Pre-operative visceral adipose tissue radiodensity is a potentially novel prognostic biomarker for early endoscopic post-operative recurrence in Crohn's disease.

BACKGROUND: Evidence suggests inflammatory mesenteric fat is involved in post-operative recurrence (POR) of Crohn's disease (CD). However, its prognostic value is uncertain, in part, due to difficulties studying it non-invasively. AIM: To evaluate the prognostic value of pre-operative radiographic mesenteric parameters for early endoscopic POR (ePOR). METHODS: We conducted a retrospective cohort study of CD subjects ≥ 12 years who underwent ileocecal or small bowel resection between 1/1/2007 to 12/31/2021 with computerized tomography abdomen/pelvis ≤ 6 months pre-operatively and underwent ileocolonoscopy ≤ 15 months post-operatively. Visceral adipose tissue (VAT) volume (cm3), ratio of VAT:subcutaneous adipose tissue (SAT) volume, VAT radiodensity, and ratio of VAT:SAT radiodensity were generated semiautomatically. Mesenteric lymphadenopathy (LAD, largest lymph node > 10 mm) and severe vasa recta (VR) engorgement (diameter of the VR supplying diseased bowel ≥ 2 × VR supplying healthy bowel) were derived manually. The primary outcome was early ePOR (Rutgeert's score ≥ i2 on first endoscopy ≤ 15 months post-operatively) and the secondary outcome was ePOR severity (Rutgeert's score i0-4). Regression analyses were performed adjusting for demographic and disease-related characteristics to calculate adjusted odds ratio (aOR) and 95% confidence interval (CI). RESULTS: Of the 139 subjects included, 45% of subjects developed early ePOR (n = 63). VAT radiodensity (aOR 0.59, 95%CI: 0.38-0.90) and VAT:SAT radiodensity (aOR 8.54, 95%CI: 1.48-49.28) were associated with early ePOR, whereas, VAT volume (aOR 1.23, 95%CI: 0.78-1.95), VAT:SAT volume (aOR 0.80, 95%CI: 0.53-1.20), severe VR engorgement (aOR 1.53, 95%CI: 0.64-3.66), and mesenteric LAD (aOR 1.59, 95%CI: 0.67-3.79) were not. Similar results were observed for severity of ePOR. CONCLUSION: VAT radiodensity is potentially a novel non-invasive prognostic imaging marker to help risk stratify CD patients for POR.

Comprehensive Association Analyses of Extraintestinal Manifestations in Inflammatory Bowel Disease.

BACKGROUND & AIMS: Patients with inflammatory bowel disease (IBD) frequently develop extraintestinal manifestations (EIMs) that contribute substantially to morbidity. We assembled the largest multicohort data set to date to investigate the clinical, serologic, and genetic factors associated with EIM complications in IBD. METHODS: Data were available in 12,083 unrelated European ancestry IBD cases with presence or absence of EIMs (eg, ankylosing spondylitis [ankylosing spondylitis and sacroiliitis], primary sclerosing cholangitis [PSC], peripheral arthritis, and skin and ocular manifestations) across 4 cohorts (Cedars-Sinai Medical Center, National Institute for Diabetes and Digestive and Kidney Diseases IBD Genetics Consortium, Sinai Helmsley Alliance for Research Excellence Consortium, and Risk Stratification and Identification of Immunogenetic and Microbial Markers of Rapid Disease Progression in Children with Crohn's Disease cohort). Clinical and serologic parameters were analyzed by means of univariable and multivariable regression analyses using a mixed-effects model. Within-case logistic regression was performed to assess genetic associations. RESULTS: Most EIMs occurred more commonly in female subjects (overall EIM: P = 9.0E-05, odds ratio [OR], 1.2; 95% CI, 1.1-1.4), with CD (especially colonic disease location; P = 9.8E-09, OR, 1.7; 95% CI, 1.4-2.0), and in subjects who required surgery (both CD and UC; P = 3.6E-19, OR, 1.7; 95% CI, 1.5-1.9). Smoking increased risk of EIMs except for PSC, where there was a "protective" effect. Multiple serologic associations were observed, including with PSC (IgG and IgA, perinuclear anti-nuclear cytoplasmic antibody; anti-Saccharomyces cerevisiae antibodies; and anti-flagellin) and any EIM (IgG and IgA, perinuclear anti-nuclear cytoplasmic antibody; anti-Saccharomyces cerevisiae antibodies; and anti-Pseudomonas fluorescens-associated sequence). We identified genome-wide significant associations within major histocompatibility complex (ankylosing spondylitis and sacroiliitis, P = 1.4E-15; OR, 2.5; 95% CI, 2.0-3.1; PSC, P = 2.7E-10; OR, 2.8; 95% CI, 2.0-3.8; ocular, P = 2E-08, OR, 3.6; 95% CI, 2.3-5.6; and overall EIM, P = 8.4E-09; OR, 2.2; 95% CI, 1.7-2.9) and CPEB4 (skin, P = 2.7E-08; OR, 1.5; 95% CI, 1.3-1.8). Genetic associations implicated tumor necrosis factor, JAK-STAT, and IL6 as potential targets for EIMs. Contrary to previous reports, only 2% of our subjects had multiple EIMs and most co-occurrences were negatively correlated. CONCLUSIONS: We have identified demographic, clinical, and genetic associations with EIMs that revealed underlying mechanisms and implicated novel and existing drug targets-important steps toward a more personalized approach to IBD management.

