Influence of training and expertise on deep neural network attention and human attention during a medical image classification task.

In many different domains, experts can make complex decisions after glancing very briefly at an image. However, the perceptual mechanisms underlying expert performance are still largely unknown. Recently, several machine learning algorithms have been shown to outperform human experts in specific tasks. But these algorithms often behave as black boxes and their information processing pipeline remains unknown. This lack of transparency and interpretability is highly problematic in applications involving human lives, such as health care. One way to "open the black box" is to compute an artificial attention map from the model, which highlights the pixels of the input image that contributed the most to the model decision. In this work, we directly compare human visual attention to machine visual attention when performing the same visual task. We have designed a medical diagnosis task involving the detection of lesions in small bowel endoscopic images. We collected eye movements from novices and gastroenterologist experts while they classified medical images according to their relevance for Crohn's disease diagnosis. We trained three state-of-the-art deep learning models on our carefully labeled dataset. Both humans and machine performed the same task. We extracted artificial attention with six different post hoc methods. We show that the model attention maps are significantly closer to human expert attention maps than to novices', especially for pathological images. As the model gets trained and its performance gets closer to the human experts, the similarity between model and human attention increases. Through the understanding of the similarities between the visual decision-making process of human experts and deep neural networks, we hope to inform both the training of new doctors and the architecture of new algorithms.

Distinct blood protein profiles associated with the risk of short-term and mid/long-term clinical relapse in patients with Crohn's disease stopping infliximab: when the remission state hides different types of residual disease activity.

OBJECTIVE: Despite being in sustained and stable remission, patients with Crohn's disease (CD) stopping anti-tumour necrosis factor α (TNFα) show a high rate of relapse (~50% within 2 years). Characterising non-invasively the biological profiles of those patients is needed to better guide the decision of anti-TNFα withdrawal. DESIGN: Ninety-two immune-related proteins were measured by proximity extension assay in serum of patients with CD (n=102) in sustained steroid-free remission and stopping anti-TNFα (infliximab). As previously shown, a stratification based on time to clinical relapse was used to characterise the distinct biological profiles of relapsers (short-term relapsers: <6 months vs mid/long-term relapsers: >6 months). Associations between protein levels and time to clinical relapse were determined by univariable Cox model. RESULTS: The risk (HR) of mid/long-term clinical relapse was specifically associated with a high serum level of proteins mainly expressed in lymphocytes (LAG3, SH2B3, SIT1; HR: 2.2-4.5; p<0.05), a low serum level of anti-inflammatory effectors (IL-10, HSD11B1; HR: 0.2-0.3; p<0.05) and cellular junction proteins (CDSN, CNTNAP2, CXADR, ITGA11; HR: 0.4; p<0.05). The risk of short-term clinical relapse was specifically associated with a high serum level of pro-inflammatory effectors (IL-6, IL12RB1; HR: 3.5-3.6; p<0.05) and a low or high serum level of proteins mainly expressed in antigen presenting cells (CLEC4A, CLEC4C, CLEC7A, LAMP3; HR: 0.4-4.1; p<0.05). CONCLUSION: We identified distinct blood protein profiles associated with the risk of short-term and mid/long-term clinical relapse in patients with CD stopping infliximab. These findings constitute an advance for the development of non-invasive biomarkers guiding the decision of anti-TNFα withdrawal.

Adalimumab in Biologic-naïve Patients With Crohn's Disease After Resolution of an Intra-abdominal Abscess: A Prospective Study From the GETAID.

