Compartment-driven imprinting of intestinal CD4 T cells in inflammatory bowel disease and homeostasis.

The mucosal immune system is implicated in the etiology and progression of inflammatory bowel diseases. The lamina propria and epithelium of the gut mucosa constitute two separate compartments, containing distinct T-cell populations. Human CD4 T-cell programming and regulation of lamina propria and epithelium CD4 T cells, especially during inflammation, remain incompletely understood. We performed flow cytometry, bulk, and single-cell RNA-sequencing to profile ileal lamina propria and intraepithelial CD4 T cells (CD4CD8αα, regulatory T cells (Tregs), CD69- and CD69high Trm T cells) in controls and Crohn's disease (CD) patients (paired non-inflamed and inflamed). Inflammation results in alterations of the CD4 T-cell population with a pronounced increase in Tregs and migrating/infiltrating cells. On a transcriptional level, inflammation within the epithelium induced T-cell activation, increased IFNγ responses, and an effector Treg profile. Conversely, few transcriptional changes within the lamina propria were observed. Key regulators including the chromatin remodelers ARID4B and SATB1 were found to drive compartment-specific transcriptional programming of CD4 T(reg) cells. In summary, inflammation in CD patients primarily induces changes within the epithelium and not the lamina propria. Additionally, there is compartment-specific CD4 T-cell imprinting, driven by shared regulators, between the lamina propria and the epithelium. The main consequence of intraepithelial adaptation, irrespective of inflammation, seems to be an overall dampening of broad (pro-inflammatory) responses and tight regulation of lifespan. These data suggest differential regulation of the lamina propria and epithelium, with a specific regulatory role in the inflamed epithelium.

Mucosal α4ß7+ Lymphocytes and MAdCAM+ Venules Predict Response to Vedolizumab in Ulcerative Colitis.

BACKGROUND: Therapeutic strategies for patients with ulcerative colitis (UC) are based on patient- and disease-related factors in combination with drug characteristics but fail to predict success in individual patients. A considerable proportion of UC patients do not respond to the biological vedolizumab. Therefore, pretreatment biomarkers for therapeutic efficacy are urgently needed. Mucosal markers related to the integrin-dependent T lymphocyte homing could be potent predictors. METHODS: We prospectively included 21 biological- and steroid-naive UC patients with moderate-to-severe disease activity planned to escalate therapy to vedolizumab. At week 0, before initiating treatment, colonic biopsy specimens were obtained for immunophenotyping and immunohistochemistry. Clinical and endoscopic disease activity were determined at week 16 after 4 infusions of vedolizumab. In addition, we retrospectively included 5 UC patients who were first treated with anti-tumor necrosis factor α before receiving vedolizumab to compare with biological-naive patients. RESULTS: Abundance of α4ß7 on more than 8% of all CD3+ T lymphocytes in colonic biopsies at baseline was predictive for responsiveness to vedolizumab (sensitivity 100%, specificity 100%). The threshold for the proportion of MAdCAM-1+ and PNAd+ of all venules in the biopsies predictive for responsiveness to vedolizumab was ≥2.59% (sensitivity 89%, specificity 100%) and ≥2.41% (sensitivity 61%, specificity 50%), respectively. At week 16, a significant decrease of α4ß7+CD3+T lymphocytes was demonstrated in responders (18% [12%-24%] to 8% [3%-9%]; P = .002), while no difference was seen in nonresponders (4% [3%-6%] to 3%; P = .59). CONCLUSIONS: UC responders to vedolizumab have a higher percentage of α4ß7+CD3+ T lymphocytes and a higher proportion of MAdCAM-1+ venules in colonic biopsies than nonresponders before initiating therapy. Both analyses could be promising predictive biomarkers for therapeutic response and may lead to more patient tailored treatment in the future.

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.

Mobile application to monitor inflammatory bowel disease patients on intravenous biologic treatment: a feasibility study.

BACKGROUND: Monitoring of IBD patients on intravenous biologic treatment is recommended but time-consuming for patients and nurses. We developed a mobile application (app) to promote self-management and studied its feasibility in clinical practice. METHODS: Adult IBD patients treated with intravenous infliximab or vedolizumab used the app over four biologic treatments. The app includes information modules and an interactive timeline with notifications of blood tests and health checks before treatment. RESULTS: In total, 55 patients participated of whom 71% had Crohn's disease and 85% used infliximab. Compliance with health checks and blood tests was 67% before the first biologic treatment and 70, 87, and 80% before the second, third, and fourth treatment, respectively. The median number of times the app was used per treatment varied from 6 to 8 times (≥4 considered sufficient). Patients were satisfied with the app [median VAS score 8 (IQR 7-9)] and remained equally satisfied with IBD care [score 8 (IQR 8-9) before and after app use]. Nurses contacted all patients by telephone before the first biologic treatment, as previous standard care. Before the second, third, and fourth treatment only 47, 35, and 49% of patients were contacted. The majority (92%) wanted to continue using the app after the study. CONCLUSIONS: Monitoring of IBD patients treated with intravenous biologics using an app is feasible. We saw high compliance, sufficient app use, and high patient satisfaction. Moreover, health-care utilization was reduced and almost all patients preferred using the app over previous standard care (ClinicalTrials.gov NCT04254614).

