S2k Leitlinie akute infektiöse Gastroenteritis im Säuglings-, Kindes- und Jugendalter ­ Update 2024.

The aim of the interdisciplinary S2k guideline "Acute infectious gastroenteritis in infants, children and adolescents" is to summarise the current state of knowledge on the clinical presentation, diagnosis, treatment, prevention and hygiene of acute infectious gastroenteritis, including nosocomial gastrointestinal infections, in infants, children and adolescents on the basis of scientific evidence, to evaluate it by expert consensus and to derive practice-relevant recommendations from it. The guideline provides a corridor for action for frequent decisions. It also serves the purpose of evidence-based further education and training and is thus intended to improve the medical care of children with acute gastroenteritis. In particular, the guideline aims to avoid unnecessary hospitalisation of children with AGE and to take preventive measures to avoid and spread infection.

[Gastric vs. supragastric belching, singultus, aerophagia, and differential diagnoses : An interdisciplinary perspective for otorhinolaryngologists]. / Gastrisches versus supragastrisches "belching", Singultus, Aerophagie und Differenzialdiagnosen : Eine interdisziplinäre Übersicht für den HNO-Arzt.

Belching is the act of expelling air from the stomach or esophagus into the pharynx. Although the process is regarded as physiological, excessive belching might be associated with a significant burden for affected patients in the sense of a belching disorder. Diagnosis of a belching disorder is often challenging, and its differentiation from other conditions such as rumination syndrome, singultus, or aerophagia can be difficult. Treatment of these disorders also represents a challenge for otorhinolaryngologists. Hence, the aim of this review is to provide an interdisciplinary overview of these clinical syndromes and provide practical guidance for their diagnosis and treatment.

Live-attenuated vaccination for measles, mumps, and rubella in pediatric liver transplantation.

BACKGROUND: Infections are a serious short- and long-term problem after pediatric organ transplantation. In immunocompromised patients, they can lead to transplant rejection or a severe course with a sometimes fatal outcome. Vaccination is an appropriate means of reducing morbidity and mortality caused by vaccine-preventable diseases. Unfortunately, due to the disease or its course, it is not always possible to establish adequate vaccine protection against live-attenuated viral vaccines (LAVVs) prior to transplantation. LAVVs such as measles, mumps, and rubella (MMR) are still contraindicated in solid organ transplant recipients receiving immunosuppressive therapy (IST), thus creating a dilemma. AIM: This review discusses whether, when, and how live-attenuated MMR vaccines can be administered effectively and safely to pediatric liver transplant recipients based on the available data. MATERIAL AND METHODS: We searched PubMed for literature on live-attenuated MMR vaccination in pediatric liver transplantation (LT). RESULTS: Nine prospective observational studies and three retrospective case series were identified in which at least 833 doses of measles vaccine were administered to 716 liver transplant children receiving IST. In these selected patients, MMR vaccination was well tolerated and no serious adverse reactions to the vaccine were observed. In addition, an immune response to the vaccine was demonstrated in patients receiving IST. CONCLUSION: Due to inadequate vaccine protection in this high-risk group, maximum efforts must be made to ensure full immunization. MMR vaccination could also be considered for unprotected patients after LT receiving IST following an individual risk assessment, as severe harm from live vaccines after liver transplantation has been reported only very rarely. To this end, it is important to establish standardized and simple criteria for the selection of suitable patients and the administration of the MMR vaccine to ensure safe use.

Epidemiology, clinical features and management of autoimmune hepatitis in Switzerland: a retrospective and prospective cohort study.

