Colonic Biopsies Research Articles

ENHANCED MITOCHONDRIAL BIOGENESIS INCREASES ANTI-OXIDANT ENZYMES AND IMPROVES TISSUE INFLAMMATION IN HUMAN IBD TISSUE

Abstract BACKGROUND In patients with inflammatory bowel disease (IBD), there exists a connection between mitochondrial dysfunction and two key issues: increased oxidative stress and attenuated ATP production. Previously we presented at this meeting the effect of a novel gold-based compound (AuPhos) on enhancing mitochondrial function in attenuating mice colitis (). In the present study we interrogate the effect of AuPhos on mitochondrial biogenesis in biopsies from control and active ulcerative colitis (UC) (Mayo 1-2) patients and normal human colonic epithelial cells (NCM460). We postulate that AuPhos-induced mitochondrial function enhances biogenesis and anti-oxidant levels and improves tissue inflammation in human IBD tissue. METHODS Effects of AuPhos on mitochondrial and anti-oxidant proteins were evaluated in NCM460 cells by western blot (WB) +/- low-dose TNF(1ng/ml). Human colonic biopsy samples (n=3) were collected and treated ex-vivo with vehicle or AuPhos (3h, 4oC), and processed for protein and mRNA analysis by WB and RT-qPCR, respectively. Flow cytometry of mitotracker green quantified mitochondrial mass in NCM460 and intestinal epithelial cells (IECs) from human control and UC tissues (n=3, Mayo 1-2). RESULTS AuPhos increased mitochondrial mass (mitotracker, Fig.1A,1B) and biogenesis protein levels PGC1α, NRF2 and TFAM (Fig.1C) in human intestinal epithelial cells (IECs), biopsies, and in NCM460 cells. Protein analysis in NCM460 cells show that AuPhos increases downstream antioxidant markers such as manganese superoxide dismutase (MnSOD), glutathione peroxidase 4 (GPX4), thioredoxin reductase2 (Trx2), and catalase expression when compared to the TNF or control samples. AuPhos substantially upregulates levels of mitochondria complex (mtCO1, mtCO2 Cox6A1, ATP5A1) and anti-oxidant enzyme (MnSOD, GPX, PRDX-2, -4, and -6) mRNA and protein levels in human colonic biopsies compared to vehicle and TNF treated samples (Fig. 1D). Furthermore, AuPhos reduces tissue cytokine and chemokine mRNA levels (IL1β, MCP1, RankL, and TNFα) in human UC tissues (Fig. 1E). CONCLUSIONS The current study reveals that AuPhos increases mitochondrial biogenesis, mitochondrial complex, and antioxidant enzyme levels in human IBD tissue. THE REDUCTION IN TISSUE CYTOKINES AND CHEMOKINES SUGGESTS THAT ENHANCED MITOCHONDRIAL FUNCTION IMPROVES TISSUE INFLAMMATION. This suggests the potential of AuPhos in treating IBD through the restoration of mitochondrial biogenesis.

NANOPARTICLE ENCAPSULATION OF THE SPECIALIZED PRO-RESOLVING MEDIATOR MARESIN-2: A NOVEL APPROACH FOR PROMOTING MUCOSAL REPAIR IN THE INTESTINE

Abstract Epithelial cells form protective barriers at mucosal surfaces and play a critical role in maintaining tissue homeostasis. Active inflammation in inflammatory bowel disease (IBD) is associated with epithelial barrier disruption and mucosal erosions/wounds that contribute to the inflammatory response and disease symptoms. Therefore, efficient repair of epithelial erosions/wounds is crucial for restoring intestinal barrier function and resolving mucosal inflammation. In response to injury, epithelial cells proliferate and migrate to cover denuded surfaces and restore critical barrier properties. Resident and recruited immune cells at sites of injury release factors that play an important role in orchestrating mucosal repair. Bioactive lipid mediators released by leukocytes, including leukotrienes and specialized pro-resolving mediators (SPMs), regulate epithelial signaling pathways to influence mucosal repair processes. Liquid chromatography-mass spectrometry (LCMS) analyses of healing colonic mucosal wounds performed to detect SPMs identified high levels of MaR2 in healing colonic wounds. In vitro studies using primary colonic epithelial cells revealed MaR2-driven increases in epithelial wound repair that were potentiated by the pro-inflammatory cytokines TNFα and IFNγ. While MaR2 increased epithelial migration by activating cell matrix adhesion proteins, including Src-paxillin and focal adhesion kinase, we did not observe any influence of MaR2 on the activation of cyclin D1/D2 or on epithelial proliferation. Importantly, in vivo studies demonstrated enhanced colonic mucosal wound repair and recovery from dextran sulfate-induced colitis in mice administered MaR2. Given the thermolabile nature of MaR2 (and associated ultracold storage requirements), thermostable polylactic acid (PLA) nanoparticles (NP) containing MaR2 (PLA MaR2) were generated. PLA MaR2 nanoparticles retained bioactivity following extended storage at room temperature and exhibited potent effects on in vivo colonic biopsy induced wound repair. Taken together these data reveal that thermostable MaR2 containing nanoparticles represent a promising new therapeutic approach for regenerating epithelial barrier function and restoring mucosal homeostasis in individuals with IBD.

