Homeostatic function and inflammatory activation of ileal CD8+ tissue-resident T cells is dependent on mucosal location

Background & Aims: Tissue-resident memory T (Trm) cells, both of the CD4 and CD8 lineage, have been implicated in disease flares in inflammatory bowel disease. However, data are conflicting regarding the profile of human CD8 + Trm cells, with studies suggesting both proinflammatory and regulatory functions. It is crucial to understand the functional profile of these cells in the context of (new) therapeutic strategies targeting (trafficking of) gut Trm cells. Methods: Here, we performed imaging mass cytometry, flow cytometry, and RNA-sequencing to compare lamina propria and intraepithelial CD103 +/–CD69 +CD8 + Trm cells in healthy control subjects and patients with active ileal Crohn's disease. Results: Our data revealed that lamina propria CD103 +CD69 +CD8 + T cells have a classical Trm cell profile with active pathways for regulating cell survival/death and cytokine signaling, whereas intraepithelial CD103 +CD69 +CD8 + T cells display tightly regulated innate-like cytotoxic profile. Furthermore, within lamina propria CD8 +CD103 – Trm cells, an Itgb2 +GzmK +KLRG1 + population distinct from CD103 + CD8 + Trm cells is found. During chronic inflammation, especially intraepithelial CD103 +CD69 +CD8 + T cells displayed an innate proinflammatory profile with concurrent loss of homeostatic functions. Conclusions: Altogether, these compartmental and inflammation-induced differences indicate that therapeutic strategies could have a different impact on the same immune cells depending on the local compartment and presence of an inflammatory milieu, and should be taken into account when investigating short- and long-term effects of new gut T cell–targeting drugs

Development of Mucosal PNAd+ and MAdCAM-1+ Venules during Disease Course in Ulcerative Colitis

PNAd and MAdCAM-1 addressins on venules are of importance in T-cell homing and potential therapeutic targets in ulcerative colitis (UC). Normally, PNAd+ high endothelial venules (HEVs) are only present in lymphoid organs, whereas small numbers of MAdCAM-1+ venules can be seen in non-lymphoid tissue. We aimed to study their presence in the intestinal mucosa of UC patients at diagnosis and during follow-up, and their correlation with disease activity. Colonic biopsy specimens of 378 UC patients were analyzed by immunohistochemistry for CD3, CD20, ERG, MECA-79 (PNAd) and MECA-376 (MAdCAM-1) and compared to healthy controls (HC). The proportion of PNAd+HEVs in UC at diagnosis was 4.9% (IQR 2.0%-8.3%), while none were detected in HC. During follow-up, PNAd+HEVs completely disappeared in remission (n = 93), whereas the proportion in active disease was similar to baseline (n = 285, p = 0.39). The proportion of MAdCAM-1+venules in UC at baseline was 5.8% (IQR 2.6-10.0). During follow-up, the proportion in remission was comparable to diagnosis, but upregulated (7.5% (IQR 4.4-10.9), p = 0.001) in active disease. In conclusion, PNAd+HEVs appear in UC during active inflammation which could thus serve as a marker for disease activity, whereas MAdCAM-1+venules remain present after inflammation is resolved and increase after subsequent flares, reflecting chronicity and potentially serving as a therapeutic target

Healthy Cotwins Share Gut Microbiome Signatures With Their Inflammatory Bowel Disease Twins and Unrelated Patients

