Introduction

PD-1 downregulates activated T cells and dysregulation of its signaling impacts critical T cell responses in inflammatory and autoimmune diseases, including ulcerative colitis (UC). In UC lamina propria, multiple T cell subtypes express PD-1, including peripheral helper T cells (Tph) and effector memory T cells, and the reduction of PD-1+ Tph cells is correlated with remission.¹ While PD-1 is being evaluated in UC, it has been clinically validated as a target in two Ph2 studies in RA.^2,3 Rosnilimab, an investigational antibody, aims to leverage immune homeostatic mechanisms to regulate T cell activity by depleting PD-1^high T cells and reducing the activity of remaining PD-1+ T cells.⁴ Rosnilimab, when compared to isotype control, reduced inflammation of the colon, reduced infiltration of CD4 T cells and maintained body weight of mice in a murine model of colitis induced by the transfer of CD4+CD45Rb+ T cells from human PD-1 transgenic mice.⁵ Additionally, pathway genes indicative of fibrosis and impaired barrier function in human UC were normalized in rosnilimab-treated animals while dysregulated in the control group.⁶ Myeloid cells also contribute to inflammation in human UC, and reduction of their elevated numbers are associated with disease remission.⁷ An inflammatory myeloid cell gene signature was derived from human UC and used to assess inflammatory myeloid cells and the therapeutic impact of rosnilimab in this murine model of colitis.

Aims & Methods

A UC myeloid gene signature was derived via secondary analyses of single-cell RNA sequencing data from a published atlas of human UC tissue⁷ to identify 1,652 genes that were upregulated in inflamed myeloid cells compared to non-inflamed cells. These genes were then compared with 3,859 genes upregulated in a murine model of colitis. The resultant overlap of 625 genes was used to define the mouse colitis myeloid gene signature. Overlapping genes were analyzed for regulation in the murine model of colitis following rosnilimab treatment. Myeloid cell gene transcription in colonic tissue from mice treated with rosnilimab or isotype control was assessed via spatial transcriptomics.

Results

In a murine model of colitis, rosnilimab treatment resulted in the downregulation of 399 (64%) of the mouse colitis myeloid signature genes, suggesting an ability to impact a large proportion of the overlapping genes that are similarly dysregulated in human UC. These included mediators of immune cell recruitment (Ccl3, Ccr1) and detection of bacterial components (Cd14, Tlr2 and Tlr4). Additionally, genes involved in immune activation and amplification mediated by myeloid cells were reduced by rosnilimab (Il6, Cd80, Cd86, Myd88, Trem1, and Stat4). Spatial transcriptomic analyses of colonic tissue showed that rosnilimab reduced myeloid cell numbers, including M1 and M2 macrophage subtypes, compared to isotype control treated mice.

Conclusion

In addition to reducing pathogenic T cell numbers in this murine model of colitis, rosnilimab treatment also reduced pathogenic macrophages and the inflammatory myeloid gene signature in the colon. These data support previous preclinical findings demonstrating the potential therapeutic benefits of selectively targeting activated PD-1+ T cells and depleting PD-1^high T cells in reducing inflammation and improving UC outcomes in a murine model of colitis. These results, together with existing rosnilimab safety data in humans, support the scientific rationale for evaluating rosnilimab in an ongoing Phase 2 study in UC (NCT06127043).

References

1. Long Y, et al. Immunol Letters 2021;233:2-10.
2. AnaptysBio press release February 12, 2025. Ir.anaptsbio.com/news-release-details.
3. Tuttle J, et al. N Engl J Med 2023;388:1853-62.
4. Luu K, et al. J Crohn’s Colitis 2024;18(S1):i225 (Abstract DOP81).
5. Parmley S, et al. United Eur Gastroenterol J 2024;12:482 (Abstract MP448).
6. Linggi B, et al. J Crohn’s Colitis 2025;19(S1):i475 (Abstract P0101).
7. Thomas T, et al. Nature Immunol 2024;25:2152-65.

