Genetic determinants of ulcerative colitis include the ECM1 locus and five loci implicated in Crohn's disease

Remote control-triggering of brain autoimmune disease in the gut

Converging evidence indicates that multiple sclerosis, an inflammatory demyelinating disease of the central nervous system, is caused by brain-specific, self-reactive T lymphocytes. These are normal components embedded in the human immune system throughout healthy life. Only upon activation in the periphery, the T cells assume properties that enable them to break through the vascular blood-brain barrier and to invade the brain white matter. While activation has been traditionally associated with microbial infections, recently, studies of animal models revealed a critical role of the commensal gut flora as a key triggering factor. These findings may pave the way to new strategies to treat MS and other human autoimmune diseases, and commend a reevaluation of dietary approaches.

Associations between PTPN2 polymorphisms and susceptibility to ulcerative colitis and Crohn's disease: a meta-analysis

OBJECTIVE

Ulcerative colitis (UC) and Crohn's disease (CD) result from an interaction between genetic and environmental factors. Though several polymorphisms have been identified in PTPN2, their roles in the incidence of UC and CD are conflicting. This meta-analysis was aimed to clarify the impact of these polymorphisms on UC and CD risk.

METHOD

PubMed, EMBASE, Cochrane Library and CBM were searched until 23 July 2013 for eligible studies on three PTPN2 polymorphisms: rs2542151, rs1893217 and rs7234029. Data were extracted, and pooled odd ratios (ORs) as well as 95 % confidence intervals (95 % CIs) were calculated.

CONCLUSION

The meta-analysis indicated that rs2542151, rs1893217 and rs1893217 were associated with increased CD risk, while the former was associated with increased UC risk. The differences in age of onset and ethnic groups may influence the associations. Gene-gene and gene-environment interactions should be investigated in the future.

RESULTS

Seventeen studies with 18,308 cases and 20,406 controls were included. Significant associations were found between rs2542151 polymorphism and CD susceptibility (OR = 1.22, 95 % CI, 1.15-1.30, I (2) = 32 %), as well as between rs2542151 and UC susceptibility (OR = 1.16, 95 % CI, 1.07-1.25, I (2) = 39 %). A similar result was found in Caucasians, but not in Asians. Moreover, a significant increase in CD risk for all carriers of the minor allele of rs1893217 (OR = 1.45, 95 % CI, 1.23-1.70, I (2) = 0 %) and rs7234029 (OR = 1.36, 95 % CI, 1.16-1.59, I (2) = 0 %) were found. For children, the rs1893217 polymorphism appeared to confer susceptibility to CD (OR = 1.56, 95 % CI, 1.28-1.89, I (2) = 0 %).

Integrated enrichment analysis of variants and pathways in genome-wide association studies indicates central role for IL-2 signaling genes in type 1 diabetes, and cytokine signaling genes in Crohn's disease

Pathway analyses of genome-wide association studies aggregate information over sets of related genes, such as genes in common pathways, to identify gene sets that are enriched for variants associated with disease. We develop a model-based approach to pathway analysis, and apply this approach to data from the Wellcome Trust Case Control Consortium (WTCCC) studies. Our method offers several benefits over existing approaches. First, our method not only interrogates pathways for enrichment of disease associations, but also estimates the level of enrichment, which yields a coherent way to promote variants in enriched pathways, enhancing discovery of genes underlying disease. Second, our approach allows for multiple enriched pathways, a feature that leads to novel findings in two diseases where the major histocompatibility complex (MHC) is a major determinant of disease susceptibility. Third, by modeling disease as the combined effect of multiple markers, our method automatically accounts for linkage disequilibrium among variants. Interrogation of pathways from eight pathway databases yields strong support for enriched pathways, indicating links between Crohn's disease (CD) and cytokine-driven networks that modulate immune responses; between rheumatoid arthritis (RA) and "Measles" pathway genes involved in immune responses triggered by measles infection; and between type 1 diabetes (T1D) and IL2-mediated signaling genes. Prioritizing variants in these enriched pathways yields many additional putative disease associations compared to analyses without enrichment. For CD and RA, 7 of 8 additional non-MHC associations are corroborated by other studies, providing validation for our approach. For T1D, prioritization of IL-2 signaling genes yields strong evidence for 7 additional non-MHC candidate disease loci, as well as suggestive evidence for several more. Of the 7 strongest associations, 4 are validated by other studies, and 3 (near IL-2 signaling genes RAF1, MAPK14, and FYN) constitute novel putative T1D loci for further study.

Genetic variants in the IL12B gene are associated with inflammatory bowel diseases in the Korean population

BACKGROUND AND AIM

Recent genomic studies have identified genetic variants in the IL12B gene, which encodes the p40 subunit shared by interleukin 12 and interleukin 23, as susceptibility loci for inflammatory bowel disease (IBD). The study aimed to identify additional novel genetic variants in IL12B and investigated whether variants confer susceptibility to the development of Crohn's disease (CD) or ulcerative colitis (UC) in the Korean population.

METHODS

To detect single nucleotide polymorphisms (SNPs) in IL12B, direct sequencing of all coding exons, exon-intron boundaries, promoter region, and 5' untranslated region was performed in 24 randomly selected samples. Selected haplotype-tagging SNPs were subsequently genotyped in 493 IBD patients (245 patients with CD and 248 with UC) and 504 healthy controls.

RESULTS

Two haplotype-tagging SNPs (rs2288831 and rs919766) were selected through direct sequencing and were genotyped. Of them, SNP rs2288831 in the IL12B gene was significantly associated with CD susceptibility in allelic association analysis (odds ratio = 1.30; 95% confidence interval 1.04-1.62; P = 0.019). This significant association with CD was also observed for a haplotype consisting of SNP rs919766 and rs2288831 (odds ratio = 1.29; 95% confidence interval 1.03-1.60; P = 0.025). However, none of IL12B SNPs were associated with UC susceptibility. Finally, no specific associations between genetic variants and disease phenotype of CD were identified.

CONCLUSIONS

This study is first to identify SNP rs2288831 in the IL12B gene as a susceptible variation for CD. Further studies in other ethnic groups are warranted to validate the association of this genetic variant with IBD.

Replication study of ulcerative colitis risk loci in a Lithuanian-Latvian case-control sample

BACKGROUND

Differences between populations might be reflected in their different genetic risk maps to complex diseases, for example, inflammatory bowel disease. We here investigated the role of known inflammatory bowel disease-associated single nucleotide polymorphisms (SNPs) in a subset of patients with ulcerative colitis (UC) from the Northeastern European countries Lithuania and Latvia and evaluated possible epistatic interactions between these genetic variants.

METHODS

We investigated 77 SNPs derived from 5 previously published genome-wide association studies for Crohn's disease and UC. Our study panel comprised 444 Lithuanian and Latvian patients with UC and 1154 healthy controls. Single marker case-control association and SNP-SNP epistasis analyses were performed.

RESULTS

We found 14 SNPs tagging 9 loci, including 21q21.1, NKX2-3, MST1, the HLA region, 1p36.13, IL10, JAK2, ORMDL3, and IL23R, to be associated with UC. Interestingly, the association of UC with previously identified variants in the HLA region was not the strongest association in our study (P = 4.34 × 10, odds ratio [OR] = 1.25), which is in contrast to all previously published studies. No association with any disease subphenotype was found. SNP-SNP interaction analysis showed significant epistasis between SNPs in the PTPN22 (rs2476601) and C13orf31 (rs3764147) genes and increased risk for UC (P = 1.64 × 10, OR = 2.44). The association has been confirmed in the Danish study group (P = 0.04, OR = 3.25).

CONCLUSIONS

We confirmed the association of the 9 loci (21q21.1, 1p36.13, NKX2-3, MST1, the HLA region, IL10, JAK2, ORMDL3, and IL23R) with UC in the Lithuanian-Latvian population. SNP-SNP interaction analyses showed that the combination of SNPs in the PTPN22 (rs2476601) and C13orf31 (rs3764147) genes increase the risk for UC.

