Risk of anti-TNF therapy on pregnancy, breastfeeding, live vaccines and related information in patients with inflammatory bowel disease: Real-world data from a nationwide study.

BACKGROUND: Anti-TNF are usually maintained during pregnancy in patients with inflammatory bowel disease (IBD) but safety is still a concern for them. AIMS: To provide data on management of anti-TNF agents during pregnancy, safety of live vaccines (BCG-MMR-rotavirus) and breastfeeding in newborns and dedicated information delivered to IBD women. METHODS: We performed an observational study in 25 centers from 2016 to 2018. We administered questionnaires to women with IBD receiving anti-TNF during pregnancy with newborn follow-up ≥ one year. RESULTS: Of 153 patients, 52 % maintained anti-TNF during the third trimester. Anti-TNF was shortly resumed in 79 % (58/73) after delivery. The rate of breastfeeding was 44 % (68/153) without any complication; 38 % of the mothers denied to breastfeed based on physician's advice. 26 % (34/129) of the newborns received live vaccines before 6 months-old (BCG:30 %; MMR:63 %; Rotavirus:8 %) and only 3 complications occurred (local BCGitis=1, fever=2). Information concerning anti-TNF during pregnancy/post-partum was delivered to 92 % of the patients, mainly by a gastroenterologist (97 %) who discussed with the obstetrician or the paediatrician in only 48 % and 25 %. CONCLUSION: In IBD patients, maintaining anti-TNF during pregnancy and breastfeeding is safe. Accidental live vaccines before 6 months did not lead to significant adverse events. The communication about these questions remains to improve.

Comparative Risk of Incident Cancer in Patients with Inflammatory Bowel Disease with Prior Non-digestive Malignancy According to Immunomodulator: a Multicentre Cohort Study.

INTRODUCTION: Knowledge about the cancer risk when initiating a biologic in inflammatory bowel disease [IBD] patients with prior malignancy remains scarce, especially for vedolizumab. Our aim was to evaluate the rate of incident cancer in a cohort of IBD patients with prior non-digestive malignancy, according to the subsequent treatment given. METHODS: A multicentre retrospective study included consecutive IBD patients with prior non-digestive malignancy. Inclusion date corresponded to the diagnosis of index malignancy. Patients were categorized into different cohorts according to the first treatment [none, conventional immunosuppressant, anti-TNF, or vedolizumab] to which they were exposed after inclusion and before incident cancer [recurrent or new cancer]. RESULTS: Among the 538 patients {58% female; mean (standard deviation [SD]) age inclusion: 52 [15] years} analyzed, the most frequent malignancy was breast cancer [25%]. The first immunomodulator given after inclusion was a conventional immunosuppressant in 27% of patients, anti-TNF in 21%, or vedolizumab in 9%. With a median (interquartile range [IQR]) follow-up duration of 55 [23-100] months, 100 incident cancers were observed. Crude cancer incidence rates per 1000 person-years were 47.0 for patients receiving no immunomodulator, 36.6 in the anti-TNF cohort, and 33.6 in the vedolizumab cohort [p = 0.23]. Incident-cancer free survival rates were not different between patients receiving anti-TNF and those receiving vedolizumab [p = 0.56]. After adjustment, incidence rates were not different between patients receiving no immunomodulator, anti-TNF, or vedolizumab. CONCLUSIONS: In this large multicentre cohort study, there was no difference of cancer incidence in those IBD patients with prior non-digestive malignancy, treated with vedolizumab or anti-TNF.

Prognosis of Lymphoma in Patients With Known Inflammatory Bowel Disease: A French Multicentre Cohort Study.

