Anti-integrin αvß6 autoantibodies are increased in PSC patients with concomitant IBD and correlate with liver disease severity.

BACKGROUND AND AIMS: Anti-integrin αvß6 autoantibodies (anti-αvß6) are found in more than 50% of individuals with ulcerative colitis (UC). We aimed to determine the prevalence of anti-αvß6 in patients with primary sclerosing cholangitis (PSC) and their association with liver disease severity. METHODS: Four cohorts of pre-liver transplant PSC patients were recruited. Patients with inflammatory bowel disease (IBD) and healthy controls (HC) served as comparators. Total IgG and anti-αvß6 levels were measured using enzyme-linked immunosorbent assay (ELISA). Olink® inflammation panel was run on a subset of samples. Multivariable linear regression analysis was performed to assess the association between anti-αvß6 and indices of liver disease severity. RESULTS: A total of 137 PSC patients (including 76 with PSC-UC, 33 with PSC-Crohn's disease (CD) and 28 with PSC alone) and 160 controls (including 91 with IBD and 69 HC) were enrolled. Anti-αvß6 levels were significantly higher in PSC-UC and PSC-CD compared to PSC alone (p<0.0001 and 0.003) and HC (p<0.0001 and p<0.0001). However, anti-αvß6 levels in PSC alone were not increased compared to HC. In patients with PSC-IBD, anti-αvß6 levels correlated with markers of liver disease severity including alkaline phosphatase level (r=0.32, p=0.004), the revised Mayo PSC risk score (r=0.25, p=0.02) and liver stiffness measurement (r=0.43, p=0.008) after adjusting for age, gender, race/ethnicity and IBD subtype. Additionally, anti-αvß6 levels were associated with markers of systemic inflammation and tissue remodeling. CONCLUSION: Anti-αvß6 autoantibodies identify a subset of PSC patients with concomitant IBD.

Gastrointestinal germinal center B cell depletion and reduction in IgA+ plasma cells in HIV-1 infection.

Gastrointestinal (GI) B cells and plasma cells (PCs) are critical to mucosal homeostasis and the host response to HIV-1 infection. Here, high-resolution mapping of human B cells and PCs sampled from the colon and ileum during both viremic and suppressed HIV-1 infection identified a reduction in germinal center (GC) B cells and follicular dendritic cells (FDCs) during HIV-1 viremia. Immunoglobulin A-positive (IgA+) PCs are the major cellular output of intestinal GCs and were significantly reduced during viremic HIV-1 infection. PC-associated transcriptional perturbations, including type I interferon signaling, persisted in antiretroviral therapy (ART)-treated individuals, suggesting ongoing disruption of the intestinal immune milieu during ART. GI humoral immune perturbations were associated with changes in the intestinal microbiome composition and systemic inflammation. These findings highlight a key immune defect in the GI mucosa due to HIV-1 viremia.

A unique serum IgG glycosylation signature predicts development of Crohn's disease and is associated with pathogenic antibodies to mannose glycan.

Inflammatory bowel disease (IBD) is characterized by chronic inflammation in the gut. There is growing evidence in Crohn's disease (CD) of the existence of a preclinical period characterized by immunological changes preceding symptom onset that starts years before diagnosis. Gaining insight into this preclinical phase will allow disease prediction and prevention. Analysis of preclinical serum samples, up to 6 years before IBD diagnosis (from the PREDICTS cohort), revealed the identification of a unique glycosylation signature on circulating antibodies (IgGs) characterized by lower galactosylation levels of the IgG fragment crystallizable (Fc) domain that remained stable until disease diagnosis. This specific IgG2 Fc glycan trait correlated with increased levels of antimicrobial antibodies, specifically anti-Saccharomyces cerevisiae (ASCA), pinpointing a glycome-ASCA hub detected in serum that predates by years the development of CD. Mechanistically, we demonstrated that this agalactosylated glycoform of ASCA IgG, detected in the preclinical phase, elicits a proinflammatory immune pathway through the activation and reprogramming of innate immune cells, such as dendritic cells and natural killer cells, via an FcγR-dependent mechanism, triggering NF-κB and CARD9 signaling and leading to inflammasome activation. This proinflammatory role of ASCA was demonstrated to be dependent on mannose glycan recognition and galactosylation levels in the IgG Fc domain. The pathogenic properties of (anti-mannose) ASCA IgG were validated in vivo. Adoptive transfer of antibodies to mannan (ASCA) to recipient wild-type mice resulted in increased susceptibility to intestinal inflammation that was recovered in recipient FcγR-deficient mice. Here we identify a glycosylation signature in circulating IgGs that precedes CD onset and pinpoint a specific glycome-ASCA pathway as a central player in the initiation of inflammation many years before CD diagnosis. This pathogenic glyco-hub may constitute a promising new serum biomarker for CD prediction and a potential target for disease prevention.