Intestinal epithelium and autophagy: partners in gut homeostasis

One of the most significant challenges of cell biology is to understand how each type of cell copes with its specific workload without suffering damage. Among the most intriguing questions concerns intestinal epithelial cells in mammals; these cells act as a barrier between the internally protected region and the external environment that is exposed constantly to food and microbes. A major process involved in the processing of microbes is autophagy. In the intestine, through multiple, complex signaling pathways, autophagy including macroautophagy and xenophagy is pivotal in mounting appropriate intestinal immune responses and anti-microbial protection. Dysfunctional autophagy mechanism leads to chronic intestinal inflammation, such as inflammatory bowel disease (IBD). Studies involving a number of in vitro and in vivo mouse models in addition to human clinical studies have revealed a detailed role for autophagy in the generation of chronic intestinal inflammation. A number of genome-wide association studies identified roles for numerous autophagy genes in IBD, especially in Crohn’s disease. In this review, we will explore in detail the latest research linking autophagy to intestinal homeostasis and how alterations in autophagy pathways lead to intestinal inflammation.

Molecular mechanisms and cell targets of Th17 cells in the gastrointestinal tract: an innate sense of adaptivity

T-helper (TH) 17 activation is crucial for protective immune responses against bacteria and fungi at mucosal surfaces, but it can also be implicated in the pathogenesis of several autoimmune and chronic inflammatory diseases, such as inflammatory bowel diseases (IBD). Although rapid progress was made elucidating induction and functional heterogeneity of Th17 responses, the underlying molecular effects of Th17 response including the most relevant different cell targets of Th17 cytokines remain poorly understood. Cytokines produced by Th17 cells have broad effects on both hematopoietic and nonhematopoietic cells and can act in synergy with various inflammatory factors. In this review, we will focus on the effects of Th17-derived cytokines in the gastrointestinal tract and discuss how Th17 responses can affect both innate and adaptive immunity and may contribute to the pathogenesis of inflammatory GI processes.

Deep resequencing of GWAS loci identifies rare variants in CARD9, IL23R and RNF186 that are associated with ulcerative colitis

Genome-wide association studies and follow-up meta-analyses in Crohn's disease (CD) and ulcerative colitis (UC) have recently identified 163 disease-associated loci that meet genome-wide significance for these two inflammatory bowel diseases (IBD). These discoveries have already had a tremendous impact on our understanding of the genetic architecture of these diseases and have directed functional studies that have revealed some of the biological functions that are important to IBD (e.g. autophagy). Nonetheless, these loci can only explain a small proportion of disease variance (~14% in CD and 7.5% in UC), suggesting that not only are additional loci to be found but that the known loci may contain high effect rare risk variants that have gone undetected by GWAS. To test this, we have used a targeted sequencing approach in 200 UC cases and 150 healthy controls (HC), all of French Canadian descent, to study 55 genes in regions associated with UC. We performed follow-up genotyping of 42 rare non-synonymous variants in independent case-control cohorts (totaling 14,435 UC cases and 20,204 HC). Our results confirmed significant association to rare non-synonymous coding variants in both IL23R and CARD9, previously identified from sequencing of CD loci, as well as identified a novel association in RNF186. With the exception of CARD9 (OR = 0.39), the rare non-synonymous variants identified were of moderate effect (OR = 1.49 for RNF186 and OR = 0.79 for IL23R). RNF186 encodes a protein with a RING domain having predicted E3 ubiquitin-protein ligase activity and two transmembrane domains. Importantly, the disease-coding variant is located in the ubiquitin ligase domain. Finally, our results suggest that rare variants in genes identified by genome-wide association in UC are unlikely to contribute significantly to the overall variance for the disease. Rather, these are expected to help focus functional studies of the corresponding disease loci.

Mapping colitis susceptibility in mouse models: distal chromosome 3 contains major loci related to Cdcs1

Inflammatory bowel disease (IBD) summarizes a group of chronic intestinal disorders with Crohn's disease and ulcerative colitis being most prominent. Though much effort is put into identification of causative factors, its etiology is still not understood. Risk factors for disease development include genetic predisposition and environmental triggers. Crucial for identification and analysis of relevant factors are mouse models. Experimental IBD in mice occurs spontaneously or is induced by chemicals, cell transfer, pathogens, or genetic mutation. These models were utilized for analyzing genetic contribution to disease and genotype-environmental interactions. In these studies, a variety of modifier loci were identified, thereby demonstrating the complexity of disease. A major contribution of distal chromosome 3 was independently replicated in several studies. The first colitogenic QTL in this region was detected using the IL-10-deficient mouse model and called cytokine deficiency-induced colitis susceptibility (Cdcs)1. This quantitative trait locus contains at least three subintervals with independent genetic factors. This locus or defined subintervals were replicated in at least seven studies, using models based on dysregulation of innate or adaptive immunity or pathogen control. In this review we illustrate the various models used for genetic mapping of susceptibility to experimental IBD and display Cdcs1-related loci as well as the mechanism of their contribution identified so far.

Polymorphisms in the IL2RA and IL2RB genes in inflammatory bowel disease risk

Associations with different autoimmune diseases of polymorphisms in genes encoding the IL2RA and IL2RB subunits (located in 10p15 and 22q13, respectively), were identified through genome-wide studies. Polymorphisms in these two genes were studied in 107 inflammatory bowel disease (IBD) patients (39 Crohn's disease [CD] and 68 ulcerative colitis [UC]) and in 162 ethnically healthy controls from Tunisia (Sfax). Two of the 15 IL2RA single-nucleotide polymorphisms (SNPs) genotyped (rs4749924 and rs706778) were significantly associated with UC (pcorr=0.018 and 0.048, respectively), but no evidence of association with CD was observed. The IL2RA GTCT haplotype was also more frequent in UC patients compared to controls (2.6% vs. 0%; p=0.002). One of the 6 IL2RB SNPs genotyped (rs743776) was significantly associated with CD (pcorr= 0.039), but no evidence of association with UC was observed. No significant association between IL2RB haplotypes was observed among investigated groups. Our study identified markers in the IL2RA and IL2RB genes that are significantly associated with UC and CD, respectively. Our results supporting IL2RA and IL2RB as promising candidate genes for IBD and suggesting a potential role of IL2R in the pathogenesis of IBD, likely involves regulatory T cells.

Role of miR-19a targeting TNF-α in mediating ulcerative colitis

OBJECTIVE

Ulcerative colitis (UC) is a widely studied inflammatory disease associated with differential expression of genes involved in immune function, wound healing, and tissue remodeling. MicroRNAs have been reported to play a role in various cancer types. However, the mechanism of how microRNAs regulate UC remains unclear.

METHODS

In the present study, we investigated the role of miR-19a and tumor necrosis factor (TNF)-α in human colon tissues with UC and dextran sodium sulfate (DSS)-induced experimental colitis.

RESULTS

We identified that the expression of miR-19a was significantly reduced and TNF-α was remarkably increased in human colon tissue with UC. Moreover, this observation of miR-19a and TNF-α was also occurred in DSS-treated mice colitis. Further, we observed that miR-19a directly regulated TNF-α expression because miR-19a can suppress the expression of wild-type TNF-α reporter, but not the mutant form. The expression of inflammatory factors TNF-α, IL-8, and GM-GSF were significantly elevated upon application of miR-19a inhibitor.

CONCLUSION

Taken together, this study determines the levels of miR-19a and TNF-α in both DSS-induced experimental murine colitis and human UC and further demonstrates that miR-19a might directly regulate TNF-α. The findings may provide a new insight in the clinical treatment of UC.

Innate and adaptive immunity in inflammatory bowel disease

Inflammatory bowel disease (IBD) includes Crohn's disease (CD) and ulcerative colitis (UC). The exact cause of IBD remains unknown. Available evidence suggests that an abnormal immune response against the microorganisms of the intestinal flora is responsible for the disease in genetically susceptible individuals. The adaptive immune response has classically been considered to play a major role in the pathogenesis of IBD. However, recent advances in immunology and genetics have clarified that the innate immune response is equally as important in inducing gut inflammation in these patients. In particular, an altered epithelial barrier function contributes to intestinal inflammation in patients with UC, while aberrant innate immune responses, such as antimicrobial peptide production, innate microbial sensing and autophagy are particularly associated to CD pathogenesis. On the other hand, besides T helper cell type (Th)1 and Th2 immune responses, other subsets of T cells, namely Th17 and regulatory T (Treg) cells, are likely to play a role in IBD. However, given the complexity and probably the redundancy of pathways leading to IBD lesions, and the fact that Th17 cells may also have protective functions, neutralization of IL-17A failed to induce any improvement in CD. Studying the interactions between various constituents of the innate and adaptive immune systems will certainly open new horizons in the knowledge about the immunologic mechanisms implicated in gut inflammation.