BACKGROUND & AIMS: The management of intra-abdominal abscesses complicating Crohn's disease (CD) is challenging, and surgery with delayed intestinal resection is often recommended. The aims of this study were to estimate the success rate of adalimumab (ADA) in patients with CD with an intra-abdominal abscess resolved without surgery, and to identify predictive factors for success. METHODS: A multicenter, prospective study was conducted in biologic-naïve patients with CD with resolved intra-abdominal abscess treated with ADA with a 2-year follow-up. The primary endpoint was ADA failure at week (W) 24 defined as a need for steroids after W12, intestinal resection, abscess recurrence, and clinical relapse. Secondary post-hoc endpoint was the long-term success defined as the survival without abscess relapse or intestinal resection at W104. The factors associated with ADA failure at W24 and W104 were identified using a logistic and a Cox regression, respectively. RESULTS: From April 2013 to December 2017, 190 patients from 27 GETAID centers were screened, and 117 were included in the analysis. Fifty-eight patients (50%) were male, and the median age at baseline was 28 years. At W24, 87 patients (74%; 95% confidence interval [CI], 65.5%-82.0%; n = 117) achieved ADA success. Among the 30 patients with ADA failure, 15 underwent surgery. At W104, the survival rate without abscess recurrence or surgery was 72.9% (95% CI, 62.1%-79.8%; n = 109). Abscess drainage was significantly associated with ADA failure at W24 (odds ratio, 4.18; 95% CI, 1.06-16.5; P =0 .043). Disease duration (hazard ratio [HR], 1.32; 95% CI, 1.09-1.59; P = .008), abscess drainage (HR, 5.59; 95% CI, 2.21-14.15; P = .001), and inflammatory changes in mesenteric fat (HR, 0.4; 95% CI, 0.17-0.94; P = .046) were significantly associated with ADA failure at W104. CONCLUSION: Provided that the abscess was carefully managed before initiating medical treatment, this study showed the high efficacy of ADA in the short and long term in biologic-naïve patients with CD complicated by an intra-abdominal abscess. CLINICALTRIALS: gov, Number: NCT02856763.

Sacral neuromodulation for refractory ulcerative colitis: safety and efficacy in a prospective observational series of eight patients.

PURPOSE: Ulcerative colitis (UC) treatment is mainly based on immunosuppressive therapy. As anti-inflammatory effects of sacral neuromodulation (SNM) have been previously reported in animal models, we conducted a pilot study aimed at assessing clinical, biological, and endoscopic response but also safety of SNM use in UC refractory to medical therapy. METHODS: Adult patients with histologically proven UC resistant to immunosuppressive therapy were invited to enroll in the study. Primary outcome was the rate of UC remission (UCDAI score ≤ 2, without any criteria > 1) at 8 weeks (W8). Secondary outcomes were biological and endoscopic response also evaluated at W8 and W16. Subsequently, every patient was followed every 6 months. Adverse events were prospectively collected for safety assessment during the follow-up. RESULTS: Eight patients, with mean age 47 years old, suffering from UC for 2-13 years were included. There were no complications in relation to SNM procedure. The acceptance of the device was excellent in all patients. Clinical and endoscopic remission was obtained at W8 in one patient (12.5%) and three other patients (37.5%) were responders at W16. At review (mean follow-up of 4 years), two patients (25%) were in remission and two (25%) were responders. CONCLUSION: SNM application is safe in patients suffering from refractory UC. Effects on disease activity were mainly observed after 16 weeks. Larger prospective studies are mandatory, but SNM could be a way to reinforce medical therapy and reduce the use of immunosuppressive drugs.

A Magnetic Resonance Imaging Index to Predict Crohn's Disease Postoperative Recurrence: The MONITOR Index.

BACKGROUND & AIMS: We developed and validated a magnetic resonance imaging-based index to predict Crohn's disease (CD) postoperative recurrence (POR). METHODS: Patients with CD who underwent a postoperative evaluation for recurrence (with colonoscopy and MRI no longer than 105 days apart) were included between 2006 and 2016 in University Hospital of Nancy, France. MRI items with good levels of intra-rater and inter-rater agreement (Gwet's coefficient ≥0.5) were selected. The MRI in Crohn's Disease to Predict Postoperative Recurrence (MONITOR) index's performance was assessed in terms of the area under the receiver operating characteristic curve (AUROC) and accuracy, by considering the Rutgeerts score as the gold standard. The MONITOR index was validated with a bootstrap method and an independent cohort. RESULTS: Seventy-three MRI datasets were interpreted by 2 radiologists. Seven items (bowel wall thickness, contrast enhancement, T2 signal increase, diffusion-weighted signal increase, edema, ulcers, and the length of the diseased segment) had a Gwet's coefficient ≥0.5 and were significantly associated with the Rutgeerts score, leading to their inclusion in the MONITOR index. All the items had a weighting of 1, except the "ulcers" item weighting 2.5, reflecting the higher adjusted odds ratio. The AUROC [95% confidence interval] for the prediction of endoscopic POR (Rutgeerts score >i1) was 0.80 [0.70-0.90]. The optimal threshold was a MONITOR index ≥1, giving a sensitivity of 79%, a specificity of 55%, a predictive positive value of 68%, and a predictive negative value of 68%. The bootstrap validation gave an AUROC of 0.85 [0.73-0.97]. In the validation cohort, a MONITOR index ≥1 gave a sensitivity of 87%, a specificity of 75%, a predictive positive value of 84.6%, and a predictive negative value of 75%. CONCLUSIONS: The MONITOR index is an efficient, reliable, easy-to-apply tool that can be used in clinical practice to predict the POR of CD.

