Raised immunoglobulin A and circulating T follicular helper cells are linked to the development of food allergy in paediatric liver transplant patients.

BACKGROUND: Post-transplant food allergy (LTFA) is increasingly observed after paediatric liver transplantation (LT). Although the immunopathology of LTFA remains unclear, immunoglobulin (Ig) E seems to be implicated. OBJECTIVE: To study humoral and cellular immunity in paediatric LT patients in search for factors associated with LTFA, and compare with healthy controls (HC) and non-transplant food-allergic children (FA). METHODS: We studied serum Ig levels in 29 LTFA, 43 non-food-allergic LT patients (LTnoFA), 21 FA patients and 36 HC. Serum-specific IgA and IgE against common food allergens in LTFA, IgA1 , IgA2 and joining-chain-containing polymeric IgA (pIgA) were measured. Peripheral blood mononuclear cells were analysed by flow cytometry for B and T cell populations of interest. RESULTS: Serum IgA and specific IgA were higher in LTFA compared to LTnoFA. LTFA patients had the highest proportion of circulating T follicular helper cells (cTfh). The percentage of cTfh correlated positively with serum IgA. Unique in LTFA was also the significant increase in serum markers of mucosal IgA and the decrease in the Th17 subset of CXCR5(-) CD4(+) cells compared to HC. Both LT patients exhibited a rise in IgA(+) memory B cells and plasmablasts compared to HC and FA. CONCLUSIONS: LT has an impact on humoral immunity, remarkably in those patients developing FA. The increase in serum markers of mucosal IgA, food allergen-specific IgA and cTfh cells observed in LTFA, point towards a disturbance in intestinal immune homoeostasis in this patient group.

[Pigmented villonodular synovitis of the knee]. / Le cas clinique du mois. Synovite villonodulaire pigmentée du genou.

This case report is concerned with a 30 year old patient diagnosed with pigmented villonodular synovitis (PVNS) in the knee. The patient underwent an orthopedic surgical operation to remove the lesions. PVNS is a rare proliferative disorder, mostly benign and affecting the knee; its aetiology remains unclear. It represents a medical challenge because of non-specific symptoms that delay the diagnosis with a very high rate of recurrence. MRI imaging is necessary to explore the lesions, but the final diagnosis can only be made after anatomopathologic analysis of the excised lesions. When multiple lesions are present, the treatment consists of their excision by arthrotomy, or by arthroscopy if the disease is localized.

Acquired antithrombin type IIb deficiency after liver transplantation: a case report.

A 3-year-old girl with multifocal hepatoblastoma was referred to our clinic for living-donor liver transplantation, the patient's father being the donor. Pretransplant evaluation revealed that the father presented partial asymptomatic antithrombin (AT) deficiency, with no inherited AT deficiency found in the girl. The genetic testing showed an AT type IIb deficiency responsible for a defect in the heparin-binding region of AT which is less thrombogenic but more common than the other AT qualitative defects. Her mother was ABO incompatible. Despite the thrombophilia on the father's side, transplantation was successfully performed under replacement therapy with intravenous AT concentrate and low-molecular-weight heparin thromboprophylaxis given to both the recipient and the donor. No thrombotic complications occurred. In the posttransplantation course, acquired partial AT deficiency was detected in the recipient, who received adjuvant chemotherapy without thrombotic complications. This case report highlights the relevance of full thrombophilic work-up before liver transplantation from a living donor, while illustrating that the procedure can be successfully performed in the case of AT deficiency on the donor's side provided that appropriate AT supplementation and thromboprophylaxis are administered to both the recipient and the donor.

The interferon-alpha and interleukin-10 responses in neonates differ from adults, and their production remains partial throughout the first 18 months of life.