BACKGROUND AND AIMS: The prognosis of lymphoma that occurs in patients with inflammatory bowel disease [IBD] is poorly known. METHODS: A multicentre retrospective cohort analysis was done in seven French tertiary centres from 1999 to 2019. Only lymphoma occurring in patients with previous established diagnosis of IBD were analysed. The primary outcome was progression-free survival at 3 years. RESULTS: A total of 52 patients [male 65%, Crohn's disease 79%, median age 48.3 years, median duration of IBD 10.1 years] were included, of whom 37 had been previously exposed to immunosuppressants and/or biologics for at least 3 months and 20 had primary intestinal lymphomas. The lymphoma histological types were: diffuse large B cell lymphomas [N = 17], Hodgkin lymphomas [N = 17], indolent B cell lymphomas [N = 12], and others including T cell lymphomas, mantle cell lymphomas, and unclassifiable B cell lymphoma [N = 6]. The median follow-up after lymphoma was 5.1 years (interquartile range [IQR] 4-7.8). Progression-free survival at 3 years was 85% in the overall population (95% confidence interval [CI] 75%-96%) with no significant difference between the exposed and unexposed group, 79% for patients exposed to immunosuppressants and/or biologics [95% CI 67%-94%], and 83% for patients diagnosed with primary intestinal lymphoma [95% CI 67%-100%]. No relapse of IBD has been observed during chemotherapy. The IBD relapse rate at the end of the last chemotherapy cycle was 23% at 3 years [95% CI 11%-39%] in the overall population. CONCLUSIONS: In this large cohort, the prognosis for lymphomas occurring in IBD appears to be good and similar to what is expected, irrespective of the exposure to biologics and/or immunosuppressants.

Efficacy and safety of golimumab in Crohn's disease: a French national retrospective study.

BACKGROUND: Anti-tumour necrosis factor (TNF) agents have improved the care of Crohn's disease (CD). After the first anti-TNF discontinuation, it is possible to switch to another anti-TNF. Three anti-TNF agents are available for ulcerative colitis (infliximab, adalimumab and golimumab), but only the first 2 have been approved for CD because golimumab has not been studied for this indication. AIM: To report the efficacy and safety of golimumab in CD. METHODS: Crohn's disease patients who received golimumab were identified in 12 French tertiary centres and were retrospectively analysed. The primary endpoint was the duration of golimumab treatment before escalation or discontinuation. The clinical response was defined as a decrease of more than 3 points in the Harvey-Bradshaw index or by global physician assessment. RESULTS: One hundred and fifteen patients were included. The golimumab treatment duration was 9.8 months (0.55-44), and 48.7% of the patients were still under treatment at the end of follow-up. Clinical response was observed in 55.8% of the patients after a mean duration of 3.8 months. The probability of remaining under treatment without escalation at 6, 12 and 24 months was 54.6%, 34.9% and 19.3% respectively. In multivariate analysis, discontinuation of the first anti-TNF agent due to intolerance (odds ratio, OR = 2.16; 95% CI, confidence interval [1.25-3.86]; P = .005) and co-immunosuppression for more than 6 months (OR = 3.98; 95% CI [2.3-7.1]; P < .0001) were predictive factors of efficacy. Six per cent of the patients discontinued treatment due to intolerance. CONCLUSION: After failure of infliximab or adalimumab for Crohn's disease, golimumab was safe and seemed beneficial in half of the patients.

The effects of aminosalicylates or thiopurines on the risk of colorectal cancer in inflammatory bowel disease.

BACKGROUND: Whether aminosalicylates or thiopurines reduce the risk of colorectal cancer (CRC) in inflammatory bowel (IBD) disease is controversial. AIM: To assess simultaneously the chemopreventive effect of aminosalicylates or thiopurines in a case-control study nested in the CESAME observational cohort that enrolled consecutive patients with IBD between May 2004 and June 2005. Patients were followed up to December 2007. METHODS: Study population comprised 144 case patients who developed CRC from the diagnosis of IBD (65 and 79 cases diagnosed, respectively, before and from 2004, starting year of the prospective observational period of CESAME) and 286 controls matched for gender, age, IBD subtype and year of diagnosis, and cumulative extent of colitis. Exposure to aminosalicylates or thiopurines was defined by an exposure to the treatment during the year of the diagnosis of cancer. The propensity of receiving 5-ASA and thiopurines was quantified by a composite score taking into account patient and IBD characteristics. The role of aminosalicylates or thiopurines was assessed by multivariate analysis. Propensity scores and the history of primary sclerosing cholangitis were entered into the multivariate model for adjustment. RESULTS: By multivariate analysis adjusted for propensity, a significant protective effect of exposure to drugs during the year of cancer was found for aminosalicylates (OR = 0.587, 95% CI: 0.367-0.937, P = 0.0257), but not for thiopurines (OR = 0.762, 95% CI: 0.432-1.343, P = 0.3468). CONCLUSION: In a case-control study nested in the CESAME cohort, a significant decrease in the risk of colorectal cancer in IBD was associated with exposure to aminosalicylates, not to thiopurines.