IRE1A-XBP1 CONTROLS GROUP 2 INNATE LYMPHOID CELLS IN INTESTINAL INFLAMMATION AND FIBROSIS

Abstract BACKGROUNDS Group 2 innate lymphoid cells (ILC2s) are increased in peripheral blood and intestinal samples from patients with ulcerative colitis or Crohn’s disease and murine models of IBD. ILC2s produce a large amount of type 2 cytokines including IL-5 and IL-13 and growth factor amphiregulin (AREG) that induce goblet cell hyperplasia and mitigate acute inflammation in the gut. On the other hand, prolonged or uncontrolled ILC2 activation may contribute to chronic inflammation and tissue fibrosis. However, the regulatory mechanisms and functional impact of ILC2s in IBD remains elusive. The IRE1a-XBP1 pathway orchestrates cellular stress response that plays a key role in intestinal inflammation. METHODS We generated conditional knockout Ire1aflo/floxIl5-Cre (Ire1aΔIl5) with Ire1a deleted in ILC2s. Rag-/-Ire1aΔIl5 mice were also generated to exclude possible contribution of T cells during chronic inflammation. Dextran sodium sulfate (DSS) was given in drinking water to induce acute/chronic colitis and intestinal fibrosis. We also collected colonic biopsies from healthy individuals and sort-purified ILC2s for flow cytometry analysis. RESULTS Mouse intestinal ILC2s express high level of Ire1a. The number of ILC2s increased in small intestine (SI) and colon of Ire1aΔIl5 mice compared to Il5-Cre controls. Additionally, SI and colonic Ire1aΔIl5 ILC2s produced more IL-5, IL-13, and AREG after ex vivo stimulation with IL-33 and IL-25. Upon DSS challenge, Ire1aΔIl5 mice exhibited milder signs of disease including weight loss, clinical scores as well as colon shortening and histology (Figure 1), which was accompanied by elevations in ILC2-derived cytokines and AREG as well as heightened goblet cell differentiation and mucin production. In response to 3 cycles of DSS, Rag-/-Ire1aΔIl5 mice developed worsened chronic colitis, fibrosis, and increased fibrosis markers including collagens and vimentin. Intraperitoneal injection of neutralizing antibody against IL-13 or AREG reversed the phenotype. In sort-purified human ILC2s, selective IRE1 inhibitor 4u8C enhanced production of IL-13, while selective IRE1 activator IXA4 suppressed IL-13 in response to IL-2, IL-7, and IL-33 ex vivo (Figure 2). CONCLUSIONS We demonstrate that IRE1a-XBP1 constrains cytokine production by intestinal ILC2s during inflammation. IRE1a deficiency in ILC2s protected against acute colitis with heightened type 2 cytokines and AREG; while loss of IRE1a exacerbated chronic colitis and fibrosis. We identified IRE1a as a potential therapeutic target for fibrostenotic CD. Figure 1 Ire1aΔIl5 mice harbor elevated ILC2s (A) and produce increased IL-5, IL-13, and AREG by (B) SI and (C) colonic ILC2s ex vivo. (D-H) Ire1aΔIl5 mice are protected from acute DSS colitis. *P<0.001. Figure 2 IRE1 modulators control IL-13 production by human ILC2s. **P<0.01.

ORGANIC ANION TRANSPORTER POLYPEPTIDE (OATP) 3A1 AMELIORATES INTESTINAL MUCOSAL DAMAGE IN INFLAMMATORY BOWEL DISEASE

Abstract BACKGROUND Inflammatory bowel disease (IBD) is a chronic condition characterised by disruption of the colonic mucosal barrier. OATP3A1/SLCO3A1 is a bile acid efflux transporter, alleviating cholestasis-associated liver injury. However, the functional role and regulational mechanism of intestinal OATP3A1 in IBD remain unclear. METHODS The expression and correlation of SLCO3A1 were investigated in the public datasets with IBD patients. Intestinal epithelial cell-specific Slco3a1 knockout (Slco3a1ΔIEC) mice were generated and fed with 4% DSS for functional studies. RESULTS Intestinal SLCO3A1 expression was significantly elevated in the ulcerative colitis (UC) and Crohn's disease (CD) patients, and positively correlated with TNFα, IL1β and MADCAM1. Compared with Slco3a1flox/flox littermates administrated by DSS, Slco3a1ΔIEC mice exhibited exacerbated colitis, characterized by more severe weight loss, enhanced colon shortening and spleen swelling. Interestingly, intestine histology assessments revealed that epithelial Oatp3a1 ablation significantly aggravated extensive disruption of the mucosal epithelium and inflammatory infiltration. The intestinal mucosal barrier function of Slco3a1ΔIEC mice was more severely damaged, as assessed by detecting serum permeated FITC-dextran. Expression of tight junction-associated proteins was decreased in Slco3a1ΔIEC mice. CONCLUSION Our data showed that intestinal OATP3A1 expression was markedly upregulated and exerted a protective role in inflammatory bowel disease. Overexpression of intestinal OATP3A1 may hold potential as a novel approach to alleviate intestinal inflammation- associated mucosal damage. Figure 1 SLCO3A1 mRNA levels in the intestinal tissues of IBD patients and generation of Slco3a1ΔIECmice. (A) SLCO3A1 mRNA expression in patients with active UC or active CD and matched controls, revealed by analyzing databases of RNA-Seq data. (B and C) Pearson’s correlation analysis between SLCO3A1 expression and TNF-α, IL1β, or MADCAM1 in colon biopsy samples from active UC (n = 74) and CD (n = 52) patients. Data were collected from GEO database GSE75214. (D) Schematic diagram of Slco3a1ΔIEC mice. (E) Genotyping of Slco3a1ΔIEC mice using genomic DNA extracted from mice tails. (F) Western blot confirmed the intestine epithelia ablation of OATP3A1 in Slco3a1ΔIEC mice. Figure 2 Effects of intestinal epithelia-specific ablation of OATP3A1 on colitis and mucosal damage in a 4% DSS treatment mouse model of IBD. (A, B) Body weight loss and spleen weight were measured from Slco3a1flox/flox or Slco3a1ΔIEC mice. (C) Serum FITC-dextran level was detected by fluorescence spectrophotometer. (D) Gross morphology images of the colon, and colon length were measured. (E) Representative images of H&E-stained colons, and histopathology analysis of colitis were performed. (F) Immunoblots of colonic lysates on Zo-1, Occludin or Claudin-1(n = 4 for each group). **P < 0.01; ***P < 0.001. n = 5 for Slco3a1flox/flox group; n =6 for Slco3a1ΔIEC group treated with DSS.

P626 JNJ-77242113, an oral peptide selectively targeting the IL-23 receptor, demonstrates pharmacodynamic activity in rat and human colon tissue explants following oral dosing