Efficacy and Safety of Infliximab Retreatment in Crohn's Disease: A Multicentre, Prospective, Observational Cohort (REGAIN) Study from the GETAID.

INTRODUCTION: The objective of this study was to describe the efficacy and safety of infliximab (IFX) reintroduction in Crohn's disease (CD) after stopping for loss of response or intolerance. METHODS: We conducted a prospective multicenter observational cohort study including adult patients with clinically (CD Activity Index >150) and objectively active luminal CD in whom IFX was reintroduced after at least 6 months of discontinuation. The reasons for the initial discontinuation could be a secondary loss of response or IFX intolerance. The reintroduction schedule included 3 IFX infusions at weeks 0, 4, and 8, after a systematic premedication. The primary end point was the efficacy of IFX retreatment at week 26 defined by a CD Activity Index of <150 in the absence of IFX discontinuation or use of corticosteroids, surgery, or other biologic. RESULTS: At week 26, 24 patients (35%) among the 69 analyzed reached the primary end point. No significant difference was observed between rates of clinical remission at week 26 in patients with prior LOR (n = 48) and those with IFX intolerance (n = 21) (35% and 33%, P = 0.87, respectively). Thirty-two acute infusion reactions were recorded in 27 patients, leading to withdrawal of IFX in 20 patients. No pharmacokinetic characteristic at baseline but detection of positive anti-drug antibodies at week 4 was predictive of IFX failure or infusion reaction at week 26. DISCUSSION: In this first prospective cohort study, IFX retreatment was safe and effective in one-third of the patients with CD, regardless the reason of prior discontinuation. Early detection of anti-drug antibodies can predict subsequent IFX reintroduction failure and infusion reactions.

Comparative real-world effectiveness of vedolizumab and ustekinumab for patients with ulcerative colitis: a GETAID multicentre cohort study.

INTRODUCTION: There are currently no comparative data on the efficacy and safety of vedolizumab and ustekinumab in ulcerative colitis (UC) after anti-TNF therapy fails. METHODS: We retrieved the full datasets of two observational, multicentre, retrospective studies of patients with UC for whom anti-TNF therapy failed and the patients were then treated with either vedolizumab or ustekinumab. The outcomes included steroid-free clinical remission, clinical remission, treatment persistence, colectomy, hospitalization, and serious and infectious adverse events. Propensity scores weighted comparison was applied. RESULTS: In total, 121 patients were included in the vedolizumab group and 97 were included in the ustekinumab group. At week 14 and week 52, in the weighted cohort, no difference was found between vedolizumab and ustekinumab for steroid-free clinical remission (OR = 0.55 [0.21-1.41], p = .21 and 0.94 [0.40-2.22], p = .89, respectively). There was no difference between vedolizumab and ustekinumab for secondary outcomes such as clinical remission, hospitalization, UC-related surgery, treatment persistence and serious and infectious adverse events. CONCLUSION: In patients with UC for whom anti-TNF therapy failed, no difference was found between vedolizumab and ustekinumab after propensity scores weighted comparison. Further studies are required to determine predictive factors of the efficacy of both biological agents.

Efficacy of ustekinumab, vedolizumab, or a second anti-TNF agent after the failure of a first anti-TNF agent in patients with Crohn's disease: a multicentre retrospective study.