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.

Distribution of mucosal PD-1 expressing T cells in patients with colitis of different etiologies.

BACKGROUND: Immunotherapy, targeting programmed death-1 (PD-1) enhances antitumor T-cell activity in patients with malignancies. Blocking PD-1 or its ligand may lead to fulminant colitis as serious adverse event in these patients. Since little is known of the presence and role of PD-1+T cells in colitis of different etiologies, we determined PD-1+T cells in mucosal specimens of patients with inflammatory bowel disease, infectious colitis (InfC), immunotherapy-related colitis (ImC) and healthy controls (HC). METHODS: Newly diagnosed patients with ulcerative colitis (UC, n = 73), Crohn's disease (CD, n = 50), InfC (n = 5), ImC (n = 8) and HC (n = 8) were included. Baseline inflamed colonic biopsies were studied with immunohistochemistry and flowcytometry. RESULTS: Using immunohistochemistry, PD-1 was not present on lymphocytes in the epithelium of all patients, nor in HC. The percentage PD-1+ of all lymphocytes in the lamina propria was 40% in UC, 5% in InfC, 3% in ImC and 0% in HC. Flowcytometry showed significant higher percentages of PD-1+T cells in inflamed biopsy specimens of UC patients (22%) compared to all other groups: CD patients (13%), InfC (12%), ImC (5%) and HC (6%). CONCLUSION: There are relevant differences in distribution and frequencies of mucosal PD-1+ T-cell subsets in patients with UC, CD, InfC and ImC, supporting the hypothesis that these types of colitis are driven by different immunological pathways. The increased numbers of PD-1+ and PD-L1+ lymphocytes in the colonic mucosa of UC patients suggest that the PD-1/PD-L1 pathway might be more activated in UC than in CD.

Improvement of Fatigue and Quality of Life in Patients with Quiescent Inflammatory Bowel Disease Following a Personalized Exercise Program.

BACKGROUND AND AIMS: Fatigue significantly impacts the quality of life of patients with inflammatory bowel disease (IBD). This study aimed to assess the effect of a personalized, intensive exercise program on fatigue, health-related quality of life (HRQoL), and cardiorespiratory fitness in patients with quiescent IBD and severe fatigue. METHODS: A pilot study was performed including IBD patients in remission with severe fatigue. The 12-week exercise program consisted of three times per week 1-h sessions, including aerobic- and progressive-resistance training at personalized intensity based on a cardiopulmonary exercise test (CPET) and one-repetition maximum. CPET was repeated after 12 weeks. Fatigue and HRQoL were assessed using the checklist individual strength and 32-item IBD questionnaire. RESULTS: Twenty-five IBD patients with mean age of 45 (± 2.6) years were included of which 22 (88%) completed the exercise program. Fatigue significantly improved from 105 (± 17) points on the checklist individual strength before, to 66 (± 20) after completion of exercise program (p < 0.001). Patients' HRQoL significantly improved from 156 (± 21) to 176 (± 19) (p < 0.001). When looking at the subdomains of HRQoL, significant improvement was seen in emotional (58 ± 12 vs. 69 ± 9.1, p = 0.003), systemic (19 ± 3.9 vs. 24 ± 4.7, p < 0.001), and social function (25 ± 5.4 vs. 30 ± 3.9, p < 0.001). Bowel symptoms did not change (53 ± 7.7 vs. 55 ± 7.3, p = 0.208). Repeat CPET showed a significant improvement in maximum power patients were able to deliver (2.4 ± 0.5 vs. 2.7 ± 0.5 W/kg, p = 0.002). CONCLUSIONS: A personalized, intensive exercise program can lead to significant improvement of fatigue, HRQoL, and cardiorespiratory fitness in patients with quiescent IBD and severe fatigue.

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.

Intestinal CD103+CD4+ and CD103+CD8+ T-Cell Subsets in the Gut of Inflammatory Bowel Disease Patients at Diagnosis and During Follow-up.