Comparative Persistence of Non-tumor Necrosis Factor (TNF) vs. TNF Antagonists for Post-operative Prophylaxis in Crohn's Disease (CD).

BACKGROUND: The comparative safety and effectiveness of available biologics for post-operative prophylaxis in Crohn's disease (CD) is uncertain. Drug persistence may serve as a real-world proxy for tolerability and effectiveness. We evaluated the comparative persistence of non-TNF and TNF antagonists for post-operative prophylaxis and their comparative effectiveness for preventing early endoscopic post-operative recurrence (POR). METHODS: We conducted a single-center, retrospective study of surgically naïve CD subjects undergoing ileocecal or small bowel resection between 1/1/2000 and 12/31/2021 and prescribed a biologic for post-operative prophylaxis. We compared the risk of prophylaxis failure (requiring recurrent surgery or discontinuation of therapy due to persistent POR despite optimized drug level or dose escalation, immunogenicity, and/or adverse event) and early endoscopic POR (Rutgeert's score ≥ i2 within 15 months postoperatively) between non-TNF and TNF antagonist prophylaxis using Cox proportional hazard and logistic regression, respectively, adjusting for demographic and disease characteristics. RESULTS: The study included 291 subjects (81% TNF antagonists). After multivariable adjustment, non-TNF antagonist prophylaxis was associated with a significantly lower risk of prophylaxis failure than TNF antagonists (hazard ratio 0.26; 95% confidence interval (CI) [0.13-0.53]). Prophylaxis with non-TNF and TNF antagonists had similar risk of early endoscopic POR (odds ratio 0.66; 95% CI [0.32-1.36]). Stratifying the non-TNF antagonists by anti-integrin and anti-IL12/23 yielded similar results. CONCLUSION: In a cohort of surgically naïve CD subjects prescribed a biologic for post-operative prophylaxis, non-TNF antagonists had greater persistence than TNF antagonists with similar risk for early endoscopic POR. If confirmed by large, prospective studies, these findings can inform post-operative management strategies in CD.

Sex-Dimorphic Analyses Identify Novel and Sex-Specific Genetic Associations in Inflammatory Bowel Disease.