Prevention of colitis-associated cancer: natural compounds that target the IL-6 soluble receptor

The risk of developing colorectal cancer increases in patients with inflammatory bowel disease (IBD) and a growing body of evidence shows the critical role of interleukin (IL-6) in this process. IL-6 is both a pro- and anti-inflammatory cytokine whose effects are mediated through activation of STAT3. Recent studies have also demonstrated that IL-6 trans-signaling through its soluble receptor occurs in IBD and cancer. IL-6 trans-signaling therefore is emerging as an attractive approach to diminish the inflammatory signals in conditions of chronic inflammation. The purpose of cancer chemoprevention is to either delay the onset or progression from precancerous lesions. Natural compounds because of their low toxicity render themselves excellent candidates that can be administered over the lifetime of an individual. With the focus of managing IBD over a long time and preventing onset of colitis-associated cancer, we believe that there should be increased research focus on identifying chemopreventive compounds that can render themselves to long term use possibly for the lifetime of predisposed individuals. Here, we review the role of IL-6 signaling in IBD and colitis-associated cancer and underscore the importance of searching for natural compounds that would target the IL-6 trans-signaling pathway as a way to diminish chronic inflammatory conditions in the gastrointestinal tract and possibly hamper the progression to colon cancer. We propose that effective screening and identification of natural chemopreventive compounds that target IL-6 trans-signaling has important implications for the development of optimal strategies against cancer development triggered by inflammation.

Combined serological, genetic, and inflammatory markers differentiate non-IBD, Crohn's disease, and ulcerative colitis patients

BACKGROUND

Previous studies have demonstrated that serological markers can assist in diagnosing inflammatory bowel disease (IBD). In this study, we aim to build a diagnostic tool incorporating serological markers, genetic variants, and markers of inflammation into a computational algorithm to examine patterns of combinations of markers to (1) identify patients with IBD and (2) differentiate patients with Crohn's disease (CD) from ulcerative colitis (UC).

METHODS

In this cross-sectional study, patient blood samples from 572 CD, 328 UC, 437 non-IBD controls, and 183 healthy controls from academic and community centers were analyzed for 17 markers: 8 serological markers (ASCA-IgA, ASCA-IgG, ANCA, pANCA, OmpC, CBir1, A4-Fla2, and FlaX), 4 genetic markers (ATG16L1, NKX2-3, ECM1, and STAT3), and 5 inflammatory markers (CRP, SAA, ICAM-1, VCAM-1, and VEGF). A diagnostic Random Forest algorithm was constructed to classify IBD, CD, and UC.

RESULTS

Receiver operating characteristic analysis compared the diagnostic accuracy of using a panel of serological markers only (ASCA-IgA, ASCA-IgG, ANCA, pANCA, OmpC, and CBir1) versus using a marker panel that in addition to the serological markers mentioned above also included gene variants, inflammatory markers, and 2 additional serological markers (A4-Fla2 and FlaX). The extended marker panel increased the IBD versus non-IBD discrimination area under the curve from 0.80 (95% confidence interval [CI], ±0.05) to 0.87 (95% CI, ±0.04; P < 0.001). The CD versus UC discrimination increased from 0.78 (95% CI, ±0.06) to 0.93 (95% CI, ±0.04; P < 0.001).

CONCLUSIONS

Incorporating a combination of serological, genetic, and inflammation markers into a diagnostic algorithm improved the accuracy of identifying IBD and differentiating CD from UC versus using serological markers alone.

Pulmonary-intestinal crosstalk in the pathological process of COPD and IBD: A perspective from the lung and the large intestine being interior-exteriorly related theory

Traditional Chinese medicine theory believes that the lung and intestine are closely related physiologically and pathologically. With the help of this, unexpected clinical efficacy can be achieved in the treatment of lung and intestinal diseases. Chronic obstructive pulmonary disease (COPD) and inflammatory bowel disease (IBD) are chronic inflammatory diseases of mucosal tissues that affect the respiratory and gastrointestinal tracts, respectively. Both COPD and IBD are driven by recurrent cycles of inflammation that lead to tissue damage and remodeling and progressively worsen symptoms. There have been no cures for either disease and both require lifelong health maintenance. Exploration of the correlation in the pathological process between COPD and IBD will help us find new ways of treatment of these two diseases.

Taking Crohn's disease personally

Crohn's disease (CD) is a heterogeneous disorder that can involve any segment of the gastrointestinal tract. The pathogenesis of CD is unknown but is thought to involve an uncontrolled immune response triggered by an environmental factor in a genetically susceptible host. The heterogeneity of disease pathogenesis and clinical course, combined with the variable response to treatment and its associated side effects, creates an environment of complex therapeutic decisions. Despite this complexity, significant progress has been made which allows physicians to start and predict disease behavior and natural course, response to therapy, and factors associated with significant side effects. In this manuscript the data pertaining to these variables including clinical, endoscopic and the various biological and genetic markers are reviewed, and the possibility of tailoring personal treatment is discussed.

Genome-wide association study of ulcerative colitis in Koreans suggests extensive overlapping of genetic susceptibility with Caucasians

BACKGROUND

Recent genome-wide association studies and meta-analyses have identified 47 susceptibility loci for ulcerative colitis (UC) in Caucasian populations. A previous genome-wide association study of UC in a Japanese population suggested marginal sharing of susceptibility loci between Caucasian and Asian populations. We performed a genome-wide association studies to identify UC susceptibility loci in a Korean population and further comparative study.

METHODS

We analyzed 581,060 autosomal single-nucleotide polymorphisms (SNPs) in 388 individuals with UC and 739 control subjects in the discovery stage. For the validation, 64 suggestive SNPs were analyzed in an additional 417 affected individuals and 732 control subjects.

RESULTS

Three genetic loci were validated for significant association, and all were previously reported in Caucasians including the major histocompatibility complex region (top SNP, rs9271366; P = 1.03 × 10(-18), odds ratio [OR] = 2.10), 16q24.1 (rs16940186; P = 4.39 × 10(-10), OR = 1.56), and RNF186-OTUD3-PLA2G2E at chromosome arm 1p36.13 (top SNP, rs4654903 in OTUD3; P = 7.43 × 10(-9), OR = 0.64). Although failed to reach genome-wide statistical significance, 2 additional loci previously reported in Caucasians including rs17085007 at chromosome arm 13q12 and JAK2 at chromosome arm 9p24 were significant after Bonferroni correction (P(corrected) = 0.0016 and P(corrected) = 0.0056, respectively). FOS, UBE2L3, the JAK2 gene region, and rs1297265 at chromosome arm 21q21.1 likely play a role in both Crohn's disease and UC.

CONCLUSIONS

Our data support the biologic significance of the overlapping loci for UC between Caucasian and Korean populations. Our data suggest that genetic associations for UC tend to overlap more extensively among different ethnic groups than those for Crohn's disease, which shows well-established dependence on ethnicity.

Replication of genetic loci for sarcoidosis in US black women: data from the Black Women's Health Study

In the United States, incidence and mortality from sarcoidosis, a chronic, granulomatous disease, are increased in black women. In data from the Black Women's Health Study, a follow-up of US black women, we assessed two SNPs (rs2076530 and rs9268480) previously identified in the BTNL2 gene (chromosome 6p21), of which rs4424066 and rs3817963 are perfect proxies, to determine if they represent independent signals of disease risk. We also assessed whether local ancestry in four genomic regions previously identified through admixture mapping was associated with sarcoidosis. Finally, we assessed the relation of global percent African ancestry to risk. We conducted a nested case-control study of 486 sarcoidosis cases and 943 age- and geography-matched controls. Both BTNL2 SNPs were associated with risk of sarcoidosis in separate models, but in a combined analysis the increased risk was due to the A-allele of the rs3817963 SNP; each copy of the A-allele was associated with a 40 % increase in risk of sarcoidosis (p = 0.02) and was confirmed by our haplotypic analysis. Local African ancestry around the rs30533 ancestry informative marker at chromosome 5q31 was associated with a 29 % risk reduction (p = 0.01). Therefore, we adjusted our analysis of global African ancestry for number of copies of African alleles in rs30533. Subjects in the highest quintile of percent African ancestry had a 54 % increased risk of sarcoidosis. The present results from a population of African-American women support the role of the BTNL2 gene and the 5q31 locus in the etiology of sarcoidosis, and also demonstrate that percent African ancestry is associated with disease risk.

