MAP kinase activating death domain deficiency is a novel cause of impaired lymphocyte cytotoxicity.

Most hereditary forms of hemophagocytic lymphohistiocytosis (HLH) are caused by defects of cytotoxicity, including the vesicle trafficking disorder Griscelli syndrome type 2 (GS2, RAB27A deficiency). Deficiency of the mitogen-activated protein kinase activating death domain protein (MADD) results in a protean syndrome with neurological and endocrinological involvement. MADD acts as a guanine nucleotide exchange factor for small guanosine triphosphatases, including RAB27A. A homozygous splice site mutation in MADD was identified in a female infant with syndromic features, secretory diarrhea, and features of HLH. Aberrant splicing caused by this mutation leads to an in-frame deletion of 30 base pairs and favors other aberrant variants. Patient natural killer (NK) cells and cytotoxic T cells showed a severe degranulation defect leading to absent perforin-mediated cytotoxicity. Platelets displayed defective adenosine triphosphate secretion, similar to that in GS2. To prove causality, we introduced a CRISPR/Cas9-based MADD knockout in the NK cell line NK-92mi. MADD-deficient NK-92mi cells showed a degranulation defect and impaired cytotoxicity similar to that of the patient. The defect of cytotoxicity was confirmed in another patient with MADD deficiency. In conclusion, RAB27A-interacting MADD is involved in vesicle release by cytotoxic cells and platelets. MADD deficiency causes a degranulation defect and represents a novel disease predisposing to an HLH phenotype.

Vaccination rate and immunity of children and adolescents with inflammatory bowel disease or autoimmune hepatitis in Germany.

BACKGROUND AND AIMS: Immunosuppressed patients are at risk of severe infections with vaccination preventable diseases. We evaluated vaccination rate and immunity of children and adolescents with inflammatory bowel disease (IBD) and autoimmune hepatitis (AIH). METHODS: Immunization rate of 329 children with IBD (n = 300) and AIH (n = 29) was assessed in seven German centres using vaccination certificates, history of chicken pox and by determining anti-varicella zoster virus (VZV) and anti-measles IgG antibodies. RESULTS: Of the total cohort 86% received long-term immunosuppression. Four doses of a hexavalent vaccine were documented in 89%, at least one dose of measles, mumps, and rubella (MMR) vaccination was documented in 325 (99%), with 300 (92%) receiving two doses. Anti-measles IgG concentrations were insufficient in 11% of the immunized patients. VZV vaccination was officially recommended in Germany since 2004, and implemented in 88% born from 2005 onwards. In patients born earlier VZV catch up vaccination only reached 25% (n = 67). Of 118 patients with documented VZV vaccination 25 (21%) did not display sufficient anti-VZV IgG. Of 198 patients with a history of chicken pox, six had undetectable anti-VZV IgG. Of 29 patients having neither had chicken pox nor VZV vaccination, 20 were found to have sufficient anti-VZV IgG. CONCLUSIONS: In our cohort vaccination coverage for hexavalent and MMR vaccinations was good, but insufficient for VZV vaccination in patients born before 2005. Neither the vaccination certificate nor the history of chicken pox is reliable to predict VZV immunity indicating a need for serologic investigations and if needed vaccination before initiating immunosuppressive therapy.

Impact on the hepatic flow velocity after pediatric combined liver-kidney transplantation compared to isolated pediatric liver transplantation-A matched-pair analysis.

BACKGROUND: Combined liver-kidney transplantation (CLKT) in children is still a rarely performed procedure. Our aim was to analyze the effect of the simultaneous transplantation of the kidney in pediatric CLKT on the liver graft flow velocity, and vascular complications compared to singular liver transplantation (LTX) in children. METHODS: All pediatric CLKT performed at our institution from 1998 to 2016 were matched with singular LTX and retrospectively analyzed. RESULTS: Overall 30 CLKT were performed in 28 children (median age 8 years, range 1-16) and matched with 30 children undergoing singular LTX (median age 7.9 years, range 1-16). No significant differences were found concerning the systolic peak flow velocity of the hepatic artery (HA) or the resistance index (RI). Vascular complications of the hepatic vessels occurred in 16.7% (CLKT) and 6.7% (LTX). The 1-/5- and 10-year patient survival was 93.3%/93.3% and 93.3% (CLKT) and 100%/100% and 92.9% (LTX). 1-/5-and 10-year liver graft survival was 76.7%/73.2% and 73.2% (CLKT) and 84.4%/75.9% and 69.6% (LTX). CONCLUSION: The simultaneous transplantation of the kidney in CLKT had no negative impact on hepatic flow velocity or vascular complications. Frequent Doppler ultrasound examinations, accurate volume management, and avoidance of abdominal pressure might be an explanation for the results and an excellent graft- and patient survival.

