Research Models to Mimic Necrotizing Enterocolitis and Inflammatory Bowel Diseases: Focus on Extracellular Vesicles Action.

This review focuses on the crucial role of the intestinal epithelium in maintaining intestinal homeostasis and its significance in the pathogenesis of necrotizing enterocolitis (NEC) and inflammatory bowel diseases (IBD). NEC is a devastating neonatal disease, while IBD represents a global healthcare problem with increasing incidence. The breakdown of the intestinal barrier in neonates is considered pivotal in the development and progression of both disorders. This review provides an overview of the current state of in vitro, ex vivo, and animal models to study epithelial injury in NEC and IBD, addressing pertinent questions that engage clinicians and researchers alike. Despite significant advancements in early recognition and aggressive treatment, no single therapy has been conclusively proven effective in reducing the severity of these disorders. Although early interventions have improved clinical outcomes, NEC and IBD continue to impose substantial morbidity, mortality, and economic burdens on affected individuals and society. Consequently, exploring alternative therapeutic options capable of preventing and treating the sequelae of NEC and IBD has become a pressing necessity. In recent decades, extracellular vehicles (EVs) have emerged as a potential solution to modulate the pathogenic mechanism in these multifactorial and complex disorders. Despite the diverse array of proposed models, a comprehensive model to investigate and decelerate the progression of NEC and IBD remains to be established. To bridge the translational gap between preclinical studies and clinical applications, enhancements in the technical development of gut-on-a-chip models and EVs hold considerable promise.

Clinicopathologic Features of Primary Immunodeficiency Monogenic Disease-related Very Early Onset Inflammatory Bowel Disease: Focus on Gastrointestinal Histologic Features in IFIH1 Mutations.

Very early onset inflammatory bowel disease (VEO-IBD) is a clinical term referring to IBD-like symptomatology arising in children younger than 6 years. VEO-IBD may be due to polygenic etiology in "pure" IBD (Crohn disease-CD and ulcerative colitis-UC), or it may be caused by primary immunodeficiency underlined by monogenic disease. Primary immunodeficiency monogenic diseases have a Mendelian inheritance and affect the immune system with multiorgan morbidity and possible effects on the gastrointestinal system. Primary Immunodeficiency monogenic diseases differ from "pure" IBD as the latter primarily affect the gastrointestinal tract with mitigated extraintestinal symptomatology. Since their first description, primary immunodeficiency monogenic diseases, although rare, have been the subject of increasing interest due to their dramatic phenotype, difficulty in reaching a timely diagnosis, and specific therapeutic approach. In this paper, we present a brief review of primary immunodeficiency monogenic diseases, focusing on to their clinicopathologic features as well as delving, in greater detail, into monogenic diseases caused by IFIH1 mutations. The clinicopathologic features of 4 patients with IFIH1, a gene involved in interferon pathway deficiency, will be described using a histologic pattern of damage approach confirming the need to avoid the histologic diagnosis of VEO-IBD in children younger than 6 years.

Long-term follow-up of a patient with neonatal form of Gaucher disease.

Gaucher disease is the most common of the lysosomal storage diseases. It presents a wide phenotypic continuum, in which one may identify the classically described phenotypes, including type 1 form with visceral involvement, type 2 acute neuropathic early-infantile form, and type 3 subacute neuronopathic form. At the most severe end there is the perinatal form with onset in utero or during the neonatal period. The very few reported cases of neonatal onset Gaucher disease presented high and early mortality, due to neurological or visceral involvement, including liver failure. We report our experience treating a patient with the neonatal form of Gaucher disease who presented at birth with thrombocytopenia, hepatosplenomegaly and cholestasis. Despite early enzyme replacement therapy, liver disease was progressive. Liver biopsy showed hepatocellular giant-cell transformation, a nonspecific finding consistent with inflammation. The lack of response to enzyme replacement therapy and the microscopic findings suggested that mechanisms apart from substrate accumulation and Gaucher cells may play a role in the hepatic pathogenesis in Gaucher disease. An attempt to use corticosteroids at the age of 3 months resulted in a dramatic improvement in liver function and resulted in long-term survival. The patient is alive and 2 years old at this writing. Our case suggests that inflammatory processes may be important in the early pathogenesis of Gaucher disease and that early use of corticosteroids may open the way to a new therapeutic approach.