Abstract Background The interleukin (IL)-23 pathway is a pathogenic driver in psoriasis, psoriatic arthritis, and inflammatory bowel disease (IBD). There are currently no approved oral therapies selectively targeting the IL-23 pathway. JNJ-77242113 (JNJ-2113) is a targeted oral peptide that binds the IL-23 receptor with high affinity, and potently and selectively inhibits IL-23 proximal signaling and downstream cytokine production. Oral JNJ-2113 showed dose-dependent inhibition of IL-23–induced IL-17A production in rat blood and attenuated signs of disease in a rat colitis model. A Phase 1 study showed inhibition of IL-23–induced IFN-γ production in blood from participants dosed with JNJ-2113 (Fourie et al. ISID. 2023). Methods We evaluated IL-23–induced IL-22 expression in colon tissue after exposure to JNJ-2113 or JNJ-2100 (a tool molecule with similar affinity and potency). IL-22 mRNA was measured after IL-23 stimulation in rat colon biopsies treated with JNJ-2100 in vitro or in colon tissue from rats 6 h after oral JNJ-2100 dosing. Human colon explants from donors were treated in vitro with JNJ-2100 or JNJ-2113, stimulated with IL-23, and IL-22 mRNA was measured. Colon and rectum biopsies from healthy participants dosed for 10 days with oral JNJ-2113 or placebo in a Phase 1 study were obtained, stimulated with IL-23 ex vivo, and IL-22 mRNA was evaluated. Results Overall, inhibition of IL-23–induced IL-22 expression was observed in colon tissue exposed to JNJ-2100 or JNJ-2113. Dose-dependent inhibition of IL-22 expression was observed in rat colon biopsies exposed to JNJ-2100 in vitro. Colon explants from rats dosed with 0.3, 3, and 30 mg/kg oral JNJ-2100 showed dose-dependent inhibition of IL-22 expression (52%, 88% and 96%, respectively) compared with explants from rats treated with vehicle. Human colon explants exposed to JNJ-2100 or JNJ-2113 in vitro also showed dose-dependent inhibition of IL-23–induced IL-22 expression, with >90% inhibition at the highest doses. Importantly, in colon biopsies from Phase 1 participants dosed with oral JNJ-2113 versus placebo, significant inhibition of IL-23–induced IL-22 expression was seen (P<0.05), with an average of 65% and 66% inhibition observed in sigmoid colon and rectum biopsies, respectively. Conclusion These results demonstrate pharmacodynamic activity of JNJ-2100 in vitro and ex vivo in rat colon tissue, of JNJ-2100 and JNJ-2113 in vitro in human colon explants, and of JNJ-2113 in colon biopsies from healthy human volunteers. These data support development of JNJ-2113 for the treatment of IBD. Of note, a Phase 2b dose-ranging study has demonstrated clinical activity of JNJ-2113 in moderate-to-severe plaque psoriasis (NCT05223868).

P632 Isolation of a novel metalloproteinases transcriptional signature with robust anti-TNF therapy predictive power in patients with Ulcerative Colitis

Abstract Background Anti-TNF agents were the only biologic for Inflammatory Bowel Disease (IBD) patients. However, new drugs targeting α4β7 integrin, IL-12/IL-23, and janus kinases were added to the IBD therapeutic armamentarium. Anti-TNFs are first-line biological agents in our country, and for that reason, the discrimination of patients who will be refractory of those therapies before treatment is relevant to prevent IBD patients from the exposition to multiple therapeutic failures. Therefore, we wanted to isolate robust and reproducible transcriptional markers able to specifically predict the response to anti-TNF therapy, which will contribute to targeted prevention, improve individual outcomes and decrease therapy expenditures. Methods We analysed publicly available microarray and RNAseq datasets of colon biopsies (GSE12251, GSE16879 and GSE73661) and whole blood cells from different cohorts of patients with Ulcerative Colitis (UC) (GSE191328). R package was used to perform the differential expression analyses and calculation of receiver operating characteristic (ROC). Cytoscape software and Morpheus (broadinstitute.org) was used to perform network data integration and visualization. Also, we used our local cohort of UC patients to further validate our results by RT-qPCR (n=21). Results We isolated a transcriptional signature composed of eight metalloproteases (MMPs) with high association with disease activity. Most of the transcripts of that signature were significantly upregulated in colon biopsies of non-responder patients to anti-TNFs before treatment in three different microarray datasets, but not in vedolizumab-treated patients. ROC curves of the different MMPs showed variability in the correlation to anti-TNF response among the different datasets analysed. Only three out of eight MMPs were still showing robust predictive power with an area under the curve around of 80% when all dataset were combined. Interestingly, PBMCs isolated from our local cohort of IBD patients presented increased expression of those MMPs in refractory patients to anti-TNF therapy, confirming that these three MMPs have the highest predictive power both in colon tissue and in peripheral mononuclear cells. Conclusion Overall, our study revealed a novel and robust MMP-transcriptional signature associated with anti-TNF but not vedolizumab therapy response. Nevertheless, our results should be corroborated in independent cohorts of patients with UC to test their efficacy and sensitivity in the clinical setting. Our data definitively contribute to the change from a reactive approach to predictive, preventive and personalised medicine.

P148 Longitudinal single-cell data informs deterministic modelling of inflammatory bowel disease

Abstract Background Crucial contributions to our understanding of the inflammatory process in inflammatory bowel disease (IBD) have been made using single cell level approaches. Extracting mechanistic details of cell and gene dynamics would be critical to understanding the mechanisms mediating mucosal healing and predicting response to specific therapies. However, this remains challenging. Therefore, our aim was to use ordinary differential equations (ODEs) for mathematical modelling of cell abundance and prediction of biological processes in IBD. Methods We used mathematical modelling of published longitudinal single-cell mRNA sequencing (scRNA-seq) data from DSS colitis in mice to simulate cellular dynamics during IBD. We validated our predictions using pseudo-bulk gene expression analysis and flow cytometry. We also analysed a published microarray dataset from colonic biopsies of 51 IBD patients prior to infliximab treatment. Results Based on the scRNA-seq data, we used our mathematical model to predict the immune dynamics of a different mouse colitis protocol. We validated these predictions experimentally using flow cytometry and found good agreement between model simulation and experimental data (predicted vs. observed, Pearson's rho=0.92). We found that the estimated turnover rates predicted the protein level of the proliferation marker KI-67 (rho=0.88) in DSS colitis. Finally, we wanted to investigate whether our mathematical model reflected processes in human IBD. We reasoned that genes correlated with epithelial cell dynamics might be indicative of mucosal healing after DSS retrieval. We found more highly correlated genes when using simulated epithelial abundance compared to experimentally measured epithelial abundance. Many genes associated with tight junctions (Cldn8, Cftr, Crb3, Jam2) were among the highly positively correlated genes and genes associated with inflammation (Il1b, Jak2, Il10ra) were among the negatively correlated genes with epithelial cell abundance. We then looked for differentially expressed (DE) genes in pre-treatment colon biopsies between responders and non-responders to infliximab. We found a significant overlap of 25 positively correlated genes with upregulated DE genes in responders, i.e. associated with tight junctions, and 73 negatively correlated genes with upregulated genes in non-responders, i.e. associated with inflammatory pathways. Conclusion We demonstrate that mathematical modelling of colonic cell dynamics provides insight into IBD progression and treatment response. Furthermore, our results suggest that pre-treatment barrier integrity may predict and influence response to infliximab treatment.