Adalimumab or infliximab as monotherapy, or in combination with an immunomodulator, in the treatment of Crohn's disease.

BACKGROUND: The comparative efficacy of adalimumab (ADA) and infliximab (IFX) in Crohn's disease, and the benefit of initial combotherapy with an immunomodulator, are debated. AIM: To assess the best anti-TNF treatment regimens in Crohn's disease. METHODS: We included 906 biologic-naïve Crohn's disease patients [median age, 31 years (24-41)] and performed a retrospective analysis of 1284 therapeutic exposures to ADA (n = 521) or IFX (n = 763) between 2006 and 2015. An immunomodulator was associated during the first 4-6 months (initial combotherapy) during 706 therapeutic exposures (55%). Median duration of anti-TNF therapy was 39 months (IQR 17-67). Primary outcomes were 6-month and 2-year response rates and drug survival. Logistic regression with propensity scoring and Cox proportional hazard analysis determined variables associated with outcomes. RESULTS: The response rates at 6 months and 2 years were 64% and 44% on ADA mono, 86% and 70% on ADA combo, 72% and 45% on IFX mono, and 84% and 68% on IFX combotherapy, respectively. Differences between ADA and IFX were not significant, whereas combotherapy was superior to monotherapy (P < 0.001). Drug survival was longer with combotherapy vs. monotherapy [adjusted hazard ratio 2.17 (1.72-2.70)] and not significantly different between ADA and IFX. During subsequent anti-TNF exposures, IFX combotherapy fared better than other groups regarding response rates, drug survival, disease activity, hospitalisations and abdominal surgery. CONCLUSION: In this retrospective analysis of a large tertiary centre cohort of Crohn's disease patients, ADA and IFX had similar efficacy as first line treatment, while initial combotherapy with an immunomodulator improved all outcome measures.

Excess risk of urinary tract cancers in patients receiving thiopurines for inflammatory bowel disease: a prospective observational cohort study.

BACKGROUND: The risk of urinary tract cancers, including kidney and bladder cancers, was increased in transplant recipients receiving thiopurines. AIM: To assess the risk of urinary tract cancers in patients with inflammatory bowel disease (IBD) receiving thiopurines in the CESAME observational cohort. METHODS: Between May 2004 and June 2005, 19 486 patients with IBD, 30.1% of whom were receiving thiopurines, were enrolled. Median follow-up was 35 months (IQR: 29-40). RESULTS: Ten and six patients developed respectively kidney and bladder cancer. The incidence rates of urinary tract cancer were 0.48/1000 patient-years in patients receiving thiopurines (95% CI: 0.21-0.95), 0.10/1000 patient-years in patients who discontinued thiopurines (95% CI: 0.00-0.56) and 0.30/1000 patient-years in patients never treated with thiopurines (95% CI: 0.12-0.62) at entry. The standardised incidence ratio of urinary tract cancer was 3.40 (95% CI: 1.47-6.71, P = 0.006) in patients receiving thiopurines, 0.64 (95% CI: 0.01-3.56, P = 0.92) in patients previously exposed to thiopurines and 1.17 (95% CI: 0.47-12.42, P = 0.78) in patients never treated with thiopurines. The multivariate-adjusted hazard ratio (HR) of urinary tract cancer between patients receiving thiopurines and those not receiving thiopurines was 2.82 (95% CI: 1.04-7.68, P = 0.04). Other significant risk factors were male gender (HR: 3.98, 95% CI: 1.12-14.10, P = 0.03) and increasing age (HR after 65 years (ref <50): 13.26, 95% CI: 3.52-50.03, P = 0.0001). CONCLUSION: Patients with IBD receiving thiopurines have an increased risk of urinary tract cancers. Clinically relevant excess risk is observed in older men.

Extra-intestinal malignancies in inflammatory bowel diseases: An update with emphasis on MDCT and MR imaging features.

Inflammatory bowel diseases (IBD) are associated with an increased risk of gastrointestinal cancers and more specifically in sites affected by chronic inflammation. However, patients with IBD have also an increased risk for developing a variety of extra-intestinal cancers. In this regard, hepatobiliary cancers, such as cholangiocarcinoma, are more frequently observed in IBD patients because of a high prevalence of primary sclerosing cholangitis, which is considered as a favoring condition. Extra-intestinal lymphomas, mostly non-Hodgkin lymphomas, and skin cancers are also observed with an increased incidence in IBD patients by comparison with that in patients without IBD. This review provides an update on demographics, risk factors and clinical features of extra-intestinal malignancies, including cholangiocarcinoma, hepatocellular carcinoma and lymphoma, that occur in patients with IBD along with a special emphasis on the multidetector row computed tomography and magnetic resonance imaging features of these uncommon conditions.