Genetic susceptibility in IBD: overlap between ulcerative colitis and Crohn's disease

BACKGROUND

The etiology of ulcerative colitis (UC) and Crohn's disease (CD) involves both genetic and environmental components. Multiple UC and CD susceptibility genes have been identified through genome-wide association studies and subsequent meta-analyses. These studies have also highlighted the presence of genes common to both diseases, and shared with several other autoimmune disorders. The aim of this study was to identify single nucleotide polymorphisms (SNPs) recently identified by the International IBD Genetics Consortium (IIBDGC) demonstrating that highly significant associations with CD could also confer genetic susceptibility to UC.

METHODS

Statistical modeling was performed on 29 CD-associated SNPs. The study comprised of 1652 UC cases from the Australia and New Zealand IBD Consortium and 2363 Australian population-based controls.

RESULTS

After adjustment for multiple comparisons, only one SNP, rs3024505, was significantly associated with UC (P = 0.001). Independent chi-square analyses identified odds ratios of 2.22 (1.48-3.37) for the rare homozygous genotype, and 1.20 (1.06-1.35) for the minor allele. Five other SNPs demonstrated moderate to weak associations with UC.

CONCLUSIONS

Of the 29 SNPs conferring high genetic susceptibility to CD, 28 were not associated with UC, thus indicating that for this SNP set there is a low level of overlap between the two major forms of IBD. Only one SNP, rs3024505 (Chr 1q32.1, upstream of IL10), was associated with susceptibility to UC. The identification of this SNP replicates a finding from Franke et al (2008), where the rs3024505 SNP was strongly associated with UC across multiple European populations.

IRGM variants and susceptibility to inflammatory bowel disease in the German population

Background & Aims

Genome-wide association studies identified the autophagy gene IRGM to be strongly associated with Crohn's disease (CD) but its impact in ulcerative colitis (UC), its phenotypic effects and potential epistatic interactions with other IBD susceptibility genes are less clear which we therefore analyzed in this study.

Methodology/Principal Findings

Genomic DNA from 2060 individuals including 817 CD patients, 283 UC patients, and 961 healthy, unrelated controls (all of Caucasian origin) was analyzed for six IRGM single nucleotide polymorphisms (SNPs) (rs13371189, rs10065172 = p.Leu105Leu, rs4958847, rs1000113, rs11747270, rs931058). In all patients, a detailed genotype-phenotype analysis and testing for epistasis with the three major CD susceptibility genes NOD2, IL23R and ATG16L1 were performed.

Our analysis revealed an association of the IRGM SNPs rs13371189 (p = 0.02, OR 1.31 [95% CI 1.05–1.65]), rs10065172 = p.Leu105Leu (p = 0.016, OR 1.33 [95% CI 1.06–1.66]) and rs1000113 (p = 0.047, OR 1.27 [95% CI 1.01–1.61]) with CD susceptibility. There was linkage disequilibrium between these three IRGM SNPs. In UC, several IRGM haplotypes were weakly associated with UC susceptibility (p<0.05). Genotype-phenotype analysis revealed no significant associations with a specific IBD phenotype or ileal CD involvement. There was evidence for weak gene-gene-interaction between several SNPs of the autophagy genes IRGM and ATG16L1 (p<0.05), which, however, did not remain significant after Bonferroni correction.

Conclusions/Significance

Our results confirm IRGM as susceptibility gene for CD in the German population, supporting a role for the autophagy genes IRGM and ATG16L1 in the pathogenesis of CD.

Higher apoptosis index and proliferation index in colonocytes of patients with ulcerative colitis in remission

Ulcerative colitis (UC) is a inflammatory disease of large bowel. The amount of people suffering from UC increases from year to year. Pathogenesis of this affection is still not entirely clear. Mechanisms of proliferation and apoptosis in colonocytes in the course of the disease are defected.

THE AIM OF THE STUDY

was to assess the rate of proliferation and intensity of apoptosis in colonocytes in patients with diagnose UC.

MATERIAL AND METHODS

Colon pathological samples taken from patients with diagnosed ulceraive colitis were examined. Patients were in both clinical and endoscopic remission and were treated with mesalazin. They were patient of Department of General and Colorectal Surgery. To estimate proliferation index dye with monoclonal antibody against Ki67. To determine apoptosis level immunohistochemistry with antybody against Bax was used.

RESULTS

Average Ki-67 in the test group was 42,13%, the largest value amounted to 57% and the lowest of 33%. Average value of Bax was 1.47 and ranged between 0-3. High index of bax appear not only in the bottom of the crypt, but also at their outlet.

CONCLUSIONS

In ulecerative colitis genetic and immunological disturbances occur despite treatment. Mesalazine acting only on certain routes associated with the UC holds the remission, without, however "the molecular remission". Thus, it appears that the results of our research are another proof of the necessary caution in weaning support treatment.

Targeting IL-17 and TH17 cells in chronic inflammation

The key role of interleukin-17 (IL-17) and T helper 17 (T(H)17) cells in tissue inflammation, autoimmunity and host defence led to the experimental targeting of these molecules in mouse models of diseases as well as in clinical settings. Moreover, the demonstration that IL-17 and T(H)17 cells contribute to local and systemic aspects of disease pathogenesis, as well as the finding that the IL-17-T(H)17 cell pathway is regulated by IL-23, prompted the identification of inhibitors. These inhibitors include biotechnology products that target IL-23 as well as the leading member of the IL-17 family, IL-17A, and one of its receptors, IL-17 receptor A. Several clinical trials of these inhibitors are underway, and positive results have been obtained in psoriasis, rheumatoid arthritis and ankylosing spondylitis. This Review focuses on the current knowledge of the IL-17-T(H)17 cell pathway to better understand the positive as well as potential negative consequences of targeting them.

Regulation of epithelial barrier function by the inflammatory bowel disease candidate gene, PTPN2

Protein tyrosine phosphatase nonreceptor type 2 (PTPN2) has been identified as an inflammatory bowel disease (IBD) candidate gene. However, the mechanism through which mutations in the PTPN2 gene contribute to the pathogenesis of IBD has not been identified. PTPN2 acts as a negative regulator of signaling induced by the proinflammatory cytokine, interferon-gamma (IFN-γ). IFN-γ is known not only to play an important role in the pathogenesis of Crohn's disease (CD), but also to increase permeability of the intestinal epithelial barrier. We have shown that PTPN2 protects epithelial barrier function by restricting the capacity of IFN-γ to increase epithelial permeability and prevent induction of expression of the pore-forming protein, claudin-2. These data identify an important functional role for PTPN2 as a protector of the intestinal epithelial barrier and provide clues as to how PTPN2 mutations may contribute to the pathophysiology of CD.

Increased small intestinal permeability in ulcerative colitis: rather genetic than environmental and a risk factor for extensive disease?

BACKGROUND

A disturbed epithelial barrier could play a pivotal role in ulcerative colitis (UC). We performed a family-based study analyzing in vivo gastrointestinal permeability in patients with UC, their healthy relatives, spouses, and controls.

METHODS

In total, 89 patients with UC in remission, 35 first-degree relatives (UC-R), 24 nonrelated spouses (UC-NR), and 99 healthy controls (HC) were studied. Permeability was assessed by a sugar-drink test using sucrose (gastroduodenal permeability), lactulose/mannitol (intestinal permeability), and sucralose (colonic permeability). Data were correlated with clinical characteristics including medical treatment.

RESULTS

Increased intestinal permeability was detected significantly more often in UC patients in remission (25/89, 28.1%) compared with HC (6/99, 6.1%; P < 0.001). Similar results were obtained in UC-R (7/35, 20.0%; P = 0.01 compared with HC) regardless of sharing the same household with the patients or not. No difference was found between UC-NR (3/24, 12.5%) and HC. Notably, in UC patients increased intestinal permeability was found in 12/28 patients (42.9%) with pancolitis, 7/30 (23.3%) patients with left-sided colitis, and in 2/19 (10.5%) patients with proctitis (P = 0.04). Gastroduodenal and colonic permeability were similar in all groups. Among patients on azathioprine, increased intestinal permeability was only seen in 1/18 (5.6%) patients. In contrast, in 24/70 (34.3%) patients without azathioprine, an increased intestinal permeability was found (P = 0.005).