P232 Common variable immunodeficiency-associated enteropathy in consecutive patients from a tertiary hospital

Abstract Background Common variable immunodeficiency (CVID) patients may develop intestinal inflammatory involvement in 9-20% of cases, although its diagnosis, management and prognosis are not well established. Methods We performed a transversal study with retrospective data collection. We reviewed all clinical records from consecutive adult CVID patients followed in Gregorio Marañón Hospital (Spain) from January 1st 1990 to January 1st 2023. A diagnosis of CVID-associated enteropathy (CVID-E) was established if patchy intestinal inflammation (Crohn-like pattern) or colonic inflammation (ulcerative colitis-like pattern) was demonstrated, or villous atrophy was observed in duodenal biopsies (celiac-like pattern) or inflammatory infiltrate was observed in colonic biopsies (microscopic colitis-like pattern). Differences between CVID-E patients and the rest of the CVID cohort were evaluated using chi-square and T student methods, when appropriate. Results 89 patients with confirmed CVID following ESID criteria were included. Patients’ characteristics are summarised in Table 1. All patients were receiving intravenous or subcutaneous Igs and reached an Ig G trough level >1000 mg/dL. CVID-E was diagnosed in 26 patients (29,2%), at a median of 6,4 years after CVID diagnosis. Surprisingly, 10 patients (38,5%) were diagnosed with CVID-E before or at the same time of CVID diagnosis. 5 patients were dead (19,2%), and the causes of death were gastric cancer (1 patient), liver complications (1), infectious complications (1), enteropathy (1) and unknown cause (1). 73,1% suffered from GI infections (Giardia lamblia, Campylobacter jejuni and Clostridioides difficile were the most frequent agents). The most frequent pattern of the disease was Crohn-like disease (Figure 1). Although exclusive celiac-like pattern was found in only 3 patients, 5 Crohn-like, 4 UC-like and 2 microscopic colitis-like pattern patients also presented duodenal atrophy. Unexpectedly, 46,2% of CVID-E patients suffered from concomitant liver involvement. Eight patients received corticosteroids, 2 azathioprine and 1 patient received infliximab and subsequent ustekinumab. One patient needed subtotal colectomy, another ileal resection and another patient received a terminal colostomy due to severe perianal disease. CVID-E patients presented statistically more frequent liver involvement, more GI infections, and a tendency towards more GI cancer. Conclusion CVID-E is frequent among CVID patients. These patients suffer from more GI infections, liver involvement and probably more GI cancer. Screening of levels of Igs at diagnosis of IBD and celiac disease is advisable as CVID diagnosis can occur at the same time or even after enteropathy diagnosis.

P016 Reduction of mucosal (active) eosinophils, B cells and T cells after vedolizumab therapy in patients with ulcerative colitis

Abstract Background Patients with ulcerative colitis (UC) are often treated with biological therapies or small molecules. Knowledge about the impact of these therapies on the intestinal and peripheral blood immune cell composition is scarce. Therefore, we investigated how advanced therapies modulate immune cell distribution in UC patients. Methods We included 30 UC patients (53% male, median age 42 years) who started a biological or small molecule. Before the first drug administration, mucosal colonic biopsies and a peripheral blood sample were obtained. At the end of induction, colonic biopsies and peripheral blood were sampled again. Patients starting adalimumab (n=2), infliximab (n=3), vedolizumab (n=11), ustekinumab (n=6), ozanimod (n=2) and the JAK inhibitors filgotinib (n=3) and tofacitinib (n=3) were included. Endoscopic improvement was defined as a Mayo endoscopic subscore of 0-1 at the end of induction. From the biopsies, a single-cell suspension was made. Intestinal and circulating immune cells were characterized via flow cytometry. Statistical analysis was performed using a paired t-test. Results Independent of the mechanism of action (MOA), patients responding to therapy showed a decrease of colonic granulocytes (neutrophils (p<0.0001) (Figure 1A), basophils (p<0.0001) (Figure 1B) and eosinophils (p=0.008) (Figure 1C)), active eosinophils (p=0.002) (Figure 1D)), B cells (p=0.05) (Figure 1E), regulatory T cells (p<0.0001) (Figure 1F) and T helper (Th) 2 cells (p=0.02) (Figure 1G), balanced with an increase of Th1 cells (p=0.03) (Figure 1H). In peripheral blood, eosinophils increased in patients not responding to therapy (p=0.05) (Figure 1I). Furthermore, we observed that only patients starting vedolizumab (n=11) showed a decrease in colonic eosinophils (p=0.02) (Figure 1J), active eosinophils (p=0.002) (Figure 1K), B cells (p=0.03) (Figure 1L) and T cells (p=0.004) (Figure 1M). Considering only non-vedolizumab patients (n=19), we did not observe this effect. Conclusion UC patients responding to advanced therapies showed a different intestinal immune cell distribution compared to non-responders, regardless of MOA. Vedolizumab therapy furthermore decreased several mucosal immune cell subsets that migrate to the gut through α4β7-MAdCAM-1 binding. While the effect of vedolizumab on B cells and T cells was previously described, we have now potentially identified an additional eosinophil-reducing effect in the colon.

OP39 Vedolizumab response in ulcerative colitis associates with reduced IgG+ plasma cells and FcγR signaling