Previous studies have suggested that the susceptibility of newborns to infections is linked to the immaturity of their immune system, but very few data are available on the early stages of maturation of the immune response. Therefore, we decided to investigate the evolution of the interferon (IFN)-α and interleukin (IL)-10 responses in neonatal mononuclear cells. To this end, mononuclear cells isolated from cord blood and peripheral blood of 2-, 6- and 18-month-old children and adults were stimulated with unmethylated cytosine-phosphate-guanosine oligodeoxynucleotide (CpG-ODN) 2216 (IFN-α response) or lipopolysaccharide (LPS) (IL-10 response) for 24 h. The production of IFN-α and IL-10 was then measured in culture supernatants using enzyme-linked immunosorbent assay (ELISA) or a 6-plex cytokine array, respectively. Compared to adults, we found a significant impairment in both the IFN-α and IL-10 responses of neonatal mononuclear cells. Interestingly, both responses had increased significantly after 2 months, but remained lower than the adult responses throughout the first 18 months of life. This study shows that although the immune response of neonates tends to mature fairly quickly, it remains different when compared to the adult immune response throughout the first 18 months of life. This could have important consequences on children's ability to mount an appropriate immune response to various challenges and to establish tolerance and immune homeostasis.

The Belgian Association for Study of the Liver Guidance Document on the Management of Adult and Paediatric Non-Alcoholic Fatty Liver Disease.

Non-Alcoholic Fatty Liver Disease (NAFLD) is highly prevalent and associated with considerable liver-related and non-liverrelated morbidity and mortality. There is, however, a lot of uncertainty on how to handle NAFLD in clinical practice. The current guidance document, compiled under the aegis of the Belgian Association for the Study of the Liver by a panel of experts in NAFLD, from a broad range of different specialties, covers many questions encountered in daily clinical practice regarding diagnosis, screening, therapy and follow-up in adult and paediatric patients. Guidance statements in this document are based on the available evidence whenever possible. In case of absence of evidence or inconsistency of the data, guidance statements were formulated based on consensus of the expert panel. This guidance document is intended as a help for clinicians (general practitioners and all involved specialties) to implement the most recent evidence and insights in the field of NAFLD within a Belgian perspective.

Possible effects of repeated exposure to ibuprofen and acetaminophen on the intestinal immune response in young infants.

There has been an exponential increase in the frequency of immune deviations in young children. Consequently, research investigating environmental causes for this increase has become a Public Health priority. We have summarized the experimental observations and epidemiological data that could link repeated acetaminophen and ibuprofen exposure in early infancy to this increase. Recent observations on the maturational immunity of the intestinal sub-mucosal lamina propria underscore indeed the importance of prostaglandins (PGE2s). PGE2 appearing at this sub-mucosal level is a product of arachidonic acid metabolism mediated by type-2 cyclooxygenase (COX-2) situated on the membrane of many immune cells. Moreover, it seems that acetaminophen - like ibuprofen - also carries a non-selective inhibitory action on peripheral COXs, besides its central action. This inhibitory action of acetaminophen on COX2 only relates to physiological, low arachidonic acid concentrations. This explains the difference in anti-inflammatory effects. The impact of repeated inhibition of mucosal PGE2 synthesis due to COX-inhibitor exposure on maturational immunity has been demonstrated in animal experiments. Repeatedly exposed young animals do not develop tolerance to food antigens and exhibit autoimmune deviations. Several recent epidemiological studies have also reported on the magnitude of acetaminophen and ibuprofen exposure in children and the increase in immune deviations, it is important to better understand the potential negative impact of repeated inhibitions of prostaglandin synthesis by COX2s during infancy. Since acetaminophen and ibuprofen are commonly administered analgesics and antipyretics, a well-designed prospective strategy for pharmacovigilance and -epidemiology of COX-inhibitor exposure in infancy is urgently needed.

Progressive Fibrosis Is Driven by Genetic Predisposition, Allo-immunity, and Inflammation in Pediatric Liver Transplant Recipients.

