Evaluation of genetic variants associated with the risk of thiopurine-related pancreatitis: a case control study from ENEIDA registry.

BACKGROUND: Risk factors for developing pancreatitis due to thiopurines in patients with inflammatory bowel disease (IBD) are not clearly identified. AIM: Our aim was to evaluate the predictive pharmacogenetic risk of pancreatitis in IBD patients treated with thiopurines. METHODS: We conducted an observational pharmacogenetic study of acute pancreatitis events in a cohort study of IBD patients treated with thiopurines from the prospectively maintained ENEIDA registry biobank of GETECCU. Samples were obtained and the CASR, CEL, CFTR, CDLN2, CTRC, SPINK1, CPA1, and PRSS1 genes, selected based on their known association with pancreatitis, were fully sequenced. RESULTS: Ninety-five cases and 105 controls were enrolled, 57% were women. Median age at pancreatitis diagnosis was 39 years. We identified 81 benign variants (50 in cases and 67 in controls) and a total of 35 distinct rare pathogenic and unknown significance variants (10 in CEL, 21 in CFTR, 1 in CDLN2, and 3 in CPA1). None of the cases or controls carried pancreatitis-predisposing variants within the CASR, CPA1, PRSS1, and SPINK1 genes, nor a pathogenic CFTR mutation. Four different variants of unknown significance were detected in the CDLN and CPA1 genes; one of them was in the CDLN gene in a single patient with pancreatitis, and 3 in the CPA1 gene in 5 controls. After the analysis of the variants detected, no significant differences were observed between cases and controls. CONCLUSION: In patients with IBD, genes known to cause pancreatitis seem not to be involved in thiopurine-related pancreatitis onset.

The Natural History of Patients With Pre-Existing and De Novo Inflammatory Bowel Disease After Solid Organ Transplantation: EITOS Study of GETECCU.

BACKGROUND: Limited data are available on the outcome of inflammatory bowel disease (IBD) in patients with solid organ transplantation (SOT). We describe the natural history of pre-existing IBD and de novo IBD after SOT. METHODS: This was a retrospective, multicenter study that included patients with pre-existing IBD at the time of SOT and patients with de novo IBD after SOT. The primary outcome was IBD progression, defined by escalation of medical treatment, surgical therapy, or hospitalization due to refractory IBD. Risk factors were identified using multivariate Cox proportional hazard analysis. RESULTS: A total of 177 patients (106 pre-existing IBD and 71 de novo IBD) were included. Most patients with pre-existing IBD (92.5%) were in remission before SOT. During follow-up, 32% of patients with pre-existing IBD had disease progression, with a median time between SOT and IBD progression of 2.2 (interquartile range, 1.3-4.6) years. In the de novo cohort, 55% of patients had disease progression with a median time to flare of 1.9 (interquartile range, 0.8-3.9) years after diagnosis. In the pre-existing IBD cohort, active IBD at the time of SOT (hazard ratio, 1.80; 95% confidence interval, 1.14-2.84; P = .012) and the presence of extraintestinal manifestations (hazard ratio, 3.10; 95% confidence interval, 1.47-6.54; P = .003) were predictive factors for IBD progression. CONCLUSIONS: One-third of patients with pre-existing IBD and about half of patients with de novo IBD have disease progression after SOT. Active IBD at the time of SOT and the presence of extraintestinal manifestations were identified as risk factors for IBD progression.

Intensification with Intravenous Ustekinumab in Refractory Crohn's Disease.

BACKGROUND: The rates of clinical and biochemical responses in Crohn's disease (CD) patients treated with intravenous (IV) ustekinumab (UST) intensification are scarcely described. METHODS: Patients with diagnosis of CD who were under intensified IV ustekinumab treatment (130 mg every 4 weeks) were retrospectively included, evaluating the clinical and biochemical response 12 weeks after the change in treatment regimen (switch from SC to IV), as well as the serum levels of the drug. RESULTS: Twenty-seven patients, all of whom had transitioned to intensified intravenous ustekinumab treatment due to a secondary loss of response to the drug, were included in the retrospective analysis. At the baseline visit, prior to changing IV UST, differences in levels were observed between intensified and non-intensified patients (7216 vs. 2842 ng/mL, p = 0.00005). However, no significant differences were found between these two groups 12 weeks after IV intensification (7949 vs. 7937 ng/mL; p = 0.99). In patients with previous intensified UST SC, a decrease in fecal calprotectin was observed 12 weeks after starting IV intensification, going from a mean of 1463 ug/g to 751 ug/g, although the differences were not significant (p = 0.14). CONCLUSION: In our experience, intensifying treatment with IV UST leads to clinical and biochemical improvements in CD patients with a secondary loss of response to SC maintenance with this drug, and an increase in drug levels was observed 12 weeks after IV UST intensification.