Abstract Background Vedolizumab (VDZ) targets the gut-homing receptor α4β7. Despite its widespread use as a frontline therapy for ulcerative colitis (UC), its mode of action (MOA) remains unclear. Previously, we documented that response to VDZ is associated with size loss of gut-associated lymphoid tissues (GALT). To further understand drug MOA, here we aimed at defining the relationship between GALT attrition and resolution of inflammation. Methods Tissue immunofluorescence (IF) was performed on two independent UC cohorts (n=60, n=21) studied longitudinally pre- and post-VDZ. Peripheral blood mononuclear cells from UC patients (n=56) were examined at week 0 (pre-VDZ) and 14 (post-VDZ) by flow cytometry, while intestinal biopsies were analyzed in a subset of patients. Transcriptomic analyses were performed in a third cohort of 401 UC patients and 243 controls where bulk RNA-sequencing was performed on intestinal biopsies. Finally, data from a fourth validation cohort (n=31) was examined pre- and post-VDZ. Results Using IF, we examined follicular naïve B (FB) cells (IgD+), germinal center (GC) B cells (BCL6+CD3-) and total T cells (CD3+), and identified three GALT types: organized aggregates (demarcated B/T cell zones) with GC, organized aggregates without GC, and poorly organized aggregates (Fig1A). When comparing pre- and post-VDZ, Responders (R) had a significant reduction in GALT organization, while no change was seen in Non-Responders (NR). The number of FB cells was significantly reduced post-VDZ in R but not in NR (Fig1B), with no change in T cells (Fig1C). The reduction in FB was validated using transcriptomic data (Fig1D). To explore potential consequences of GALT attrition, we analyzed circulating β7+ (GALT-generated) and β7- plasmablasts (PB). The frequencies of β7+IgG+ and β7+IgA+ PB were significantly reduced post-VDZ in R, but not in NR (Fig1E). No change was observed in β7- PB post-VDZ (Fig1F). Among β7+ PB, there was a greater reduction in IgG+ compared to IgA+ (Fig1G). Furthermore, colonic IgG+ plasma cells (PC) were significantly reduced post-VDZ in R but not in NR (Fig1H). To evaluate IgG-mediated proinflammatory function, we studied the expression of FcγR-pathway genes in colonic biopsies. Importantly, the FcγR-pathway was enhanced in inflamed tissues of UC patients (Fig1I-J) and was significantly reduced in R (but not in NR) post-VDZ (Fig1K). Conclusion Our work demonstrates a novel effect of anti-α4β7 blockade that results in intestinal lymphoid aggregate attrition through impaired recruitment of naïve B cells, leading to the suppression of IgG-driven immune responses and proinflammatory FcγR signaling. These data highlight the targeting of GALT as a novel therapeutic paradigm in IBD.

P139 A potential protective rule of Mannose Binding lectin (MBL) against SARS-COV2 infection in IBD patients

Abstract Background Since the beginning of the COVID-19 pandemic, IBD patients have appeared to be less susceptible to a severe form of the disease, despite undergoing immunosuppressive treatments. Mannose binding lectin (MBL) is a humoral fluid-phase pattern recognition molecule (PRM) crucial for activating the lectin complement pathway. It is capable of binding to the spike protein and blocking SARS-CoV-2 infection. Low MBL expression has been linked to poor outcomes in both SARS and SARS- CoV-2 infections. In IBD patients, the role of MBL is controversial; low concentrations seem to predispose individuals to the development of IBD, while high concentrations have been observed in severe forms of Crohn's disease. Methods Since April 2020, 104 IBD patients have been enrolled, with 20% treated with mesalazine, 50% with Anti-TNFa, 20% with Vedolizumab, and 20% receiving no treatment. Additionally, 45 healthy controls (HC) from North Italy were included. Serum samples and colon biopsies from inflamed and non- inflamed mucosa were collected. Serum samples underwent an ELISA test to quantify circulating MBL concentration, and MBL gene expression in biopsies was analyzed using qPCR. Results Both Crohn's disease and Ulcerative Colitis patients exhibited significantly higher circulating MBL levels than HC (411.6 ± 45.5 ng/ml vs. 160.9 ± 35.3 ng/ml, p < 0.05). Patients treated with Anti-TNFa showed significantly higher circulating MBL levels compared to those not undergoing therapy (530.1 ± 76.5 ng/ml vs. 225.4 ± 61.6 ng/ml, p < 0.05) and patients receiving Vedolizumab (530.1 ± 76.5 ng/ml vs. 155.3 ± 32.1 ng/ml, p < 0.05). MBL intestinal gene expression is higher in IBD patients than HC (5.55 ± 0.9 vs. 2.36 ± 0.6; p=0.591) and tended to be elevated at similar levels in inflamed and non-inflamed mucosa (5.14 ± 1.4 vs. 5.79 ± 1.1; p=0.337), suggesting a prevalent genetic determination of MBL concentration regardless of the inflammatory background. Conclusion MBL appears to play a key role in SARS-CoV-2 infection. We demonstrate that IBD patients have, on average, higher circulating MBL levels than HC independently of their inflammatory status. The highest MBL levels were observed in patients treated with Anti-TNFa. These findings contribute to understanding the reported low mortality and hospitalization for COVID-19 among IBD patients treated with Anti-TNFa.

P021 Higher TNFα and IL-6 mucosal levels in ulcerative colitis patients with more severe endoscopic activity

Abstract Background Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterised by colonic mucosa inflammation. Its clinical course is marked by alternating periods of relapse and remission that impair patients' quality of life. In the last decades, novel therapies have shown to be effective for UC resulting in lower rates of colectomy. However, there is still a significant proportion of non-responding patients that change from one treatment to another, being exposed to its potential adverse events. Thus, predictive factors of response to available drugs are needed to tailor the best treatment strategy for each patient. The aim of our study was to measure TNFα and IL-6 levels in colonic biopsies from patients with UC with moderate to severe endoscopic activity. Methods A prospective, observational single-centre study was designed and it is currently on going. Adult UC patients with moderate to severe endoscopic activity (Mayo Endoscopic Score (MES) > 1) in a routine colonoscopy were included. Biopsies from inflamed (MES>1) and non-inflamed (MES=0) colon of each patient were homogenised and processed by using RIPA buffer and ultrasounds to obtain cell lysates. Human Luminex Discovery Assay (2 plex) was used for the simultaneous detection and quantitation of IL-6 and TNFα. Data are shown as percentage, median, interquartile range (IQR) and mean ± standard deviation (SD) as appropriate. Results So far, 21 patients were consecutively included (mean age 53.8 years (SD 17.0), 52.4% female). About 43% of patients had left-sided UC, 28.5% extensive UC and 28.5% proctitis. Regarding endoscopic activity, 61.9% of patients showed MES=2 and 38.1% were MES=3. Fourteen patients (66.6%) were bio-naïve and 7 (33.3%) had been exposed to anti-TNFα. IL-6 was detected in biopsies from colon with MES ≥ 2 of 18 (85.7%) patients, of which 10 (55.6%) patients also TNFα was found. Neither IL-6 nor TNFα were detected in biopsies from non-inflamed colon (p=0.00). Median IL-6 in inflamed colonic samples from patients with MES-2 was 25.6pg/ml (IQR 0.2-74.3) and 92.2pg/ml (IQR 16.9-314.3) in those with MES-3 (p=0.09). Median TNFα in inflamed colonic biopsies from patients with MES-2 was 0.0pg/ml (IQR 0.0-20.0) and 22.2pg/ml (IQR 0.0-34.3) in patients with MES-3 (p=0.12) (Figure 1). No differences were found in TNFα levels between anti-TNFα naïve patients and those patients previously exposed to anti-TNFα (p=0.96). Conclusion IL-6 and TNFα are elevated in inflamed colonic mucosa, particularly in those patients with more severe endoscopic activity, while they are not found in non-inflamed colonic mucosa. The correlation between cytokine levels and endoscopic severity suggests their potential as biomarkers for treatment response.