BACKGROUND AND AIMS: The Swiss Autoimmune Hepatitis Cohort Study is a nationwide registry, initiated in 2017, that collects retrospective and prospective clinical data and biological samples from patients of all ages with autoimmune hepatitis treated at Swiss hepatology centres. Here, we report the analysis of the first 5 years of registry data. RESULTS: A total of 291 patients with autoimmune hepatitis have been enrolled, 30 of whom were diagnosed before 18 years of age and composed the paediatric cohort. Paediatric cohort: median age at diagnosis 12.5 years (range 1-17, interquartile range (IQR) 8-15), 16 (53%) girls, 6 (32%) with type 2 autoimmune hepatitis, 8 (27%) with autoimmune sclerosing cholangitis, 1 with primary biliary cholangitis variant syndrome, 4 (15%) with inflammatory bowel disease and 10 (41%) with advanced liver fibrosis at diagnosis. Adult cohort: median age at diagnosis 54 years (range 42-64, IQR 18-81), 185 (71%) women, 51 (20%) with primary biliary cholangitis variant syndrome, 22 (8%) with primary sclerosing cholangitis variant syndrome, 9 (4%) with inflammatory bowel disease and 66 (32%) with advanced liver fibrosis at diagnosis. The median follow-up time for the entire cohort was 5.2 years (IQR 3-9.3 years). Treatment in children: 29 (97%) children were initially treated with corticosteroids, 28 of whom received combination treatment with azathioprine. Budesonide was used in four children, all in combination with azathioprine. Mycophenolate mofetil was used in five children, all of whom had previously received corticosteroids and thiopurine. Treatment in adults (data available for 228 patients): 219 (96%) were treated with corticosteroids, mostly in combination with azathioprine. Predniso(lo)ne was the corticosteroid used in three-quarters of patients; the other patients received budesonide. A total of 78 (33%) patients received mycophenolate mofetil, 62 of whom had previously been treated with azathioprine. Complete biochemical response was achieved in 13 of 19 (68%) children and 137 of 182 (75%) adults with available follow-up data. All children were alive at the last follow-up, and none had undergone liver transplantation. Five (2%) adults underwent liver transplantation, two of whom had a fulminant presentation. Four (2%) adults with autoimmune hepatitis died (two from liver-associated causes). CONCLUSION: Patients with autoimmune hepatitis in Switzerland had clinical features similar to those in other cohorts. The proportion of patients diagnosed with primary biliary cholangitis variant syndrome was higher than expected. Autoimmune hepatitis was managed according to guidelines, except for the use of budesonide in a small proportion of paediatric patients. The outcomes were excellent, but the findings must be confirmed over a longer follow-up period.

Microbiome analysis and fecal microbiota transfer in pediatric gastroenterology - a structured online survey in German-speaking countries.

PURPOSE: To assess the current attitude and the status quo towards the use of microbiome analysis and fecal microbiota transfer (FMT) in pediatric patients in German-speaking pediatric gastroenterology centers. METHODS: A structured online survey among all certified facilities of the German-speaking society of pediatric gastroenterology and nutrition (GPGE) was conducted from November 01, 2020, until March 30, 2021. RESULTS: A total of 71 centers were included in the analysis. Twenty-two centers (31.0%) use diagnostic microbiome analysis, but only a few perform analysis frequently (2; 2.8%) or regularly (1; 1.4%). Eleven centers (15.5%) have performed FMT as a therapeutic approach. Most of these centers use individual in-house donor screening programs (61.5%). One-third (33.8%) of centers rate the therapeutic impact of FMT as high or moderate. More than two-thirds (69.0%) of all participants are willing to participate in studies assessing the therapeutic effect of FMT. CONCLUSIONS: Guidelines for microbiome analyses and FMT in pediatric patients and clinical studies investigating their benefits are absolutely necessary to improve the patient-centered care in pediatric gastroenterology. The long-term and successful establishment of pediatric FMT centers with standardized procedures for patient selection, donor screening, application route, volume, and frequency of use is highly required to obtain a safe therapy.

Phase III Randomized Non-Inferiority Study of OSS Versus PEG + Electrolyte Colonoscopy Preparation in Adolescents.