AIM: To determine predisposing factors of idiopathic allograft fibrosis among pediatric liver transplant recipients. BACKGROUND: Protocol biopsies (PB) from stable liver transplant (LT) recipient children frequently exhibit idiopathic fibrosis. The relation between allograft inflammation, humoral immune response and fibrosis is uncertain. Also the role of HLA-DRB1 genotype has not been evaluated, though it's associated with fibrosis in autoimmune hepatitis. PATIENTS AND METHODS: This observational study, included 89 stable LT recipient transplanted between 2004-2012 with mean follow-up of 4.3years, 281 serial PBs (3.1 biopsy/child) and human leukocyte antigen (HLA) antibody data. PBs were taken 1-2, 2-3, 3-5, 5-7, and 7-10years post-LT, and evaluated for inflammation and fibrosis using liver allograft fibrosis score (LAFSc). The evolution of fibrosis, inflammation and related predisposing factors were analysed. FINDINGS: HLA-DRB1*03/04 allele and Class II DSA were significantly associated with portal fibrosis (p=0.03; p=0.03, respectively). Portal inflammation was predisposed by Class II DSA (p=0.02) and non-HLA antibody presence (p=0.01). Non-portal fibrosis wasn't predisposed by inflammation. Lobular inflammation was associated with non-HLA antibodies. INTERPRETATION: We conclusively demonstrated that allograft inflammation results in fibrosis and is associated with post-LT Class II DSA and non-HLA antibodies. The HLA-DRB1*03/04 allele caused genetic predisposition for fibrosis. FUNDING: None.

Post-transplant lymphoproliferative disorder with supraglottic involvement.

OBJECTIVE: Transplant patients with primary Epstein-Barr virus (EBV) infection may develop post-transplant lymphoproliferative disorder (PTLD). Since many infants are seronegative at the time of transplantation, PTLD is a major concern for paediatric transplant centres. First manifestations of PTLD are frequently observed in the ENT area with adenoidal and/or tonsillar involvement. DESIGN: Retrospective study of two cases of PTLD with confirmed supraglottic involvement, their management and outcome. Only patients with pathologically and immunologically demonstrated B-cell proliferation were diagnosed as PTLD. RESULT: Two infants developed an acute stridor during PTLD respectively 8 and 10 months after orthotopic liver transplantation (OLT). These infants were seronegative for EBV at the time of transplantation. IgM anti-EBV and/or detection of EBV genome by polymerase chain reaction were positive. Laryngeal examination revealed hypopharyngeal and/or supraglottic mucosal hyperplasia. Immunostaining of laryngeal biopsy was positive for latent membrane protein-1 (LMP1). Patients were treated by a reduction in immunosuppression as far as tolerated with the intent to recover natural immune response by the patient over the proliferation of EBV-infected cells. Complete remission of PTLD was observed in these two cases. CONCLUSION: Tonsillar hypertrophy and adenoid enlargement are the most encountered features of PTLD in OLT occurring in the ENT area. Acute stridor with supraglottic involvement may also be observed in PTLD and must be promptly diagnosed as the prognosis of this disorder is related to rapid reduction in immunosuppression and consequently to the recovering of a natural immune response against the EBV infection.

[Influence of chest physiotherapy on gastro-œsophageal reflux in children]. / Influence de la kinésithérapie respiratoire sur le reflux gastro-œsophagien chez l'enfant.

INTRODUCTION: Chest physiotherapy is regularly prescribed for children, particularly in cystic fibrosis. Gastro-oesophageal reflux is common in this disease and is associated with certain chest physiotherapy manoeuvres. AIM OF THE STUDY: To evaluate the influence of two chest physiotherapy techniques on gastro-oesophageal reflux in children. MATERIAL AND METHOD: Twenty-nine children were investigated by routine pHmetry. During the examination, they performed two chest physiotherapy manoeuvres in a seated position for 10 minutes each with a 5 minutes rest between them. The two manoeuvres used were a slow expiration technique (ELPr) and positive expiratory pressure (PEP). It was a prospective study and the order of manoeuvres was randomised. The pH traces were analysed blindly when all the studies had been completed. RESULTS: In the sample, 21% of children had gastro-oesophageal reflux during the physiotherapy session. No relationship was found between reflux during physiotherapy and pathological reflux (P=0.411) nor the physiotherapy technique used (P=0.219). CONCLUSION: The use of these two chest physiotherapy techniques in children in a seated position can produce gastro-oesophageal reflux.