ECCO Grant Dissecting the intestinal mucosa-associated HUMoral immune response in ileal Crohn’s Disease: the HUM-CD study

Abstract Background and Aims The pathophysiology of Crohn's disease (CD) is complex and not fully understood. While CD can affect the entire gastrointestinal tract, it primarily affects the terminal ileum. The underlying mechanistic reasons for this preferential location are unknown. Patients with isolated ileal CD have higher levels of circulating IgG antibodies targeting flagellins. These antibodies are associated with the ileal location of CD as well as with a complicated phenotype (intestinal stenosis and fistulae). Cellular determinants of this humoral response in ileal CD are yet to be unraveled. Techniques to study B cells at the single-cell levels have tremendously evolved these recent years and our laboratory has developed expertise in most of these techniques. The objectives of our study are to comprehensively characterize the humoral B cell response in patients with ileal CD. Methods To fulfill our aim, we will use different approaches: 1. Extensive characterization of the B cell cellular and molecular landscape of the intestinal ileum in CD as compared to homeostasis states at the single-cell level 2. Dissection of the intestinal B cell antigen-specific response in CD and assess differences between inflamed and non-inflamed, and ileal and colonic mucosa and the cross-reactivity of the flagellin-specific response 3. Identification of the antigenic reactivity and clonal dynamics of memory B cells extracted from the terminal ileum of patients with CD. We will work from human samples, collected from ileal, colonic biopsies, and blood of patients with CD and healthy controls using Anticipated Impact Using advanced B-cell-focused single-cell techniques, we will unravel the humoral response at the ileal level and its association with clinical outcomes. By doing so, we aim to identify the main antigenic drivers and putative therapeutic targets of ileal CD.

P128 Salt-Inducible Kinase 2 is a promising therapeutic target in patients with ulcerative colitis

Abstract Background Salt-Inducible Kinases (SIKs) are a family of 3 serine/threonine kinases which represent promising therapeutic targets in a number of inflammatory diseases including ulcerative colitis (UC). Their catalytic activity is highly phosphoregulated in response to changes in cellular homeostasis. Inactivation of SIKs results in proinflammatory cytokine downregulation and the concomitant upregulation of anti-inflammatory IL-10. Of the three isozymes, SIK2 is the most active in myeloid cells and is thought to be the key driver of IL-10 production. Selective pharmacological inhibition of SIKs has thus far proved challenging: a number of SIK inhibitors have previously been developed and whilst they have demonstrated biological activity in UC, dosing has been limited due to potential side effects underlining the need for improved selectivity. We hypothesized that more selective inhibition of SIK2 represents a promising approach in ulcerative colitis. Methods We sought to examine the effects of inhibiting SIK2 with a potent small molecule in both in vitro cell cultures and in ex vivo biopsies from UC patients. CD14+ monocytes were isolated from donor PBMCs and differentiated into hMDMs (monocyte-derived macrophages) and moDCs (monocyte-derived DCs). Cultures were treated with compound followed by LPS stimulation for 4 hours (hMDMs) or maturation for 48 hours (moDCs). To recapitulate the disease microenvironment ex vivo, a colonic explant culture model was used: colonic biopsies were collected from patients with active (Mayo 1 /2) and inactive UC and cultured in the presence of compound or control for 24-48h. Supernatants were assayed for cytokine and chemokine release. Cells or biopsies were lysed for qPCR. Surface markers were assessed by flow cytometry Results Using more SIK2-selective small molecules, we show that SIK inhibition modulates inflammatory and immunometabolic pathways in human myeloid cells. Furthermore, SIK2 inhibition drives a tolerogenic phenotype in dendritic cells, as demonstrated by suppression of proinflammatory cytokines and chemokines such as TNFα and the CC/CXC chemokine family as well as downregulation of activation markers such as CD80 and 83; functionally these modulated DCs can suppress Th1 CD4 T cell IFNγ production. Modulation of cytokine and chemokine production by SIK2 inhibition was also observed in colonic explant cultures from UC patients with a reduction in levels of TNFα and the CC chemokine family. Conclusion In both myeloid cellular cultures and UC biopsies, SIK2 inhibition modulates an inflammatory environment into a pro-resolution state supporting the therapeutic potential of SIK2 inhibition in UC.

P096 Human extrachromosomal circular DNA is an emerging biomarker in Inflammatory Bowel Disease

Abstract Background Inflammatory Bowel Diseases (IBD) are chronic multifactorial disorders, which affect the gastrointestinal tract, including Ulcerative Colitis (UC) and Crohn’s Disease (CD). The existence of extrachromosomal circular DNA fragments (eccDNA) is well established, and it arises from all parts of the genome. eccDNA has mainly been studied in the context of cancer and not in relation to other diseases, and it has become a promising diagnostic and prognostic biomarker for different types of cancer. Herein, we investigate for the first time the role of eccDNA in IBD. Methods Forty consecutive IBD patients (19 CD, 21 UC) and 13 HC were enrolled, who underwent screening colonoscopy were prospectively enrolled at our center in this observational, case-controlled study. In IBD patients, disease activity was assessed using PMS and MES for UC, and HBI and SES-CD for CD. Colonic biopsies were collected from both inflamed and healthy mucosa in IBD patients and from HC. eccDNA was enriched, sequenced, and identified with Circle Finder from intestinal biopsies. Results Colonic mucosal samples from IBD patients showed increased average of eccDNAs, across all chromosomes than samples from HC. Furthermore, there was a slight yet significant tendency for larger eccDNAs in IBDs compared to HCs. Focusing on eccDNA coming from genic elements ("genic eccDNAs"), approximately 60% were fragments from protein coding genes, 32% from non-coding RNAs and 8% from pseudogenes. IBD patients had, on average, significantly more genic eccDNAs in their intestines as compared to HC. Moreover, IBD in remission had fewer eccDNAs in their intestines than active disease, although not statistically significant. eccDNAs from phosphodiesterase genes and genes involved in lipid metabolism were enriched in patients with active IBD than patients in remission. eccDNA from inflamed mucosa (both in UC and in CD) show an enrichment of genes related to inflammatory and immune pathways, such as MAPK, mTOR, ErB, Rap-1 and cGMP (SPOKE3, GRID2, DLEU1, ITGA8, NRG1). Conclusion We are the first to uncover an IBD-specific pattern of eccDNA production. Furthermore, we identified genic hotspots which characterize active vs. inactive disease and inflamed vs. healthy colonic tissue. We propose that eccDNA identification could be a promising new diagnostic marker for IBD patients.