Gastrointestinal germinal center B cell depletion and reduction in IgA + plasma cells in HIV-1 infection.

Gastrointestinal (GI) B cells and plasma cells (PCs) are critical to mucosal homeostasis and the host response to HIV-1 infection. Here, high resolution mapping of human B cells and PCs sampled from the colon and ileum during both viremic and suppressed HIV-1 infection identified a reduction in germinal center (GC) B cells and follicular dendritic cells (FDCs) during HIV-1 viremia. IgA + PCs are the major cellular output of intestinal GCs and were significantly reduced during viremic HIV-1 infection. PC-associated transcriptional perturbations, including type I interferon signaling, persisted in antiretroviral therapy (ART)-treated individuals, suggesting ongoing disruption of the intestinal immune milieu during ART. GI humoral immune perturbations were associated with changes in the intestinal microbiome composition and systemic inflammation. These findings highlight a key immune defect in the GI mucosa due to HIV-1 viremia. One Sentence Summary: Intestinal germinal center B cell reduction in HIV-1 infection linked to reduced IgA + plasma cells and systemic inflammation.

Safety of Immunosuppression in a Prospective Cohort of Inflammatory Bowel Disease Patients With a HIstoRy of CancEr: SAPPHIRE Registry.

BACKGROUND & AIMS: In patients with inflammatory bowel disease (IBD) and a history of cancer, retrospective studies have suggested that exposure to immunosuppressive agents does not increase the risk of incident (recurrent or new) cancer compared with unexposed patients. SAPPHIRE is a prospective registry aimed at addressing this issue. METHODS: Since 2016, patients with IBD and confirmed index cancer before enrollment were followed up annually. Patients receiving chemotherapy or radiation at enrollment, or recurrent cancer within 5 years, were excluded. The primary outcome was development of incident cancer related to exposure to immunosuppressive medications. RESULTS: Among 305 patients (47% male, 88% white), the median age at IBD diagnosis and cancer were 32 and 52 years, respectively. Index cancers were solid organ (46%), dermatologic (32%), gastrointestinal (13%), and hematologic (9%). During a median follow-up period of 4.8 years, 210 patients (69%) were exposed to immunosuppressive therapy and 46 patients (15%) developed incident cancers (25 new, 21 recurrent). In unadjusted analysis, the crude rate of incident cancer in unexposed patients was 2.58 per 100 person-years vs 4.78 per 100 person-years (relative risk, 1.85; 95% CI, 0.92-3.73) for immunosuppression-exposed patients. In a proportional hazards model adjusting for sex, smoking history, age and stage at index malignancy, and nonmelanoma skin cancer, no significant association was found between receipt of immunosuppression and incident cancer (adjusted hazard ratio, 1.41; 95% CI, 0.69-2.90), or with any major drug class. CONCLUSIONS: In this interim analysis of patients with IBD and a history of cancer, despite numerically increased adjusted hazard ratios, we did not find a statistically significant association between subsequent exposure to immunosuppressive therapies and development of incident cancers.

Comprehensive proteogenomic characterization of rare kidney tumors.