Patients at risk for development of posttransplant lymphoproliferative disorder: plasma versus peripheral blood mononuclear cells as material for quantification of Epstein-Barr viral load by using real-time quantitative polymerase chain reaction.

BACKGROUND: Early diagnosis of Epstein-Barr virus (EBV)-associated posttransplant lymphoproliferative disorder (PTLD) is required to detect a stage of disease that is more likely to respond to treatment. Elevated levels of EBV DNA were found in peripheral blood of patients at the onset of PTLD. METHODS: To compare plasma and peripheral blood mononuclear cells (PBMCs) as material for real-time quantitative polymerase chain reaction (RQ-PCR) measurement of Epstein-Barr viral load, we used two sets of primers and probes specific for the BAM HI-K or BAM HI-W region of the EBV genome. RESULTS: Patients with PTLD had a median viral load of 19,200 EBV genomes/microg DNA (n=9) or 3,225 EBV genomes/100 microl plasma (n=5), being significantly higher compared with immunosuppressed patients with primary (n=9) or reactivated (n=20) EBV infection or immunosuppressed patients without serological signs of active EBV infection (n=67) (P<0.001). Hence, a value of greater than 5,000 EBV genomes/microg PBMC DNA was considered as a diagnostic parameter for PTLD with a sensitivity and specificity of 1.00 or 0.89, respectively. When plasma was analyzed, however, a value of greater than 1,000 EBV genomes/100 microl plasma had both a sensitivity and specificity of 1.00 for the diagnosis of PTLD. During remission of PTLD, viral load was more effectively cleared in plasma compared with PBMCs. In plasma of nonimmunosuppressed individuals, even a qualitative detection of EBV-related sequences was sensitive and specific for the diagnosis of primary EBV infection, whereas for analysis of PBMC DNA a quantitative parameter had to be considered to differentiate healthy individuals (< 100 EBV genomes/microg PBMC DNA) from patients with primary EBV infection (>100 EBV genomes/microg PBMC DNA). CONCLUSION: Although both PBMCs and plasma were useful as material for EBV-specific RQ-PCR in immunosuppressed patients and nonimmunosuppressed individuals, the specificity of analysis seemed to be higher if plasma was taken for analysis.

Indications and results of chemotherapy in children with posttransplant lymphoproliferative disease after liver transplantation.

Among 39 posttransplant lymphoproliferative diseases (PTLD) in a cohort of 450 pediatric liver transplant recipients, 3 had a malignant lymphoma, unresponsive to arrest of immunosuppression and to gancyclovir, interferon, and anti-interleukin 6 antibodies. Lymphoma appeared 20, 46, and 96 months posttransplantation and 16, 43, and 90 months after primary Epstein-Barr virus infection. In one case, the patient had histological progression from plasmacytic hyperplasia PTLD, concomitant with symptomatic primary infection, to Burkitt-like lymphoma 43 months later. These three patients received five courses of chemotherapy, after a cyclophosphamide, doxorubicin, vincristine, and prednisone regimen for Burkitt-like or LH 89 scheme for Hodgkin-like PTLDs. Chemotherapy was well tolerated, and all three were free of disease and without immunosuppression 19, 14, and 4 months after chemotherapy. In Burkitt-like or Hodgkin-like PTLDs, immunomodulatory or antiviral drugs were inefficient. Chemotherapy is indicated and can be safely and successfully used. Long-term arrest of immunosuppression seems feasible without graft rejection.

Epstein-Barr virus infection in sixty pediatric liver graft recipients: diagnosis of primary infection and virologic follow-up.