Disclosure

All authors are employees and shareholders of AnaptysBio

Introduction

Inflammatory Bowel Diseases (IBD) are chronic immune-mediated disorders of the gastrointestinal tract. Fibrosis is a frequent manifestation in IBD driven by inflammatory cytokines. During fibrosis, extracellular matrix proteins accumulate in the tissue, causing the disruption of the epithelial barrier and stenosis, ultimately causing malabsorption and intestinal motility issues. This can eventually lead to further serious complications, strictures, fistulas, or ileus. No drugs are available targeting fibrosis, in these cases, only surgical intervention can be used. A defined primary in vitro cell culture model is not available for intestinal fibrosis modeling.

Aims & Methods

Therefore, we aimed to establish and characterize human primary fibroblast cell culture from intestinal biopsies of control and IBD patients.
Human primary fibroblast cell cultures were generated from colonic biopsy of patients with IBD (N=4) and control (N=4). All downstream analyses were applied in passage number 3. For the phenotype observation, immunofluorescent staining was used. Targeted proteins were COL1A1, TGF-ß1, PAI-1, α-SMA, and PHH3. Proteome Profiler Human Cytokine Array Kit was used for the secreted cytokine pattern observation. For the gene expression analysis, RNA was isolated, and the qRT-PCR technique was utilized for the following target genes: COL1A1, ACTA2, TGF-ß1, FN1, PAI-1, H3C4. Scratch assay was used to examine wound closure, we monitored the closing for 48 hours taking photographs throughout. We evaluated the collected data and performed statistical analysis.

Results

We can successfully generate and maintain human colon primary fibroblast cell cultures from colonic biopsies of healthy and Crohn’s disease (CD) origins. Morphological differences were observed between control and diseased patient samples. In the protein examinations, the fluorescent intensity of fibrotic markers (COL1A1, TGF-ß1, PAI-1) and the mitosis marker PHH3 were significantly higher in the CD samples, indicating that the cells maintained fibrotic phenotype and the diseased fibroblasts had a higher proliferation rate. The myofibroblast marker, α-SMA, didn’t show a significant difference. In the cytokine pattern analysis, 22 cytokines showed a twofold increase or decreased by half between the two groups. HGF and DPPIV showed higher quantities in the CD-originated fibroblast. These cytokines are connected to the induction of fibrosis. However, the ANG, BDNF, PTX-3, VEGF, and VCAM-1 were higher in the control samples. Interestingly, no significant differences were noted between the two groups in the targeted genes examined by qRT-PCR measurements. We observed the closure of the artificial wound was faster and more effective in the Crohn’s disease culture compared to the control.

Conclusion

In conclusion, we can generate primary human intestinal fibroblast cell cultures and maintain them to passage number 3, approximately a month long. Fibrotic markers, secreted cytokines and morphological differences distinguish the diseased cultures from the healthy subjects; therefore, it could be useful for in vitro fibrosis modeling in the future. On the other hand, the gene expression analysis doesn’t discriminate between the two groups at passage number 3. To continue with our work, we will observe the fibrotic properties in earlier passage numbers.

Introduction

The Mayo Endoscopic Subscore (MES) is widely used in clinical trials and daily practice to assess disease activity and response to treatment in UC.

Aims & Methods

The objective of this study was to identify any nuances in patients with MES > 1 treated with non-TNF biologics and targeted oral therapies. The Ipsos UC Therapy Monitor, a multi-centre online medical chart review study of patients with UC, was conducted between July and September 2024 among gastroenterologists practicing across hospital and private practices in the UK, France, Germany, Italy, and Spain. Physicians were screened for practice duration and patient volume. Charts of patients prescribed advanced therapy were included in the analysis.

Results

205 sampled physicians collectively reported 820 UC patients. Of the reported patients with MES > 1, 62 were treated with non-TNF biologics and 62 were treated with novel oral therapies. Among the patients treated with non-TNF biologics, a higher proportion were female vs those receiving oral therapy (48% vs 31%); they were also older in age (mean years: 43 vs 38).
The patients treated with non-TNF biologics had a higher prevalence of comorbidities, including depression/anxiety (24% vs 19%), cardiovascular disease (8% vs 0%), and dyslipidemia/hyperlipidemia/hypercholesterolemia (11% vs 7%), compared to those treated with novel oral therapy.
Mean CRP levels were higher in the oral therapy group (10.2 mg/L vs 9.1 mg/L), while mean Mayo scores were slightly lower (4.7 vs 5.2). Fecal calprotectin levels were elevated in patients treated with non-TNF biologics vs oral therapy group (441 µg/g vs 503 µg/g).
When analysing reasons for prescribing selected advanced therapy between the two patient groups, a greater proportion of patients treated with non-TNF biologics had safety reasons specified more frequently by the sampled physicians.