DOP23 The role of histology for the prediction of clinical relapse in Crohn’s Disease: A substudy of the STORI cohort

Abstract Background Deep remission has become the target in the management of Crohn’s disease (CD). The role of histology in the management of CD has not yet been established. The aim of this work was to study the impact of histological inflammation on the risk of clinical relapse in patients with CD in clinical and endoscopic remission and to study the correlation between histology and endoscopic scores and biomarkers. Methods All patients included in STORI (1) were eligible for inclusion. Fecal calproptectin and colonoscopy with CDEIS calculation were performed at inclusion. Two biopsies, taken either from the most inflammed macroscopic area or from an area with previous inflammation in case of mucosal healing (MH) were prospectively performed. MH was defined by the absence of ulcers. Different histological scores were calculated by 2 independent pathologists: Robart, Geboes, modified Geboes, Nancy, and DCA-IBD scores. Histological remission was defined by Nancy=0 ; Geboes ≤2 ; modified Geboes of grade 0 ; Robarts ≤3, IBD-DCA of C≤1 and A=0. Clinical relapse was prospectively evaluated in the STORI trial as CDAI>250 or CDAI between 150 and 250 with an increase of 70 points during 2 successive weeks compared to the inclusion visit. (1) Louis E et al .Gastroenterology 2012 Results Eighty biopsies (22 ileal and 58 colonic) were available from 76/115 patients included in STORI. Among the 45 patients with MH, 30 had colonic biopsies, 11 had ileal biopsies and 4 had biopsies in both locations. Among colonic biopsies 68% had histological remission according to Nancy and modified Geboes scores, 65% according to DCA-IBD and Geboes scores and 71% according to Robarts score. Among ileal biopsies 53% had histological remission according to Nancy score, 47% according to Modified Geboes, Geboes and DCA-IBD scores, and 67% according to the Robarts score. Thirty-five patients (46%) experienced a clinical relapse during the follow-up including 16/45 (36%) and 19/31 (61%) in the group with MH and without MH respectively. Histological characteristics and histological scores were not predictive of clinical relapse. In the total cohort (n=76), the CDEIS score was correlated to Nancy (p<0,001, r=0,43), Geboes (p<0,001, r=0,47) and Robarts (p<0,001, r=0,45) scores. Fecal calprotectin was correlated to Nancy (p<0,001, r=0,48), Geboes (p<0,001, r=0,45) and Robarts (p<0,001, r=0,46) scores. The histological scores of Nancy, Robarts and Geboes were highly correlated (p<0,0001 ; r > 0,9). Conclusion Although correlated with endoscopy and biomarkers, histology was not predictive of clinical relapse in CD patients in clinical and endoscopic remission. These findings do not support the use of histology to predict clinical relapse in CD in clinical practice.

DOP24 Multi-omic sequencing reveals distinctive gene expression and DNA methylation alterations as potential predictors of primary sclerosing cholangitis development in treatment-naïve paediatric Ulcerative Colitis

Abstract Background Primary sclerosing cholangitis (PSC) is a progressive choleostatic disease and up to 80% of patients also have ulcerative colitis (PSC-UC). This presents a clinical challenge owing to difficulty in diagnosis and increased risk for developing cancer. While several multifactorial processes including inflammation and microbial dysbiosis have been associated with PSC-UC pathogenesis, the precise molecular factors that regulate the phenotype of this disease subtype remain unknown. Methods We applied methyl-capture sequencing and mRNA sequencing to colonic mucosal biopsies derived from the DOCHAS study (GEN-193/11), to identify transcriptomic and epigenetic differences between treatment naïve paediatric UC (n=10), PSC-UC (n=10) and healthy controls (n=10) samples. Results Differential gene expression between UC and PSC-UC identified 9 up-regulated genes - ADMTS14, PNCK, NLRP3, SLC6A19, DLL1, FCGR2C, KLHL17, APOB, EHBP1L1 and 5 downregulated - SLC37A2, SLC14A2, RPL27, RPS25, SLC38A4 in PSC-UC relative to UC. Importantly, we show that expression of these genes was intricately regulated by master transcriptional regulators (pro-caspases, IL7RA) and transcription factors (TFs) :AR, p53, JUND, CEBPA. Similarly, differential methylation analysis between PSC-UC and UC identified 22 differentially methylated regions (DMRs) relative to controls, where 5 were hypermethylated and 8 hypomethylated. Intriguingly, in general we show that these DMRs are largely localised in gene promoter regions as opposed to enhancers. Importantly, we show that these DMR’s identified between PSC-UC vs UC is enriched for binding sites for the TF: ASCL1, suggesting its activity likely is effected due to the altered methylation of its binding site in PSC-UC patients. Collectively, these results highlight the importance of TF’s in driving molecular differences between PSC-UC and UC paediatric patients in a treatment naïve setting. Conclusion In summary, for the first time this study provides a critical insight into the transcriptional differences between treatment naïve children with PSC-UC vs UC as well as highlights the intricate regulatory processes involving master transcriptional regulators, transcription factors and DNA methylation. These processes thus warrant further examination in larger cohorts to rationalise their role as diagnostic/therapeutic targets.

