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.

Pediatric liver transplantation (PLT) has very good results at experienced transplant centers. However, there is still an ongoing discussion about inferior outcomes, especially in young infants. The aim of this retrospective study was to evaluate outcomes of infants compared to older recipients in a single center over 20 years. We conducted a retrospective study of children who received liver transplants at our center between 1991 and 2011. Only patients without other limiting organ involvement were included and compared according to age. The inclusion criteria were fulfilled by 351 patients (173 vs. 178). The most common indication in both groups was biliary atresia (82.1% vs. 49.4%). The 1-, 5-, and 10-year patient survivals were 93.8%/91.8%/91.1% and 93%/90.8%/90.1%, and the graft survivals were 90.4%/83.5%/79.6% and 89.4%/81.8%/77.5%, respectively. Complications such as postoperative bleeding, biliary complications, or perfusion impairment occurred more often in infants. Leading indications for retransplantation (vascular complications/primary nonfunction) and leading causes of death (sepsis/multiorgan failure) were the same in both groups. Significant predictors for patient loss were decade of transplantation, retransplantation, postoperative bleeding, and infections for infants. Predictors for graft loss were bowel perforation, arterial thrombosis, and age >12 months. Children can have excellent results, independent of age at PLT.

Almost 2 years into the pandemic and with vaccination of children significantly lagging behind adults, long-term pediatric humoral immune responses to SARS-CoV-2 are understudied. The C19.CHILD Hamburg (COVID-19 Child Health Investigation of Latent Disease) Study is a prospective cohort study designed to identify and follow up children and their household contacts infected in the early 2020 first wave of SARS-CoV-2. We screened 6113 children < 18 years by nasopharyngeal swab-PCR in a low-incidence setting after general lockdown, from May 11 to June 30, 2020. A total of 4657 participants underwent antibody testing. Positive tests were followed up by repeated PCR and serological testing of all household contacts over 6 months. In total, the study identified 67 seropositive children (1.44%); the median time after infection at first presentation was 83 days post-symptom onset (PSO). Follow-up of household contacts showed less than 100% seroprevalence in most families, with higher seroprevalence in families with adult index cases compared to pediatric index cases (OR 1.79, P = 0.047). Most importantly, children showed sustained seroconversion up to 9 months PSO, and serum antibody concentrations persistently surpassed adult levels (ratio serum IgG spike children vs. adults 90 days PSO 1.75, P < 0.001; 180 days 1.38, P = 0.01; 270 days 1.54, P = 0.001). In a low-incidence setting, SARS-CoV-2 infection and humoral immune response present distinct patterns in children including higher antibody levels, and lower seroprevalence in families with pediatric index cases. Children show long-term SARS-CoV-2 antibody responses. These findings are relevant to novel variants with increased disease burden in children, as well as for the planning of age-appropriate vaccination strategies.

Background: Assessing liver fibrosis in patients after liver transplantation is still largely dependent on liver biopsy. Especially in children, noninvasive methods are of utmost importance. We evaluated tissue inhibitor of metalloproteinase 1 (TIMP1) and AST-to-Platelet Ratio Index (APRI) and their potential as serum biomarkers to predict liver allograft fibrosis (LAF) in a pediatric cohort. Methods:In this retrospective, observational study, we analyzed 91 protocol liver biopsy specimens from 73 children after pediatric liver transplantation (PLT) and compared histological stage of liver fibrosis using LAF Score (LAFSc) and Ishak Score (IshakSc) to TIMP1-serum concentration and APRI using ROC analysis.Results: In our cohort, TIMP1 and APRI reliably predict LAF. Depending on the histological scoring system, cutoff values for TIMP1 were 328 ng/mL (IshakSc ≥ IV) and 351 ng/mL (LAFSc ≥ 5) with AUC of 0.86 and 0.98. The cutoff for APRI was 0.8 with AUC of 0.87 (IshakSc ≥ IV) and 0.94 (LAFSc ≥ 5). Using LAFSc, TIMP1 and APRI showed excellent diagnostic accuracy to detect severe LAF (LAFSc ≥ 5) with PPV of ≥ 90% and NPV of 100%.Conclusion: TIMP1 and APRI are accurate biomarkers to predict severe LAF in children. The use of TIMP1 and APRI will not replace but complement liver biopsies after PLT to further improve our understanding of each individual patient. K E Y W O R D SAST-to-Platelet Ratio Index, Ishak score, LAF score, liver allograft fibrosis, noninvasive biomarker, pediatric liver transplantation, tissue inhibitor of metalloproteinase 1This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.