BACKGROUND: No study has performed a face-to-face comparison of biologics after the failure of the first anti-TNF agent in patients with Crohn's disease (CD). The aim of the study was to compare the efficacy of biologics in this setting. METHODS: Patients with CD who were refractory to a first anti-TNF agent, and treated with ustekinumab (UST), vedolizumab (VDZ), or a second anti-TNF drug as a second-line biological agent at 10 French tertiary centres from 2013 to 2019 were retrospectively included in this study. RESULTS: Among the 203 patients included, 90 (44%) received UST, 42 (21%) received VDZ and 71 (35%) received a second anti-TNF agent. The first anti-TNF agent was discontinued due to a primary nonresponse in 42 (21%) patients. At weeks 14-24, the rates of steroid-free remission were similar between the UST, VDZ and second anti-TNF groups (29%, 38% and 44%, respectively, p = 0.15). With a mean follow-up of 118 weeks, drug survival was shorter for patients who received ustekinumab treatment (p = 0.001). In the case of trough level less than 5 µg/ml, patients treated with a second anti-TNF agent had a higher postinduction remission rate (p = 0.002), and drug survival (p = 0.0005). No other relevant factors were associated with treatment efficacy, including trough levels greater than 5 µg/ml. CONCLUSIONS: VDZ, UST and a second anti-TNF agent exhibit similar efficacy in the short term, as second-biological line treatment in patients with CD who are refractory to a first anti-TNF agent, but shorter drug maintenance is observed for patients treated with UST.

Evolution of Endoscopic Lesions in Steroid-Refractory Acute Severe Ulcerative Colitis Responding to Infliximab or Cyclosporine.

BACKGROUND/AIMS: Few data on the evolution of endoscopic findings are available in patients with acute severe ulcerative colitis (ASUC). The aim of this study was to describe this evolution in a prospective cohort. METHODS: Patients admitted for a steroid-refractory ASUC and included in a randomized trial comparing infliximab and cyclosporine were eligible if they achieved steroid-free clinical remission at day 98. Flexible sigmoidoscopies were performed at baseline, days 7, 42 and 98. Ulcerative colitis endoscopic index of severity (UCEIS) and its sub-scores - vascular pattern, bleeding and ulceration/erosion - were post-hoc calculated. Global endoscopic remission was defined by a UCEIS of 0, and partial endoscopic remission by any UCEIS sub-score of 0. RESULTS: Among the 55 patients analyzed (29 infliximab and 26 cyclosporine), 49 (83%) had UCEIS ≥6 at baseline at baseline. Partial endoscopic remission rates were higher for bleeding than for vascular pattern and for ulcerations/erosions at day 7 (20% vs. 4% and 5% (n = 55); p = .004 and p=.04), for bleeding and ulceration/erosion than for vascular pattern at day 42 [63% and 65% vs. 33% (n=54); p<.001 for both] and at day 98 [78% and 92% vs. 56% (n = 50); p = .007 and p < .001]. Global endoscopic remission rates at day 98 were higher in patients treated with infliximab than with cyclosporine [73% vs. 25% (n = 26 and 24); p < .001]. CONCLUSION: In steroid-refractory ASUC patients responding to a second-line medical therapy, endoscopic remission process started with bleeding remission and was not achieved in half the patients at day 98 for vascular pattern. Infliximab provided a higher endoscopic remission rate than cyclosporine at day 98.

Tau accumulates in Crohn's disease gut.

A sizeable body of evidence has recently emerged to suggest that gastrointestinal (GI) inflammation might be involved in the development of Parkinson's disease (PD). There is now strong epidemiological and genetical evidence linking PD to inflammatory bowel diseases and we recently demonstrated that the neuronal protein alpha-synuclein, which is critically involved in PD pathophysiology, is upregulated in inflamed segments of Crohn's colon. The microtubule associated protein tau is another neuronal protein critically involved in neurodegenerative disorders but, in contrast to alpha-synuclein, no data are available about its expression and phosphorylation patterns in inflammatory bowel diseases. Here, we examined the expression levels of tau isoforms, their phosphorylation profile and truncation in colon biopsy specimens from 16 Crohn's disease (CD) and 6 ulcerative colitis (UC) patients and compared them to samples from 16 controls. Additional experiments were performed in full thickness segments of colon of five CD and five control subjects, in primary cultures of rat enteric neurons and in nuclear factor erythroid 2-related factor (Nrf2) knockout mice. Our results show the upregulation of two main human tau isoforms in the enteric nervous system (ENS) in CD but not in UC. This upregulation was not transcriptionally regulated but instead likely resulted from a decrease in protein clearance via an Nrf2 pathway. Our findings, which provide the first detailed characterization of tau in CD, suggest that the key proteins involved in neurodegenerative disorders such as alpha-synuclein and tau, might also play a role in CD.