Non-clear cell renal cell carcinomas (non-ccRCCs) encompass diverse malignant and benign tumors. Refinement of differential diagnosis biomarkers, markers for early prognosis of aggressive disease, and therapeutic targets to complement immunotherapy are current clinical needs. Multi-omics analyses of 48 non-ccRCCs compared with 103 ccRCCs reveal proteogenomic, phosphorylation, glycosylation, and metabolic aberrations in RCC subtypes. RCCs with high genome instability display overexpression of IGF2BP3 and PYCR1. Integration of single-cell and bulk transcriptome data predicts diverse cell-of-origin and clarifies RCC subtype-specific proteogenomic signatures. Expression of biomarkers MAPRE3, ADGRF5, and GPNMB differentiates renal oncocytoma from chromophobe RCC, and PIGR and SOSTDC1 distinguish papillary RCC from MTSCC. This study expands our knowledge of proteogenomic signatures, biomarkers, and potential therapeutic targets in non-ccRCC.

Gut-associated lymphoid tissue attrition associates with response to anti-α4ß7 therapy in ulcerative colitis.

Vedolizumab (VDZ) is a first-line treatment in ulcerative colitis (UC) that targets the α4ß7- mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1) axis. To determine the mechanisms of action of VDZ, we examined five distinct cohorts of patients with UC. A decrease in naïve B and T cells in the intestines and gut-homing (ß7+) plasmablasts in circulation of VDZ-treated patients suggested that VDZ targets gut-associated lymphoid tissue (GALT). Anti-α4ß7 blockade in wild-type and photoconvertible (KikGR) mice confirmed a loss of GALT size and cellularity because of impaired cellular entry. In VDZ-treated patients with UC, treatment responders demonstrated reduced intestinal lymphoid aggregate size and follicle organization and a reduction of ß7+IgG+ plasmablasts in circulation, as well as IgG+ plasma cells and FcγR-dependent signaling in the intestine. GALT targeting represents a previously unappreciated mechanism of action of α4ß7-targeted therapies, with major implications for this therapeutic paradigm in UC.

Decomprolute is a benchmarking platform designed for multiomics-based tumor deconvolution.

Tumor deconvolution enables the identification of diverse cell types that comprise solid tumors. To date, however, both the algorithms developed to deconvolve tumor samples, and the gold-standard datasets used to assess the algorithms are geared toward the analysis of gene expression (e.g., RNA sequencing) rather than protein levels. Despite the popularity of gene expression datasets, protein levels often provide a more accurate view of rare cell types. To facilitate the use, development, and reproducibility of multiomic deconvolution algorithms, we introduce Decomprolute, a Common Workflow Language framework that leverages containerization to compare tumor deconvolution algorithms across multiomic datasets. Decomprolute incorporates the large-scale multiomic datasets produced by the Clinical Proteomic Tumor Analysis Consortium (CPTAC), which include matched mRNA expression and proteomic data from thousands of tumors across multiple cancer types to build a fully open-source, containerized proteogenomic tumor deconvolution benchmarking platform. http://pnnl-compbio.github.io/decomprolute.

Pan-cancer proteogenomics characterization of tumor immunity.

Despite the successes of immunotherapy in cancer treatment over recent decades, less than <10%-20% cancer cases have demonstrated durable responses from immune checkpoint blockade. To enhance the efficacy of immunotherapies, combination therapies suppressing multiple immune evasion mechanisms are increasingly contemplated. To better understand immune cell surveillance and diverse immune evasion responses in tumor tissues, we comprehensively characterized the immune landscape of more than 1,000 tumors across ten different cancers using CPTAC pan-cancer proteogenomic data. We identified seven distinct immune subtypes based on integrative learning of cell type compositions and pathway activities. We then thoroughly categorized unique genomic, epigenetic, transcriptomic, and proteomic changes associated with each subtype. Further leveraging the deep phosphoproteomic data, we studied kinase activities in different immune subtypes, which revealed potential subtype-specific therapeutic targets. Insights from this work will facilitate the development of future immunotherapy strategies and enhance precision targeting with existing agents.

Proteogenomic analysis of chemo-refractory high-grade serous ovarian cancer.