BACKGROUND: Epstein-Barr virus (EBV) is an important cause of infection after pediatric liver transplantation. Earlier detection of EBV could result in shortening the delay in diagnosis and allow better management of a pediatric high risk population. OBJECTIVES: To determine the timing of EBV primary infection after graft and to compare the performances of different assays for an early detection of the virus. METHODS: Sixty pediatric liver graft recipients were followed. Kinetics of appearance of different EBV serologic parameters (anti-EBV-IgG, -IgM and -IgA, and anti-EBV nuclear antigen-IgG) and of the viral DNA in peripheral blood lymphocytes by PCR were compared. RESULTS: Thirty-six patients had a primary EBV infection. The first PCR and IgM positive result appeared after a mean delay of 56 and 61 days, respectively, and preceded the IgG response (mean delay, 143 days). Most of the studied patients (13 of 16) developed anti-EBV-IgA and only 3 developed anti-EBNA-IgG during the follow-up period. CONCLUSIONS: EBV primary infection occurred in most cases during the first 2 months after graft. The IgG response was delayed. The best performance was obtained by PCR. However, the IgM test compared well with the PCR and could be a more widely accessible measure to follow regularly.

MR enterography in children with Crohn disease: results from the Belgian pediatric Crohn registry (Belcro).

INTRODUCTION: Magnetic Resonance enterography (MRE) is an imaging modality avoiding ionizing radiation and the discomfort associated with enteroclysis. The results of MRE at diagnosis in the patients of the Belgian pediatric Crohn registry (Belcro) are compared to endoscopical and histological results. METHODS: Results of MRE, endoscopy and histology were obtained from the medical charts and assigned to one of the following segments: jejunum, ileum, ascending colon, transverse colon, descending colon or rectosigmoid. MRE images were reviewed in a blinded way by 4 radiologists with specific interest in pediatric MRE. RESULTS: From the Belcro registry, twenty-two patients underwent a MRE during their work-up for Crohn disease. The results of endoscopy, histology and MRE were concordant (either all negative or positive) in the ileum in 16/18 patients and in the rectosigmoid, descending colon, transverse colon and ascending colon in resp 9, 8, 8 and 8/22 patients. In the non-concordant cases (MRE colon negative but endoscopy and/or histology positive), MRE could not reflect the subtle endoscopic or histologic lesions such as erosions that were described.In 4 cases where ileocaecal valve intubation was impossible ileal MRE findings were abnormal. MRE detected ileal stenosis, jejunal lesions and fistula in resp 4/22, 3/22 en 2/22 patients. The 100% and 75% interobserver agreement was resp 50-82% and 773-100% according to the different intestinal segments. CONCLUSIONS: MRE is a promising imaging modality avoiding radiation in Crohn disease. It should probably become the technique of first choice for the evaluation of extensive small bowel disease in children with Crohn disease.

Profile of pediatric Crohn's disease in Belgium.

AIM: A Belgian registry for pediatric Crohn's disease, BELCRO, was created. This first report aims at describing disease presentation and phenotype and determining associations between variables at diagnosis and registration in the database. METHODS: Through a collaborative network, children with previously established Crohn's disease and newly diagnosed children and adolescents (under 18 y of age) were recruited over a 2 year period. Data were collected by 23 centers and entered in a database. Statistical association tests analyzed relationships between variables of interest at diagnosis. RESULTS: Two hundred fifty-five patients were included. Median age at diagnosis was 12.5 y (range: 1.6-18 y); median duration of symptoms prior to diagnosis was 3 m (range: 1-12 m). Neonatal history and previous medical history did not influence disease onset nor disease behavior. Fifty three % of these patients presented with a BMI z-score < -1. CRP was an independent predictor of disease severity. Steroids were widely used as initial treatment in moderate to severe and extensive disease. Over time, immunomodulators and biological were prescribed more frequently, reflecting a lower prescription rate for steroids and 5-ASA. A positive family history was the sole significant determinant for earlier use of immunosuppression. CONCLUSION: In Belgium, the median age of children presenting with Crohn's disease is 12.5 y. Faltering growth, extensive disease and upper GI involvement are frequent. CRP is an independent predictive factor of disease activity. A positive family history appears to be the main determinant for initial treatment choice.

Hepatocyte transplantation using the domino concept in a child with tetrabiopterin nonresponsive phenylketonuria.