BACKGROUND: Sex is an integral variable often overlooked in complex disease genetics. Differences between sexes have been reported in natural history, disease complications, and age of onset in inflammatory bowel disease (IBD). While association studies have identified >230 IBD loci, there have been a limited number of studies investigating sex differences underlying these genetic associations. METHODS: We report the first investigation of sex-dimorphic associations via meta-analysis of a sex-stratified association study (34 579 IBD cases, 39 125 controls). In addition, we performed chromosome (chr) X-specific analyses, considering models of X inactivation (XCI) and XCI escape. Demographic and clinical characteristics were also compared between sexes. RESULTS: We identified significant differences between sexes for disease location and perianal complication in Crohn's disease and disease extent in ulcerative colitis. We observed genome-wide-significant sex-dimorphic associations (P < 5 × 10-8) at loci not previously reported in large-scale IBD genetic studies, including at chr9q22, CARMIL1, and UBASH3A. We identified variants in known IBD loci, including in chr2p15 and within the major histocompatibility complex on chr6, exhibiting sex-specific patterns of association (P < 5 × 10-7 in one sex only). We identified 3 chrX associations with IBD, including a novel Crohn's disease susceptibility locus at Xp22. CONCLUSIONS: These analyses identified novel IBD loci, in addition to characterizing sex-specific patterns of associations underlying sex-dimorphic associations. By elucidating the role of sex in IBD genetics, our study will help enhance our understanding of the differences between the sexes in IBD biology and underscores a need to move beyond conventional sex-combined analyses to appreciate the genetic architecture of IBD more comprehensively.

Sex-dimorphic meta-analyses of sex-stratified case-control (n = 73 704) regression identified 3 novel inflammatory bowel disease loci reaching genome-wide significance and highlighted chromosome 2 and major histocompatibility complex variants exhibiting sex-specific association. In addition, a novel chromosome X Crohn's disease susceptibility locus was identified.

Genetic coding variant in complement factor B (CFB) is associated with increased risk for perianal Crohn's disease and leads to impaired CFB cleavage and phagocytosis.

OBJECTIVE: Perianal Crohn's disease (pCD) occurs in up to 40% of patients with CD and is associated with poor quality of life, limited treatment responses and poorly understood aetiology. We performed a genetic association study comparing CD subjects with and without perianal disease and subsequently performed functional follow-up studies for a pCD associated SNP in Complement Factor B (CFB). DESIGN: Immunochip-based meta-analysis on 4056 pCD and 11 088 patients with CD from three independent cohorts was performed. Serological and clinical variables were analysed by regression analyses. Risk allele of rs4151651 was introduced into human CFB plasmid by site-directed mutagenesis. Binding of recombinant G252 or S252 CFB to C3b and its cleavage was determined in cell-free assays. Macrophage phagocytosis in presence of recombinant CFB or serum from CFB risk, or protective CD or healthy subjects was assessed by flow cytometry. RESULTS: Perianal complications were associated with colonic involvement, OmpC and ASCA serology, and serology quartile sum score. We identified a genetic association for pCD (rs4151651), a non-synonymous SNP (G252S) in CFB, in all three cohorts. Recombinant S252 CFB had reduced binding to C3b, its cleavage was impaired, and complement-driven phagocytosis and cytokine secretion were reduced compared with G252 CFB. Serine 252 generates a de novo glycosylation site in CFB. Serum from homozygous risk patients displayed significantly decreased macrophage phagocytosis compared with non-risk serum. CONCLUSION: pCD-associated rs4151651 in CFB is a loss-of-function mutation that impairs its cleavage, activation of alternative complement pathway, and pathogen phagocytosis thus implicating the alternative complement pathway and CFB in pCD aetiology.

Prevalence and Effect of Genetic Risk of Thromboembolic Disease in Inflammatory Bowel Disease.