CONCLUSIONS

An increased intestinal but not colonic permeability was found in UC patients in clinical remission that could mark a new risk factor for extensive disease location. Similar findings in healthy relatives but not spouses suggest that this barrier defect is genetically determined.

Type I IFN-mediated regulation of IL-1 production in inflammatory disorders

Although contributing to inflammatory responses and to the development of certain autoimmune pathologies, type I interferons (IFNs) are used for the treatment of viral, malignant, and even inflammatory diseases. Interleukin-1 (IL-1) is a strongly pyrogenic cytokine and its importance in the development of several inflammatory diseases is clearly established. While the therapeutic use of IL-1 blocking agents is particularly successful in the treatment of innate-driven inflammatory disorders, IFN treatment has mostly been appreciated in the management of multiple sclerosis. Interestingly, type I IFNs exert multifaceted immunomodulatory effects, including the reduction of IL-1 production, an outcome that could contribute to its efficacy in the treatment of inflammatory diseases. In this review, we summarize the current knowledge on IL-1 and IFN effects in different inflammatory disorders, the influence of IFNs on IL-1 production, and discuss possible therapeutic avenues based on these observations.

Gene network analysis of small molecules with autoimmune disease associated genes predicts a novel strategy for drug efficacy

Numerous genes/SNPs in autoimmune diseases (ADs) are identified through genome-wide association studies (GWAS) and likely to contribute in developing autoimmune phenotypes. Constructions of biologically meaningful pathways are necessary to determine how these genes interact with each other and with other small molecules to develop various complex AD phenotypes prior to beginning time-consuming rigorous experimentation. We have constructed biological pathways with genetically identified genes leading to shared AD phenotypes. Various environmental and endogenous factors interact with these AD associated genes suggesting their critical role in developing diseases and further association studies could be designed for assessing the role of these factors with risk allele in a specific gene. Additionally, existing drugs that have been used long before the identification of these genetically associated genes also interact with these newly associated genes. Thus advanced therapeutic strategies could be designed by grouping patients with risk allele(s) in particular genes that directly or closely interact with the specified drugs. This drug-susceptible gene network will not only increase our understanding about the additional molecular basis for effectiveness against these diseases but also indicate which drug could be more effective for those patients carrying risk allele(s) in that gene. Additionally, we have also identified several interlinking genes in the pathways that could be used for designing future association studies.

IBDsite: a Galaxy-interacting, integrative database for supporting inflammatory bowel disease high throughput data analysis

BACKGROUND

Inflammatory bowel diseases (IBD) refer to a group of inflammatory conditions concerning colon and small intestine, which cause socially uncomfortable symptoms and often are associated with an increased risk of colon cancer. IBD are complex disorders, which rely on genetic susceptibility, environmental factors, deregulation of the immune system, and host relationship with commensal microbiota. The complexity of these pathologies makes difficult to clearly understand the mechanisms of their onset. Therefore, the study of IBD must be faced exploiting an integrated and multilevel approach, ranging from genes, transcripts and proteins to pathways altered in affected tissues, and carefully considering their regulatory mechanisms, which may intervene in the pathology onset. It is also crucial to have a knowledge base about the symbiotic bacteria that are hosted in the human gut. To date, much data exist regarding IBD and human commensal bacteria, but this information is sparse in literature and no free resource provides a homogeneously and rationally integrated view of biomolecular data related to these pathologies.

METHODS

Human genes altered in IBD have been collected from literature, paying particular interest for the immune system alterations prompted by the interaction with the gut microbiome. This process has been performed manually to assure the reliability of collected data. Heterogeneous metadata from different sources have been automatically formatted and integrated in order to enrich information about these altered genes. A user-friendly web interface has been created for easy access to structured data. Tools such as gene clustering coefficients, all-pairs shortest paths and pathway lengths calculation have been developed to provide data analysis support. Moreover, the implemented resource is compliant to the Galaxy framework, allowing the collected data to be exploited in the context of high throughput bioinformatics analysis.

RESULTS

To fill the lack of a reference resource for 'omics' science analysis in the context of IBD, we developed the IBDsite (available at http://www.itb.cnr.it/ibd), a disease-oriented platform, which collects data related to biomolecular mechanisms involved in the IBD onset. The resource provides a section devoted to human genes identified as altered in IBD, which can be queried at different biomolecular levels and visualised in gene-centred report pages. Furthermore, the system presents information related to the gut microbiota involved in IBD affected patients. The IBDsite is compliant with all Galaxy installations (in particular, it can be accessed from our custom version of Galaxy, http://www.itb.cnr.it/galaxy), in order to facilitate high-throughput data integration and to enable evaluations of the genomic basis of these diseases, complementing the tools embedded in the IBDsite.

CONCLUSIONS

Lots of sparse data exist concerning IBD studies, but no on-line resource homogeneously and rationally integrate and collect them. The IBDsite is an attempt to group available information regarding human genes and microbial aspects related to IBD, by means of a multilevel mining tool. Moreover, it constitutes a knowledge base to filter, annotate and understand new experimental data in order to formulate new scientific hypotheses, thanks to the possibility of integrating genomics aspects by employing the Galaxy framework. Discussed use-cases demonstrate that the developed system is useful to infer not trivial knowledge from the existing widespread data or from novel experiments.

Association of genetic variation in the NR1H4 gene, encoding the nuclear bile acid receptor FXR, with inflammatory bowel disease

Background

Pathogenesis of inflammatory bowel diseases (IBD), ulcerative colitis (UC) and Crohn’s disease (CD), involves interaction between environmental factors and inappropriate immune responses in the intestine of genetically predisposed individuals. Bile acids and their nuclear receptor, FXR, regulate inflammatory responses and barrier function in the intestinal tract.

Methods

We studied the association of five variants (rs3863377, rs7138843, rs56163822, rs35724, rs10860603) of the NR1H4 gene encoding FXR with IBD. 1138 individuals (591 non-IBD, 203 UC, 344 CD) were genotyped for five NR1H4 genetic variants with TaqMan SNP Genotyping Assays.

Results

We observed that the NR1H4 SNP rs3863377 is significantly less frequent in IBD cases than in non-IBD controls (allele frequencies: P = 0.004; wild-type vs. SNP carrier genotype frequencies: P = 0.008), whereas the variant rs56163822 is less prevalent in non-IBD controls (allele frequencies: P = 0.027; wild-type vs. SNP carrier genotype frequencies: P = 0.035). The global haplotype distribution between IBD and control patients was significantly different (P = 0.003). This also held true for the comparison between non-IBD and UC groups (P = 0.004), but not for the comparison between non-IBD and CD groups (P = 0.079).

Conclusions

We show that genetic variation in FXR is associated with IBD, further emphasizing the link between bile acid signaling and intestinal inflammation.

Autophagy in immunity: implications in etiology of autoimmune/autoinflammatory diseases

Autophagy is now emerging as a spotlight in trafficking events that activate innate and adaptive immunity. It facilitates innate pathogen detection and antigen presentation, as well as pathogen clearance and lymphocyte homeostasis. In this review, we first summarize new insights into its functions in immunity, which underlie its associations with autoimmunity. As some lines of evidence are emerging to support its role in autoimmune and autoinflammatory diseases, we further discuss whether and how it affects autoimmune diseases including systemic lupus erythematosus, rheumatoid arthritis, diabetes mellitus and multiple sclerosis, as well as autoinflammatory diseases, such as Crohn disease and vitiligo.

Genetic variations in interleukin-12 related genes in immune-mediated diseases

The interleukin-12 (IL-12) family comprises a group of heterodimeric cytokines and their respective receptors that play key roles in immune responses. A growing number of autoimmune diseases has been found to be associated with genetic variation in these genes. Based on their respective associations with the IL-12 genes, autoimmune diseases appear to cluster in two groups that either show strong associations with the Th1/Th17 pathway (as indicated by genetic association with IL12B and IL23R) or the Th1/IL-35 pathway as the consequence of their association with polymorphisms in the IL12A gene region. The genetic associations are described in relation to what is known of the functionality of these genes in the various diseases. Comparing association data for gene families in different diseases may lead to better insight in the function of the genes in the onset and course of the disease.