Paediatric porto-sinusoidal vascular disease: Two different clinical phenotypes with subtle histological differences.

BACKGROUND AND AIMS: In paediatrics, porto-sinusoidal vascular disease (PSVD) is relatively unknown and probably underdiagnosed. We aimed to describe clinical phenotypes, histology and outcome of children diagnosed with PSVD. METHODS: Retrospective multicentre study of children diagnosed with PSVD. Diagnosis of PSVD was based on histopathology reports; liver specimens were re-evaluated by two expert liver pathologists. RESULTS: Sixty two children diagnosed with PSVD (M/F = 36/26, median age 6.6 years, range 3.3-10.6), from 7 centres, were included. Thirty-six presented with non-cirrhotic portal hypertension, PH, (PH-PSVD Group = 58%) while 26 had a liver biopsy because of chronic elevation of transaminases without PH (noPH-PSVD Group = 42%). On histology review, the two groups differed for the prevalence of obliterative portal venopathy (more prevalent in PH-PSVD, p = 0.005), and hypervascularised portal tracts (more common in noPH-PSVD, p = 0.039), the other histological changes were equally distributed. At multivariate analysis, platelet count ≤185 000/mm3 was the only independent determinant of PH (p < 0.001). After a median follow-up of 7 years (range 3.0-11.2), in PH-PSVD group 3/36 (8%) required TIPS placement, 5/36 (14%) developed pulmonary vascular complications of PH, and 7/36 (19%) required liver transplantation. In noPH-PSVD none progressed to PH nor had complications. CONCLUSIONS: Paediatric patients with PSVD present with two different clinical phenotypes, one characterised by PH and one by chronic elevation of transaminases without PH. PSVD should be included among the conditions causing isolated hypertransaminasaemia. On histology, the differences between the two groups are subtle. Medium-term outcome is favourable in patients without PH; progression of the disease is observed in those with PH.

Inadequate Hospital Practices to Prevent Mother-to-Child Transmission of Hepatitis B Virus Infection: A European Survey.

OBJECTIVES: Prevention of vertical transmission of hepatitis B virus (HBV) infection is crucial to eliminate viral hepatitis as a major public health threat by 2030. We aimed to assess the current hospital policies and practices implemented before, at, and after birth, and to evaluate potential barriers to the full application of international guidelines. METHODS: A web-based survey was supported by PENTA Foundation and distributed across Europe from October to December 2021. RESULTS: Overall, 76 centers with delivery departments completed the survey. Hepatitis B surface antigen (HBsAg) maternal screening is performed in the first trimester of pregnancy in 53% of the centers and in the third in 46%. HBsAg positive pregnant women are tested for serologic HBV markers and HBV-DNA in 78% and 63% of the departments; 38% of the HBeAg positive women with high HBV-DNA levels are treated during the last trimester of pregnancy. At birth, 91% of the departments administer HBV vaccine to infants born to HBsAg positive mothers within 12 hours of birth; 74% test women with unknown HBsAg status and 78% of them wait for the maternal testing results before administering HBV vaccine to their newborns. After birth, 47% of the departments provide postvaccination serological testing for infants born to HBsAg positive mothers. The timing of the HBV vaccine schedule varies greatly. CONCLUSIONS: There is significant heterogeneity in the hospital policies and correlated procedures. The implementation of a multidisciplinary clinical pathway is a must if a stronger connection between the prenatal, perinatal, and postnatal phases is to be established.

Vaccination practices in pediatric transplantation: A survey among member centers of the European reference network TransplantChild.

BACKGROUND: There is considerable variation in vaccination practices between pediatric transplant centers. This study aims to evaluate active immunization attitudes and practices among ERN-TransplantChild centers and identify potential areas of improvement that could be addressed by shared evidence-based protocols. METHODS: A cross-sectional questionnaire of attitudes and practices toward immunization of pediatric SOT and HSCT candidates and recipients was sent to a representative member of multidisciplinary teams from 27 European centers belonging to the ERN-TransplantChild. RESULTS: A total of 28/62 SOT programs and 6/12 HSCT programs across 21 European centers participated. A quarter of centers did not have an on-site protocol for the immunizations. At the time of transplantation, pediatric candidates were fully immunized (80%-100%) in 57% and 33% of the SOT and HSCT programs. Variations in the time between vaccine administration and admission to the waiting list were reported between the centers, with 2 weeks for inactivated vaccines and variable time (2-4 weeks) for live-attenuated vaccines (LAVs). Almost all sites recommended immunization in the post-transplant period, with a time window of 4-8 months for the inactivated vaccines and 16-24 months for MMR and Varicella vaccines. Only five sites administer LAVs after transplantation, with seroconversion evaluated in 80% of cases. CONCLUSIONS: The immunization coverage of European pediatric transplant recipients is still inconsistent and far from adequate. This survey is a starting point for developing shared evidence-based immunization protocols for safe vaccination among pediatric transplant centers and generating new research studies.