BACKGROUND AND AIMS: The largest cause of mortality in patients with inflammatory bowel disease (IBD) remains thromboembolic disease (TED). Recent reports have demonstrated that both monogenic and polygenic factors contribute to TED and 10% of healthy subjects are genetically at high risk for TED. Our aim was to utilize whole-exome sequencing and genome-wide genotyping to determine the proportion of IBD patients genetically at risk for TED and investigate the effect of genetic risk of TED in IBD. METHODS: The TED polygenic risk score was calculated from genome-wide genotyping. Thrombophilia pathogenic variants were extracted from whole-exome sequencing. In total, 792 IBD patients had both whole-exome sequencing and genotyping data. We defined patients at genetically high risk for TED if they had a high TED polygenic risk score or carried at least 1 thrombophilia pathogenic variant. RESULTS: We identified 122 of 792 IBD patients (15.4%) as genetically high risk for TED. Among 715 of 792 subjects whose documented TED status were available, 63 of the 715 patients (8.8%) had TED events. Genetic TED risk was significantly associated with increased TED event (odds ratio, 2.5; P = .0036). In addition, we confirmed an additive effect of monogenic and polygenic risk on TED (P = .0048). Patients with high TED genetic risk more frequently had thrombosis at multiple sites (78% vs 42%, odds ratio, 3.96; P = .048). CONCLUSIONS: Genetic risk (both poly- and monogenic) was significantly associated with TED history. Our results suggest that genetic traits identify approximately 1 in 7 patients with IBD who will experience 2.5-fold or greater risk for TED.

Altered Intestinal ACE2 Levels Are Associated With Inflammation, Severe Disease, and Response to Anti-Cytokine Therapy in Inflammatory Bowel Disease.

BACKGROUND AND AIMS: The host receptor for severe acute respiratory syndrome coronavirus 2, angiotensin-converting enzyme 2 (ACE2), is highly expressed in small bowel (SB). Our aim was to identify factors influencing intestinal ACE2 expression in Crohn's disease (CD), ulcerative colitis (UC), and non-inflammatory bowel disease (IBD) controls. METHODS: Using bulk RNA sequencing or microarray transcriptomics from tissue samples (4 SB and 2 colonic cohorts; n = 495; n = 387 UC; n = 94 non-IBD), we analyzed the relationship between ACE2 with demographics and disease activity and prognosis. We examined the outcome of anti-tumor necrosis factor and anti-interleukin-12/interleukin-23 treatment on SB and colonic ACE2 expression in 3 clinical trials. Univariate and multivariate regression models were fitted. RESULTS: ACE2 levels were consistently reduced in SB CD and elevated in colonic UC compared with non-IBD controls. Elevated SB ACE2 was also associated with demographic features (age and elevated body mass index) associated with poor coronavirus disease 2019 outcomes. Within CD, SB ACE2 was reduced in patients subsequently developing complicated disease. Within UC, colonic ACE2 was elevated in active disease and in patients subsequently requiring anti-tumor necrosis factor rescue therapy. SB and colonic ACE2 expression in active CD and UC were restored by anti-cytokine therapy, most notably in responders. CONCLUSIONS: Reduced SB but elevated colonic ACE2 levels in IBD are associated with inflammation and severe disease, but normalized after anti-cytokine therapy, suggesting compartmentalization of ACE2-related biology in SB and colonic inflammation. The restoration of ACE2 expression with anti-cytokine therapy might be important in the context of severe acute respiratory syndrome coronavirus 2 infection and potentially explain reports of reduced morbidity from coronavirus disease 2019 in IBD patients treated with anti-cytokines.

Translocation of Viable Gut Microbiota to Mesenteric Adipose Drives Formation of Creeping Fat in Humans.

A mysterious feature of Crohn's disease (CD) is the extra-intestinal manifestation of "creeping fat" (CrF), defined as expansion of mesenteric adipose tissue around the inflamed and fibrotic intestine. In the current study, we explore whether microbial translocation in CD serves as a central cue for CrF development. We discovered a subset of mucosal-associated gut bacteria that consistently translocated and remained viable in CrF in CD ileal surgical resections, and identified Clostridium innocuum as a signature of this consortium with strain variation between mucosal and adipose isolates, suggesting preference for lipid-rich environments. Single-cell RNA sequencing characterized CrF as both pro-fibrotic and pro-adipogenic with a rich milieu of activated immune cells responding to microbial stimuli, which we confirm in gnotobiotic mice colonized with C. innocuum. Ex vivo validation of expression patterns suggests C. innocuum stimulates tissue remodeling via M2 macrophages, leading to an adipose tissue barrier that serves to prevent systemic dissemination of bacteria.