OBJECTIVES: Many protocols and preparations are used for bowel cleansing before pediatric colonoscopy but few are based on scientific evidence. We evaluated efficacy, safety, tolerability, and patient preference of oral sulfate solution (OSS) at 75% of the adult dose versus polyethylene glycol (PEG)-electrolyte solution in adolescents presenting for diagnostic colonoscopy. METHODS: Phase III, randomized, evaluator-blinded, non-inferiority study of OSS and PEG in adolescents aged 12-17 years. OSS and PEG were administered in 2 doses on the day before colonoscopy. Primary endpoint included proportion of patients with successful overall preparation (4-point scale). Secondary endpoints included overall and segmental bowel cleansing (Boston Bowel Preparation Scale; BBPS), completed colonoscopies, duration of examination, time to cecal intubation, proportion of nasogastric tubes (NGTs), adverse events (AEs) and acceptability. RESULTS: Successful cleansing was achieved in 71.4% and 79.0% of patients receiving OSS and PEG, respectively [adjusted difference -7.61 (95% confidence interval, CI, -18.45 to 3.24); P = 0.0907]. Segmental BBPS score for the left and transverse colon were similar between treatment groups, but better for the right colon with PEG than OSS [2.2 (95% CI, 2.0-2.4) and 1.9 (95% CI, 1.7-2.1), respectively; P = 0.0015]. Significantly fewer OSS patients needed NGT placement to ingest the whole solution [9/125 (7.2%)] than PEG patients [36/116 (31.0%); P < 0.0001]. Treatment acceptability was significantly higher with OSS than PEG ( P < 0.0001). Duration of examination, completed colonoscopies, and time to cecal intubation were similar between preparations. Gastrointestinal AEs including nausea, vomiting, abdominal pain, and distension were similar in both groups but more patients receiving PEG had AEs assessed as incapacitating. CONCLUSIONS: Non-inferiority of OSS to PEG was not demonstrated, but OSS was associated with a lower requirement for NGT, better acceptability, and less frequent severe AEs than with PEG.

How to Respond to Misinformation From the Anti-Vaccine Movement.

Vaccines are doubtlessly one of the most crucial life-saving medical interventions to date. However, perplexingly, they court more public controversy than their objectively excellent safety profile warrants. While doubts about the safety of vaccines, as well as opposition to vaccine policies, can be traced back at least to the mid-19th century, the modern anti-vaccine movement has come in 3 distinct waves, or generations, each precipitating around distinct key events. Here, we describe the first 2 generations and trace the origins of an emerging third generation anti-vaccine movement. Currently, this third generation is an integral part of the larger anti-COVID movement and in this more libertarian environment propagates the idea of individualism superseding the responsibility for community health. We highlight the need for a better science education of the young, as well as the general public to further enhance overall science literacy and suggests strategies to achieve these goals.

Pediatric endoscopy training across Europe: a survey of the ESPGHAN National Societies Network 2016-2019.

Background and study aims The ability to perform endoscopy procedures safely and effectively is a key aspect of quality clinical care in Pediatric Gastroenterology, Hepatology and Nutrition (PGHN). The aim of this survey, which was part of a global survey on PGHN training in Europe, was to assess endoscopy training opportunities provided across Europe. Methods Responses to standardized questions related to endoscopy training were collected from training centers across Europe through the presidents/representatives of the European Society for Paediatric Gastroenterology, Hepatology and Nutrition National Societies from June 2016 to December 2019. Results A total of 100 training centers from 19 countries participated in the survey. In 57 centers, the endoscopy suit was attached to the PGHN center, while in 23, pediatric endoscopies were performed in adult endoscopy facilities. Ninety percent of centers reported the availability of specialized endoscopy nurses and 96 % of pediatric anesthetists. Pediatric endoscopies were performed by PGHN specialists in 55 centers, while 31 centers reported the involvement of an adult endoscopist and 14 of a pediatric surgeon. Dividing the number of procedures performed at the training center by the number of trainees, ≤ 20 upper, lower, or therapeutic endoscopies per trainee per year were reported by 0 %, 23 %, and 56 % of centers, respectively, whereas ≤ 5 wireless capsule endoscopies per trainee per year by 75 %. Only one country (United Kingdom) required separate certification of competency in endoscopy. Conclusions Differences and deficiencies in infrastructure, staffing, and procedural volume, as well as in endoscopy competency assessment and certification, were identified among European PGHN training centers limiting training opportunities in pediatric endoscopy.