BACKGROUND: The integrin CD103 is proposed to be a potential therapeutical target in inflammatory bowel disease (IBD), as it can form a heterodimeric integrin with ß7 (Etrolizumab, anti-ß7 integrin) on epithelial T cells. Therefore, we aimed to study the frequencies of different intestinal CD103+T-cell subsets, both CD4+ and CD8+, in newly diagnosed, untreated IBD patients at baseline and during follow-up, compared with healthy controls. METHODS: Intestinal biopsies from inflamed segments during colonoscopy and peripheral blood samples were prospectively taken from IBD patients at diagnosis and during follow-up. Blood and single cell suspensions from biopsies were analyzed for CD103+ T-cell subpopulations by flow cytometry and expressed as median percentages of the total T-cell population. RESULTS: In total, 75 Crohn's disease (CD) patients, 49 ulcerative colitis (UC) patients, and 16 healthy controls were included. At presentation, IBD patients displayed lower percentages of CD103+T-cell subsets in inflamed biopsies: 3% (1 to 5) CD103+CD4+ in IBD vs 5% (5 to 7) in healthy controls (P = 0.007) and 9% (4 to 15) CD103+CD8+ compared with 42% (23 to 57) in healthy controls (P = 0.001). The majority of intestinal T cells was composed of CD103-CD4+ T cells (65% [52 to 74]) in IBD compared with 30% (21 to 50) in healthy controls (P = 0.001). In patients with endoscopic remission during follow-up (n = 27), frequencies of CD103+ and CD103-T-cell subsets were comparable with healthy controls. CONCLUSION: At diagnosis, active inflammation in IBD was associated with decreased percentages of both CD103+CD4+ and CD103+CD8+T-cell subsets in colon and ileum biopsies. In active disease during follow-up, these T-cell populations remained low but increased in remission to values comparable with healthy controls. A shift toward more CD103-T cells was observed during active inflammation.

Clinical outcomes of home parenteral nutrition patients using taurolidine as catheter lock: A long-term cohort study.

BACKGROUND & AIMS: Central venous access device (CVAD)-related complications, such as central-line associated bloodstream infections (CLABSIs), CVAD-related venous thromboses (CRVTs) and -occlusions frequently occur in home parenteral nutrition (HPN) patients. A preventive strategy to decrease the incidence of CLABSIs is the use of CVAD lock solutions, such as 2% taurolidine. The aim of this study was to evaluate long-term clinical outcomes of our HPN cohort while using taurolidine as lock solution. In addition, we explored risk factors associated with CVAD-related complications. METHODS: We conducted a retrospective analysis of complications (CLABSIs, CRVTs and CVAD occlusions) and adverse events in adult HPN patients while using taurolidine as lock solution. Patients with a benign underlying disease leading to intestinal failure were included between 2006 and 2017 at our tertiary referral centre for intestinal failure. Primary outcome was the effectiveness of taurolidine, as described by complication incidence rates. Secondary objectives were to assess adverse events of taurolidine, complication rates of patients who subsequently discontinued taurolidine and started using 0.9% saline alternatively, and risk factors associated with complications. RESULTS: In total, 270 HPN patients used taurolidine during 338521 catheter days. CLABSIs, CRVTs and CVAD occlusions occurred at a rate of 0.60 (CI95% 0.52-0.69), 0.28 (CI95% 0.23-0.34), and 0.12 (CI95% 0.08-0.16) events per 1000 catheter days, respectively. In 24 (9%) patients, mild to moderate adverse events resulted in discontinuation of 2% taurolidine. A subsequent switch to 0.9% saline resulted in an increased CLABSI rate (adjusted rate ratio 4.01 (95%CI 1.23-13.04), P = 0.02). Several risk factors were identified for CLABSIs (a lower age, nontunneled catheters, infusion frequency), CRVTs (site of vein insertion), and CVAD occlusions (type of CVAD). CONCLUSION: Complication rates remained low in the long-term, and use of taurolidine was generally safe. The identified risk factors may help to create new strategies to further prevent CVAD-related complications and improve HPN care in the future.

Intestinal T Cell Profiling in Inflammatory Bowel Disease: Linking T Cell Subsets to Disease Activity and Disease Course.

INTRODUCTION: A dysregulated intestinal T cell response is presumed in patients with inflammatory bowel disease [IBD]. In this longitudinal study, we investigated the changes in intestinal T lymphocyte subsets in IBD at first presentation and over time during endoscopic active or inactive disease, and relate them to disease activity and outcome. METHODS: We included 129 newly diagnosed patients (87 Crohn's disease [CD], 42 ulcerative colitis [UC]) and 19 healthy controls [HC]. Follow-up biopsy specimens were analysed from 70 IBD patients. Immunophenotyping of specimens was performed by flow cytometry identifying lymphocyte subpopulations. RESULTS: IBD patients at diagnosis displayed higher percentages of CD4 T+ cells, Tregs, and central memory T cells [TCM] and with lower percentages of CD8 and CD103 T lymphocytes than HC. Follow-up specimens of patients with endoscopic inactive disease showed T cell subset recovery comparable to HC. Endoscopic active disease at follow-up coincided with T cell subsets similar to those at diagnosis. In UC, lower baseline percentages of CD3 cells was associated with milder disease course without the need of an immunomodulator, whereas in CD, higher baseline percentages of CD4 and Tregs were associated with complicated disease course. CONCLUSIONS: The intestinal T cell infiltrate in IBD patients with active endoscopic disease is composed of increased percentages of CD4+ T cells, Tregs, and TCM, with lower percentages of CD8+ T cells and CD103+ T cells, compared with HC and endoscopic inactive IBD. Baseline percentages of CD3, CD4, and Tregs were associated with disease outcome. Further research is needed to demonstrate the predictive value of these lymphocyte subsets.