To improve the understanding of chemo-refractory high-grade serous ovarian cancers (HGSOCs), we characterized the proteogenomic landscape of 242 (refractory and sensitive) HGSOCs, representing one discovery and two validation cohorts across two biospecimen types (formalin-fixed paraffin-embedded and frozen). We identified a 64-protein signature that predicts with high specificity a subset of HGSOCs refractory to initial platinum-based therapy and is validated in two independent patient cohorts. We detected significant association between lack of Ch17 loss of heterozygosity (LOH) and chemo-refractoriness. Based on pathway protein expression, we identified 5 clusters of HGSOC, which validated across two independent patient cohorts and patient-derived xenograft (PDX) models. These clusters may represent different mechanisms of refractoriness and implicate putative therapeutic vulnerabilities.

Myeloid cell influx into the colonic epithelium is associated with disease severity and non-response to anti-Tumor Necrosis Factor Therapy in patients with Ulcerative Colitis.

Ulcerative colitis (UC) is an idiopathic chronic inflammatory disease of the colon with sharply rising global prevalence. Dysfunctional epithelial compartment (EC) dynamics are implicated in UC pathogenesis although EC-specific studies are sparse. Applying orthogonal high-dimensional EC profiling to a Primary Cohort (PC; n=222), we detail major epithelial and immune cell perturbations in active UC. Prominently, reduced frequencies of mature BEST4+OTOP2+ absorptive and BEST2+WFDC2+ secretory epithelial enterocytes were associated with the replacement of homeostatic, resident TRDC+KLRD1+HOPX+ γδ+ T cells with RORA+CCL20+S100A4+ TH17 cells and the influx of inflammatory myeloid cells. The EC transcriptome (exemplified by S100A8, HIF1A, TREM1, CXCR1) correlated with clinical, endoscopic, and histological severity of UC in an independent validation cohort (n=649). Furthermore, therapeutic relevance of the observed cellular and transcriptomic changes was investigated in 3 additional published UC cohorts (n=23, 48 and 204 respectively) to reveal that non-response to anti-Tumor Necrosis Factor (anti-TNF) therapy was associated with EC related myeloid cell perturbations. Altogether, these data provide high resolution mapping of the EC to facilitate therapeutic decision-making and personalization of therapy in patients with UC.

Preclinical Serological Signatures are Associated With Complicated Crohn's Disease Phenotype at Diagnosis.

BACKGROUND: At diagnosis, up to one-third of patients with Crohn's disease (CD) have a complicated phenotype with stricturing (B2) or penetrating (B3) behavior or require early surgery. We evaluated protein biomarkers and antimicrobial antibodies in serum archived years before CD diagnosis to assess whether complicated diagnoses were associated with a specific serological signature. METHODS: Prediagnosis serum was obtained from 201 patients with CD and 201 healthy controls. Samples were evaluated with a comprehensive panel of 1129 proteomic markers (SomaLogic) and antimicrobial antibodies. CD diagnosis and complications were defined by the International Classification of Diseases-Ninth Revision and Current Procedural Terminology codes. Cox regression models were utilized to assess the association between markers and the subsequent risk of being diagnosed with complicated CD. In addition, biological pathway and network analyses were performed. RESULTS: Forty-seven CD subjects (24%) had a B2 (n = 36) or B3 (n = 9) phenotype or CD-related surgery (n = 2) at diagnosis. Subjects presenting with complicated CD at diagnosis had higher levels of antimicrobial antibodies six years before diagnosis as compared with those diagnosed with noncomplicated CD. Twenty-two protein biomarkers (reflecting inflammatory, fibrosis, and tissue protection markers) were found to be associated with complicated CD. Pathway analysis of the altered protein biomarkers identified higher activation of the innate immune system and complement or coagulation cascades up to six years before diagnosis in complicated CD. CONCLUSIONS: Proteins and antimicrobial antibodies associated with dysregulated innate immunity, excessive adaptive response to microbial antigens, and fibrosis precede and predict a complicated phenotype at the time of diagnosis in CD patients.