Selective granulocyte-monocyte apheresis during induction with vedolizumab in moderate-severe ulcerative colitis: Experience in a tertiary hospital.

AIM: Granulocyte and monocyte apheresis (GMA) is a potential therapeutic option when combined with various drugs for treatment of ulcerative colitis (UC). In this study, we analyze the efficacy and safety of GMA combined with vedolizumab (VDZ) during induction in patients with moderate-severe UC and incomplete response to steroids. PATIENTS AND METHODS: Single-center retrospective review of patients receiving GMA+VDZ. Data on the disease and previous treatments were collected. Clinical response was classified as no response, response without remission, and remission. Available data on biochemical and endoscopic response were included. Adverse events (AEs) were recorded. RESULTS: The study population comprised 6 patients with UC who had received GMA+VDZ during induction after failure of an anti-TNF agent. The median number of GMA sessions was 5 (IQR 4-5; 3-10). All the patients received VDZ 300mg iv at 0, 2, and 6 weeks, and 5 (83%) received an additional dose at week 10. During maintenance, all the patients continued VDZ iv every 8 weeks. The median follow-up was 57.6 months (IQR: 39-74). Four of the 6 patients achieved clinical remission after GMA+VDZ and continued in deep remission until the end of follow-up. A median, non-significant decrease of 1378µg/g (IQR: 924-5778µg/g) was observed for calprotectin and 42.2mg/l (IQR: 15.3-113.5) for CRP vs. baseline. No patient underwent colectomy. No treatment-related AEs were observed. CONCLUSIONS: GMA+VDZ during induction can be effective and safe in selected patients with moderate-severe UC and partial response to steroids.

Current management of bowel failure due to Crohn's disease in Spain: Results of a GETECCU survey. / Manejo actual del fracaso intestinal por enfermedad de Crohn en nuestro medio: resultados de una encuesta GETECCU.

INTRODUCTION: Intestinal failure is a rare pathology which requires knowledge and highly specialized multidisciplinary management. Crohn's disease (CD) being one of the most frequent causes in adults. MATERIAL AND METHODS: Survey format study carried out within the GETECCU group, included closed format questions about the diagnosis, management and current knowledge of intestinal failure in CD. RESULTS: Forty-nine doctors participated, belonging to different Spanish centers (19 cities). It was considered that a patient suffered from intestinal failure, in 67.3% (33/49 surveyed) when there was a disorder malabsorptive associated regardless of the intestinal length resected, with surgeries resective ileal repeated (40.8%, 20/49), the most frequent cause. It highlights frequent ignorance about the pathology (24.5%) did not know if there were patients in their center and also 40% did not know the pharmacological treatment. A total of 228 patients were registered for follow-up due to intestinal failure of any aetiology, 89 patients (39.5%) were identified with CD. Regarding the therapeutic management of patients with CD and intestinal failure (72.5%) were receiving total parenteral nutrition (NTP) and 24 patients (27%) with teduglutide. Regarding the response to the drug: 37.5% had no response to teduglutide, 37.5% partial response (reduce NTP) and 25% good response (withdrawal of home NTP). In questions related to knowledge about intestinal failure, it was considered limited (53.1%) or very limited (12.2%) by the surveyed. CONCLUSION: It is necessary to carry out a combined management of intestinal failure and CD in the context of a multidisciplinary approach.

Human intestinal spirochetosis: an entity associated with sexual transmitted infections.

INTRODUCTION: Human intestinal spirochetosis (HIE) is a poorly studied clinical entity with variable clinical manifestations. However, in recent years it has gained special relevance because an increasing number of cases have been described in people living with HIV (PWH) and in patients with a history of sexually transmitted infections (STI) or immunosuppression. METHODS: Retrospective review of all HIE cases identified in a tertiary level hospital (Hospital Universitario la Paz, Madrid) between 2014 and 2021. RESULTS: 36 Cases of HIE were identified. Most cases corresponded to males (94%) with a median age of 45 years. 10 patients (29.4%) were PWH and 20 (56%) were men who had sex with men. Although the clinical manifestations were very heterogeneous, the most frequent was chronic diarrhea (47%), and up to 25% of the subjects had clinical proctitis. 39% percent of patients had been diagnosed with an STI in the previous two years, this characteristic being more frequent in PWH (90% vs. 28%; p < 0.01) than in patients without HIV infection. The STI most frequently associated with a diagnosis of HIE was syphilis (31%). CONCLUSION: HIE is frequently diagnosed with other STIs and affects mostly men who have sex with men, which supports that this entity could be considered as a new STI.