Benefit of infliximab reintroduction after successive failure of infliximab and adalimumab in Crohn's disease.

BACKGROUND: Infliximab [IFX] and adalimumab [ADA] are effective in Crohn's disease [CD] for induction and maintenance therapy. However, high annual rate of discontinuation for loss of response or intolerance may lead to a switch to another anti-tumor necrosis factor agent. Patients with successive failure to IFX and ADA are becoming more frequent. The aim of this study was to assess the efficacy and the tolerance of re-treatment with IFX in CD patients who successively failed IFX and ADA. METHODS: A total of 61 patients with CD who received and discontinued successively IFX and ADA, and who were re-exposed to IFX, were identified in four French tertiary centers and retrospectively analyzed. Clinical data, follow-up and outcome were abstracted from medical records. RESULTS: Median treatment duration after reintroduction was 16 months, and probability of remaining under IFX was 60% and 51%, respectively, at 12 and 24 months. In all 29 patients discontinued the second IFX treatment due to intolerance [13], primary non-response [8], loss of response [7] or patient's wish [1]. Remission was achieved in 42% at week 6-8 after IFX re-induction, and was predictive of better long-term response [p = 0.006]. In multivariate analysis, receiving co-immunosuppression in both first and second IFX treatments [p = 0.04] and shorter interval between first and second IFX treatments [p = 0.017] were independently associated with longer duration of second IFX treatment. CONCLUSION: For CD patients who successively failed IFX and ADA, reintroducing IFX is feasible and often clinically efficient, particularly in patients who received co-immunosuppression during both first and second IFX treatments.

The impact of cytomegalovirus reactivation and its treatment on the course of inflammatory bowel disease.

BACKGROUND: Consequences of latent cytomegalovirus (CMV) infection reactivation on inflammatory bowel disease (IBD) flare, as a flare-worsening factor or simple bystander, are debated. Impact of anti-viral treatment on IBD course is poorly known. AIM: To assess the impact of CMV reactivation on patients hospitalised for IBD flare and the effect of anti-viral treatment on IBD flare in patients with CMV reactivation. METHODS: First, a population of UC patients from Saint-Antoine hospital, in flare with positive blood CMV PCR without anti-viral treatment (n = 26), were compared to matched patients with negative blood CMV PCR in a case-control study. Secondly, a total of 110 hospitalisations between October 2003 and May 2012 for IBD flare-up with CMV reactivation (80 diagnosed on blood PCR, 33 on tissue PCR) were identified in three French referral centres. Evolution following CMV reactivation diagnosis was compared between patients receiving anti-viral treatment and those who did not. RESULTS: In the case-control study, no differences were observed between the two groups regarding length of hospital stay and colectomy rate. Comparing treated and untreated patients, no differences were observed at inclusion regarding age, gender, IBD type, immunosuppressant, CRP and haemoglobin level. No differences were observed regarding CRP level decrease at 10 days and colectomy rate at 3 months. Anti-viral treatment was associated with lower serum albumin level at inclusion and longer hospitalisation. CONCLUSIONS: CMV reactivation does not appear to alter the course of IBD flare. CMV treatment does not seem to impact the course of IBD. These results should be confirmed prospectively.

Impact of the diagnosis and treatment of cancer on the course of inflammatory bowel disease.

BACKGROUND: The effects of extra-intestinal cancer on the course of inflammatory bowel disease (IBD) are poorly understood. AIM: To evaluate the impact of cancer and its management on IBD outcomes. METHODS: A total 80 IBD patients (51 Crohn's disease, 29 ulcerative colitis; 33 men, median age at cancer diagnosis 48yrs) diagnosed with extra-intestinal cancer were selected from a prospective database. IBD activity and therapeutic requirements (assessed year-by-year) were compared before and after cancer diagnosis, with a control group of patients without cancer matched for gender, birth date, date of IBD diagnosis and IBD phenotype. RESULTS: Paired comparisons of the consecutive periods before and after cancer diagnosis did not show significant changes in median (IQR) percentages of years with active disease (27% [0-50] vs. 19% [0-53]), while the proportion of patient-years on any immunosuppressant remained stable (26% vs. 28%). Chemotherapy had no significant effect on IBD activity. Compared to controls, patients with cancer had a similar IBD activity and use of anti-TNF, but less use of immunomodulators (19% vs. 25%, p<0,001) and an increased rate of surgery (4% vs. 2.5%, p<0,05). Individual variations in IBD activity after cancer diagnosis were not significantly different in patients with cancer and their matched controls. CONCLUSION: Occurrence of extra-intestinal cancer impacts IBD therapeutic management, with a trend towards less use of immunomodulators and more surgery. In the long-term, cancer diagnoses and treatments do not modify IBD outcomes.