Single-nucleotide polymorphisms in inflammatory bowel disease

Strong evidence indicates that inflammatory bowel disease, including Crohn disease and ulcerative colitis, is a result of an inappropriate inflammatory response in which genetic and environmental factors play important roles. This review discusses several single-nucleotide polymorphisms with either susceptibility or protective effects on inflammatory bowel disease.

Psoriasis: new insight about pathogenesis, role of barrier organ integrity, NLR / CATERPILLER family genes and microbial flora

Psoriasis is a common, inflammatory, chronic, relapsing skin disease. New insight about the etiology of this disease shows the important role played by the epidermal barrier function, its integrity and pathogen responses in combination with microbial environmental factors. A pivotal role in the management of this balance is played by NLR genes, also known as NBD-LRR or CATERPILLER, that encode important mediators of innate immunity and provide the first line of defense against pathogens. The polymorphism of these genes is implicated in the pathogenesis of several immunological diseases and might be of importance in the pathogenesis of barrier organ disorders. Crohn's disease is considered archetypal of these kinds of disorders; similarities between Crohn's disease and psoriasis and their similar pathogenetic mechanisms may support the concept of psoriasis as a barrier organ disorder and common genetic ground lying behind these illnesses. Considering psoriasis as a "barrier organ disease" is not only a mere mental exercise; this consideration may, in fact, open new prospects in the treatment of these disorders just by preventing alterations of microbial flora or regulating the response of the host to infective diseases.

The emerging role of IL-17 in the pathogenesis of psoriasis: preclinical and clinical findings

Although the histological changes seen in psoriasis have long been well characterized, the underlying cellular and molecular mechanisms have only begun to be elucidated over the past 20 years. Proinflammatory factors such as tumor necrosis factor (TNF)-α have a central role in psoriasis pathogenesis, and many T-helper 1 (Th1) cytokines and messenger RNAs are elevated in psoriatic lesions. IL-17A, IL-17F, and other Th17 cell-derived cytokines have been shown in murine models to induce features that mimic human psoriasis. This review focuses on the emerging biology of the IL-17 cytokine family in psoriasis, and on the molecular and genetic information gained from animal models and human clinical studies that confirm IL-17 as a crucial proinflammatory cytokine in psoriasis. Expression of IL-17A, IL-17C, and IL-17F is strikingly increased in psoriatic lesions, and successful therapy is associated with restoration of the expression of a wide range of genes (including effector molecules downstream of IL-17 such as cytokines, chemokines, and antimicrobial peptides) to near-normal levels. Therapeutic agents in development that target IL-17 are discussed, and an emerging model of the key role of IL-17 in the pathogenesis of psoriasis is presented.

Macrophage-stimulating protein polymorphism rs3197999 is associated with a gain of function: implications for inflammatory bowel disease

Crohn's disease and ulcerative colitis, the two main types of inflammatory bowel disease (IBD), were reported to be associated with a variety of genetic polymorphisms. A subset of these polymorphisms was identified in both diseases and only three of them were found in primary sclerosing cholangitis (PSC). rs3197999 (Arg689Cys) located in the MST1 gene is one of the most convincingly replicated IBD/PSC-associated polymorphisms but its functional consequences have not been investigated, yet. We expressed both MST1 gene variants (Arg(689) (MSP(wt)) and Cys(689) (MSP(mut)) in a eukaryotic cell system and compared their stimulatory effects on macrophage-like THP-1 cells. Except for the rate of apoptosis that remained unchanged, MSP(mut) significantly increased the stimulatory effect of MSP (macrophage-stimulating protein) on chemotaxis and proliferation by THP-1 cells, indicating a gain of function associated with the Arg689Cys exchange. A broad set of evidence reported previously suggests that pro-inflammatory changes in macrophage function have a major role in the initiation of the inflammatory process in IBD and PSC. Therefore, the gain of function observed with rs3197999 in MST1 might provide a cellular mechanism for the consistent association of this polymorphism with an increased risk for IBD and PSC.

Genetics of inflammatory bowel disease in Asia: systematic review and meta-analysis

BACKGROUND

Inflammatory bowel diseases (IBD) result from an interaction between genetic and environmental factors. Preliminary findings suggest that susceptibility genes differ between IBD patients in Asia and the West. We aimed to evaluate disease-predisposing genes in Asian IBD patients.

METHODS

A systematic review and meta-analysis were performed of published studies from 1950 to 2010 using keyword searches in MEDLINE, EMBASE, EBM Reviews, and BIOSIS Previews.

RESULTS

In all, 477 abstracts were identified and data extracted from 93 studies, comprising 17,976 IBD patients and 27,350 age- and sex-matched controls. Major nucleotide oligomerization domain (NOD)-2 variants in Western Crohn's disease (CD) patients were not associated with CD in Han Chinese, Japanese, South Korean, Indian, and Malaysian populations. New NOD2 mutations were, however, associated with CD in Malaysians (JW1), Han Chinese, and Indians (P268S). Autophagy-related protein 16-linked 1 (ATG16L1) was not associated with CD in East Asians (odds ratio [OR] 0.97; 95% confidence interval [CI] 0.84-1.13). Interleukin (IL)-23R was associated with CD in South Koreans (OR 1.8; 95% CI 1.16-2.82) and a single nucleotide polymorphism in IL-23R (Gly149Arg) was protective of CD in Han Chinese (OR 0.3; 95% CI 0.15-0.60). Tumor necrosis factor (TNF) superfamily gene-15 (SF15) polymorphisms were associated with CD (OR 2.68; 95% CI 1.86-3.86), while TNF-308 polymorphisms (OR 1.82; 95% CI 1.15-2.9), cytotoxic T lymphocyte antigen (CTLA)-4 (OR 2.75; 95% CI 1.22-6.22) and MICA allele (OR 2.41; 95% CI 1.89-3.07) were associated with ulcerative colitis in Asians.

CONCLUSIONS

Genetic mutations of IBD in Asians differ from Caucasians. New mutations and susceptibility genes identified in Asian IBD patients provide an opportunity to explore new disease-associated mechanisms in this population of rising incidence.

Community Perspectives: Combining Serology, Genetics, and Inflammation Markers for the Diagnosis of IBD and Differentiation Between CD and UC

Diagnosis of inflammatory bowel disease (IBD) is complicated and is based on a combination of patient history and physical examination in association with laboratory, endoscopic, histologic, and radiographic investigations. Determination of the correct diagnosis is important for its implications in selecting treatment and in the timing and type of surgery that may be required. Information from testing incorporating serologic, genetic, and inflammatory markers can help to clarify the clinical picture. Measurement of biomarkers not only helps to differentiate a diagnosis of IBD versus non-IBD, it can also help to distinguish between ulcerative colitis and Crohn's disease in difficult cases. In this monograph, 5 cases illustrate how specialized testing can provide important information that can aid in diagnosis.

Chronic intestinal inflammation: inflammatory bowel disease and colitis-associated colon cancer

The inflammatory bowel diseases (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), are chronic inflammatory disorders of the intestine. The prevalence in the United States is greater than 200 cases per 100,000, with the total number of IBD patients between 1 and 1.5 million. CD may affect all parts of the gastrointestinal tract, from mouth to anus, but most commonly involves the distal part of the small intestine or ileum, and colon. UC results in colonic inflammation that can affect the rectum only, or can progress proximally to involve part of or the entire colon. Clinical symptoms include diarrhea, abdominal pain, gastrointestinal bleeding, and weight loss. A serious long-term complication of chronic inflammation is the development of colorectal cancer. A genetic basis for IBD had long been recognized based on the increased familial risk. However, significant discordance for CD in twins, and a much less robust phenotypic concordance for UC, suggested additional factors play a role in disease pathogenesis, including environmental factors. In the past several years, progress in understanding the molecular basis of IBD has accelerated, beginning with the generation of animal models of colitis and progressing to the identification of specific genetic markers from candidate gene, gene linkage, and genome-wide association analyses. Genetic studies have also resulted in the recognition of the importance of environmental factors, particularly the crucial role of the gut microbiota in CD and UC. Altered immune responses to the normal intestinal flora are key factors in IBD pathogenesis. In this research topic, the genetic basis of IBD, the genetic and cellular alterations associated with colitis-associated colon cancer, and the emerging role of the intestinal microbiota and other environmental factors will be reviewed.