Serologic response to COVID-19 vaccines in patients with inflammatory bowel disease: a prospective study.

BACKGROUND AND AIMS: response to the SARS-CoV-2 vaccine can be altered in patients with immune-mediated diseases, such as inflammatory bowel disease, and in patients under immunosuppressive treatment. The aims of this study were to evaluate the serologic response to the SARS-CoV-2 vaccine in patients with inflammatory bowel disease, to analyze the influence of immunosuppressive drugs on response, and to describe any adverse events in this population. METHODS: this was a prospective study that included adult patients with inflammatory bowel disease. Baseline characteristics, concomitant treatments and previous COVID-19 symptoms were collected. Patients underwent serological testing before the first and after the second vaccine dose. RESULTS: a total of 265 patients were consecutively included. Patients received one of the following vaccines: messenger RNA vaccines from Pfizer/BioNTech and Moderna; and adenovirus vaccines from AstraZeneca and Janssen. All adverse events were mild, and the most frequent was injection site pain in 141 (86 %) patients. The seroconversion rate according to the treatment that patients were receiving was: 100 % for those without treatment, 92.5 % for patients treated with mesalazine, 90.3 % for those receiving immunomodulators, 88.9 % for patients with biological monotherapy and 92.5 % for patients on combined treatment. The generation of antibodies according to the vaccine administered was: Pfizer 92.9 %, Moderna 93.3 %, AstraZeneca 98.4 %, and Janssen 12.5 %. CONCLUSION: the antibody response after vaccination against SARS-CoV-2 is high in patients with inflammatory bowel disease. However, patients treated with immunosuppressive or biologic drugs had a lower response. Adverse events were frequent, but not serious.

Influence of biologic therapy on cardiovascular risk factors in patients with inflammatory bowel disease. / Influencia del tratamiento biológico en los factores de riesgo cardiovascular de los pacientes con enfermedad inflamatoria intestinal.

INTRODUCTION: Chronic immune-mediated diseases, including inflammatory bowel disease (IBD), present an increased risk of developing early atherosclerosis and cardiovascular events (CVE) at early age. OBJECTIVE: To describe the baseline and 1-year cardiovascular profile of patients with IBD according to the biologic treatment received, taking into account the inflammatory activity. PATIENTS AND METHODS: It is a retrospective, observational study that included 374 patients. Cardiovascular risk factors (CVRF) and CVE were collected at the baseline visit and at one-year follow-up to describe the cardiovascular risk according to the biological treatment received, also assessing clinical and biological remission. RESULTS: A total of 374 patients were included: 146 (38.73%) were treated with Infliximab, 128 (33.95%) with adalimumab, 61 (16.18%) with ustekinumab and 42 (11.14%) with vedolizumab. The changes in blood glucose levels are [86.31mg/dL (84.57-88.06) vs. 89.25mg/dL (87.54-90.96), P=.001] for those treated with antiTNFα and [86.52mg/dL (83.48-89.55) vs. 89.44mg/dL (85.77-93.11), P=.11] in the other group. In the group treated with antiTNFα total cholesterol values at baseline visit are [169.40mg/dL (164.97-173.83) vs. 177.40mg/dL (172.75-182.05) at one year of treatment, P=<.001], those of HDL [50.22mg/dL (48.39-52.04) vs. 54.26mg/dL (52.46-56.07), P=<.001] and those of triglycerides [114.77mg/dL (106.36-123.18) vs. 121.83mg/dL (112.11-131.54), P=.054]. Regarding weight, an increase was observed, both in those patients treated with antiTNFα [71.39kg (69.53-73.25) vs. 72.87kg (71.05-74.70), P<.001], and in the group treated with ustekinumab and vedolizumab [67.59kg (64.10-71.08) vs. 69.43kg (65.65-73.04), P=.003]. Concerning CVE, no significant differences were observed neither according to the drug used (p=0.36), nor according to personal history of CVE (P=.23) nor according to inflammatory activity (P=.46). CONCLUSIONS: Our results on a real cohort of patients with IBD treated with biologic drugs show a better control of certain cardiovascular parameters such as CRP or HDL, but a worsening of others such as total cholesterol or triglycerides, regardless of the treatment. Therefore, it is possibly the disease control and not the therapeutic target used, the one that affect the cardiovascular risk of these patients.