Impact of Genotype, Serum Bile Acids, and Surgical Biliary Diversion on Native Liver Survival in FIC1 Deficiency.

BACKGROUND AND AIMS: Mutations in ATPase phospholipid transporting 8B1 (ATP8B1) can lead to familial intrahepatic cholestasis type 1 (FIC1) deficiency, or progressive familial intrahepatic cholestasis type 1. The rarity of FIC1 deficiency has largely prevented a detailed analysis of its natural history, effects of predicted protein truncating mutations (PPTMs), and possible associations of serum bile acid (sBA) concentrations and surgical biliary diversion (SBD) with long-term outcome. We aimed to provide insights by using the largest genetically defined cohort of patients with FIC1 deficiency to date. APPROACH AND RESULTS: This multicenter, combined retrospective and prospective study included 130 patients with compound heterozygous or homozygous predicted pathogenic ATP8B1 variants. Patients were categorized according to the number of PPTMs (i.e., splice site, frameshift due to deletion or insertion, nonsense, duplication), FIC1-A (n = 67; no PPTMs), FIC1-B (n = 29; one PPTM), or FIC1-C (n = 34; two PPTMs). Survival analysis showed an overall native liver survival (NLS) of 44% at age 18 years. NLS was comparable among FIC1-A, FIC1-B, and FIC1-C (% NLS at age 10 years: 67%, 41%, and 59%, respectively; P = 0.12), despite FIC1-C undergoing SBD less often (% SBD at age 10 years: 65%, 57%, and 45%, respectively; P = 0.03). sBAs at presentation were negatively associated with NLS (NLS at age 10 years, sBAs < 194 µmol/L: 49% vs. sBAs ≥ 194 µmol/L: 15%; P = 0.03). SBD decreased sBAs (230 [125-282] to 74 [11-177] µmol/L; P = 0.005). SBD (HR 0.55, 95% CI 0.28-1.03, P = 0.06) and post-SBD sBA concentrations < 65 µmol/L (P = 0.05) tended to be associated with improved NLS. CONCLUSIONS: Less than half of patients with FIC1 deficiency reach adulthood with native liver. The number of PPTMs did not associate with the natural history or prognosis of FIC1 deficiency. sBA concentrations at initial presentation and after SBD provide limited prognostic information on long-term NLS.

IFIH1 loss-of-function variants contribute to very early-onset inflammatory bowel disease.

Genetic defects of innate immunity impairing intestinal bacterial sensing are linked to the development of Inflammatory Bowel Disease (IBD). Although much evidence supports a role of the intestinal virome in gut homeostasis, most studies focus on intestinal viral composition rather than on host intestinal viral sensitivity. To demonstrate the association between the development of Very Early Onset IBD (VEOIBD) and variants in the IFIH1 gene which encodes MDA5, a key cytosolic sensor for viral nucleic acids. Whole exome sequencing (WES) was performed in two independent cohorts of children with VEOIBD enrolled in Italy (n = 18) and USA (n = 24). Luciferase reporter assays were employed to assess MDA5 activity. An enrichment analysis was performed on IFIH1 comparing 42 VEOIBD probands with 1527 unrelated individuals without gastrointestinal or immunological issues. We identified rare, likely loss-of-function (LoF), IFIH1 variants in eight patients with VEOIBD from a combined cohort of 42 children. One subject, carrying a homozygous truncating variant resulting in complete LoF, experienced neonatal-onset, pan-gastrointestinal, IBD-like enteropathy plus multiple infectious episodes. The remaining seven subjects, affected by VEOIBD without immunodeficiency, were carriers of one LoF variant in IFIH1. Among these, two patients also carried a second hypomorphic variant, with partial function apparent when MDA5 was weakly stimulated. Furthermore, IFIH1 variants were significantly enriched in children with VEOIBD as compared to controls (p = 0.007). Complete and partial MDA5 deficiency is associated with VEOIBD with variable penetrance and expressivity, suggesting a role for impaired intestinal viral sensing in IBD pathogenesis.