Expression of CCR6 and CXCR6 by Gut-Derived CD4+/CD8α+ T-Regulatory Cells, Which Are Decreased in Blood Samples From Patients With Inflammatory Bowel Diseases.

BACKGROUND & AIMS: Faecalibacterium prausnitzii, a member of the Clostridium IV group of the Firmicutes phylum that is abundant in the intestinal microbiota, has anti-inflammatory effects. The relative level of F prausnitzii is decreased in fecal samples from patients with inflammatory bowel diseases (IBDs) compared with healthy individuals. Reduced F prausnitzii was correlated with relapse of Crohn's disease after surgery. We identified, in human colonic mucosa and blood, a population of T regulatory type 1-like T regulatory (TREG) cells that express CD4 and CD8α (DP8α T cells) and are specific for F prausnitzii. We aimed to determine whether they are altered in patients with IBD. METHODS: We isolated DP8α T cells from human colon lamina propria and blood samples and used flow cytometry to detect markers of cells that are of colon origin. We quantified DP8α cells that express colon-specific markers in blood samples from 106 patients with IBD, 12 patients with infectious colitis, and 35 healthy donors (controls). We identified cells that respond to F prausnitzii. Cells were stimulated with anti-CD3, and their production of interleukin 10 was measured by enzyme-linked immunosorbent assay. We compared the frequency and reactivity of cells from patients vs controls using the 2-sided Student t test or 1-way analysis of variance. RESULTS: Circulating DP8α T cells that proliferate in response to F prausnitzii express the C-C motif chemokine receptor 6 (CCR6) and C-X-C motif chemokine receptor 6 (CXCR6). These cells also have features of TREG cells, including production of IL-10 and inhibition of T-cell proliferation via CD39 activity. The proportion of circulating CCR6+/CXCR6+ DP8α T cells was significantly reduced (P < .0001) within the total population of CD3+ T cells from patients with IBD compared with patients with infectious colitis or controls. A threshold of <7.875 CCR6+/CXCR6+ DP8α T cells/10,000 CD3+ cells discriminated patients with IBD from those with infectious colitis with 100% specificity and 72.2% sensitivity. CONCLUSIONS: We identified a population of gut-derived TREG cells that are reduced in blood samples from patients with IBD compared with patients with infectious colitis or controls. These cells should be studied further to determine the mechanisms of this reduction and how it might contribute to the pathogenesis of IBD and their prognostic or diagnostic value.

Quantitative assessment of mucosal architecture using computer-based analysis of confocal laser endomicroscopy in inflammatory bowel diseases.

BACKGROUND AND AIMS: Confocal laser endomicroscopy (CLE) might discriminate mucosal lesions between Crohn's disease (CD) and ulcerative colitis (UC). However, the analysis of CLE images requires time-consuming methods, a long training time, and potential impediments, such as significant interobserver variability. Therefore, we developed a computer-based method to analyze mucosal architecture from CLE images and discriminate between healthy subjects and patients with inflammatory bowel disease (IBD) as well as between UC and CD patients. METHODS: We retrospectively screened patients who had undergone CLE either for an evaluation of IBD in remission or for colorectal cancer screening (control subjects) between 2009 and 2016. We assessed 14 morphologic and functional parameters in each CLE recording from 23 CD patients, 27 UC patients, and 9 control patients. Next, we constructed 2 scores, 1 for the IBD diagnosis and 1 for the differential diagnosis between UC and CD. RESULTS: In IBD patients, the mean intercrypt distance, wall thickness, and fluorescein leakage through the colonic mucosa were significantly increased compared with control patients by 155%, 188%, and 297%, respectively (P < .05). In UC patients, the same parameters were significantly increased by 109%, 117%, and 174%, respectively (P < .05), compared with CD patients. IBD diagnosis had 100% (95%CI, 93%; 100%) sensitivity and 100% (95%CI, 66%; 100%) specificity. IBD differential diagnosis provided discrimination of UC from CD patients with 92% (95%CI, 75%; 99%) sensitivity and 91% (95%CI, 72%; 99%) specificity. CONCLUSIONS: Confirming these results using prospective validation cohorts can substantiate that computer-based analysis of CLE images may provide new biomarkers for the diagnosis and characterization of IBD.