Double major papilla: diagnostic challenge of an unusual anatomical variant.

We report the endoscopic finding of a double papilla of Vater in a patient presenting choledocholithiasis who underwent endoscopic retrograde cholangiopancreatography (ERCP). The images showed the presence of two perfectly delimited papillary orifices, 1cm apart from each other. After cannulation of each orifice, we observed the Wirsung and the common bile duct (CBD) as completely independent ducts. Given the diagnostic challenge posed by this entity and the importance of differentiating it from a bilioenteric fistula, we believe it is worth knowing about it in order to manage it properly and to minimize secondary risks during the exploration.

Duodenal pyogenic granuloma: An unusual cause of chronic anemia.

We present the endoscopic finding of a juxtapapillary duodenal pyogenic granuloma in a patient under study for chronic recurrent anemia. The images show the presence of an enlarged papilla, with an exophytic growth of erythematous and friable tissue at its lower border. Although this is a very rare entity, it is necessary to take it into account in the differential diagnosis of refractory anemia because there is an effective endoscopic treatment for it.

Randomized clinical trial evaluating three low-volume preparations for colonoscopy in outpatients with Inflammatory Bowel Disease: the EII-PREP trial.

BACKGROUND: Data regarding bowel preparation in patients with Inflammatory Bowel Disease (IBD) are scarce. AIM: To compare efficacy, safety, and tolerability of low-volume preparations in patients with IBD. METHODS: Single-center, randomized, prescriber, and colonoscopist-blinded clinical trial. IBD outpatients undergoing colonoscopy were randomized 1:1:1 to receive 1 Liter-polyethylene glycol-ascorbate (1L-PEG), 2 Liters-PEG, or sodium picosulfate (SP). The primary endpoint was percentage of quality cleansing assessed via the Boston Bowel Preparation Scale (BBPS ≥6, segments ≥2). Secondary endpoints were total high quality cleansing (BBPS 8 or 9), high-quality segmental BBPS (≥2), and patients' tolerability, symptoms, and satisfaction, assessed by questionnaires. Safety was monitored by adverse event reporting, laboratory evaluation at colonoscopy, and telephonic follow-up. RESULTS: Ninety-two patients were included (33 1L-PEG, 28 2L-PEG, and 31 SP). No significant differences between preparations were observed in quality or high-quality total BBPS or high-quality segmental BBPS. Complete intake of the solution was higher for SP (p = 0.006) and lower for 1L-PEG (p = 0.02) compared to 2L-PEG intake (p = 0.55). Clinically irrelevant hyponatremia was higher in the SP group (p < 0.0001). SP instructions were easier to understand from patient's point of view (p = 0.01). Willingness to retake was higher with SP (p < 0.0001) and less for 1L-PEG (p < 0.0001). No serious adverse events were reported. CONCLUSIONS: We observed no differences in efficacy between low-volume preparations in patients with IBD. Complete intake was higher for SP and lower for 1L-PEG. SP and 2L-PEG instructions were better understood and graded, and SP was more likely to be retaken. Willingness to retake was lower for 1L-PEG. No serious adverse events were reported. SUMMARY: No differences in terms of efficacy were regarded in this clinical trial comparing low-volume preparations for colonoscopy in patients with IBD: however, Sodium Pisoculfate is better tolerated and accepted from patient's point of view. No serious adverse events were reported.

Serologic response to COVID-19 vaccines in patients with inflammatory bowel disease: a prospective study

Background and aims: response to the SARS-CoV-2 vaccine can be altered in patients with immune-mediated diseases, such as inflammatory bowel disease, and in patients under immunosuppressive treatment. The aims of this study were to evaluate the serologic response to the SARS-CoV-2 vaccine in patients with inflammatory bowel disease, to analyze the influence of immunosuppressive drugs on response, and to describe any adverse events in this population. Methods: this was a prospective study that included adult patients with inflammatory bowel disease. Baseline characteristics, concomitant treatments and previous COVID-19 symptoms were collected. Patients underwent serological testing before the first and after the second vaccine dose. Results: a total of 265 patients were consecutively included. Patients received one of the following vaccines: messenger RNA vaccines from Pfizer/BioNTech and Moderna; and adenovirus vaccines from AstraZeneca and Janssen. All adverse events were mild, and the most frequent was injection site pain in 141 (86 %) patients. The seroconversion rate according to the treatment that patients were receiving was: 100 % for those without treatment, 92.5 % for patients treated with mesalazine, 90.3 % for those receiving immunomodulators, 88.9 % for patients with biological monotherapy and 92.5 % for patients on combined treatment. The generation of antibodies according to the vaccine administered was: Pfizer 92.9 %, Moderna 93.3 %, AstraZeneca 98.4 %, and Janssen 12.5 %. Conclusion: the antibody response after vaccination against SARS-CoV-2 is high in patients with inflammatory bowel disease. However, patients treated with immunosuppressive or biologic drugs had a lower response. Adverse events were frequent, but not serious (AU)