Antimicrobial antibodies are associated with a Crohn's disease-like phenotype after ileal pouch-anal anastomosis

BACKGROUND & AIMS

Pouchitis and Crohn's disease (CD)-like (CDL) complications of the pouch occur at rates near 50% and 20%, respectively, after colectomy with ileal pouch-anal anastomosis (IPAA) for ulcerative colitis (UC). We investigated whether antimicrobial antibodies are associated with pouch outcome after IPAA.

METHODS

We studied clinical and endoscopic data from 399 individuals with UC who underwent colectomy with IPAA at Mount Sinai Hospital in Toronto, Canada; patients were classified as no pouchitis (NP), chronic pouchitis (CP), or CDL. Serum samples were analyzed from 341 patients for antibodies against Saccharomyces cerevisiae (ASCA), OmpC, CBir1, and perinuclear antineutrophil cytoplasmic antibody (pANCA).

RESULTS

Of the subjects, 70.7% had NP, 16.8% developed CP, and 12.5% developed CDL. Smoking was associated with CDL (P = .003). Ashkenazi Jewish individuals more commonly had CP (P = .008). Of patients with CDL, 53.5% and 14.0% had positive test results for anti-CBir1 and ASCA (immunoglobulin G), respectively, compared with 21.4% and 3.8% of those with NP and 28.3% and 5.0% of those with CP (P < .0001 and P = .03). Anti-CBir1 was associated with CDL, compared with NP (P = 2.8 × 10(-5); odds ratio [OR], 4.2; 95% confidence interval [CI], 2.2-8.3) or CP (P = .011; OR, 2.9; 95% CI, 1.3-6.6). ASCA immunoglobulin G was associated with CDL, compared with patients with NP (P = .01; OR, 4.1; 95% CI, 1.4-12.3). In a combined model, pANCA and the antimicrobial antibodies were associated with CP (P = .029) and CDL (P = 4.7 × 10(-4)).

CONCLUSIONS

Antimicrobial antibodies and pANCA are associated with inflammatory complications of the pouch. The CDL phenotype is associated with factors that characterize Crohn's disease, including smoking, anti-CBir1, and ASCA.

Genetics of spondyloarthritis--beyond the MHC

Ankylosing spondylitis (AS), psoriasis and inflammatory bowel disease (IBD) often coexist in the same patient and in their families. In AS, genes within the MHC region, in particular HLA-B27, account for nearly 25% of disease hereditability, with additional small contributions from genes outside of the MHC locus, including those involved in intracellular antigen processing (that is, ERAP1, which interacts with HLA-B27) and cytokine genes such as those involved in the IL-17-IL-23 pathway. Similar to AS, the strongest genetic signal of susceptibility to psoriasis and psoriatic arthritis also emanates from the MHC region (attributable mostly to HLA-C(*)06:02 although other genes have been implicated), and gene-gene interaction of HLA-C with ERAP1. The remaining hereditary load is from genes involved in cytokine production, specifically genes in the IL-17-IL-23 pathway, the NFκB pathway and the type 2 T-helper pathway. In IBD, similar genetic influences are operative. Indeed, genes important in the regulation of the IL-17-IL-23 pathway and, in Crohn's disease, genes important for autophagy (that is, NOD2 and ATG16L1 and IRGM) have a role in conferring susceptibility of individuals to these diseases. Thus, AS, psoriasis and IBD seem to share similar pathogenic mechanisms of aberrant intracellular antigen processing or elimination of intracellular bacteria and cytokine production, especially in the IL-17-IL-23 pathway.

The IL-23/IL-17 pathway in inflammatory bowel disease

The etiology of inflammatory bowel disease is unknown but available evidence suggests that a deregulated immune response towards the commensal bacterial flora is responsible for intestinal inflammation in genetically predisposed individuals. IL-23 promotes expansion and maintenance of Th17 cells, which secrete the proinflammatory cytokine IL-17 and have been implicated in the pathogenesis of many chronic inflammatory disorders. Recent studies have shown that IL-23 also acts on cells of the innate immune system that can contribute to inflammatory cytokine production and tissue inflammation. A role for the IL-23/IL-17 pathway in the pathogenesis of chronic intestinal inflammation in inflammatory bowel disease has emerged from both animal and human studies. Here we aim to review the recent advances in this rapidly moving field.

Functional consequences of mutations in the autophagy genes in the pathogenesis of Crohn's disease

Genome-wide association studies have highlighted a number of genes involved in autophagy, which are of potential importance in the pathogenesis of Crohn's disease (CD). The associated polymorphisms in ATG16L1 and IRGM have been confirmed, and functional studies have begun to shed light on how they link to CD pathogenesis. In this review we consider the most salient aspects of this rapidly expanding field.

Psoriasis and other complex trait dermatoses: from Loci to functional pathways

Driven by advances in molecular genetic technologies and statistical analysis methodologies, there have been huge strides taken in dissecting the complex genetic basis of many inflammatory dermatoses. One example is psoriasis, for which application of classical linkage analysis and genome-wide association investigation has identified genetic loci of major and minor effect. Although most loci independently have modest genetic effects, they identify important biological pathways potentially relevant to disease pathogenesis and therapeutic intervention. In the case of psoriasis, these appear to involve the epidermal barrier, NF-κB mechanisms, and T helper type 17 adaptive immune responses. The advent of next-generation sequencing methods will permit a more detailed and complete map of disease genetic architecture, a key step in developing personalized medicine strategies in the clinical management of the complex inflammatory dermatoses.

The role of human defensins in gastrointestinal diseases

In clarifying the pathogenesis of inflammatory bowel diseases, a dysregulation of the adaptive immune function was the main focus of research in the last decade. With increasing knowledge of antimicrobial peptides, a primary disturbed barrier function and the system of innate immunity has recently received increasing attention. Contrary to the common understanding of irritable bowel syndrome as a functional disorder, there is first evidence for an involvement of innate immunity for this condition. Peptides with high relevance seem to be the class of human defensins. This article will thus discuss current advances in immunologic research of inflammatory bowel disease and irritable bowel syndrome, focusing on defensins and their possible role as biomarkers of these diseases.

Cutting edge issues in primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic inflammatory liver disease characterized by the destruction of medium- to large-sized bile ducts and intense concentric fibrosis. Complications from PSC include bacterial cholangitis, cirrhosis, and cholangiocarcinoma and a therapy that might alter the natural history of the disease remains lacking. Our understanding of the pathogenesis of PSC also remains rudimentary but the strong association between PSC and inflammatory bowel disease suggest causal links between the diseases. The male predominance in PSC, lack of a defined, pathogenic auto-antigen, and the potential role of the innate immune system suggest that PSC may be due to dysregulation of immunity rather than a classic autoimmune disease. However, PSC shares several genetic susceptibility loci with other autoimmune diseases including the human leukocyte antigen DRB01*03 haplotype. The precise immune response of PSC is largely unknown but likely involves activation of the innate immune system by bacterial components delivered to the liver via the portal vein. Induction of adhesion molecules and chemokines leads to the recruitment of intestinal lymphocytes. Bile duct injury results from the sustained inflammation and production of inflammatory cytokines. Biliary strictures may cause further damage as a result of bile stasis and recurrent secondary bacterial cholangitis. Progress in our basic understanding of PSC is desperately needed in order to rationally design new therapeutic approaches to this disease.

Mutations in IRGM are associated with more frequent need for surgery in patients with ileocolonic Crohn's disease

BACKGROUND

There are no clear criteria for judging the severity of disease in patients with Crohn's disease. Yet classification of patients into low- and high-risk severity groups would benefit both medical and surgical management. At the time of this study, approximately 80 single-nucleotide polymorphisms within 55 genes had been associated with IBD.

OBJECTIVE

The aim of this study was to identify genetic determinants (single-nucleotide polymorphisms) that could be markers of Crohn's disease severity by the use of frequency of ileocolic surgery as a surrogate for disease severity.