P1226 Determination of oral and gut mucosal microbiome profiles of patients with treatment-naïve ulcerative colitis

Abstract Background The oral microbiome in ulcerative colitis (UC) patients and its role in the pathogenesis of the disease are still poorly understood. Although there are studies investigating the composition of oral microbiome in UC, there are no studies on concomitant analyses of oral and colonic mucosal samples in treatment-naïve patients. In this study, the oral and mucosal gut microbiome of UC patients and oral microbiota of healthy individuals (HC) were compared. Methods Sixty patients with newly-diagnosed active (mild-moderate severity) UC patients (n=30) and HC (n=30) were included in the study. Dietary habits were stable in the last three months of participants (checked by dietary recall questionnaires) and co-morbidities affecting microbiota profiles were excluded. Multiple colonic mucosa biopsies were obtained from inflamed areas before treatment in UC group. Simultaneously, subgingival plaque samples were analyzed. All samples were identified through next-generation DNA sequencing analysis, evaluated using bioinformatic tests. Results The potential signature bacterial species associated with UC were determined by examining of both gut and oral microbiomes. According to the Microbiome Lefse analysis, Prevotella copri emerged as the prominent common species in the colonic mucosal and subgingival plaque biopsies of UC group. Oral microbiome comparison between UC and HC patients revealed increased Haemophilus parainfluenza and Corynebacterium durum species and decreased F. prastnutzii and Akkermansia muciniphilia in the UC group (p<0.022). Comparative Boxplot analysis of bacterial abundance and alpha-diversity, as indicated by the Shannon index data, revealed that the HC group exhibited higher bacterial abundance and diversity in subgingival plaque samples than the UC group. We found significant association of Bacteroides vulgatus, Prevotella copri, Bacteroides fragilis, Parabacteroides merdae in both colonic mucosal and subgingival plaque samples (oral microbiome) of UC patients (p<0.044). Conclusion Our study is the first to show the oral and colonic mucosal microbiome relationship in UC. The presence of oral dysbiosis associated with UC in our study supports the hypothesis that UC could be associated not only with gut dysbiosis, as previously observed, but also with an imbalance in the oral microbial communities. Interestingly, we could not detect previously reported species of Streptococcus, Oribacterium, Rothia, Neisseria and Porphyromonas in the oral microbiome samples of the UC group. However, oral and gut microbiome profiles share some common microorganisms such as Prevotella copri and Bacteroides fragilis. Further studies are required for determining the potential role of oral dysbiosis is disease severity.

P078 Inflammatory transcriptomic signatures and cell type compositions in colonic mucosa of ulcerative colitis

Abstract Background Previous studies have explored transcriptomic profiles associated with active inflammation in patients with IBD patients, but consistent characteristics of gene expression and enriched pathways, particularly in Asian patients with UC, remain unconfirmed. Here, we aimed to assess distinctive transcriptomic changes associated with persistent active mucosal inflammation in Asian patients with UC despite of medical treatment. Methods We obtained colonic mucosa biopsies of inflamed and noninflamed tissue from 15 patients with UC and 15 healthy controls and performed RNA sequencing analysis. Utilizing publicly available single cell RNA sequencing (scRNAseq) data, we also identified cell types expressing differentially expressed genes from RNAseq data and performed data deconvolution using CIBERSORTx. Results Transcriptomics profiling revealed that the inflammatory transcriptomic signature was highly enriched in the colonic mucosa of UC-active compared to UC-inactive and controls. By incorporating scRNAseq data, the genes upregulated in UC-active were highly expressed in M cells, inflammatory monocytes, and inflammatory fibroblasts, while downregulated genes were prominent in BEST4+ enterocytes and WNT5B+ fibroblasts. Notably, a sub-cluster of enterocytes associated with SAA1, SLC6A14, and DUOXA2 genes exhibited high expression in UC-active. Deconvolution analysis using CIBERSORTx identified significant enrichment of natural killer cells, inflammatory monocytes, Tuft cells, inflammatory fibroblast, WNT2B+Fos-lo1, and pericytes in UC-active. Conclusion Our RNAseq analysis not only identified significant gene expression changes but also revealed shifts in cell type proportions associated with persistent inflammation. These findings offer valuable insights for developing novel treatment strategies for UC.

P1218 Non-invasive point-of-care stool sample for detection of Cytomegalovirus infection in patients with Active or Refractory Ulcerative Colitis using multiplex polymerase chain reaction (mPCR): a pilot feasibility study

Abstract Background Cytomegalovirus (CMV) infection is associated with more flare-ups and deteriorates the prognosis of active inflammatory bowel disease (IBD). Patients with refractory IBD should be tested for CMV colitis, especially if they are not responding to immunosuppressive therapy. The prevalence of CMV co-infection ranges from 10% to 30% in steroid-refractory acute colitis. Concurrent CMV-colitis is associated with an increased risk of worse therapeutic outcomes, resistance to corticosteroids, and need for salvage therapy. One of the two gold standards of diagnosis of CMV colitis in IBD patients with active disease requires the analysis of tissue biopsies using PCR. The aim of our pilot study was to evaluate the diagnostic accuracy of non-invasive point-of-care faecal samples using mPCR for detecting CMV in patients with ulcerative colitis compared to standard practice biopsies PCR. Methods We performed a prospective, observational, feasibility study including 62 consecutive patients with active ulcerative colitis (UC) requiring intravenous steroids or steroid-refractory UC in the Department of Gastroenterology of University Hospital „Tsaritsa Yoanna – ISUL", from April 2022 to October 2023. In all UC patients, colonic tissue biopsies were performed and analyzed by qualitative CMV PCR. Faecal sample mPCR CMV was performed on the positive patient cohort to compare the feasibility of (ME) Panel IVD using FilmArray mPCR (Biofire, bioMerieux, France). All the tested patients had undergone immunosuppressive therapy and initial stool specimen cultures were obtained to exclude infection with C. difficile and other pathogen flora. Results Out of 62 active UC patients with colonic tissue samples qualitative CMV PCR, n=5 (8%) were positive. Of these n=5 UC patients, n=4 (80%) were positive from the Fecal sample mPCR CMV, resulting in a compatibility of 80% for diagnosing CMV in these patients by the two DNA extraction methods. Calculated Sensitivity and diagnostic accuracy was 80% (95% CI) for the mPCR CMV. The patient cohort predominantly comprised males (75%) with a median age of 45 years (range: 30–72 years). Three patients (75%) out of this cohort group were treated with peroral antiviral agent Valganciclovir, one (25%) of them went into clinical and endoscopic remission after the treatment and two patients (50%) received colectomy. The median time performing the Faecal sample mPCR CMV was approx. 1 hour. Conclusion This novel faecal mPCR point-of-care test is a promising, fast and easy non-invasive tool for detection CMV in active or refractory UC patients, comparable with the colonic tissue CMV-DNA PCR.