Table 1: % of reported UC patients receiving advanced therapy for specific cited reasons

Conclusion

This study highlights key differences in patient characteristics and treatment considerations among UC patients with MES > 1 treated with non-TNF biologics compared to those treated with targeted oral therapies. Patients on non-TNF biologics tend to be older, more often female, and have a higher prevalence of comorbidities. Physicians prescribing non-TNF biologics prioritize safety, while those prescribing oral therapies focus on rapid symptom control. These findings highlight the importance of considering patient characteristics and treatment goals when selecting advanced therapies for UC patients with MES > 1. Further investigation using comparator cohort is warranted.

Introduction

The Mayo Endoscopic Subscore (MES) is the most widely used endoscopic index for assessing disease activity in ulcerative colitis (UC). Although artificial-intelligence　(AI)–assisted colonoscopy is expected to reduce inter-observer variability, the MES 4-point scale (0–3) lacks sufficient sensitivity to detect subtle changes in mucosal activity, limiting its ability to capture incremental improvement or deterioration. Moreover, because MES focuses on qualitative features—such as bleeding and erosions—without considering the extent or surface area of inflammation, it provides an incomplete estimate of a patient’s overall inflammatory burden.

Aims & Methods

We sought to develop and validate a quantitative, AI–driven colonoscopic score—Quantitative Ulcerative Colitis Assessment using Deep-learning (QUAD)—and to determine whether it predicts clinical relapse in patients with UC. The QUAD system was trained on 84 743 colonoscopic images from 998 UC patients at three centers and comprises three main functions: i) Image filtering: Automatic exclusion of low-quality images that are unsuitable for analysis owing to light saturation (halation), inadequate insufflation, excessive proximity to the mucosa, chromoendoscopy, or virtual chromoendoscopy. ii) Frame-level scoring: Each frame is divided into four quadrants; inflammation in each quadrant is graded from 0 to 3, and the quadrant scores are summed to yield a QUAD score of 0–12. iii) Video-level aggregation: Full-length withdrawal videos are processed to generate (i) an Entire QUAD score (0–60), representing pan-colonic inflammation, and (ii) a Distal QUAD score (0–12) for the rectosigmoid segment (final 20 % of the video).
The QUAD system contains mainly three function: i) automatically exclude low quality images that is ineligible for analysis in cases of halation, inadequate air de­livery, proximity to mucosa, chromoendoscopy, and virtual chromoendoscopy; ii) fully auto­mated twelve-class score output based on frame analysis: Each frame was divided into four quadrants; inflammation in each quadrant was graded 0–3 and summed to yield a QUAD score of 0–12; and iii) full-length withdrawal videos were processed to generate (I) an Entire QUAD (0–60) for considering whole-colon inflammation status and (II) a Distal QUAD (0–12) for the distal rectum–sigmoid segment (final 20 % of the video). An open-label cohort of adults with quiescent UC (partial Mayo score ≤ 2 for ≥6 months) was prospectively enrolled at a single center (August 2022–February 2023), and followed for 24 months after baseline colonoscopy; clinical relapse was defined as partial Mayo score > 2. The predictive value of QUAD scores for relapse was evaluated.

Results

Frame-level QUAD scores correlated strongly with expert-assigned MES values (Spearman r = 0.68, p < 0.01). Among 156 participants (median age, 51 years; 49 % male), 22 experienced relapse during follow-up. Relapse occurred in 19.4 % (19/98) of patients with a QUAD score > 3 versus 5.2 % (3/58) with a score ≤ 3 (log-rank p = 0.01).
In video analysis, an Entire QUAD > 6 did not significantly stratify relapse risk (16.8 % [17/101] vs 9.1 % [5/55]; log-rank p = 0.17). In contrast, a Distal QUAD > 3 was strongly associated with relapse (43.8 % [7/16] vs 10.7 % [15/140]; log-rank p < 0.01).