Reduced expression of COVID-19 host receptor, ACE2 is associated with small bowel inflammation, more severe disease, and response to anti-TNF therapy in Crohn's disease.

Angiotensin-Converting Enzyme 2 ( ACE2 ) has been identified as the host receptor for SARS-coronavirus 2 (SARS-CoV-2) which has infected millions world-wide and likely caused hundreds of thousands of deaths. Utilizing transcriptomic data from four cohorts taken from Crohn's disease (CD) and non-inflammatory bowel disease (IBD) subjects, we observed evidence of increased ACE2 mRNA in ileum with demographic features that have been associated with poor outcomes in COVID-19 including age and raised BMI. ACE2 was downregulated in CD compared to controls in independent cohorts. Within CD, ACE2 expression was reduced in inflamed ileal tissue and also remarkably, from uninvolved tissue in patients with a worse prognosis in both adult and pediatric cohorts. In active CD, small bowel ACE2 expression was restored by anti-TNF therapy particularly in anti-TNF responders. Collectively our data suggest that ACE2 downregulation is associated with inflammation and worse outcomes in CD.

A three-dimensional graphene-based ratiometric signal amplification aptasensor for MUC1 detection.

A three-dimensional graphene-based ratiometric signal amplification aptasensor for highly sensitive and selective detection of mucin1 (MUC1) by electrochemical method has been developed. Au-reduced graphene oxide (Au-RGO) composite, which was synthesized through hydrothermal reaction and freeze-drying treatment, was used as substrate for fabricating the sensor interface on glassy carbon electrode (GCE). The application of Au-RGO is beneficial for improving electrochemical performance and immobilizing aptamer. Ferrocene labeled aptamer (Fc-Apt), grafting on Au-RGO composite, worked for specific recognition of MUC1 and as internal reference to improve the detection accuracy. Au nanoparticle modified with methyl blue labeled aptamer (MB-Apt@Au) was adopted to combine with MUC1 that captured on the electrode surface to amplify the electrical signal. Under optimal experimental conditions, this sensor was applied to detect a series concentration of MUC1 solution by alternating current voltammetry method. The aptasensor shows satisfactory detection results with a wide linear range of 1 pM to 1 µM, a low detection limit of 0.25 pM and good specificity. The good performance of the prepared electrochemical aptasensor implies that this method has potential for MUC1 detection, and it would be promising for early screening and diagnosis of cancer diseases. The proposed method also lays an important foundation for preparing ratiometric signal amplification aptasensor for other biomarkers detection.

Late-Onset Crohn's Disease Is A Subgroup Distinct in Genetic and Behavioral Risk Factors With UC-Like Characteristics.

Background: Age of onset is linked to variations in clinical phenotypes and natural history in Crohn's disease (CD). We aim to define etiologically more homogenous subgroups in CD based on ages of onset. Methods: We examined the distribution of CD polygenetic risk score (PRS) across ages of diagnosis in a Caucasian cohort of 2344 independent CD patients. We identified subgroups with a distinct distribution of PRS and compared those groups in genetics, demographic characteristics, clinical subphenotypes, and serological markers. The results were replicated in an independent cohort of 13,065 CD patients from the International Inflammatory Bowel Diseases Genetic Consortium (IIBDGC). Results: We identified a late-onset (LO) subgroup in CD (age at diagnosis ≥ 55 years) with significantly lower PRS compared with the intermediate group (age at diagnosis between 5 and 55 years) in both cohorts. Smoking cessation, a risk factor for ulcerative colitis (UC) and protective factor for CD, had a higher rate in this LO subgroup in comparison with the intermediate group. We also compared the LO group with the intermediate group, and, consistent with previous reports, the LO group more often had colonic CD, had less penetrating disease behavior, and had less need for surgery. Serological analysis showed that LO CD patients were more antineutrophil cytoplasmic antibody positive and less antisaccharomyces cerevisiae antibody positive compared with the intermediate group. Variance component analysis indicated that overall genetic contribution to LO CD was lower relative to the middle group, and genetic heterogeneity testing indicated that LO CD was different from the middle group in underlying genetic architecture. Conclusions: Late-onset CD is subgroup distinct in genetic and behavioral risk factors with UC-like characteristics. 10.1093/ibd/izy148_video1izy148.video15791413461001.

