammatory processes seen in chronic inflammatory bowel disease (IBD) including calprotectin, a complex of two S100 proteins, which has been evaluated and validated as a faecal marker of inflammation. However, the systemic and mucosal expression patterns of calprotectin and related S100 proteins are not well characterized in this disease. The objective of this study was to assess serum and mucosal levels of calprotectin, S100A12 and soluble receptor for advanced glycation end products (sRAGE), a putative S100 ligand, in a paediatric population with IBD.

MATERIAL AND METHODS

Children were enrolled at diagnosis of IBD, along with groups of children without IBD. Standard inflammatory markers and disease activity scores were collated. Calprotectin, S100A12 and sRAGE levels in serum and biopsy culture supernatants were measured by ELISA and tissue distribution of S100 proteins was investigated by immunohistochemistry.

RESULTS

Serum and mucosal calprotectin and S100A12 levels were increased in children with IBD as compared with non-IBD controls. Serum calprotectin levels correlated with S100A12 levels and with disease activity scores in children with IBD. sRAGE levels were not increased in IBD. S100A8, S100A9 and S100A12 were abundantly expressed throughout the lamina propria and epithelium in inflamed mucosa. In contrast, these proteins were present in the lamina propria, but not the epithelium, in non-inflamed mucosa.

CONCLUSIONS

Serum calprotectin and S100A12 are increased in children with IBD and indicate disease activity. Elevated levels of these proteins are present in the colonic mucosa and may contribute to the pathogenesis of IBD. Furthermore, an imbalance between sRAGE and S100A12 may contribute to inflammatory changes present in IBD.

Has toll-like receptor 4 been prematurely dismissed as an inflammatory bowel disease gene? Association study combined with meta-analysis shows strong evidence for association

OBJECTIVES

Published association studies of the TLR4 Asp299Gly polymorphism and inflammatory bowel disease (IBD) in caucasian populations have inconsistent results. We tested two TLR4 variants for association with IBD in the New Zealand caucasian population and assessed the cumulative evidence for association of TLR4 Asp299Gly and IBD.

METHODS

The TLR4 Asp299Gly and Thr399Ile polymorphisms were genotyped and tested for case-control frequency differences in a New Zealand white cohort of 389 Crohn's disease (CD) patients, 405 ulcerative colitis (UC) patients, and 416 population controls. Meta-analysis using a random effects model was performed to test whether 299Gly carriage was associated with UC, CD, or phenotypes of CD patients.

RESULTS

There were no significant allele or genotype frequency differences between cases and controls or between CD phenotypes in our New Zealand data. Meta-analysis did not identify any significant associations between CD phenotypes and 299Gly carriage. However, meta-analysis demonstrated significantly higher 299Gly carrier frequencies in CD patients (odds ratio 1.45, 95% CI 1.11-1.90) and in IBD patients (odds ratio 1.36, 95% CI 1.01-1.84) compared to controls.

CONCLUSIONS

The meta-analysis provides evidence that Asp299Gly is associated with CD and IBD in whites. Only the Asp299Gly polymorphism has been consistently genotyped in previous TLR4 studies with IBD patients, therefore other TLR4 variants with stronger associations with IBD may exist. Additional well-powered studies of Asp299Gly and other TLR4 variants are urgently needed.

Long-term clinical results of ileocecal resection for Crohn's disease

BACKGROUND

The efficacy of biologic agents in Crohn's disease (CD) has led to proposals that they be introduced early in the disease (top-down treatment) with the aim of reducing corticosteroid dependency and surgical resection. However, the long-term use of biologic agents in limited CD may be difficult to justify. The aims were to assess outcomes for ileocecal resection in CD and evaluate its role in the current era.

METHODS

The study included 139 CD patients who underwent ileocecal resection between 1980 and 2000. Data were retrieved from a prospectively maintained database. Disease recurrence was defined as symptoms in addition to endoscopic or radiological evidence of disease activity. Severe disease recurrence was defined as a need for repeat resection surgery.