DESIGN

Sixty-six patients (30 male) with ileocolonic Crohn's disease who previously underwent ileocolectomy were retrospectively studied. The severity of Crohn's disease was quantified by dividing the total number of ileocolectomy procedures by the time between IBD diagnosis and the patient's last clinic visit, the rationale being that more severe disease would be associated with a more frequent need for surgery. Genotyping for the 83 single-nucleotide polymorphisms associated with IBD was done on a customized Illumina Veracode genotyping platform. Three genetic models (general, additive, and dominant) were used to statistically quantify the genetic association of the studied single-nucleotide polymorphisms to the frequency of surgery after adjusting for covariates (age, smoking, family history, disease location, and disease behavior).

RESULTS

For the entire group the average number of ileocolectomies per patient was 1.7 (range, 1-5) with an average duration of disease of 14.7 years. Single-nucleotide polymorphism rs4958847 in the IRGM gene (immunity-related GTPase family, M) was the most significant single-nucleotide polymorphism in all 3 models tested (p = 0.007) as being associated with ileocolectomy, and it remained significant even after a Benjamini-Hochberg false-discovery correction for multiple observations. Patients carrying the "at-risk" allele for this single-nucleotide polymorphism (n = 20) had an average of 1 surgery every 6.87 ± 1.33 years in comparison with patients carrying the wild-type genotype (n = 46) who averaged 1 surgery in 11.43 ± 1.21 years (p = 0.007, Mann-Whitney U test).

CONCLUSIONS

: Single-nucleotide polymorphism rs4958847 in the IRGM gene correlated very significantly with frequency of surgery in patients with ileocolonic Crohn's disease. IRGM is a mediator of innate immune responses and is involved in autophagy. The presence of this IRGM SNP may be a marker for disease severity and/or early recurrence after ileocolectomy and may assist in surgical and medical decision making.

Investigation of JAK2, STAT3 and CCR6 polymorphisms and their gene-gene interactions in inflammatory bowel disease

Genome-wide association studies identified many loci associated with the two forms of inflammatory bowel disease (IBD), Crohn's disease (CD) and ulcerative colitis (UC). Components of the interleukin-23 signalling pathway, such as IL23R, JAK2 and STAT3, have been implicated in both diseases. In addition, emerging evidence supports the role of IL23-driven Th17 cells in inflammation. Here, we studied the susceptibility nature of three components of IL23 signalling and Th17 cell differentiation: JAK2 rs10758669, STAT3 rs744166 and CCR6 rs2301436 initially associated with CD in Hungarian CD and UC patients. A total of 616 unrelated subjects with either form of IBD and 496 healthy controls were genotyped with PCR-RFLP methods. We also tested the genetic interactions of JAK2, STAT3 and CCR6 polymorphisms in a pairwise fashion with regard to disease risk. We could confirm the susceptibility of STAT3 rs744166 TT homozygotes for UC (OR: 1.483, 95% CI: 1.103-1.992, P = 0.009). Data on genetic interaction reveals that the above JAK2 and STAT3 risk alleles contribute to CD susceptibility in combination with each other (OR: 2.218; 95% CI: 1.097-4.487; P = 0.024), while the JAK2 variant shows a tendency to confer UC risk only on a wild-type STAT3 background (OR: 1.997, 95%CI: 0.994-4.009, P = 0.049). Our results may help in understanding how these natural variants contribute to development of IBD through their genetic association.

The relation between the level of interleukin-23 with duration and severity of ulcerative colitis

AIM

In this study, we determined the relationship between the serum level of IL-23 and the severity of ulcerative colitis (UC) among our population.

BACKGROUND

A recent major breakthrough for describing the pathogenesis of intestinal tissue injury in inflammatory bowel disease (IBD) is the pathway related to interleukin-23 (IL-23).

PATIENTS AND METHODS

We performed a prospective case-control study on a total of 85 new patients with ulcerative colitis, recruited from a general referral hospital. Forty ethnically matched healthy controls were also enrolled among hospital staffs and analyzed. Serum IL-23 level was quantified using an electrochemiluminescence immunoassay (ECLIA) method with an immunoassay analyzer.

RESULTS

The mean serum IL-23 level in the group with ulcerative colitis was significantly higher than the healthy individuals (347.5±130.8 pg/ml versus 233.5±86.3 pg/ml; p< 0.001). There was a positive correlation between the serum level of IL-23 and disease duration (r = 0.27, p = 0.04). Also, a direct relationship was found between the serum level of IL-23 and the severity of disease (mean IL-23 in mild UC = 296.2±51.2 pg/ml; in moderate UC= 356.1±142.9 pg/ml; and in severe UC= 399.3±163.8 pg/ml, p = 0.04).

CONCLUSION

Serum level of IL-23 is directly correlated with the duration and severity of ulcerative colitis.

Inflammatory bowel disease: is it a primary immunodeficiency?

Inflammatory bowel diseases (IBD) such as ulcerative colitis and Crohn's disease are chronic and relapsing conditions, characterized by abdominal pain, diarrhea, bleeding and malabsorption. IBD has been considered a hyperinflammatory state due to disturbed interactions between the immune system and the commensal bacterial flora of the gut. However, there is evidence that Crohn's disease might be the consequence of a reduced release of pro-inflammatory cytokines and an impaired acute inflammatory response, thereby suggesting that IBD might be an immunodeficiency rather than an excessive inflammatory reaction. This theory has been supported by observations in patients with primary immunodeficiencies such as the Wiskott-Aldrich syndrome and IPEX (immunodysregulation, polyendocrinopathy, enteropathy, X-linked syndrome). In contrary, defects in the anti-inflammatory down-regulation of the immune response as they are seen in patients with Mendelian defects in the IL10 signaling pathway support the hyper-inflammatory theory. In this review, we describe and discuss primary immunodeficiencies associated with IBD and show that the bowel is a highly sensitive indicator of dysregulations, making IBD a model disease to study and identify key regulators required to balance the human mucosal immune system.

Pulmonary-intestinal cross-talk in mucosal inflammatory disease

Chronic obstructive pulmonary disease (COPD) and inflammatory bowel diseases (IBDs) are chronic inflammatory diseases of mucosal tissues that affect the respiratory and gastrointestinal tracts, respectively. They share many similarities in epidemiological and clinical characteristics, as well as in inflammatory pathologies. Importantly, both conditions are accompanied by systemic comorbidities that are largely overlooked in both basic and clinical research. Therefore, consideration of these complications may maximize the efficacy of prevention and treatment approaches. Here, we examine both the intestinal involvement in COPD and the pulmonary manifestations of IBD. We also review the evidence for inflammatory organ cross-talk that may drive these associations, and discuss the current frontiers of research into these issues.

Replication study of 10 genes showing evidence for association with multiple sclerosis: validation of TMEM39A, IL12B and CBLB [correction of CLBL] genes

BACKGROUND AND OBJECTIVES

Ten genes previously showing different evidence of association with multiple sclerosis have been selected to validate.

METHODS

Eleven polymorphisms were genotyped with the iPLEX™ Sequenom in a well-powered collection of Spanish origin including 2863 multiple sclerosis cases and 2930 controls.

RESULTS

Replication extended to the following polymorphisms: PKN2 (rs305217), GTF2B (rs7538427), EPHA4 (rs1517440), YTHDF3 (rs12115114), ANKFN1 (rs17758761) and PTPRM (rs4798571), which did not reach the threshold of significance in a follow-up of the first genome-wide association study (GWAS) conducted in multiple sclerosis; TMEM39A (rs1132200), which appeared as a newly identified susceptibility gene in the same study; a gene previously reaching GWAS significance in Italy, CBLB (rs9657904); IL12B (rs6887695, rs10045431), a susceptibility gene shared by diverse autoimmune diseases and, finally, another gene showing inconclusive association with multiple sclerosis, CNR1 (rs1049353).

CONCLUSIONS

Pooled analysis corroborated the effect on MS predisposition of three genes: TMEM39A [rs1132200: p(M-H)=0.001; OR(M-H) (95% CI)= 0.84 (0.75-0.93)], IL12B [rs6887695: p(M-H)=0.03; OR(M-H) (95% CI)= 1.09 (1.01-1.17)] and CBLB [rs9657904: p(M-H)=0.01; OR(M-H) (95% CI)= 0.89 (0.81-0.97)].