A graphene oxide-based label-free electrochemical aptasensor for the detection of alpha-fetoprotein.

A label-free method for the determination of alpha-fetoprotein (AFP) was successfully developed by graphene oxide (GO)-based electrochemical aptasensor. This aptasensor was constructed by covalently immobilizing NH2-functionalized AFP-specific aptamer on GO with plenty of carboxylic groups. Cyclic voltammetry (CV) and electrochemical impedance spectra (EIS) analysis were carried out to investigate the practicability of the fabrication procedures. Fourier transform infrared spectra (FTIR), Raman, atomic force microscopy (AFM) and scanning electron microscope (SEM) were performed to indicate the changes of the sensing interface. CV was used to detect the signal change of the aptasensor. Peak current of CVs changed before and after incubating the aptasensor with different concentration of AFP solution. The changes of peak current were proportional to the AFP concentration, with a wide linear range of 0.01-100 ng mL-1, a low detection limit of 3 pg mL-1 and good specificity. The proposed simple and cost-effective label-free strategy is promising for the determination of clinical biomarkers such as AFP.

Colonic Phenotypes Are Associated with Poorer Response to Anti-TNF Therapies in Patients with IBD.

BACKGROUND: Although anti-tumor necrosis factor (TNF) agents are effective in patients with inflammatory bowel disease (IBD), many patients either do not respond to anti-TNF treatment or lose response over time. The aim of this study was to determine factors associated with response to anti-TNF therapy in IBD. METHODS: Patients with Crohn's disease (CD) or ulcerative colitis who had consented to participate in a genetics registry and been treated with anti-TNF agents were evaluated retrospectively and categorized as primary nonresponders or secondary nonresponders. We evaluated clinical, serological, and genetic characteristics associated with primary nonresponse or time to loss of response to anti-TNF agents. RESULTS: We included 314 CD (51 [16.2%] primary nonresponders and 179 [57.0%] secondary nonresponders) and 145 subjects with ulcerative colitis (43 [29.7%] primary nonresponders and 74 [51.0%] secondary nonresponders). Colonic involvement (P = 0.017; odds ratio = 8.0) and anti-TNF monotherapy (P = 0.017; odds ratio = 4.9) were associated in a multivariate analysis with primary nonresponse to anti-TNF agents in CD. In addition, higher anti-nuclear cytoplasmic antibody levels (P = 0.019; hazard ratio = 1.01) in CD, anti-nuclear cytoplasmic antibody positivity (P = 0.038; hazard ratio = 1.6) in ulcerative colitis, and a positive family history of IBD (P = 0.044; hazard ratio = 1.3) in all patients with IBD were associated with time to loss of response to anti-TNF agents. Furthermore, various known IBD susceptibility single-nucleotide polymorphisms and additional variants in immune-mediated genes were shown to be associated with primary nonresponse or time to loss of response. CONCLUSIONS: Our results may help to optimize the use of anti-TNF agents in clinical practice and position these therapies appropriately as clinicians strive for a more personalized approach to managing IBD.

Association of Ribonuclease T2 Gene Polymorphisms With Decreased Expression and Clinical Characteristics of Severity in Crohn's Disease.