Infant formulas with synthetic oligosaccharides and respective marketing practices.

Human milk contains more than 150 different oligosaccharides, which together are among to the quantitatively predominant solid components of breast milk. The oligosaccharide content and composition of human milk show large inter-individual differences. Oligosaccharide content is mostly influenced by genetic variants of the mother's secretor status. Oligosaccharides in human milk are utilized by infants' intestinal bacteria, affecting bacterial composition and metabolic activity. Maternal secretor status, and respective differing fucosylated oligosaccharide content, has been associated both with reduced and increased risk of infection in different populations of breastfed infants, possibly due to environmental conditions and the infant's genotype. There are no safety concerns regarding the addition of previously approved oligosaccharides to infant formula; however, no firm conclusions can be drawn about clinically relevant benefits either. Therefore, infant formulas with synthetic oligosaccharide additives are currently not preferentially recommended over infant formulas without such additives. We consider the use of terms such as "human milk oligosaccharides" and corresponding abbreviations such as "HMO" in any advertising of infant formula to be an inappropriate idealization of infant formula. Manufacturers should stop this practice, and such marketing practices should be prevented by responsible supervisory authorities. Pediatricians should inform families that infant formulas supplemented with synthetic oligosaccharides do not resemble the complex oligosaccharide composition of human milk.

Isolated Crohn's Colitis: Is Localization Crucial? Characteristics of Pediatric Patients From the CEDATA-GPGE Registry.

Introduction: Pediatric patients with inflammatory bowel disease (IBD) are classified into Crohn's disease (CD), ulcerative colitis (UC), and unclassifiable (IBD-U). However, data provide evidence that ileal CD (L1) is distinct from colonic CD (L2). The aim of this study was to investigate the clinical features of isolated Crohn's colitis in a pediatric population. Material and Methods: Children who were prospectively included in the CEDATA-GPGE registry on diagnosis were compared according to the diagnosis of CD with L2 vs. L1 and ileocolonic (L3) involvement pattern as well as IBD-U and UC. The clinical significance of L2 was investigated with regard to extraintestinal manifestations, treatment, surgery, and disease activity. Results: Fifty-two patients with L2 CD at a median age of 13.4 years (±3.8 SD) were compared with 182 L1 (13.8 ± 2.9 SD), 782 with L3 (12.8 ± 3.3 SD), 653 with UC (12.7 ± 3.8 SD), and 111 patients with IBD-U (11.9 ± 4.7 SD). Bloody stools at diagnosis were more common in L2 (44%) than in L1 (19.7%) and L3 (28.8%), but not as common as in UC (66.5%) and IBD-U (61.3%). Fewer CD patients with L2 (10.2%) received exclusive enteral nutrition therapy (EEN) as induction than patients with L1 (34.3%) and L3 (33.3%). After induction therapy, 42.3% of patients with L2 received immunosuppressants and 21% biologicals during follow-up (L1 56.5/10.5%; L3 59/21%; CU 43.5/11.9%; IBD-U 26.1/12.6%). Extraintestinal manifestations were more frequent in L2 (23.1%) vs. L1 (18.7%), L3 (20.2%), CU (15.8%), and IBD-U (11.7%). The number of patients requiring surgery did not differ within the CD subgroups and was significantly lower in UC and IBD-U. Perianal fistula surgery was significantly more common in L2 (44%) than in L1 (4.8%) or L3 (21.7%). In addition, the frequency of surgery for perianal abscesses was also more frequent in L2 (55.6%) than in L1 (12.7%) or L3 (38.4%). Conclusions: The consideration of pediatric Crohn's colitis as a distinct disease seems necessary as it is characterized by extraintestinal manifestations (EIMs) with mainly joint involvement and perianal fistulas or abscesses requiring surgery and biologic therapy. Thus, colonic Crohn's disease may have an influence on the therapeutic stratification and should be addressed in further studies.