Gut-associated lymphoid tissue attrition associates with response to anti-α4ß7 therapy in ulcerative colitis.

Targeting the α4ß7-MAdCAM-1 axis with vedolizumab (VDZ) is a front-line therapeutic paradigm in ulcerative colitis (UC). However, mechanism(s) of action (MOA) of VDZ remain relatively undefined. Here, we examined three distinct cohorts of patients with UC (n=83, n=60, and n=21), to determine the effect of VDZ on the mucosal and peripheral immune system. Transcriptomic studies with protein level validation were used to study drug MOA using conventional and transgenic murine models. We found a significant decrease in colonic and ileal naïve B and T cells and circulating gut-homing plasmablasts (ß7+) in VDZ-treated patients, pointing to gut-associated lymphoid tissue (GALT) targeting by VDZ. Murine Peyer's patches (PP) demonstrated a significant loss cellularity associated with reduction in follicular B cells, including a unique population of epithelium-associated B cells, following anti-α4ß7 antibody (mAb) administration. Photoconvertible (KikGR) mice unequivocally demonstrated impaired cellular entry into PPs in anti-α4ß7 mAb treated mice. In VDZ-treated, but not anti-tumor necrosis factor-treated UC patients, lymphoid aggregate size was significantly reduced in treatment responders compared to non-responders, with an independent validation cohort further confirming these data. GALT targeting represents a novel MOA of α4ß7-targeted therapies, with major implications for this therapeutic paradigm in UC, and for the development of new therapeutic strategies.

Anti-Integrin αvß6 Autoantibodies Are a Novel Biomarker That Antedate Ulcerative Colitis.

BACKGROUND & AIMS: Better biomarkers for prediction of ulcerative colitis (UC) development and prognostication are needed. Anti-integrin αvß6 (anti-αvß6) autoantibodies have been described in patients with UC. We tested for the presence of anti-αvß6 antibodies in the preclinical phase of UC and studied their association with disease-related outcomes after diagnosis. METHODS: Anti-αvß6 autoantibodies were measured in 4 longitudinal serum samples collected from 82 subjects who later developed UC and 82 matched controls from a Department of Defense preclinical cohort (PREDICTS [Proteomic Evaluation and Discovery in an IBD Cohort of Tri-service Subjects]). In a distinct, external validation cohort (Crohn's and Colitis Canada Genetic Environmental Microbial project cohort), we tested 12 pre-UC subjects and 49 matched controls. Furthermore, anti-αvß6 autoantibodies were measured in 2 incident UC cohorts (COMPASS [Comprehensive Care for the Recently Diagnosed IBD Patients], n = 55 and OSCCAR [Ocean State Crohn's and Colitis Area Registry], n = 104) and associations between anti-αvß6 autoantibodies and UC-related outcomes were defined using Cox proportional hazards model. RESULTS: Anti-αvß6 autoantibodies were significantly higher among individuals who developed UC compared with controls up to 10 years before diagnosis in PREDICTS. The anti-αvß6 autoantibody seropositivity was 12.2% 10 years before diagnosis and increased to 52.4% at the time of diagnosis in subjects who developed UC compared with 2.7% in controls across the 4 time points. Anti-αvß6 autoantibodies predicted UC development with an area under the curve of at least 0.8 up to 10 years before diagnosis. The presence of anti-αvß6 autoantibodies in preclinical UC samples was validated in the GEM cohort. Finally, high anti-αvß6 autoantibodies was associated with a composite of adverse UC outcomes, including hospitalization, disease extension, colectomy, systemic steroid use, and/or escalation to biologic therapy in recently diagnosed UC. CONCLUSIONS: Anti-integrin αvß6 autoantibodies precede the clinical diagnosis of UC by up to 10 years and are associated with adverse UC-related outcomes.

Racial Difference in Efficacy of Golimumab in Ulcerative Colitis.