Correlation between endoscopy and intestinal ultrasound for the evaluation of postoperative recurrence of Crohn's disease. / Correlación entre la endoscopia y la ecografía intestinal para la evaluación de la recurrencia posquirúrgica de la enfermedad de Crohn.

OBJECTIVE: Intestinal ultrasound is considered to be a valid alternative for the evaluation of post-operative recurrence (POR) of Crohn's disease. The aim of this study is to assess the correlation between ultrasound and endoscopic findings. METHODS: Patients with Crohn's disease were retrospectively recruited who had undergone ileocecal resection, and for whom a colonoscopy and intestinal ultrasound had been performed for the detection of POR. Recurrence was assessed using the Rutgeerts score (RS). The ultrasound findings analysed were bowel wall thickness (BWT), parietal hyperaemia using power Doppler, loss of layer pattern and mesenteric fat hypertrophy. RESULTS: A total of 31 patients were included, of which 15 (48.4%) had no POR (RS<2b) and 16 (51.6%) had POR (RS≥2b). A statistically significant association was identified between BWT and the presence of endoscopic recurrence (a mean of 2.75mm vs. 5.68mm, P>0.001). There was also a statistically significant difference in hyperaemia between the 2groups (P=0.03). For wall thickness, an area under the ROC curve (AUC) of 92.9% was obtained, and with a cut-off point of 3.4mm, a sensitivity of 100% and specificity of 86.6%. When comparing with the most frequent biomarkers (fecal calprotectin and serum CRP), a higher AUC was obtained for wall thickness (72.3% and 72.3% vs. 92.9%). CONCLUSIONS: In our experience, ultrasound has high diagnostic efficacy in the detection of POR and can be considered a valid non-invasive alternative to endoscopy.

Doppler Activity and Ultrasonographic Detection of Intra-Abdominal Fistulas Are Predictors of Surgery in Crohn's Disease.

Bakground and Aim: Predictors of the need for surgery in sticturing Crohn's disease (SCD) are lacking. Bowel ultrasound (US) is a harmless, noninvasive, and inexpensive diagnostic procedure that has proven to be a valuable tool in the management of Crohn's disease (CD). Our aim was to identify ultrasonographic findings in SCD that may associate with a higher risk of surgery, allowing us to make early choices regarding treatment election in this specific group of patients. MATERIALS AND METHODS: This was a retrospective, case-control study. Twenty-four patients diagnosed with SCD between 2013 and 2017 with a past history of stricture-related surgery were included and then matched with 46 non-operated controls. Prior US from patients in both groups were analyzed. US features considered for analysis were as follows: bowel wall thickness, degree of parietal vascularization (measured by Doppler activity), prestenotic dilation, involvement of mesenteric fat, and newly detected concomitant fistulas or abscess. RESULTS: Doppler activity (p < 0.001), enteroenteric fistulas (p = 0.04), enteromesenteric fistulas (p = 0.003), and associated abscess (p = 0.004) were significantly associated with the need for surgery in the short-term period. Multivariate analysis showed strong association of these features with the risk of surgery but failed to reach statistical significance. CONCLUSION: US features may potentially be used as point-of-care tools to aid clinicians in the assessment of the surgical risk in patients with SCD.

Is the degree of i2a recurrence in Crohn's disease secondary to ischemic phenomena?