Training in pediatric neurogastroenterology and motility across Europe: a survey of the ESPGHAN National Societies Network 2016-2019.

Background: Pediatric gastrointestinal motility disorders present significant challenges for diagnosis and management, emphasizing the need for appropriate training in Pediatric Neurogastroenterology and Motility (PNGM). The aim of this survey, part of a comprehensive survey on training in pediatric gastroenterology, hepatology and nutrition, was to evaluate training related to PNGM across European training centers. Method: Standardized questionnaires were collected from training centers through the National Societies Network of the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN), from June 2016 to December 2019. Results: In total, 100 training centers from 19 countries participated in the survey. Dedicated PNGM clinics were available in 22 centers; pH-monitoring in 60; pH/impedance in 66; standard manometry in 37; and high-resolution manometry in 33. If all motility studies were performed partially or fully by the trainees, the median (range) annual numbers/per trainee were as follows: pH-monitoring 30 (1-500); pH/impedance 17 (1-131); standard manometries 10 (1-150); and high-resolution manometries 8 (1-75). The motility assessment was performed by pediatric gastroenterologists (43 centers); adult gastroenterologists (10 centers); pediatric surgeons (5 centers); and both pediatric gastroenterologists and pediatric surgeons (9 centers). Annual numbers ≤10 for pH-monitoring, pH/impedance, standard manometries and high-resolution manometries were reported by 7 (12%), 15 (23%), 11 (30%) and 14 (42%) centers, respectively. Conclusions: Significant differences exist in PNGM-related infrastructure, staff and procedural volumes at training centers across Europe. ESPGHAN and the National Societies should take initiatives to ensure the acquisition of competence in PNGM-related knowledge and skills, and develop strategies for assessment and accreditation.An infographic is available for this article at: http://www.annalsgastro.gr/files/journals/1/earlyview/2022/Infographic-AG6486.pdf.

Association of training standards in pediatric gastroenterology, hepatology and nutrition in European training centers with formal national recognition of the subspecialty: a survey of the ESPGHAN National Societies Network 2016-2019.

Background: This survey evaluated the effects of the recognition of pediatric gastroenterology, hepatology and nutrition (PGHN) on European PGHN training centers. Method: Standardized questionnaires were collected from training centers via the presidents/representatives of the National Societies Network of the European Society for Pediatric Gastroenterology, Hepatology and Nutrition, from June 2016 to December 2019. Results: A total of 100 training centers from 19 countries participated in the survey: 55 from 12 countries where PGHN is formally recognized (Group 1) and 45 from 7 countries where it is not (Group 2). Training centers in Group 2 were less likely to have an integrated endoscopy suite, a written training curriculum and a training lead (P=0.059, P<0.001 and P=0.012, respectively). Trainees in Group 2 were less likely to be exposed to an adequate number of diagnostic endoscopies, while no differences were found in relation to liver biopsies. Half of the training centers in both Groups do not have dedicated beds for PGHN patients, while in 64% and 58%, respectively, trainees do not participate in on-call programs for PGHN emergencies. Research training is mandatory in 26% of the centers. The duration of training, as well as the assessment and accreditation policies, vary between countries. Conclusions: This study has revealed significant discrepancies and gaps in infrastructure and training programs, training leadership, and assessment of training and certification across European training centers in PGHN. Strategies to support the recognition of PGHN and to standardize and improve training conditions should be developed and implemented.An infographic is available for this article at: http://www.annalsgastro.gr/files/journals/1/earlyview/2022/Infographic_AG-6496.pdf.