Efficacy of Sofosbuvir/Ledipasvir in Adolescents With Chronic Hepatitis C Genotypes 1, 3, and 4: A Real-world Study.

OBJECTIVES: Sofosbuvir/Ledipasvir (SOF/LDV) has been approved by the European Medicine Agency (EMA) for the treatment of children and adolescents (at least 3 years of age) with chronic hepatitis C (CHC) genotype 1, 3, and 4 infection. The aim of this study was to evaluate the efficacy and safety of SOF/LDV in adolescents (12 to <18 years old) with CHC in the real-world setting. METHODS: Prospective, open-label, multicentre study involving 12 Italian centres. Patients received the fixed-dose combination of SOF/LDV (400/90 mg) once daily ± ribavirin as per EMA approval and recommendations. The key efficacy endpoint was sustained virological response 12 weeks after the end of treatment (SVR12) as per intention-to-treat analysis. Safety was assessed by adverse events and clinical/laboratory data. RESULTS: Seventy-eight consecutive adolescents (median age 15.2 years, range 12-17.9; girls 53.8%) were enrolled and treated between June 2018 and December 2019. Genotype distribution was as follows: genotype 1 (82.1%), 3 (2.5%), and 4 (15.4%). Seventy-six (97.4%) patients completed treatment and follow-up. Overall, SVR12 was 98.7%. One patient was lost to follow-up after 4 weeks of treatment; 1 patient completed treatment and missed the follow-up visit. No virological breakthrough or relapse were observed. No patient experienced grade 3 to 4 adverse event or serious adverse event. CONCLUSIONS: The results of this real-world study confirmed the high efficacy and the optimal safety profile of SOF/LDV for treatment of CHC in adolescents.

Pediatric transplantation in Europe during the COVID-19 pandemic: Early impact on activity and healthcare.

The current pandemic SARS-CoV-2 has required an unusual allocation of resources that can negatively impact chronically ill patients and high-complexity procedures. Across the European Reference Network on Pediatric Transplantation (ERN TransplantChild), we conducted a survey to investigate the impact of the COVID-19 outbreak on pediatric transplant activity and healthcare practices in both solid organ transplantation (SOT) and hematopoietic stem cell transplantation (HSCT). The replies of 30 professionals from 18 centers in Europe were collected. Twelve of 18 centers (67%) showed a reduction in their usual transplant activity. Additionally, outpatient visits have been modified and restricted to selected ones, and the use of telemedicine tools has increased. Additionally, a total of 14 COVID-19 pediatric transplanted patients were identified at the time of the survey, including eight transplant recipients and six candidates for transplantation. Only two moderate-severe cases were reported, both in HSCT setting. These survey results demonstrate the limitations in healthcare resources for pediatric transplantation patients during early stages of this pandemic. COVID-19 disease is a major worldwide challenge for the field of pediatric transplantation, where there will be a need for systematic data collection, encouraging regular discussions to address the long-term consequences for pediatric transplantation candidates, recipients, and their families.

Short-term outcomes of paediatric liver transplant recipients after transition to Adult Healthcare Service.

BACKGROUND & AIMS: Survival rates after liver transplantation (LT) in paediatric recipients have significantly improved over time. However, data regarding outcomes after transition from Paediatric to Adult Healthcare Service (AHS) are still lacking. Therefore, we aimed to prospectively evaluate the outcome of LT recipients after transition, to access patients' non-adherence and identify potential risk factors for non-adherence. METHODS: All consecutive adolescent LT recipients moving to the AHS at Padua University Hospital were evaluated between 2010 and 2015. Demographic data, liver function tests, incidence of acute or chronic rejection episodes and adherence to medical prescription, were prospectively evaluated. An educational pilot study was implemented since 2015 to foster adherence during transition. RESULTS: In all, 32 patients (M/F 16/16, median age: 23 years) were evaluated. Median interval time between LT and transition was 15 years (range: 1-26 years). The main indication for LT was biliary atresia (31%), whereas immunosuppression regimen was tacrolimus-based in 75%. After a median follow-up of 29 months (range: 12-83), no significant modifications of liver function tests were observed. Biopsy-proven chronic rejection was diagnosed in 6/32 (18%) of patients, who had higher standard deviation of tacrolimus trough level than patients without (1.5 vs 1, P = .03). Non-adherence was reported in 8/32 (25%) of patients and was significantly associated with alcohol consumption (P = .003). Patient and graft survival were 96% and 93%, respectively. CONCLUSIONS: Adolescent LT patients who undergo transition to the AHS have good long-term outcomes. However, a multidisciplinary approach aiming at fostering adherence should be used.