Conclusion

AI-generated QUAD provides a sensitive, fully quantitative measure of mucosal inflammation and stratifies relapse risk in clinically quiescent UC. In particular, the automatically derived Distal QUAD—focused on the distal colon and independent of operator image selection—offers a practical, objective tool for longitudinal monitoring and treatment tailoring in UC.

Introduction

Prevalence of MASLD in patients with Inflammatory Bowel Disease (IBD) has been and 21.6% in a previous cross-sectional study from our center. However, data on the progression of MASLD in IBD patients are scanty. reported 24.4% in a recent metaanalysis

Aims & Methods

We aimed to investigate the prevalence and the progression of MASLD, diagnosed by non-invasive tools, in a homogeneous cohort of patients with IBD followed in our referral center.
Consecutive IBD patients without known chronic liver disease were retrospectively enrolled and prospectively followed between 2020 and 2024. MASLD was defined as Controlled Attenuation Parameter (CAP) ≥275 dB/m. Significant fibrosis was defined as Liver Stiffness (LSM) ≥8 kPa by FibroScan. Demographic, metabolic and biochemical data were collected at baseline and at the last follow-up visit. All patients were genotyped for PNPLA3 rs738409 C>G by Taqman assay. Appropriated statistical analysis were performed to identify risk factors associated with the prevalence of MASLD and its progression.

Results

230 patients (mean age was 46.1±13.4 years, 49.2% were males, 50.8% had Crohn’s disease, mean disease duration was 9.4±7.5 years) were recruited. 14.8% of them were obese (BMI > 30 kg/m2), 9.8% diabetic. 49.2% were PNPLA3 rs738409 CG/GG. 116 out of 230 patients had complete metabolic and biochemical assessment at follow-up. Mean follow-up time was 4 years. At baseline, 25% (29/116) had MASLD. 18% (16/87) of patients without steatosis at baseline, developed steatosis at follow-up; while 44 % of those having steatosis at baseline, did not show steatosis at follow-up. 13.5% developed obesity. Obesity was significantly associated with the prevalence of MASLD both at baseline (p=0.040) and on follow-up (p<0.001) and was a predictor of steatosis progression (p<0.001); no association was found in relation to sex, PNPLA3 polymorphism, disease characteristics and the use of biologics. Diabetes was not significantly associated with MASLD in our cohort, but the number of patients was low. The Biologics use was significantly associated with the steatosis regression (p=0.038).

Conclusion

One third of IBD patients had MASLD and obesity was the main predictor of its prevalence and progression, highlighting the relevance of active surveillance of MASLD and appropriate nutritional and lifestyle counselling especially in obese IBD patients. Further studies needed to confirm our results and to identify other risk factors for MASLD in larger populations

Introduction

While ileocecal resection (ICR) is the most common surgical procedure in Crohn's disease (CD), non-ICR surgeries account for only 20% of cases and remain underrepresented in the literature. This study aimed to identify specific clinical risk factors for surgical recurrence in CD patients undergoing small bowel or colonic resections without involving the ileocecal valve.

Aims & Methods

This multicenter retrospective cohort study included 257 patients with CD (124 small bowel resections, 133 colonic resections) across 13 Italian centers from 1978 to 2023. Univariate and multivariate logistic regression and Cox proportional hazards analyses were performed to identify clinical risk factors associated with surgical recurrence.