Phenylketonuria is a metabolic disease caused by phenylalanine hydroxylase deficiency. Treatment is based on a strict natural protein-restricted diet that is associated with the risk of malnutrition and severe psychosocial burden. Oral administration of tetrahydrobiopterin can increase residual enzyme activity, but most patients with severe clinical phenotypes are nonresponders. We performed liver cell transplantation in a 6-year-old boy with severe tetrahydrobiopterin nonresponsive phenylketonuria who failed to comply with diet prescriptions. The transplanted hepatocytes were obtained in part from an explanted glycogen storage type 1b liver. Following two infusions, blood phenylalanine levels returned within the therapeutic target while the phenylalanine half-life assessed by loading tests decreased from 43 to 19 h. However, 3 months later, blood phenylalanine concentrations increased and the phenylalanine intake had to be reduced. Cell-based therapy is a promising therapeutic option in phenylketonuria, and the domino concept may solve the issue of cell sources for hepatocyte transplantation.

Safety and cost of infliximab for the treatment of Belgian pediatric patients with Crohn's disease.

Biologicals have become an important component in the treatment of Crohn's disease in children. Their increased and long term use raises safety concerns. We describe safety and cost of infliximab in Belgian pediatric Crohn's disease patients. All patients on infliximab as part of the present or past treatment for Crohn's Disease until January 1st 2011 were selected from an existing database. Information on disease phenotype, medication and adverse events were extracted. Adverse events occurred in 25.9% of patients exposed to infliximab of which 29.6% were severe. In total 31.7% of patients stopped infliximab therapy. The main reasons for discontinuation were adverse events in 45.4% and loss of response in 30.3%. No malignancies or lethal complications occurred over this 241 patient year observation period. Immunomodulators were concomitant medication in 75% of patients and were discontinued subsequently in 38.4% of them. The cost of infliximab infusions per treated patient per year in the Belgian health care setting is approximately 9 474 euro, including only medication and hospital related costs. Even though infliximab is relatively safe in pediatric CD on the short term, close follow-up and an increased awareness of the possible adverse reactions is highly recommended. Adverse reactions appeared in 25.9% of all patients and were the main reason for discontinuation. Treatment cost has to be balanced against efficacy and modifications in disease course. In the Belgian health care system, the medication is available to all patients with moderate to severe CD.

[Long-term outcome of infliximab therapy in pediatric Crohn disease]. / Usage prolongé de l'infliximab dans la maladie de Crohn chez l'enfant.

BACKGROUND: The efficacy of infliximab (IFX) in inducing and maintaining remission in pediatric Crohn disease is currently well documented. However, the optimal treatment strategy beyond 1 year has not been established. In particular, systematic continuation of maintenance therapy and its association with immunomodulators have not yet been analyzed. OBJECTIVE: The aim of this study was to describe the long-term outcome of pediatric Crohn disease patients on IFX therapy and to evaluate the clinical response to the therapy and the effect on growth. METHODS: A single-center and retrospective chart review was conducted. The clinical maintenance response to treatment, effect on the linear growth, and long-term outcome were examined. These parameters were analyzed according to the age of the patients, duration and localization of the disease, as well as associated therapies. RESULTS: We identified 52 children with Crohn disease younger than 16 years of age at the time of diagnosis. Of these patients, 20 (38%) received a biologic therapy at a mean age of 13.9±2 years. Fifteen patients received IFX therapy and 13 (86%) were in clinical remission 10 weeks after the first infusion. Among the responders, 82% were still in remission after 1 year of therapy and 66% after 2 years. Among patients treated for more than 1 year, we observed IFX dependency in 89%. Thirty-eight percent of patients with initial IFX response showed a loss of response after a median of 30 months (range, 3-42 months). At 2 years, the median Z score for height among patients with presumed growth potential had improved slightly, from -0.7 to -0.55 DS. No serious adverse events were observed. CONCLUSION: Our results confirm the continuous efficacy of IFX in pediatric Crohn disease patients after 1 year of treatment. However, a high level of dependency was observed (89 %). A slight beneficial effect on growth was observed after 2 years of treatment.