Introduction

Diagnosis of celiac disease (CeD) is dependent on serological markers like IgA antibodies against transglutaminase 2 (TG2) and IgG antibodies against deamidated gluten peptides (DGP) caused by dietary gluten. The underlying immunological drivers of antibody response are however still poorly characterized. Clarifying these drivers may improve serology-based diagnostics and offer valuable immunobiological insight for CeD.

Aims & Methods

In this project, we aimed to identify new serum factors that are associated with celiac disease and serological response. A total of 224 serum samples (161 untreated and 63 treated) from patients with CeD were selected from Oslo University Hospital’s Intestinal Disease Biobank collected between 2018 to 2024. Data on serological response and treatment status were collected and the samples were compared with 40 healthy individuals. Serum samples from treated CeD were paired samples of untreated CeD. Serum was analyzed using the Olink® Target 96 Inflammation panel, which uses PCR-amplified dual-antibody proximity extension. Analyses were performed at the Proteomic Core Facility at Oslo University Hospital and statistics were performed in R-based with the OlinkAnalyze package.

Results

Thirty-one proteins differed significantly across all comparisons (p < 0.05) and were more abundant in CeD than in healthy controls. When untreated CeD was compared with controls, 24 proteins were elevated, namely CXCL9, CXCL10, CXCL11 (all ligands for CXCR3), CCL25 (ligand for CCR9), IFN-gamma, IL12B, IL17A, IL7, IL8, IL10, IL15RA, LIF, CCL11, CCL20, CCL28, PD-L1, TNFRSF9, CD40, VEGFA, ARTN, MMP10, ADA, ST1A1 and STAMBP. In treated CeD, 9 proteins were elevated compared to controls, namely CXCL10, CXCL11, IL12B, IL7, CD40, TNFRSF9, CSF1, VEGFA and ST1A1. Paired comparisons of treated and untreated samples showed that CXCL9, CXCL11, CCL11, CCL25, IL17A, TNFRSF9 and ADA were significantly higher in the untreated group. The proteins CXCL11 and TNFRSF9 were significant in all 3 comparisons. No significant differences were noted when comparing IgA-TG2 and IgG-DGP responses; however, IL-17A and CXCL11 were significantly lower among those with only a TG2 response compared to double positives.

Conclusion

We here report that multiple serum proteins are significantly elevated in untreated and treated CeD patients compared to healthy individuals. Many of the same serum proteins have previously been reported in serum taken hours after gluten challenge. Of particular interest, IL7, which is upregulated in intestinal CeD mucosa, was significantly upregulated in serum compared to controls. Both CXCL11 and TNFRSF9 which were found to be significant in all comparisons are immunological proteins relevant for T-cell activation and regulations. Future analyses will incorporate clinical data, including Marsh grades and serological levels, to deepen our understanding of the immunological landscape in CeD.

Introduction

In patients with ulcerative colitis (UC), total proctocolectomy with restorative ileal pouch-anal anastomosis (IPAA) is a definitive surgical treatment for refractory disease or colorectal dysplasia. A short rectal cuff is typically retained and anastomosed to the pouch, and may become inflamed over time, a condition referred to as cuffitis. The clinical relevance of cuffitis remain unexplored. In this study, we aimed to characterize the long-term disease course associated with histologic cuffitis.

Aims & Methods

Patients with UC who underwent total proctocolectomy and IPAA were prospectively followed in a comprehensive pouch clinic at a tertiary referral center for patients with inflammatory bowel diseases (IBD). We included all patients who underwent at least one pouch endoscopy with paired pouch and cuff biopsies between 2017 and 2024. Cuffitis was defined as a NANCY Index histologic score of 3-4, and pouchitis was defined as histologic subscore of PDAI³2. Outcomes assessed included documented inflammatory pouch flares, defined by clinical evaluation; antibiotics used due to pouch inflammation; and initiation of biologics. Associations were evaluated using Poisson regression to estimate incidence rate ratios (IRRs) and Fisher’s exact test for categorical comparisons.

Results

A total of 116 patients underwent 250 pouch endoscopies during the study period. Average age of the cohort was 50.4 (±14.9) and 59% were females. Histologic pouchitis was detected in 80 (68.9%), and cuffitis in 76 (65.5%) patients. Most patients had extensive disease prior to IPAA (n=105, 90.5%) and indication for surgery was refractory UC (n=94, 81.0%). Concurrent pouchitis and cuffitis were identified in 54 (46.5%) patients. Patients with histologic-proven cuffitis had a significantly higher incidence rate of subsequent disease flares(IRR 4.39, 95% CI: 2.26-9.86, p<0.001) and required more antibiotic courses (IRR 1.94, 95% CI: 1.11-3.62, p=0.027) compared to those who never developed cuffitis. These associations remained significant after adjusting for the presence of histologic pouchitis. No significant difference was observed in the initiation of biologics (p=0.81). Among patients with at least two endoscopies during follow-up and isolated cuffitis at baseline (n=61), 6 patients with isolated cuffitis further developed new-onset pouchitis, while 15 patients with isolated pouchitis subsequently developed cuffitis. The remaining 40 patients (65.5%) maintained the same inflammatory pattern over time.

Conclusion

Histologic-proven cuffitis is independently associated with adverse long-term outcomes in patients post-IPAA, including flares and repeated antibiotic use, even in the absence of pouchitis. The persistence of inflammation in the retained rectal cuff, representing a remnant of the previously diseased colonic mucosa, raises mechanistic questions about its potential role in modulating inflammatory activity of the pouch. These findings emphasize the clinical importance of evaluating the rectal cuff in patients post-IPAA. Routine histologic assessment of the cuff should be incorporated into post IPAA surveillance, and interventional studies are warranted to determine whether targeted treatment of cuffitis can mitigate pouch related morbidity.

Disclosure

Jacob E Ollech: Has received grant support from Pfizer, consulting fees from Takeda, and
speaker fees from Abbvie, Janssen, Pfizer, Takeda, Novartis, and Bristol Myers Squibb.
Iris Dotan: consultation fee or honorarium from: Abbott, Abbvie, Athos, Arena, Altman
Research, Cambridge Healthcare, Celltrion, Celgene/BMS, Eli-Lilly, Ferring, Falk Pharma, Food
Industries Organization, Gilead, Galapagos, Iterative Scopes, Integra Holdings, Janssen,
Neopharm, Pfizer, Rafa laboratories, Roche/Genentech, Sangamo, Sublimity, Sandoz, Takeda,
Wildbio. Grants: Altman Research, BMS, Pfizer