Results

The cohort comprised two distinct groups: small bowel resections (n=124), characterized by male predominance (63.71%), a high prevalence of stricturing disease (60.48%), and a median follow-up of 75.5 months; and colonic resections (n=133), featuring a more balanced gender distribution (47.37% male), higher rates of penetrating disease (47.37%), and a median follow-up of 88.0 months. Penetrating disease behaviour emerged as the only significant predictor of recurrence in logistic regression analysis (OR 2.16, 95% CI 1.03-4.52, p=0.041), while factors typically predictive in ICR, such as smoking (OR 0.90, p=0.843) and prior resections (OR 0.96, p=0.913), were non-significant. Cox regression identified prior biologic exposure as a significant predictor of earlier recurrence (HR 2.52, 95% CI 1.22-5.18, p=0.012), with TNF experience specifically associated with increased risk (HR 2.28, 95% CI 1.12-4.67, p=0.024). The cumulative number of risk factors (HR 1.35, 95% CI 1.01-1.82, p=0.046) and postoperative intra-abdominal septic complications (HR 2.75, 95% CI 1.18-6.44, p=0.020) also contributed to recurrence risk. Disease phenotypes significantly differed between resection types (p<0.001), with stricturing disease most prevalent in small bowel resections (60.48% vs. 36.09% in colonic) and penetrating disease more common in colonic resections (47.37% vs. 36.29% in small bowel). Results are summarized in Table 1.

Table 1: Univariate logistic regression analysis of predictors for postoperative surgical recurrence in patients undergoing small bowel or colonic resections. Abbreviations: CI: Confidence Interval; CD: Crohn’s Disease; IBD: Inflammatory Bowel Disease; POR: Postoperative recurrence; TNF: Tumour Necrosis Factors.

Conclusion

This study reveals distinct risk factors for surgical recurrence after non-ICR surgeries in CD. Unlike ICR where smoking, perianal disease, and prior resections predominate, non-ICR recurrence is primarily associated with penetrating disease phenotype and prior biologic exposure. These findings demonstrate that risk stratification models developed for ICR are not applicable to non-ICR surgeries, highlighting the need for procedure-specific approaches to postoperative management. Tailored prophylactic strategies should address the unique recurrence dynamics of small bowel and colonic resection surgeries.

Introduction

Infiltration of neutrophils into the intestinal tissue is a crucial component of the inflammatory response in Crohn‘s disease (CD). CPa9-HNE, a calprotectin fragment released by human neutrophil elastase during NETosis, has been shown to strongly correlate with endoscopic disease activity in inflammatory bowel disease (IBD) and serves as an indicator for pharmacodynamic response. Furthermore, emerging data suggests that neutrophil extracellular traps (NETs) significantly contribute to the pathogenesis of fibrosis.

Aims & Methods

For the first time, we investigated the association of CPa9-HNE with histological grading of both inflammation and fibrosis. The cohort included 62 patients with stenotic Crohn‘s disease. Inclusion criterion was the presence of stenotic disease requiring bowel resection, as confirmed by radiographic assessment. Upon surgery, the resected specimens were collected and histologically graded according to transmural fibrosis burden, and inflammation (D'Haens score). Serum was drawn at baseline (before resection). CPa9-HNE was measured, reflecting a human neutrophil elastase-derived fragment of calprotectin. Spearman’s rank correlation was applied.

Results

CPa9-HNE showed an overall positive correlation to the D'Haens score (ρ=0.279, p<0.005). Significant positive correlation was observed between CPa9-HNE and the presence of neutrophils, both in the epithelium and the lamina propria (ρ=0.309, ρ=0.349, p<0.005 both), as well as with epithelial damage (ρ=0.262, p<0.005). We also observed a positive correlation between CPa9-HNE and transmural fibrosis burden, specifically fibrosis in the submucosa (ρ=0.294, p<0.005)

Conclusion

This study showed that CPa9-HNE, a biomarker of neutrophil activity, correlated with the presence of neutrophils in the intestinal tissue, as well as epithelial damage. Interestingly, CPa9-HNE also showed association to submucosal fibrosis, emphasizing the importance of considering neutrophil activity when targeting the fibro-inflammatory axis. These findings highlight the potential use of CPa9-HNE as a complementary tool for histological grading of inflammation and fibrosis burden, and could be used to further explore the role of neutrophil extracellular traps in intestinal fibrosis.

Disclosure

MSA, TKA, MP, MAK, ACBJ and JHM are employees of Nordic Bioscience. MAK, ACBJ and JHM are shareholders of Nordic Bioscience.