BACKGROUND & AIMS: It is currently unclear whether reported changes in the gut microbiome are cause or consequence of inflammatory bowel disease (IBD). Therefore, we studied the gut microbiome of IBD-discordant and -concordant twin pairs, which offers the unique opportunity to assess individuals at increased risk of developing IBD, namely healthy cotwins from IBD-discordant twin pairs. METHODS: Fecal samples were obtained from 99 twins (belonging to 51 twin pairs), 495 healthy age-, sex- and BMI-matched controls, and 99 unrelated IBD patients. Whole-genome metagenomic shotgun sequencing was performed. Taxonomic and functional (pathways) composition was compared between healthy-cotwins, IBD-twins, unrelated IBD patients, and healthy controls with multivariable, i.e. adjusted for potential confounding, generalized linear models. RESULTS: No significant differences were observed in the relative abundance of species and pathways between healthy cotwins and their IBD-twins (false discovery rate (FDR)<0.10). Compared to healthy controls, 13, 19, and 18 species, and 78, 105, and 153 pathways were found to be differentially abundant in healthy-cotwins, IBD-twins and unrelated IBD patients, respectively (FDR<0.10). Of these, 8/19 (42.1%) and 1/18 (5.6%) species, and 37/105 (35.2%) and 30/153 (19.6%) pathways overlapped between healthy cotwins and IBD-twins, and healthy cotwins and unrelated IBD patients respectively. Many of the shared species and pathways have previously been associated with IBD. The shared pathways include potentially inflammation-related pathways, for example: an increase in propionate degradation and L-arginine degradation pathways. CONCLUSIONS: The gut microbiome of healthy cotwins from IBD-discordant twin pairs displays IBD-like signatures. These IBD-like microbiome signatures might precede the onset of IBD. However, longitudinal follow up studies are needed to infer a causal relationship

Tofacitinib for ulcerative colitis:results of the prospective Dutch Initiative on Crohn and Colitis (ICC) registry

Background: Tofacitinib is a Janus kinase inhibitor approved for the treatment of ulcerative colitis (UC). Aim: To evaluate effectiveness, safety and use of tofacitinib in daily practice. Methods: UC patients initiating tofacitinib were prospectively enrolled in 15 hospitals in the Netherlands. Corticosteroid-free clinical remission (short clinical colitis activity index [SCCAI] ≤2), biochemical remission (faecal calprotectin level ≤250 µg/g), combined corticosteroid-free clinical and biochemical remission, predictors of remission, safety outcomes, treatment dose and effect on lipids were determined at weeks 12 and 24. Endoscopic outcomes were evaluated in centres with routine endoscopic evaluation. Results: In total, 123 UC patients (95% anti-TNF, 62% vedolizumab and 3% ustekinumab experienced) were followed for a median duration of 24 weeks (interquartile range 12-26). The proportion of patients in corticosteroid-free clinical, biochemical, and combined corticosteroid-free clinical and biochemical remission rate at week 24 was 29% (n: 22/77), 25% (n: 14/57), and 19% (n: 11/57) respectively. Endoscopic remission (Mayo = 0) was achieved in 21% of patients at week 12 (n: 7/33). Prior vedolizumab exposure was associated with reduced clinical remission (odds ratio 0.33, 95% confidence interval [CI] 0.11-0.94). At week 24, 33% (n: 14/42) of patients still on tofacitinib treatment used 10 mg twice daily. In total, 33 tofacitinib-related adverse events (89 per 100 patient years) occurred, 7 (6% of total cohort) resulted in discontinuation. Cholesterol, HDL and LDL levels increased during induction treatment by 18% (95% CI 9-26), 18% (95% CI 8-28) and 21% (95% CI 14-39) respectively. Conclusion: Tofacitinib is an effective treatment for UC after anti-TNF and vedolizumab failure. However, a relatively high rate of adverse events was observed resulting in discontinuation in 6% of patients

Therapeutic drug monitoring of thiopurines: Effect of reduced 6-thioguanine nucleotide target levels in inflammatory bowel disease patients

AIMS: The effect of the Dutch nationwide adjustment of reducing 6-thioguanine nucleotide (6-TGN) target values (from 600-1200 to 320-630 pmol/8 × 108 red blood cells [RBC]) on toxicity and clinical outcome of thiopurine treatment in patients with inflammatory bowel disease has not yet been established. Therefore, the authors determined the incidence of toxicity-induced discontinuations and efficacy at both target concentrations. METHODS: This retrospective study was performed in inflammatory bowel disease patients treated with azathioprine or mercaptopurine. Two groups were defined: the former target (FT) group with target concentrations of 600-1200 pmol/8 × 108 RBC and the adjusted target (AT) group with target concentrations of 320-630 pmol/8 × 108 RBC. Patients were followed for maximum 52 weeks or until discontinuation of thiopurine therapy. Data were collected from the local hospital electronic health software of Rijnstate Hospital. RESULTS: In total, 151 patients were included, 76 in the FT group and 75 in the AT group. At week 52, 100 out of 151 patients (66%) of the total population discontinued thiopurine therapy. Forty-eight of the discontinuations were due toxicity (48%). The incidence of toxicity induced discontinuations was 35% in the AT group vs. 47% in the FT group (P = .25). No loss of efficacy was seen in the AT group. CONCLUSION: After reduction of the target range, there was a trend towards fewer toxicity-induced discontinuations, albeit not statistically significant. In addition, this study did not find any indication that the reduction of the target range diminished efficacy