Excellent Outcome Following Liver Transplantation for Hepatoblastoma Using an Extensive En Bloc Hepatectomy Technique.

BACKGROUND: Hepatoblastoma is a rare malignancy but the most common primary hepatic malignancy in childhood. Pediatric liver transplantation (LT) offers the possibility to achieve a complete resection in otherwise unresectable tumors. Almost no data are available regarding specific surgical technique of LT in children with hepatoblastoma. METHODS: We analyzed all children with hepatoblastoma and LT between 2007 and 2012. Special regard was given to the surgical technique and long-term follow-up. RESULTS: Overall 7 children were transplanted with the diagnosis of hepatoblastoma (5 male, 2 female). Thereof, 4 children (median age was 11 months, range, 6-31 months) underwent "primary" LT for hepatoblastoma Pretreatment Extent of Disease III to IV. A 4-year-old boy received "salvage" LT for recurrent hepatoblastoma 2.5 years after successful liver resection. Another 15-year-old boy was transplanted as a prophylactic treatment after repeated liver resection for hepatoblastoma due to the high recurrence risk. A 14-year-old boy underwent LT due to complications following liver resection for hepatoblastoma during infancy. In all children, extensive en bloc hepatectomy was performed together with resection of the adjoining retroperitoneal tissue and regional lymphadenectomy. Actually, all children are alive without tumor recurrence median 7.1 years after LT (range, 5.7-10.7 years). CONCLUSION: Our data show an excellent long-term outcome in selected children with hepatoblastoma undergoing standardized en bloc hepatectomy for "primary" and "rescue" LT with 100% overall and recurrence-free survival.

Surgical Aspects of Liver Transplantation and Domino Liver Transplantation in Maple Syrup Urine Disease: Analysis of 15 Donor-Recipient Pairs.

Liver transplantation (LT) has been shown to be a feasible treatment in patients with severe forms of maple syrup urine disease (MSUD). Because of a sufficient extrahepatic enzyme activity in non-MSUD individuals, the organ of MSUD patients can be used as a domino graft. We performed a retrospective data collection of all LTs for MSUD carried out at the University Medical Center Hamburg-Eppendorf (2016-2018). Moreover, data from all consecutive domino LTs of the MSUD grafts either transplanted at our institution or allocated to other transplant centers were analyzed. During the study period, 15 LTs in MSUD patients were performed (12 children, 3 adults; median age, 10.9 years; range, 0.3-26.1 years). Biliary complications occurred in 20%, and 13.3% suffered from bleeding complications. No further surgical problems occurred. At present, all MSUD patients are alive with a well-functioning liver graft and on an unrestricted diet. In total, 14 consecutive domino LTs were performed. No surgical complications requiring intervention occurred. One patient died because of HCC relapse, and all other patients are alive with good liver graft function. In conclusion, the use of MSUD livers as domino grafts is safe and allows application of LT in MSUD patients without net extraction of a liver graft from the limited donor pool.

Alloimmunity and Cholestasis After Liver Transplantation in Children With Progressive Familial Intrahepatic Cholestasis.

OBJECTIVES: Bile salt export pump (BSEP) deficiency is an important reason for chronic cholestasis leading to liver transplantation (LT) in early childhood. The underlying pathology is a dysfunction of BSEP due to various mutations in the ABCB11 gene. Cases of clinical recurrence after LT due to alloantibodies directed against BSEP (antibody-induced BSEP deficiency [AIBD]) have been reported. Most of these patients could be controlled by intensified immunosuppression. METHODS: We here report on 3 children with BSEP-deficiency and end-stage liver disease, which developed AIBD after LT refractory to extensive immunosuppressive and immunomodulatory treatments; retransplantation was necessary in all 3 patients. In 1 patient, a stem cell transplantation was performed successfully. RESULTS: AIBD seems to be induced by triggering factors such as initial impaired graft function or infections after LT. CONCLUSIONS: The underlying mutation may play a role in this process. Intensifying immunosuppression may be able to control AIBD, but some cases seem to be refractory to treatment and require retransplantation. Stem cell transplantation may provide a new therapeutic option for cases refractory to conservative treatment.

