Standardizing the histological assessment of late posttransplantation biopsies from pediatric liver allograft recipients.

Excellent short-term survival after pediatric liver transplantation (LT) has shifted attention toward the optimization of long-term outcomes. Despite considerable progress in imaging and other noninvasive modalities, liver biopsies continue to be required to monitor allograft health and to titrate immunosuppression. However, a standardized approach to the detailed assessment of long-term graft histology is currently lacking. The aim of this study was to formulate a list of histopathological features relevant for the assessment of long-surviving liver allograft health and to develop an approach for assessing the presence and severity of these features in a standardized manner. Whole-slide digital images from 31 biopsies obtained ≥4 years after transplantation to determine eligibility for an immunosuppression withdrawal trial were selected to illustrate a range of typical histopathological findings seen in children with clinically stable grafts, including those associated with alloantibodies. Fifty histological features were independently assessed and, where appropriate, scored semiquantitatively by six pathologists to determine inter- and intraobserver reproducibility of the histopathological features using unweighted and weighted kappa statistics; the latter metric enabled distinction between minor and major disagreements in parameter severity scoring. Weighted interobserver kappa statistics showed a high level of agreement for various parameters of inflammation, interface activity, fibrosis, and microvascular injury. Intraobserver agreement for these features was even more substantial. The results of this study will help to standardize the assessment of biopsies from long-surviving liver allografts, aid the recognition of important histological features, and facilitate international comparisons and clinical trials aiming to improve outcomes for children undergoing LT.

Pharmacokinetics, Safety, and Efficacy of Glecaprevir/Pibrentasvir in Children With Chronic HCV: Part 2 of the DORA Study.

BACKGROUND AND AIMS: Glecaprevir/pibrentasvir (GLE/PIB) has shown high efficacy and safety in chronic HCV-infected adults and adolescents; data in children were limited. DORA part 2 is a phase 2/3, nonrandomized, open-label study evaluating the pharmacokinetics, efficacy, and safety of a pediatric formulation of GLE and PIB in children ages 3 to < 12 years. APPROACH AND RESULTS: Children with chronic HCV infection, genotype 1-6, with or without compensated cirrhosis, were divided into three cohorts by age-cohort 2 (9 to < 12 years), cohort 3 (6 to < 9 years), and cohort 4 (3 to < 6 years)-and given weight-based doses of GLE and PIB for 8, 12, or 16 weeks. Primary endpoints were sustained virologic response at posttreatment week 12 (SVR12) and steady-state exposure; secondary endpoints were rates of persistent viremia, relapse, and reinfection. Safety and laboratory abnormalities were assessed. Final pediatric dosages determined to be efficacious were 250 mg GLE + 100 mg PIB (in children weighing ≥ 30 to < 45 kg), 200 mg GLE + 80 mg PIB (≥ 20 to < 30 kg), and 150 mg GLE + 60 mg PIB (12 to < 20 kg). Of 80 participants enrolled and dosed, 96% (77/80) achieved SVR12. One participant, on the initial dose ratio, relapsed by posttreatment week 4; no participants had virologic failures on the final dose ratio of GLE 50 mg/PIB 20 mg. Two nonresponders prematurely discontinued the study. Most adverse events (AEs) were mild; no drug-related serious AEs occurred. Pharmacokinetic exposures were comparable to those of adults. CONCLUSIONS: A pediatric formulation of GLE/PIB was highly efficacious and well tolerated in chronic HCV-infected children 3 to < 12 years old.

Comparison of the Lipidomic Signature of Fatty Liver in Children and Adults: A Cross-Sectional Study.

OBJECTIVE: Non-alcoholic fatty liver disease (NAFLD) is an increasingly common condition in children characterised by insulin resistance and altered lipid metabolism. Affected patients are at increased risk of cardiovascular disease (CVD) and children with NAFLD are likely to be at risk of premature cardiac events. Evaluation of the plasma lipid profile of children with NAFLD offers the opportunity to investigate these perturbations and understand how closely they mimic the changes seen in adults with cardiometabolic disease. METHODS: We performed untargeted liquid chromatography-mass spectrometry (LC-MS) plasma lipidomics on 287 children: 19 lean controls, 146 from an obese cohort, and 122 NAFLD cases who had undergone liver biopsy. Associations between lipid species and liver histology were assessed using regression adjusted for age and sex. Results were then replicated using data from 9500 adults with metabolic phenotyping. RESULTS: More severe paediatric NAFLD was associated with lower levels of long chain, polyunsaturated phosphatidylcholines (pC) and triglycerides (TG). Similar trends in pC and TG chain length and saturation were seen in adults with hepatic steatosis; however, many of the specific lipids associated with NAFLD differed between children and adults. Five lipids replicated in adults (including PC(36:4)) have been directly linked to death and cardiometabolic disease, as well as indirectly via genetic variants. CONCLUSION: These findings suggest that, whilst similar pathways of lipid metabolism are perturbed in paediatric NAFLD as in cardiometabolic disease in adults, the specific lipid signature in children is different.

Genotype correlates with the natural history of severe bile salt export pump deficiency.