The complexity of alpha E beta 7 blockade in Inflammatory Bowel Diseases

Monoclonal antibodies targeting integrins are emerging as new treatment option in Inflammatory Bowel Diseases. Integrins are molecules involved in cell adhesion and signalling. After the successful introduction of anti-α4β7, currently anti-β7 is under evaluation in a phase three trial. Anti-β7 blocks both α4β7/MAdCAM-1 and αEβ7/E-cadherin interaction, targeting both the homing to and the retention in the gut of potential pathological T cells. Since the physiological and potential pathological role of immune cells expressing αEβ7 is less distinct than of those expressing α4β7. An overview of the current state of knowledge on αEβ7 in mice and human is presented here in both health and Inflammatory Bowel Diseases, also addressing the potential consequences of anti-β7 treatment

Candidate serum markers in early Crohn's disease : Predictors of disease course

Background and Aims: More than half of patients with Crohn's disease [CD] develop disease complications requiring aggressive medical therapy or surgery over time. However, predicting disease course and treatment response remains difficult. We therefore identified distinctive serum analytes associated with disease activity and course in newly diagnosed, untreated patients at presentation and during their follow-up. Methods: In a pilot study, a multiplex immunoassay analysis on 36 markers was performed on serum from 20 CD patients at the time of primary diagnosis following endoscopic evaluation. The 12 most potent markers associated with disease activity, phenotype and course were analysed in a consecutive cohort of 66 CD patients at diagnosis and follow-up [n = 39]. A healthy control group [n = 20] was included as a reference. Results: CD patients had higher baseline levels of sTNF-R2 [p = 0.001], sIL-2R [p = 0.0001], and MMP-1 [p = 0.001] compared with healthy controls. Serial measurements revealed that these three analytes dropped statistically significantly from baseline level during remission and were high during exacerbation. Great decline of sTNF-R1 levels was found during remission, with 6.7-fold lower levels than in healthy controls [p = 0.015]. Patients who did not respond to initial prednisone treatment had higher baseline levels of sTNF-R2 [p = 0.001]. Patients experiencing relapses during follow-up had lower baseline sTNF-R2 and VCAM levels compared with patients with long-lasting remission. Conclusions: In a large cohort of newly diagnosed untreated CD patients, we identified candidate serum markers [sTNF-R1, sTNF-R2, sIL-2R, and MMP-1] associated with disease activity. Furthermore, sTNF-R2 was associated with prednisone response and, together with VCAM, with long-lasting remission

Candidate serum markers in early Crohn's disease : Predictors of disease course

Background and Aims: More than half of patients with Crohn's disease [CD] develop disease complications requiring aggressive medical therapy or surgery over time. However, predicting disease course and treatment response remains difficult. We therefore identified distinctive serum analytes associated with disease activity and course in newly diagnosed, untreated patients at presentation and during their follow-up. Methods: In a pilot study, a multiplex immunoassay analysis on 36 markers was performed on serum from 20 CD patients at the time of primary diagnosis following endoscopic evaluation. The 12 most potent markers associated with disease activity, phenotype and course were analysed in a consecutive cohort of 66 CD patients at diagnosis and follow-up [n = 39]. A healthy control group [n = 20] was included as a reference. Results: CD patients had higher baseline levels of sTNF-R2 [p = 0.001], sIL-2R [p = 0.0001], and MMP-1 [p = 0.001] compared with healthy controls. Serial measurements revealed that these three analytes dropped statistically significantly from baseline level during remission and were high during exacerbation. Great decline of sTNF-R1 levels was found during remission, with 6.7-fold lower levels than in healthy controls [p = 0.015]. Patients who did not respond to initial prednisone treatment had higher baseline levels of sTNF-R2 [p = 0.001]. Patients experiencing relapses during follow-up had lower baseline sTNF-R2 and VCAM levels compared with patients with long-lasting remission. Conclusions: In a large cohort of newly diagnosed untreated CD patients, we identified candidate serum markers [sTNF-R1, sTNF-R2, sIL-2R, and MMP-1] associated with disease activity. Furthermore, sTNF-R2 was associated with prednisone response and, together with VCAM, with long-lasting remission