Low prevalence of colonoscopic surveillance of inflammatory bowel disease patients with longstanding extensive colitis: a clinical practice survey nested in the CESAME cohort.

BACKGROUND: Surveillance colonoscopy is recommended for inflammatory bowel disease (IBD) patients with longstanding extensive colitis (LEC). AIMS: To assess modalities and results of colonoscopic surveillance in a subset of CESAME cohort patients at high risk of colorectal cancer (CRC) and followed in university French hospitals. METHODS: Among 910 eligible patients with more than a 7-year history of extensive colitis at CESAME enrolment, 685 patients completed a questionnaire on surveillance colonoscopy and 102 were excluded because of prior proctocolectomy. Finally, 583 patients provided information spanning a median period of 41months (IQR 38-43) between cohort enrolment and the end of follow-up. Details of the colonoscopic procedures and histological findings were obtained for 440 colonoscopies in 270 patients. RESULTS: Only 54% (n=312) of the patients with LEC had at least one surveillance colonoscopy during the study period, with marked variations across the nine participating centres (27% to 70%, P≤0.0001). Surveillance rate was significantly lower in Crohn's colitis than in ulcerative colitis (UC) (48% vs. 69%, P≤0.0001). Independent predictors of colonoscopic surveillance were male gender, UC IBD subtype, longer disease duration, previous history of CRC and disease management in a centre with large IBD population. Random biopsies, targeted biopsies and chromoendoscopy were performed during respectively 71%, 27 and 30% of surveillance colonoscopies. Two cases of high-grade dysplasia were detected in patients undergoing colonoscopic surveillance. Two advanced-stage CRC were diagnosed in patients who did not have colonosocopic surveillance. CONCLUSIONS: Colonoscopic surveillance rate is low in IBD patients with longstanding extensive colitis.

Inflammatory bowel disease and lymphoproliferative disorders: the dust is starting to settle.

The risk of lymphoproliferative disorders (LDs) has become a major concern for clinicians managing patients with inflammatory bowel disease (IBD). Yet it is difficult to distinguish the possible responsibility of immunosuppressive therapy from the background risk due to the inflammatory disorder itself. LDs are clonal B or T cell proliferation showing considerable heterogeneity and the incidence has increased since the 1970s. The strongest and best-established risk factors for LDs are primary and acquired immunodeficiency (HIV, immunosuppressant), notably via defective immune surveillance of Epstein-Barr virus. In many auto-immune diseases (eg, Sjögren's syndrome), inflammatory diseases (eg, rheumatoid arthritis) or chronic suppuration (chronic pyothorax), the risk of LD is increased. In IBD patients, in general, the risk of LD seems to be similar to or very slightly higher than in the general population. The role of immunosuppressants in lymphomagenesis is difficult to individualise because other factors potentially involved are inter-linked. Concordant data suggest that thiopurine therapy is associated with a moderately increased risk of LD. Data regarding methotrexate are scarce and come from diseases other than IBD but the risk seems low. Data regarding risk of LD in IBD patients receiving anti-tumour necrosis factor alpha (TNFalpha) agents are insufficient at this time, mainly because most of the patients are co-treated with thiopurines. The recently individualised risks of hepatosplenic T cell lymphoma and fatal post-mononucleosis LD, in young male patients with IBD who are co-treated with anti-TNFalpha and thiopurines, and EBV-seronegative IBD males, respectively, are probably low but remain to be better quantified.

Irritable bowel syndrome is more frequent in patients hospitalized for ischaemic colitis: results of a case-control study.