Assessing pediatric ileocolonic Crohn's disease activity based on global MR enterography scores.

OBJECTIVES: This study was aimed at correlating a magnetic resonance index of activity (MaRIA) and a magnetic resonance enterography global score (MEGS) with activity indexes in a paediatric population with Crohn's disease (CD). METHODS: This retrospective study included 32 paediatric patients (median age 14.5 years, 18 male) with proven CD who underwent magnetic resonance enterography (MRE). A correlation analysis was performed on the MRE-based scores, the simplified endoscopic score for CD (SES-CD), the paediatric Crohn's disease activity index (PCDAI), and C-reactive protein (CRP) levels. Based on PCDAI, comparison of both global MaRIA and MEGS was made between patients with mild and moderate/severe disease activity. RESULTS: Global MaRIA correlated with SES-CD (r = 0.70, p = 0.001) and PCDAI (r = 0.42, p = 0.016). MEGS correlated with PCDAI (r = 0.46, p = 0.007) and CRP levels (r = 0.35, p = 0.046). MEGS differed significantly (p = 0.027) between patients grouped by clinical disease severity. CONCLUSIONS: MRE-based global scores correlated with clinical indexes of CD activity. Therefore, they represent a potential useful tool to predict CD activity and severity, as well as a possible promising alternative to endoscopy, to monitor paediatric patients with CD during their follow-up. KEY POINTS: • MRE is widely used to for accurate assessment of CD. • Global MaRIA and MEGS have been suggested as indicators of CD activity. • Paediatric studies comparing MRE-based global scores with clinical CD activity are lacking. • Such scores can serve as predictors of CD activity/severity in paediatric patients. • MRE offers an alternative to clinical score/endoscopy for paediatric CD monitoring.

High level of oxysterols in neonatal cholestasis: a pitfall in analysis of biochemical markers for Niemann-Pick type C disease.

BACKGROUND: Niemann-Pick disease type C (NPC) is a rare lipid storage disorder characterized by progressive neurological deterioration. Diagnosing NPC is challenging as clinical signs and symptoms are variable and non-specific. Two oxysterols, cholestane-3ß,5α,6ß-triol (triol) and 7-ketocholesterol (7KC), have been proposed as biomarkers for aiding diagnosis of NPC. This study evaluated the use of triol and 7KC as biomarkers in cholestatic neonates with suspected NPC. METHODS: Plasma triol and 7KC were analysed as dimethylglycine esters using an liquid chromatography - tandem mass spectrometry (LC-MS/MS) assay in selected neonates with severe cholestasis and suspected NPC (n=7), adults with cholestasis (n=15), patients with confirmed NPC (positive controls; n=11 [one child and 10 adults]), healthy subjects (negative controls; n=40 [20 children and 20 adults]), and cholestatic adults (comparative reference; n=15). The LC-MS/MS method was subjected to a number of tests for accuracy and consistency. RESULTS: Triol and 7KC levels were substantially and significantly increased in NPC positive patients compared with healthy controls (p<0.001). However, positive results (markedly increased levels of both oxysterols) were identified in 6/7 (86%) neonates with cholestasis. Genetic testing confirmed NPC only in one neonate who had increased triol and 7KC, and increased oxysterol levels among neonates with no identified NPC gene mutations were considered likely due to biliary atresia (BA). CONCLUSIONS: While the potential of oxysterols as NPC biomarkers has been well evaluated in older patient populations (without cholestasis), our data suggest that cholestasis might represent a pitfall in oxysterol measurements intended to aid diagnosis of NPC in affected patients.

Amniotic fluid stem cells improve survival and enhance repair of damaged intestine in necrotising enterocolitis via a COX-2 dependent mechanism.