Efficacy of adalimumab in patients with Crohn's disease and symptomatic small bowel stricture: a multicentre, prospective, observational cohort (CREOLE) study.

OBJECTIVE: The efficacy of anti-tumour necrosis factors (anti-TNFs) in patients with Crohn's disease (CD) and symptomatic small bowel stricture (SSBS) is controversial. The aim of this study was to estimate the efficacy of adalimumab in these patients and to identify the factors predicting success. DESIGN: We performed a multicentre, prospective, observational cohort study in patients with CD and SSBS. The included patients underwent magnetic resonance enterography at baseline and subsequently received adalimumab. The primary endpoint was success at week 24, defined as adalimumab continuation without prohibited treatment (corticosteroids after the eight week following inclusion, other anti-TNFs), endoscopic dilation or bowel resection. The baseline factors independently associated with success were identified using a logistic regression model, leading to a simple prognostic score. Secondary endpoints were prolonged success after week 24 (still on adalimumab, without dilation nor surgery) and time to bowel resection in the whole cohort. RESULTS: From January 2010 to December 2011, 105 patients were screened and 97 were included. At week 24, 62/97 (64%) patients had achieved success. The prognostic score defined a good prognosis group with 43/49 successes, an intermediate prognosis group with 17/28 successes and a poor prognosis group with 1/16 successes. After a median follow-up time of 3.8 years, 45.7%±6.6% (proportion±SE) of patients who were in success at week 24 (ie, 29% of the whole cohort) were still in prolonged success at 4 years. Among the whole cohort, 50.7%±5.3% of patients did not undergo bowel resection 4 years after inclusion. CONCLUSIONS: A successful response to adalimumab was observed in about two-thirds of CD patients with SSBS and was prolonged in nearly half of them till the end of follow-up. More than half of the patients were free of surgery 4 years after treatment initiation. CLINICAL TRIAL REGISTRATION NUMBER: NCT01183403; Results.

Are random biopsies still useful for the detection of neoplasia in patients with IBD undergoing surveillance colonoscopy with chromoendoscopy?

BACKGROUND: Colonoscopy with pan-chromoendoscopy (CE) is superior to standard colonoscopy in detecting neoplasia in patients with IBD. Performing random biopsies in unsuspicious mucosa after CE remains controversial. METHODS: Consecutive patients with IBD who underwent surveillance colonoscopy using CE were prospectively included. The standardised procedure used CE, performed targeted biopsies or endoscopic resection on suspicious lesions and then quadrant random biopsies every 10 cm. A panel of five expert pathologists reviewed histological slides with dysplasia. Logistic regression model was used to evidence the factors associated with neoplasia in any or in random biopsies. RESULTS: 1000 colonoscopes were performed in 1000 patients (495 UC, 505 Crohn's colitis). In 82 patients, neoplasia was detected from targeted biopsies or removed lesions, and among them dysplasia was detected also by random biopsies in 7 patients. Importantly, in 12 additional patients dysplasia was only detected by random biopsies. Overall, 140 neoplastic sites were found in 94 patients, 112 (80%) from targeted biopsies or removed lesions and 28 (20%) by random biopsies. The yield of neoplasia by random biopsies only was 0.2% per-biopsy (68/31 865), 1.2% per-colonoscopy (12/1000) but 12.8% per-patient with neoplasia (12/94). Dysplasia detected by random biopsies was associated with a personal history of neoplasia, a tubular appearing colon and the presence of primary sclerosing cholangitis (PSC). CONCLUSIONS: Despite their low yield, random biopsies should be performed in association with CE in patients with IBD with a personal history of neoplasia, concomitant PSC or a tubular colon during colonoscopy. TRIAL REGISTRATION NUMBER: IRB 001508, Paris 7 University.

The multiple faces of inflammatory enteric glial cells: is Crohn's disease a gliopathy?

Gone are the days when enteric glial cells (EGC) were considered merely satellites of enteric neurons. Like their brain counterpart astrocytes, EGC express an impressive number of receptors for neurotransmitters and intercellular messengers, thereby contributing to neuroprotection and to the regulation of neuronal activity. EGC also produce different soluble factors that regulate neighboring cells, among which are intestinal epithelial cells. A better understanding of EGC response to an inflammatory environment, often referred to as enteric glial reactivity, could help define the physiological role of EGC and the importance of this reactivity in maintaining gut functions. In chronic inflammatory disorders of the gut such as Crohn's disease (CD) and ulcerative colitis, EGC exhibit abnormal phenotypes, and their neighboring cells are dysfunctional; however, it remains unclear whether EGC are only passive bystanders or active players in the pathophysiology of both disorders. The aim of the present study is to review the physiological roles and properties of EGC, their response to inflammation, and their role in the regulation of the intestinal epithelial barrier and to discuss the emerging concept of CD as an enteric gliopathy.