BACKGROUND: Observational studies have described racial differences in inflammatory bowel disease (IBD) genetics, clinical manifestations, and outcomes. Whether race impacts response to biologics in IBD is unclear. We conducted a post hoc analysis of phase 2 and 3 randomized clinical trials in ulcerative colitis to evaluate the effect of race on response to golimumab. METHODS: We analyzed pooled individual-level data from induction and maintenance trials of golimumab through the Yale Open Data Access Project. The primary outcome was clinical response. Secondary outcomes were clinical remission and endoscopic healing. Multivariable logistic regression was performed comparing White vs racial minority groups (Asian, Black, or other race), adjusting for potential confounders. RESULTS: There were 1006 participants in the induction (18% racial minority) and 783 participants in the maintenance (17% racial minority) trials. Compared with White participants, participants from racial minority groups had significantly lower clinical response (adjusted odds ratio [aOR], 0.43; 95% confidence interval [CI], 0.28-0.66), clinical remission (aOR, 0.41; 95% CI, 0.22-0.77), and endoscopic healing (aOR, 0.48; 95% CI, 0.31-0.74) at week 6. Participants from racial minority groups also had significantly lower clinical remission (aOR, 0.46; 95% CI, 0.28-0.74) and endoscopic healing (aOR, 0.63; 95% CI, 0.41-0.96) at week 30. There were no racial differences in placebo response rates. CONCLUSIONS: Ulcerative colitis participants from racial minority groups were less likely to achieve clinical response, clinical remission, and endoscopic healing with golimumab compared with White participants in induction and maintenance trials. Further studies are needed to understand the impact of race on therapeutic response in IBD.

Racial disparities exist in inflammatory bowel disease, but the influence of race on response to biologic therapy is unclear. In pooled analysis of golimumab clinical trials, participants from racial minority groups were less likely to achieve clinical efficacy compared with White participants.

Gender-Based Differences in Response to Tumor Necrosis Factor Inhibitor Therapies for Ulcerative Colitis: Individual Participant Data Meta-Analyses of Clinical Trials.

BACKGROUND: Gender-based differences are reported in inflammatory bowel diseases (IBD) pathogenesis, but their impacts on IBD outcomes are not well known. We determined gender-based differences in response to treatment with tumor necrosis factor inhibitor (TNFi) therapies in individuals with ulcerative colitis (UC). METHODS: We used the Yale University Open Data Access (YODA) platform to abstract individual participant data from randomized clinical trials to study infliximab and golimumab as induction and maintenance therapies in moderately to severely active UC. Using multivariable logistic regression, we examined associations between gender and the endpoints of clinical remission, mucosal healing, and clinical response for each study individually and in a meta-analysis. RESULTS: Of 1639 patients included in induction trials (Program of Ulcerative Colitis Research Studies Utilizing an Investigational Treatment-Subcutaneous [PURSUIT-SC], active ulcerative colitis trials [ACT] 1 and 2) and 1280 patients included in maintenance trials (Program of Ulcerative Colitis Research Studies Utilizing an Investigational Treatment-Maintenance [PURSUIT-IM], ACT 1 and 2), 696 (42.5%) and 534 (41.7%) were women, respectively. In a meta-analysis of induction trials, the adjusted odds ratios (aORs) of clinical remission (aOR, 0.55; 95% CI, 0.31-0.97), mucosal healing (aOR, 0.47; 95% CI, 0.27-0.83), and clinical response (aOR, 0.51; 95% CI, 0.29-0.90) in the treatment arm and of clinical remission in the placebo arm (aOR, 0.34; 95% CI, 0.15-0.82) were lower in men compared to women. There were no differences in outcomes by gender in the treatment and placebo arms in the meta-analysis of maintenance trials. CONCLUSIONS: Men are less likely to achieve clinical remission, mucosal healing, and clinical response compared to women during induction treatment with TNFi for UC, but not during the maintenance phase. Future studies delineating the mechanisms underlying these observations would be informative.

In our meta-analysis of individual patient data from 4 ulcerative colitis clinical trials, the odds of clinical remission, mucosal healing, and clinical response with tumor necrosis factor inhibitors were lower among men compared to women during induction therapy, but not during maintenance therapy.