BACKGROUND & AIMS: Variants in the tumor necrosis factor superfamily member 15 gene (TNFSF15, also called TL1A) have been associated with risk for inflammatory bowel disease (IBD). TL1A affects expression of multiple cytokines to promote mucosal inflammation. Little is known about the TL1A-response pathways that regulate cytokine expression. We investigated T-cell gene expression patterns to determine the mechanisms by which TL1A regulates cytokine production, and whether these associate with outcomes of patients with Crohn's disease (CD). METHODS: Peripheral T cells isolated from normal donors were cultured with TL1A. We performed gene expression profile analysis by RNA sequencing of subsets of interferon gamma (IFNG)-producing and non-producing cells purified by flow cytometry. Unsupervised hierarchical clustering analysis was used to identify gene expression differences between these subsets. Ribonuclease T2 gene (RNASET2) expression and methylation were assessed by quantitative trait loci analyses. Clinical characteristics of patients (complications, resistance to therapy, and recurrence time) were associated with single nucleotide polymorphisms in RNASET2. We performed motif screening to identify polymorphisms that disrupt transcription factor binding sites. Levels of RNASET2 were knocked down with small interfering RNA in CD4+ T cells and the effect on protein expression was determined by proteomic analysis and cytokine production. Cell aggregation was measured by flow cytometry. RESULTS: We identified 764 genes with at least a 2-fold difference in TL1A-mediated expression between IFNG-secreting and non-secreting T cells (P < 1 × 10-5). Many of these genes were located near IBD susceptibility variants. RNASET2 was the only IBD risk-associated gene with >5-fold down-regulation in the IFNG-secreting subset. RNASET2 disease risk variants were associated with decreased expression in peripheral and mucosal tissues and DNA hypermethylation in CD patients requiring surgical intervention. RNASET2 disease risk variants were associated in CD patients with more complicated disease or resistance to therapy, defined in part by failed response to treatment, increased length of intestinal resection, shorter time to repeat surgery, and high Rutgeerts score (>2) in postoperative endoscopy. The RNASET2 variant rs2149092 was predicted to disrupt a consensus binding site for the transcription factor ETS within an enhancer region. Expression of RNASET2 correlated with expression of ETS. RNASET2 knockdown in T cells increased expression of IFNG and intercellular adhesion molecule 1 (ICAM1) and induced T-cell aggregation. A blocking antibody against (ILFA1), disrupting the lymphocyte function-associated antigen 1-intercellular adhesion molecule 1 interaction, reduced T-cell production of IFNG. CONCLUSIONS: We identified decreased expression of RNASET2 as a component of TL1A-mediated increase in production of IFNG and as a potential biomarker for patients with severe CD. Further study of the role of RNASET2 in regulating mucosal inflammation may lead to development of novel therapeutic targets.

IFNG rs1861494 polymorphism is associated with IBD disease severity and functional changes in both IFNG methylation and protein secretion.

BACKGROUND: Mucosal expression of interferon (IFN)-γ plays a pivotal role in the pathogenesis of inflammatory bowel disease (IBD) and IBD risk regions flank IFNG. The conserved IFNG rs1861494 T/C introduces a new CpG methylation site, is associated with disease severity and lack of therapeutic response in other infectious and immune-mediated disorders, and is in linkage disequilibrium with a ulcerative colitis (UC) disease severity region. It seems likely that CpG-altering single nucleotide polymorphisms modify methylation and gene expression. This study evaluated the association between rs1861494 and clinical, serologic, and methylation patterns in patients with IBD. METHODS: Peripheral T cells of UC and Crohn's disease (CD) patients were genotyped for rs1861494 and analyzed for allele-specific and IFNG promoter methylation. Serum antineutrophil cytoplasmic autoantibodies and IFN-γ secretion were measured by enzyme-linked immunosorbent assay and nucleoprotein complex formation by electrophoretic mobility shift assay. RESULTS: IFNG rs1861494 T allele carriage in patients with IBD was associated with enhanced secretion of IFN-γ. T allele carriage was associated in UC with high levels of antineutrophil cytoplasmic autoantibodies and faster progression to colectomy. In CD, it was associated with complicated disease involving a stricturing/penetrating phenotype. Likewise, IFNG rs1861494 displayed genotype-specific modulation of DNA methylation and transcription factor complex formation. CONCLUSIONS: This study reports the first association of IFNG rs1861494 T allele with enhanced IFN-γ secretion and known IBD clinical parameters indicative of more aggressive disease and serological markers associated with treatment resistance to anti-tumor necrosis factor therapy in patients with IBD. These data may be useful prognostically as predictors of early response to anti-tumor necrosis factor therapy to identify patients with IBD for improved personalized therapeutics.