Outcomes 7 Years After Infliximab Withdrawal for Patients With Crohn's Disease in Sustained Remission.

BACKGROUND & AIMS: Little is known about long-term outcomes of patients with Crohn's disease (CD) after infliximab withdrawal. We aimed to describe the long-term outcomes of patients with CD in clinical remission after infliximab treatment was withdrawn. METHODS: We performed a retrospective analysis of data from the 115 patients included in the infliximab discontinuation in patients with CD in stable remission on combined therapy with antimetabolites (STORI) study, performed at 20 centers in France and Belgium from March 2006 through December 2009. The STORI cohort was a prospective analysis of risk and factors associated with relapse following withdrawal of maintenance therapy with infliximab, maintained on antimetabolites, while in clinical remission. We collected data from the end of the study until the last available follow-up examination on patient surgeries, new complex perianal lesions (indicating major complications), and need for and outcomes of restarting therapy with infliximab or another biologic agent. The de-escalation strategy was considered to have failed when a major complication or infliximab restart failure occurred. RESULTS: Of the 115 patients initially included, data from 102 patients (from 19 of the 20 study centers) were included in the final analysis. The median follow-up time was 7 years. Twenty-one percent of the patients did not restart treatment with infliximab or another biologic agent and did not have a major complication 7 years after infliximab withdrawal (95% CI, 13.1-30.3). Among patients who restarted infliximab, treatment failed for 30.1% 6 years after restarting (95% CI, 18.5-42.5). Overall, at 7 years after stopping infliximab therapy, major complications occurred in 18.5% of patients (95% CI, 10.2-26.8) whereas 70.2% of patients had no failure of the de-escalation strategy (95% CI, 60.2-80.1). Factors independently associated with major complications were upper-gastrointestinal location of disease, white blood cell count ≥ 5.0 × 109/L, and hemoglobin level ≤12.5 g/dL at the time of infliximab withdrawal. Patients with at least 2 of these factors had a more than 40% risk of major complication in the 7 years following infliximab withdrawal. CONCLUSIONS: In a long-term follow-up of the STORI cohort (7 years) one fifth of the patients did not restart infliximab or another biologic agent and did not develop major complications. Seventy percent of patients had no failure of the de-escalation strategy (no major complication and no failure of infliximab restart).

An intermediate level of CD161 expression defines a novel activated, inflammatory, and pathogenic subset of CD8+ T cells involved in multiple sclerosis.

Several lines of evidence support a key role for CD8+ T cells in central nervous system tissue damage of patients with multiple sclerosis. However, the precise phenotype of the circulating CD8+ T cells that may be recruited from the peripheral blood to invade the CNS remains largely undefined to date. It has been suggested that IL-17 secreting CD8 (Tc17) T cells may be involved, and in humans these cells are characterized by the expression of CD161. We focused our study on a unique and recently described subset of CD8 T cells characterized by an intermediate expression of CD161 as its role in neuroinflammation has not been investigated to date. The frequency, phenotype, and function of CD8+ T cells with an intermediate CD161 expression level were characterized ex-vivo, in vitro, and in situ using RNAseq, RT-PCR, flow cytometry, TCR sequencing, and immunohistofluorescence of cells derived from healthy volunteers (n = 61), MS subjects (n = 90), as well as inflammatory (n = 15) and non-inflammatory controls (n = 6). We report here that CD8+CD161int T cells present characteristics of effector cells, up-regulate cell-adhesion molecules and have an increased ability to cross the blood-brain barrier and to secrete IL-17, IFNγ, GM-CSF, and IL-22. We further demonstrate that these cells are recruited and enriched in the CNS of MS subjects where they produce IL-17. In the peripheral blood, RNAseq, RT-PCR, high-throughput TCR repertoire analyses, and flow cytometry confirmed an increased effector and transmigration pattern of these cells in MS patients, with the presence of supernumerary clones compared to healthy controls. Our data demonstrate that intermediate levels of CD161 expression identifies activated and effector CD8+ T cells with pathogenic properties that are recruited to MS lesions. This suggests that CD161 may represent a biomarker and a valid target for the treatment of neuroinflammation.