Neutralizing Anti-Granulocyte Macrophage-Colony Stimulating Factor Autoantibodies Recognize Post-Translational Glycosylations on Granulocyte Macrophage-Colony Stimulating Factor Years Before Diagnosis and Predict Complicated Crohn's Disease.

BACKGROUND & AIMS: Anti-granulocyte macrophage-colony stimulating factor autoantibodies (aGMAbs) are detected in patients with ileal Crohn's disease (CD). Their induction and mode of action during or before disease are not well understood. We aimed to investigate the underlying mechanisms associated with aGMAb induction, from functional orientation to recognized epitopes, for their impact on intestinal immune homeostasis and use as a predictive biomarker for complicated CD. METHODS: We characterized using enzyme-linked immunosorbent assay naturally occurring aGMAbs in longitudinal serum samples from patients archived before the diagnosis of CD (n = 220) as well as from 400 healthy individuals (matched controls) as part of the US Defense Medical Surveillance System. We used biochemical, cellular, and transcriptional analysis to uncover a mechanism that governs the impaired immune balance in CD mucosa after diagnosis. RESULTS: Neutralizing aGMAbs were found to be specific for post-translational glycosylation on granulocyte macrophage-colony stimulating factor (GM-CSF), detectable years before diagnosis, and associated with complicated CD at presentation. Glycosylation of GM-CSF was altered in patients with CD, and aGMAb affected myeloid homeostasis and promoted group 1 innate lymphoid cells. Perturbations in immune homeostasis preceded the diagnosis in the serum of patients with CD presenting with aGMAb and were detectable in the noninflamed CD mucosa. CONCLUSIONS: Anti-GMAbs predict the diagnosis of complicated CD long before the diagnosis of disease, recognize uniquely glycosylated epitopes, and impair myeloid cell and innate lymphoid cell balance associated with altered intestinal immune homeostasis.

Multiomics to elucidate inflammatory bowel disease risk factors and pathways.

Inflammatory bowel disease (IBD) is an immune-mediated disease of the intestinal tract, with complex pathophysiology involving genetic, environmental, microbiome, immunological and potentially other factors. Epidemiological data have provided important insights into risk factors associated with IBD, but are limited by confounding, biases and data quality, especially when pertaining to risk factors in early life. Multiomics platforms provide granular high-throughput data on numerous variables simultaneously and can be leveraged to characterize molecular pathways and risk factors for chronic diseases, such as IBD. Herein, we describe omics platforms that can advance our understanding of IBD risk factors and pathways, and available omics data on IBD and other relevant diseases. We highlight knowledge gaps and emphasize the importance of birth, at-risk and pre-diagnostic cohorts, and neonatal blood spots in omics analyses in IBD. Finally, we discuss network analysis, a powerful bioinformatics tool to assemble high-throughput data and derive clinical relevance.

Ulcerative colitis is characterized by a plasmablast-skewed humoral response associated with disease activity.

B cells, which are critical for intestinal homeostasis, remain understudied in ulcerative colitis (UC). In this study, we recruited three cohorts of patients with UC (primary cohort, n = 145; validation cohort 1, n = 664; and validation cohort 2, n = 143) to comprehensively define the landscape of B cells during UC-associated intestinal inflammation. Using single-cell RNA sequencing, single-cell IgH gene sequencing and protein-level validation, we mapped the compositional, transcriptional and clonotypic landscape of mucosal and circulating B cells. We found major perturbations within the mucosal B cell compartment, including an expansion of naive B cells and IgG+ plasma cells with curtailed diversity and maturation. Furthermore, we isolated an auto-reactive plasma cell clone targeting integrin αvß6 from inflamed UC intestines. We also identified a subset of intestinal CXCL13-expressing TFH-like T peripheral helper cells that were associated with the pathogenic B cell response. Finally, across all three cohorts, we confirmed that changes in intestinal humoral immunity are reflected in circulation by the expansion of gut-homing plasmablasts that correlates with disease activity and predicts disease complications. Our data demonstrate a highly dysregulated B cell response in UC and highlight a potential role of B cells in disease pathogenesis.