Antibiotic prophylaxis in the management of percutaneous endoscopic gastrostomy in infants and children.

BACKGROUND: In randomized controlled trials in adult patients the use of prophylactic broad-spectrum antibiotic reduces the number of insertion site and systemic infections, associated with placement of percutaneous endoscopic gastrostomy (PEG) tubes. For pediatric patients no such trials exist. The aim of this study was to assess the value of antibiotic prophylaxis in PEG placement in pediatric patients. METHODS: In a retrospective chart review PEG placement in infants and children performed in a tertiary care center was analyzed. All PEG procedures were performed by an experienced pediatric gastroenterologist using the pull-through technique under general anesthesia. RESULTS: A total of 103 procedures were analyzed; 33 patients received antibiotic prophylaxis and 70 did not. Two (6%) of the patients receiving prophylaxis developed local or systemic infections after PEG placement, whereas seven (10%) without prophylaxis suffered from a PEG-related infection. This difference was not significant on chi-squared test (P = 0.5). Sixty patients had a body temperature >38°C within the first 3 days after the PEG procedure. A total of 77% of these patients had no antibiotic prophylaxis. Mean body temperature differed significantly between patients with and without prophylaxis (37.9°C vs. 38.3°C, respectively; P = 0.02). CONCLUSIONS: The incidence of PEG-related local or systemic infection after PEG-placement was not significantly different between patients with and without antibiotic prophylaxis, but the latter had a significantly higher mean body temperature after the PEG procedure. Taking elevated mean body temperature as a marker for putative bacteremia it is suggested that antibiotic prophylaxis is indicated in all pediatric patients after PEG placement.

A new pediatric liver transplantation program in Southern Germany. The Heidelberg experience.

pLTx is a highly complex procedure. It can only be performed safely by experienced teams. Starting a new pLTx program in a country with established centers must therefore avoid a learning curve. We have initiated a liver transplantation program for children in 2003. Medical standards were defined by a team of surgeons, pediatricians, radiologists, anesthesiologists, and pathologists before the first transplantation. An external expert in the field of pLTx supervised the whole process. In a pilot phase, six children weighing more than 20 kg were successfully transplanted. Following this series, the clinical pathways were re-evaluated, and the program was opened for children of all age groups. Between 2003 and 2008, 32 children received 34 organs. Sixty-eight percent of patients received a split-liver, 26% a full size organ, and 6% a reduced size graft. Four LRLTx were performed. Patient survival rate was 91%. We conclude that a new pLTx program can be established without a significant learning curve regarding mortality if a strict strategy of team-building is followed. In the pilot phase, small children and infants have to be referred and transplanted in an established center. An interdisciplinary team of specialists closely working together is the key for sustained success.

MYO5B mutations cause microvillus inclusion disease and disrupt epithelial cell polarity.

Following homozygosity mapping in a single kindred, we identified nonsense and missense mutations in MYO5B, encoding type Vb myosin motor protein, in individuals with microvillus inclusion disease (MVID). MVID is characterized by lack of microvilli on the surface of enterocytes and occurrence of intracellular vacuolar structures containing microvilli. In addition, mislocalization of transferrin receptor in MVID enterocytes suggests that MYO5B deficiency causes defective trafficking of apical and basolateral proteins in MVID.

Pediatric liver transplantation. Introduction of a program for southern Germany in Heidelberg.

Pediatric liver transplantation in Germany is exclusively performed in four centers in the north of Germany. We report our experience with the implementation of a new pediatric liver transplantation program in Heidelberg for children living in the south of Germany. In a pilot phase, we have transplanted eight children with various transplantation techniques including reduced size, left lateral split (segments 2 and 3), and full left split (segments 1-4). All transplantations were successful. No vascular complications occurred. The immunosuppressive regimen we used was cyclosporine A and methylprednisolone. The rate of acute rejection was three of eight patients. No patient required a retransplantation. One patient died due to a severe fungal sepsis he had acquired prior to transplantation. We conclude that in a multidisciplinary approach with careful patient selection a new program for pediatric liver transplantation can be successfully established.