Development of Mucosal PNAd+ and MAdCAM-1+ Venules during Disease Course in Ulcerative Colitis

PNAd and MAdCAM-1 addressins on venules are of importance in T-cell homing and potential therapeutic targets in ulcerative colitis (UC). Normally, PNAd+ high endothelial venules (HEVs) are only present in lymphoid organs, whereas small numbers of MAdCAM-1+ venules can be seen in non-lymphoid tissue. We aimed to study their presence in the intestinal mucosa of UC patients at diagnosis and during follow-up, and their correlation with disease activity. Colonic biopsy specimens of 378 UC patients were analyzed by immunohistochemistry for CD3, CD20, ERG, MECA-79 (PNAd) and MECA-376 (MAdCAM-1) and compared to healthy controls (HC). The proportion of PNAd+HEVs in UC at diagnosis was 4.9% (IQR 2.0%&ndash;8.3%), while none were detected in HC. During follow-up, PNAd+HEVs completely disappeared in remission (n = 93), whereas the proportion in active disease was similar to baseline (n = 285, p = 0.39). The proportion of MAdCAM-1+venules in UC at baseline was 5.8% (IQR 2.6&ndash;10.0). During follow-up, the proportion in remission was comparable to diagnosis, but upregulated (7.5% (IQR 4.4&ndash;10.9), p = 0.001) in active disease. In conclusion, PNAd+HEVs appear in UC during active inflammation which could thus serve as a marker for disease activity, whereas MAdCAM-1+venules remain present after inflammation is resolved and increase after subsequent flares, reflecting chronicity and potentially serving as a therapeutic target

Complete Endoscopic Healing Is Associated With Lower Relapse Risk After Anti-TNF Withdrawal in Inflammatory Bowel Disease

Background & Aims: Discontinuation of anti–tumor necrosis factor-α treatment (anti-TNF) (infliximab and adalimumab) in patients with inflammatory bowel disease (IBD) is associated with a high relapse risk that may be influenced by endoscopic activity at the time of stopping. We assessed the relapse rate after anti-TNF withdrawal in patients with endoscopic healing and studied predictors of relapse including the depth of endoscopic healing. Methods: This was a multicenter, prospective study in adult patients with Crohn's disease (CD), ulcerative colitis (UC), or IBD-unclassified (IBDU), with ≥6 months of corticosteroid-free clinical remission (confirmed at baseline) and endoscopic healing (Mayo <2/SES-CD <5 without large ulcers), who discontinued anti-TNF between 2018 and 2020 in the Netherlands. We performed Kaplan-Meier and Cox regression analyses to assess the relapse rate and evaluate potential predictors: partial (Mayo 1/SES-CD 3–4) versus complete (Mayo 0/SES-CD 0–2) endoscopic healing, anti-TNF trough levels, and immunomodulator and/or mesalamine use. Results: Among 81 patients (CD: n = 41, 51%) with a median follow-up of 2.0 years (interquartile range, 1.6–2.1), 40 patients (49%) relapsed. Relapse rates in CD and UC/IBDU patients were comparable. At 12 months, 70% versus 35% of patients with partial versus complete endoscopic healing relapsed, respectively (adjusted hazard rate [aHR], 3.28; 95% confidence interval [CI], 1.43–7.50). Mesalamine use was associated with fewer relapses in UC/IBDU patients (aHR, 0.08; 95% CI, 0.01–0.67). Thirty patients restarted anti-TNF, and clinical remission was regained in 73% at 3 months. Conclusions: The relapse risk was high after anti-TNF withdrawal in IBD patients with endoscopic healing, but remission was regained in most cases after anti-TNF reintroduction. Complete endoscopic healing and mesalamine treatment in UC/IBDU patients decreased the risk of relapse