Training in pediatric hepatology across Europe: a survey of the National Societies Network (2016-2019) of the European Society for Paediatric Gastroenterology, Hepatology and Nutrition.

Background: The widely recognized burden of liver diseases makes training in pediatric hepatology (PH) imperative. The aim of this survey, which was part of a global survey on training in pediatric gastroenterology, hepatology and nutrition (PGHN) across Europe, was to assess the PH and liver transplantation (LT) infrastructure, staff and training programs in PGHN training centers. Method: Standardized questionnaires were collected from training centers via the presidents/representatives of the National Societies Network of the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) from June 2016 to December 2019. Results: A total of 100 PGHN training centers participated in the survey (14/100 were national referral centers in PH and/or LT). Dedicated PH clinics were available in 75%, but LT clinics in only 11%. Dedicated beds for PGHN inpatients were available in 47/95 (49%) centers. Full-time or part-time specialists for PH care were available in 31/45 (69%) and 11/36 (31%) centers, respectively. Liver biopsies (LB) were performed in 93% of centers by: a PGHN specialist (35%); an interventional radiologist (26%); a pediatric surgeon (4%); or a combination of them (35%). Dividing the annual number of LBs in the centers performing LBs by the number of trainees gave a median (range) of 10 (1-125) per trainee. Transient elastography was available in 60/92 (65%) of centers. Conclusions: The survey highlighted the differences and shortcomings in PH training across Europe. ESPGHAN should take initiatives together with National Societies to ensure the acquisition of PH knowledge and skills according to the ESPGHAN curriculum.An infographic is available for this article at: http://www.annalsgastro.gr/files/journals/1/earlyview/2022/Infographic-Hepatology-training-paper.pdf.

[Paediatric gastroenterological and hepatological care in Germany: results of a nationwide survey]. / Kindergastroenterologische und hepatologische Versorgung in Deutschland: Ergebnisse einer deutschlandweiten Umfrage.

INTRODUCTION: Children and adolescents with chronic gastrointestinal, pancreatic and liver diseases need age-appropriate and qualified treatment. A representative survey is used to analyse the structural and personnel-related outpatient and inpatient care of children with chronic gastrointestinal, pancreatic and liver diseases in Germany. METHODOLOGY: 319 paediatric and adolescent medicine clinics and 50 paediatric gastroenterology practices in Germany were invited to participate in the anonymous online survey via EFS Survey. The structure of the facilities, further training authorisations, cooperations, treatment and care data and an assessment of the need for care were systematically recorded and descriptively evaluated. RESULTS: 81 clinics and 10 practices participated in the survey. Almost two thirds of the clinics (n=52) provide outpatient paediatric gastroenterology services. Mostly up to 10 (25.4%) or 20 hours/week (33.8%). A quarter of the clinics do not offer consultation hours. Outpatient care needs cannot be met by two-thirds of the institutions. Half of all clinics stated that inpatient paediatric gastroenterology care needs can be met. However, one third cannot cover this and only rarely are there unused capacities. 35 clinics (43.2%) have a further training authorisation according to the state medical association (n=33) and/or are a further training centre of the Society for Paediatric Gastroenterology and Nutrition (GPGE) (n=18). CONCLUSION: There is a deficit in both outpatient and inpatient care in paediatric and adolescent gastroenterology. This results, among other things, from the economic framework conditions and a lack of personnel. Well-trained specialists with specialisation in paediatric and adolescent gastroenterology are still needed to provide qualified care throughout the country. Future studies should also include the need for paediatric gastroenterological care from the perspective of other groups, such as affected patients, internal gastroenterologists and paediatricians in private practice.

Compound heterozygous variants in OTULIN are associated with fulminant atypical late-onset ORAS.