OBJECTIVE: Necrotising enterocolitis (NEC) remains one of the primary causes of morbidity and mortality in neonates and alternative strategies are needed. Stem cells have become a therapeutic option for other intestinal diseases, which share some features with NEC. We tested the hypothesis that amniotic fluid stem (AFS) cells exerted a beneficial effect in a neonatal rat model of NEC. DESIGN: Rats intraperitoneally injected with AFS cells and their controls (bone marrow mesenchymal stem cells, myoblast) were analysed for survival, behaviour, bowel imaging (MRI scan), histology, bowel absorption and motility, immunofluorescence for AFS cell detection, degree of gut inflammation (myeloperoxidase and malondialdehyde), and enterocyte apoptosis and proliferation. RESULTS: AFS cells integrated in the bowel wall and improved rat survival and clinical conditions, decreased NEC incidence and macroscopic gut damage, improved intestinal function, decreased bowel inflammation, increased enterocyte proliferation and reduced apoptosis. The beneficial effect was achieved via modulation of stromal cells expressing cyclooxygenase 2 in the lamina propria, as shown by survival studies using selective and non-selective cyclooxygenase 2 inhibitors. Interestingly, AFS cells differentially expressed genes of the Wnt/ß-catenin pathway, which regulate intestinal epithelial stem cell function and cell migration and growth factors known to maintain gut epithelial integrity and reduce mucosal injury. CONCLUSIONS: We demonstrated here for the first time that AFS cells injected in an established model of NEC improve survival, clinical status, gut structure and function. Understanding the mechanism of this effect may help us to develop new cellular or pharmacological therapies for infants with NEC.

Bitter lupine beans ingestion in a child: a disregarded cause of acute anticholinergic toxicity.

UNLABELLED: We describe the case of a 6-year-old girl brought to the emergency department for the sudden onset of anticholinergic syndrome after the ingestion of a few home-made partially debittered lupine beans. She complained of blurry vision, headache, photophobia and nausea. No specific treatment was needed, and the symptoms resolved about 12 h after the exposure. Lupine beans are a popular and worldwide-diffused food. The bitter variety is rich in alkaloids harbouring anticholinergic activity and thus requires a debittering process before lupines can be eaten. Only four cases of acute toxicity, due to the ingestion of incompletely detoxified bitter lupines, have been reported in children so far; notwithstanding the small amount of lupines ingested, three of these cases were lethal. CONCLUSION: Acute anticholinergic syndrome can arise after the consumption of a wide range of exogenous substances including partially debittered lupine beans. Paediatricians should be aware of bitter lupine toxicity, recognize possible cases of intoxication, ensure a prompt and appropriate supportive treatment and provide appropriate information about their danger.

Disseminated Mycobacterial Infection With Reactive Polyarthritis (Poncet's Disease) During Immune-suppressive Treatment Including Ustekinumab for Pediatric Crohn's Disease.

BACKGROUND: The incidence of pediatric inflammatory bowel disease is increasing. tumor necrosis factor alpha inhibitors medicines improved the prognosis of affected subjects. Nonetheless, a proportion of patients do not respond or lose response to treatment. Newer biologics, like ustekinumab, have been approved for adults. The pediatric off-label use of these drugs is increasing, despite limited safety evidence. We report a case of disseminated mycobacterial infection (MI) presenting with reactive polyarthritis (Poncet's disease, PD) in a girl with Crohn's disease receiving various immunosuppressants, including ustekinumab. CASE REPORT: A 12-year-old girl with Crohn's disease was admitted for acute-onset migratory polyarthritis of large and small joints and opioid-resistant pain. She had recently received adalimumab and methotrexate and was currently under treatment with ustekinumab. She was vaccinated with Bacillus Calmette-Guérin and screened for tuberculosis before starting immunosuppressants. Interferon-gamma release assay, Mantoux test and chest computed tomography scan were negative. Disseminated MI with PD was diagnosed following positive cultures for Mycobacterium tuberculosis complex in blood and intestinal biopsies (with negative in synovial fluid and gastric aspirate). Whole-exome sequencing did not identify any genetic susceptibility to MI. Antituberculosis treatment eradicated MI. CONCLUSIONS: Children with inflammatory bowel disease receiving combination immunosuppressive treatments including tumor necrosis factor alpha inhibitors and anti-IL-12/23 agents are at higher risk for MI. Disseminated MI should be considered and ruled out in these patients when presenting with pulmonary, extrapulmonary or unusual clinical manifestations, like PD. The collection of multiple specimens (including intestinal biopsies) for mycobacterial culture is recommended when mycobacterial disease is suspected.