It has been suspected that there is an epidemiological link between irritable bowel syndrome (IBS) and ischaemic colitis (IC). We performed a retrospective case-control study to compare the frequency of IBS in patients hospitalized for IC compared with that of patients with peptic ulcer bleeding. Cases were patients with a first episode of IC and controls were patients with a first episode of peptic ulcer bleeding, matched to cases for sex and 10-year age-class. Diagnosis of IBS was based on medical information extracted from hospital medical files and a standard self-questionnaire. The association between IBS and IC was tested using Mc Nemar's paired odds ratio (OR); confidence interval at 95% (CI 95%) was calculated; Mantel-Haenzel's Chi(2) was applied. A total of 113 cases and 113 matched controls were studied. There were 37 males and 76 females and the mean age was 69 +/- 15 years in each group. The prevalence of IBS in cases was 16.9%vs 1.8% in controls. The risk of IBS was 11.05 times higher among cases than in controls (P < 0.001); CI 95%: (2.45-49.74). A total of 87 pairs with complete data were used for OR calculation. The risk of IBS was 7.5 times higher in cases than in controls (P = 0.002); CI 95%: (1.72-32.80). This case-control study shows that IBS is more frequent in IC patients than in controls.

Incidence of benign upper respiratory tract infections, HSV and HPV cutaneous infections in inflammatory bowel disease patients treated with azathioprine.

BACKGROUND: There are few data on the incidence of benign infections (upper respiratory tract infections, herpes lesions and viral warts) during exposure to azathioprine. AIMS: To determine the incidence of benign infections in IBD out-patients receiving azathioprine (AZA+) and to look at the influence of leucocyte counts in the onset of these events. METHODS: A total of 230 patients were included in a prospective cohort and observed during 207 patient-years. Episodes of benign infections were collected and incidences of benign infections were compared between the AZA+ group and patients without AZA (AZA-). RESULTS: The incidence of upper respiratory tract infections in the cohort was 2.1 +/- 2.2 per observation-year. There was no difference between the AZA+ (n = 169) and AZA- (n = 61) groups (2.2 +/- 2.3 vs. 2.1 +/- 2.1, P = 0.77). The incidence of herpes flares was significantly increased in the AZA+ group compared to the AZA- group (1.0 +/- 2.6 vs. 0.2 +/- 0.8 per year, P = 0.04). Similarly, there were significantly more patients with appearance or worsening viral warts in the AZA+ group (17.2% (AZA+) vs. 3.3% (AZA-), P = 0.004). CONCLUSION: This study suggests that the incidence of herpes flares and the appearance or worsening of viral warts are increased in IBD patients receiving AZA.

Low counts of Faecalibacterium prausnitzii in colitis microbiota.

BACKGROUND: The intestinal microbiota is suspected to play a role in colitis and particularly in inflammatory bowel disease (IBD) pathogenesis. The aim was to compare the fecal microbiota composition of patients with colitis to that of healthy subjects (HS). METHODS: fecal samples from 22 active Crohn's disease (A-CD) patients, 10 CD patients in remission (R-CD), 13 active ulcerative colitis (A-UC) patients, 4 UC patients in remission (R-UC), 8 infectious colitis (IC) patients, and 27 HS were analyzed by quantitative real-time polymerase chain reaction (PCR) targeting the 16S rRNA gene. Bacterial counts were transformed to logarithms (Log(10) CFU) for statistical analysis. RESULTS: Bacteria of the phylum Firmicutes (Clostridium leptum and Clostridium coccoides groups) were less represented in A-IBD patients (9.7; P = 0.004) and IC (9.4; P = 0.02), compared to HS (10.8). Faecalibacterium prausnitzii species (a major representative of the C. leptum group) had lower counts in A-IBD and IC patients compared to HS (8.8 and 8.3 versus 10.4; P = 0.0004 and P = 0.003). The Firmicutes/Bacteroidetes ratio was lower in A-IBD (1.3; P = 0.0001) and IC patients (0.4; P = 0.002). Compared to HS, Bifidobacteria were less represented in A-IBD and IC (7.9 and 7.7 versus 9.2; P = 0.001 and P = 0.01). CONCLUSIONS: The fecal microbiota of patients with IBD differs from that of HS. The phylum Firmicutes and particularly the species F. prausnitzii, are underrepresented in A-IBD patients as well as in IC patients. These bacteria could be crucial to gut homeostasis since lower counts of F. prausnitzii are consistently associated with a reduced protection of the gut mucosa.