Autoinflammatory diseases are a heterogenous group of disorders defined by fever and systemic inflammation suggesting involvement of genes regulating innate immune responses. Patients with homozygous loss-of-function variants in the OTU-deubiquitinase OTULIN suffer from neonatal-onset OTULIN-related autoinflammatory syndrome (ORAS) characterized by fever, panniculitis, diarrhea, and arthritis. Here, we describe an atypical form of ORAS with distinct clinical manifestation of the disease caused by two new compound heterozygous variants (c.258G>A (p.M86I)/c.500G>C (p.W167S)) in the OTULIN gene in a 7-year-old affected by a life-threatening autoinflammatory episode with sterile abscess formation. On the molecular level, we find binding of OTULIN to linear ubiquitin to be compromised by both variants; however, protein stability and catalytic activity is most affected by OTULIN variant p.W167S. These molecular changes together lead to increased levels of linear ubiquitin linkages in patient-derived cells triggering the disease. Our data indicate that the spectrum of ORAS patients is more diverse than previously thought and, thus, supposedly asymptomatic individuals might also be affected. Based on our results, we propose to subdivide the ORAS into classical and atypical entities.

Training in Paediatric Clinical Nutrition Across Europe: A Survey of the National Societies Network (2016-2019) of the European Society for Paediatric Gastroenterology, Hepatology and Nutrition.

OBJECTIVES/BACKGROUND: Disease-related malnutrition is common in patients with chronic diseases and has detrimental effects, therefore, skills in nutrition care are essential core competencies for paediatric digestive medicine. The aim of this survey, conducted as part of a global survey of paediatric gastroenterology, hepatology and nutrition (PGHN) training in Europe, was to assess nutrition care-related infrastructure, staff, and patient volumes in European PGHN training centres. METHODS: Standardized questionnaires related to clinical nutrition (CN) care were completed by representatives of European PGHN training centres between June 2016 and December 2019. RESULTS: One hundred training centres from 17 European countries, Turkey, and Israel participated in the survey. Dedicated CN clinics exist in 66% of the centres, with fulltime and part-time CN specialists in 66% and 42%, respectively. Home tube feeding (HTF) andhome parenteral nutrition (HPN) programmes are in place in 95% and 77% of centres, respectively. Twenty-four percent of centres do not have a dedicated dietitian and 55% do not have a dedicated pharmacist attached to the training centre. Even the largest centres with >5000 outpatients reported that 25% and 50%, respectively do not have a dedicated dietitian or pharmacist. Low patient numbers on HTF and HPN of <5 annually are reported by 13% and 43% of centres, respectively. CONCLUSIONS: The survey shows clear differences and deficits in Clinical Nutrition training infrastructure, including staff and patient volumes, in European PGHN training centres, leading to large differences and limitations in training opportunities in Clinical Nutrition.

Positive and negative selection shape the human naive B cell repertoire.

Although negative selection of developing B cells in the periphery is well described, yet poorly understood, evidence of naive B cell positive selection remains elusive. Using 2 humanized mouse models, we demonstrate that there was strong skewing of the expressed immunoglobulin repertoire upon transit into the peripheral naive B cell pool. This positive selection of expanded naive B cells in humanized mice resembled that observed in healthy human donors and was independent of autologous thymic tissue. In contrast, negative selection of autoreactive B cells required thymus-derived Tregs and MHC class II-restricted self-antigen presentation by B cells. Indeed, both defective MHC class II expression on B cells of patients with rare bare lymphocyte syndrome and prevention of self-antigen presentation via HLA-DM inhibition in humanized mice resulted in the production of autoreactive naive B cells. These latter observations suggest that Tregs repressed autoreactive naive B cells continuously produced by the bone marrow. Thus, a model emerged, in which both positive and negative selection shaped the human naive B cell repertoire and that each process was mediated by fundamentally different molecular and cellular mechanisms.