INTRODUCTION: the Rutgeerts score is used to assess post-surgical recurrence of Crohn's disease (CD). The score initially consisted of four grades, with a subsequent sub-classification of grade 2, under which ulcers confined to the anastomosis (i2a) are considered to be of a probable ischemic origin. The aim of this study was to assess whether ulcers confined to the anastomosis appear at the same frequency in patients undergoing surgery for other causes and can therefore be attributed to post-surgical changes. MATERIAL AND METHODS: this was a retrospective cohort study with patients who had undergone colonoscopy as per clinical practice between 2017 and 2018. There were two cohorts, one cohort of patients to assess the post-surgical recurrence of CD and another cohort for follow-up after colorectal cancer (CRC) treated with ileocolonic anastomosis. RESULTS: a total of 185 patients were included; 33 % had undergone surgery for CD and 67 % had undergone surgery for CRC. Fifty-six percent of patients were male. Of the patients in the group with ulcers confined to the anastomosis, 75 % had CD and 25 % had been operated on for CRC; the difference was statistically significant (p < 0.0001). In turn, of the patients operated on for CRC, 95 % had no anastomotic lesions compared to 18 % of patients with CD. These differences reached statistical significance (p < 0.0001). CONCLUSIONS: In our experience, the occurrence of ulcers on the ileocolonic anastomosis is uncommon in patients that have undergone surgery for CRC, in comparison to patients operated on due to CD. It is possible that these alterations in CD cannot therefore be attributed to solely ischemic or post-surgical phenomena.

Prognostic value of ultrasound activity and parietal healing in patients with Crohn's disease.

INTRODUCTION: the "treat to target" strategy for the management of patients with Crohn's disease (CD) requires simple, reliable and non-invasive tools for continuous monitoring of the disease. Intestinal ultrasound has been proposed as an emerging technique that could be very useful in this field. MATERIAL AND METHODS: patients who had undergone an intestinal ultrasound in the clinical practice between February 2013 and October 2018 at our hospital were retrospectively included. The evolution of the patients during follow-up was assessed based on the presence of ultrasound activity and the therapeutic changes based on the results. RESULTS: two hundred and seventy-seven CD patients were included and the median follow-up time was 24 months (range 5-73 months). Signs of ultrasound inflammatory activity were identified in 166 patients (60 %), and of them, treatment was escalated in 116 patients (70 %) based on the results of the ultrasound. Among patients with identified ultrasound activity, in 166 patients (60 %) the evolution was less favorable than in those without activity, with a shorter time until the next outbreak. Thus, the median disease-free survival (without outbreaks) after performing the ultrasound was 18 months when ultrasound activity was identified (although in most of the patients [70 %] the treatment had been escalated) vs 47 months in patients without ultrasound activity. However, these differences were not statistically significant (p < 0.0001). Among the 111 patients without ultrasound activity, those who achieved "parietal healing" (74 patients) had a better evolution with a 12 % subsequent outbreak vs 27 % during follow-up (p = 0.05). Thus, 15 % of patients with parietal healing had an outbreak vs 34 % of those who had not normalized the ultrasound findings after three years of follow-up. CONCLUSION: intestinal ultrasound is a technique capable of detecting inflammatory activity in patients with Crohn's disease and the presence of ultrasound activity is a risk factor for a new outbreak of activity and/or clinical relapse. Likewise, the presence of "parietal or transmural healing" (PH) is associated with a better evolution of patients during follow-up. Thus, it could be a more precise objective to consider deep remission in CD, with intestinal ultrasound being a useful technique for this purpose.

Optimization of azathioprine dose in combined treatment with anti-TNF-alpha in inflammatory bowel disease.

INTRODUCTION: The dose of thiopurine drugs in combined treatments with anti-TNF in inflammatory bowel disease (IBD) has not been clearly established. The purpose of this study is to assess whether the dose of azathioprine influences clinical and biochemical response/remission rates, and anti-TNF drug levels/antibody formation. MATERIAL AND METHODS: Patients with IBD on combined maintenance treatment with azathioprine and infliximab or adalimumab were selected. Based on the dose of azathioprine, two groups were defined (standard: 2-2.5mg/kg/day; and decreased: less than 2mg/kg/day). RESULTS: In the IFX group, there were no statistically significant differences (p=0.204) in the rates of remission (39% vs 41.3%), response (10% vs 21.7%) or failure (51.5% vs 37%) depending on the dose of thiopurine drugs. No differences were found between AZA-dose dependent IFX levels (2.46 vs 3.21µg/mL; p=0.211). In the adalimumab group, there were no statistically significant differences (p=0.83) in the rates of remission (66% vs 56%), response without remission (15.38% vs 25%) or failure (18% vs 18%) depending on the dose of thiopurines. With respect to ADA-levels, no differences were found in both groups (7.69 vs 8.23µg/mL; p=0.37). CONCLUSION: In our experience, no statistically significant differences were found in either anti-TNF levels or clinical-biological response/remission rates based on doses of azathioprine.