RESULTS

Seventy-two (52%) patients developed disease recurrence. Median (interquartile range) time to recurrence was 7.1 (5-10.6) years. Forty-nine (35%) patients required repeat resection surgery. Median (IQ range) time to repeat surgery was 7.2 (4.9-10.8) years. The presence of granulomas was associated with disease recurrence (P = 0.03) and repeat resection surgery (P = 0.01).

CONCLUSIONS

Long-term outcomes for ileocecal resection in CD are excellent with 48% of patients remaining symptom-free and only 35% requiring repeat resection surgery at 10 years. This should be borne in mind when considering biologic therapy.

Association of a CXCL9 polymorphism with pediatric Crohn’s disease

Genetic and environmental factors contribute to the etiopathogenesis of Crohn's disease (CD) and ulcerative colitis (UC). To identify new susceptibility genes, we determined the mRNA expression level of 88 genes from different biological contexts on colonic biopsies of CD and UC patients. We show that CXCL9 was overexpressed in colonic tissue of 3/5 CD and 3/3 UC patients compared to healthy controls. SNP genotyping for the 77147452G-->A polymorphism of the CXCL9 gene on 114 pediatric IBD patients and 120 ethnically matched unaffected adults detected a minor allele frequency of 20.3% in CD patients compared to 31.3% in controls (p=0.016). Strikingly, children with homozygosity for the wild-type allele had a significant earlier onset of CD than heterozygous individuals (11.1 versus 13.8 years). This is the first report of inverse association of the CXCL9 77147452G-->A polymorphism with pediatric CD. Our data may contribute to a better understanding of the pathophysiology underlying CD.

6-thioguanine associated nodular regenerative hyperplasia in patients with inflammatory bowel disease may induce portal hypertension

BACKGROUND

Recent studies suggest an association between 6-thioguanine (6-TG) therapy and hepatic nodular regenerative hyperplasia (NRH) in patients with inflammatory bowel disease (IBD). An influence of 6-TG on portal pressure remains to be determined. The aim of the study was to examine the functional relevance of long-term 6-TG treatment on hepatic hemodynamics in IBD patients and its association with NRH.

METHODS

Patients treated with 6-TG for IBD underwent measurement of the hepatic venous pressure gradient (HVPG) and liver biopsy. 6-TG therapy was stopped when NRH was diagnosed. If elevated, HVPG measurement was repeated after 1 yr.

RESULTS

Twenty-six patients (15 women, 11 men; median age 41 yr, range 23-76) treated with 6-TG for 38 months (median; range 12-45) were included. Among 24 patients with sufficient liver biopsy, 6 patients (25%) were diagnosed with NRH. In these 6 patients, the HVPG was higher (median HVPG 7 mmHg, range 3-14) than in the 18 patients without NRH (median 3 mmHg, range 2-5; P < 0.001). In the patients with NRH, two had clinically significant portal hypertension (CSPH) (13 and 14 mmHg, respectively); in one patient the HVPG was slightly elevated (7 mmHg). No overt clinical signs of portal hypertension were observed. One year after stopping 6-TG therapy, HVPG decreased in all 3 patients with initially elevated HVPG levels.

CONCLUSIONS

We demonstrate that IBD patients under long-term 6-TG therapy are at a substantial risk for developing NRH. NRH results in elevation of HVPG and may cause CSPH. Discontinuation of 6-TG therapy extenuates portal hypertension and may thus reduce the risk of complications.

Application of the Montreal classification for Crohn's disease to a single clinician database of 1015 patients

Crohn's disease involves different gastrointestinal sites and may be characterized by high rates of strictures and penetrating complications. The present study applied the newly described Montreal schema of classification to a large, prospectively accumulated clinical database. In addition, age dependence was evaluated at diagnosis, with regard to disease location and disease behaviour. There were 1015 consecutively evaluated patients (449 male and 566 female). Disease was most often localized in the ileocolon and was usually complex with stricture formation or penetrating complications. For both sexes, with increasing age at diagnosis, Crohn's disease was less extensive, more often localized in the colon alone and characterized by less complex disease behaviour, especially with less penetrating disease complications. Using the Montreal classification for Crohn's disease, these results define the clinical features in a large, single clinician database and demonstrate age dependence in the phenotypic clinical expression of Crohn's disease.