Methotrexate Is Not Superior to Placebo for Inducing Steroid-Free Remission, but Induces Steroid-Free Clinical Remission in a Larger Proportion of Patients With Ulcerative Colitis.

BACKGROUND & AIMS: Parenteral methotrexate is an effective treatment for patients with Crohn's disease, but has never been adequately evaluated in patients with ulcerative colitis (UC). We conducted a randomized controlled trial to determine its safety and efficacy in patients with steroid-dependent UC. METHODS: We performed a double-blind, placebo-controlled trial to evaluate the efficacy of parenteral methotrexate (25 mg/wk) in 111 patients with corticosteroid-dependent UC at 26 medical centers in Europe from 2007 through 2013. Patients were given prednisone (10 to 40 mg/d) when the study began and were randomly assigned to groups (1:1) given placebo or methotrexate (intramuscularly or subcutaneously, 25 mg weekly) for 24 weeks. The primary end point was steroid-free remission (defined as a Mayo score ≤2 with no item >1 and complete withdrawal of steroids) at week 16. Secondary endpoints included clinical remission (defined as a Mayo clinical subscore ≤2 with no item >1) and endoscopic healing without steroids at weeks 16 and/or 24, remission without steroids at week 24, and remission at both weeks 16 and 24. RESULTS: Steroid-free remission at week 16 was achieved by 19 of 60 patients given methotrexate (31.7%) and 10 of 51 patients given placebo (19.6%)--a difference of 12.1% (95% confidence interval [CI]: -4.0% to 28.1%; P = .15). The proportion of patients in steroid-free clinical remission at week 16 was 41.7% in the methotrexate group and 23.5% in the placebo group, for a difference of 18.1% (95% CI: 1.1% to 35.2%; P = .04). The proportions of patients with steroid-free endoscopic healing at week 16 were 35% in the methotrexate group and 25.5% in the placebo group--a difference of 9.5% (95% CI: -7.5% to 26.5%; P = .28). No differences were observed in other secondary end points. More patients receiving placebo discontinued the study because of adverse events (47.1%), mostly caused by UC, than patients receiving methotrexate (26.7%; P = .03). A higher proportion of patients in the methotrexate group had nausea and vomiting (21.7%) than in the placebo group (3.9%; P = .006). CONCLUSIONS: In a randomized controlled trial, parenteral methotrexate was not superior to placebo for induction of steroid-free remission in patients with UC. However, methotrexate induced clinical remission without steroids in a significantly larger percentage of patients, resulting in fewer withdrawals from therapy due to active UC. ClinicalTrials.gov ID NCT00498589.

Neuropathologic, phenotypic and functional analyses of Mucosal Associated Invariant T cells in Multiple Sclerosis.

BACKGROUND: The involvement of Mucosal Associated Invariant T (MAIT) cells, which are anti-microbial semi-invariant T cells, remains elusive in Multiple Sclerosis (MS). OBJECTIVE: Deciphering the potential involvement of MAIT cells in the MS inflammatory process. METHODS: By flow cytometry, blood MAIT cells from similar cohorts of MS patients and healthy volunteers (HV) were compared for frequency, phenotype, activation potential after in vitro TCR engagement by bacterial ligands and transmigration abilities through an in vitro model of blood-brain barrier. MS CNS samples were also studied by immunofluorescent staining and quantitative PCR. RESULTS AND CONCLUSION: Blood MAIT cells from relapsing-remitting MS patients and HV presented similar frequency, ex vivo effector phenotype and activation abilities. MAIT cells represented 0.5% of the total infiltrating T cells on 39 MS CNS lesions. This is low as compared to blood frequency (p<0.001), but consistent with their low transmigration rate. Finally, transcriptional over-expression of MR1 - which presents cognate antigens to MAIT cells - and of the activating cytokines IL-18 and IL-23 was evidenced in MS lesions, suggesting that the CNS microenvironment is suited to activate the few infiltrating MAIT cells. Taken together, these data place MAIT cells from MS patients as minor components of the inflammatory pathological process.