BACKGROUND & AIMS: Mutations in ABCB11 can cause deficiency of the bile salt export pump (BSEP), leading to cholestasis and end-stage liver disease. Owing to the rarity of the disease, the associations between genotype and natural history, or outcomes following surgical biliary diversion (SBD), remain elusive. We aimed to determine these associations by assembling the largest genetically defined cohort of patients with severe BSEP deficiency to date. METHODS: This multicentre, retrospective cohort study included 264 patients with homozygous or compound heterozygous pathological ABCB11 mutations. Patients were categorized according to genotypic severity (BSEP1, BSEP2, BSEP3). The predicted residual BSEP transport function decreased with each category. RESULTS: Genotype severity was strongly associated with native liver survival (NLS, BSEP1 median 20.4 years; BSEP2, 7.0 years; BSEP3, 3.5 years; p <0.001). At 15 years of age, the proportion of patients with hepatocellular carcinoma was 4% in BSEP1, 7% in BSEP2 and 34% in BSEP3 (p = 0.001). SBD was associated with significantly increased NLS (hazard ratio 0.50; 95% CI 0.27-0.94: p = 0.03) in BSEP1 and BSEP2. A serum bile acid concentration below 102 µmol/L or a decrease of at least 75%, each shortly after SBD, reliably predicted NLS of ≥15 years following SBD (each p <0.001). CONCLUSIONS: The genotype of severe BSEP deficiency strongly predicts long-term NLS, the risk of developing hepatocellular carcinoma, and the chance that SBD will increase NLS. Serum bile acid parameters shortly after SBD can predict long-term NLS. LAY SUMMARY: This study presents data from the largest genetically defined cohort of patients with severe bile salt export pump deficiency to date. The genotype of patients with severe bile salt export pump deficiency is associated with clinical outcomes and the success of therapeutic interventions. Therefore, genotypic data should be used to guide personalized clinical care throughout childhood and adulthood in patients with this disease.

Cardiac and Liver Disease in Children: Implications for Management Before and After Liver Transplantation.

There is close interaction between the functions of the liver and heart affecting the presentation, diagnosis, and outcome of acute and chronic cardiac and liver disease. Conditions affecting both organ systems should be considered when proposing transplantation because the interaction between cardiac disease and liver disease has implications for diagnosis, management, selection for transplantation, and, ultimately, for longterm outcomes after liver transplantation (LT). The combination of cardiac and liver disease is well recognized in adults but is less appreciated in pediatric patients. The focus of this review is to describe conditions affecting both the liver and heart and how they affect selection and management of LT in the pediatric population.

Endoscopic Retrograde Cholangiopancreatography in Infants: Availability Under Threat: A Survey on Availability, Need, and Clinical Practice in Europe and Israel.

Endoscopic retrograde cholangiopancreatography (ERCP) in infants (younger than 1 year of age) is a highly specialized procedure. Since 2014 opportunities to maintain or purchase duodenoscopes for ERCP in infants have disappeared. In a survey among European hepatology centers (including Israel) we evaluated the availability, need, indications, and practice of ERCP procedures in infants. It shows that infant ERCP is a low-volume procedure (median 5 procedures/year) in the 14 centers that perform this procedure. Since 2014 several centers no longer have an infant ERCP duodenoscope due to breakdown. In addition, substantial differences exist between centers in indications, types of interventions performed, and practical execution of ERCP procedures in infants. We conclude that a concerted effort by the pediatric hepatology community is needed to secure the future availability of infant ERCP. In addition, consensus on the indications and optimal use of infant ERCP could improve the quality of ERCP care for infants.

Epidemiology and natural history of hepatitis C virus infection among children and young people.

BACKGROUND & AIMS: Chronic hepatitis C virus (HCV) infection is a global health burden. Although HCV infection rarely contributes to morbidity during childhood, most HCV-infected children develop chronic HCV with a lifetime risk of liver disease. Little is known about the development of long-term liver disease and the effect of treatment in patients infected with HCV in childhood. METHOD: This study was a retrospective review of patients infected with HCV in childhood enrolled in HCV Research UK. A total of 1,049 patients were identified and included. RESULTS: The main routes of infection were intravenous drug use (53%), blood product exposure (24%) and perinatal infection (11%). Liver disease developed in 32% of patients, a median of 33 years after infection, irrespective of the mode of infection. Therefore, patients with perinatal exposure developed cirrhosis at an earlier age than the rest of the risk groups. The incidence of hepatocellular carcinoma (HCC) was 5%, liver transplant 4% and death occurred in 3%. Overall, 663 patients were treated (55% with interferon/pegylated interferon and 40% with direct-acting antivirals). Sustained virological response (SVR) was achieved in 406 (75%). There was a higher mortality rate among patients without SVR vs. those with SVR (5% vs. 1%, p = 0.003). Treatment was more effective in patients without cirrhosis and disease progression was less frequent (13%) than in patients with cirrhosis at the time of therapy (28%) p < 0.001. Patients with cirrhosis were more likely to develop HCC, require liver transplantation, or die. CONCLUSION: HCV infection in young people causes significant liver disease, which can now be prevented with antiviral therapy. Early treatment, especially before development of cirrhosis is essential. Detection of HCV should be aimed at relevant risk groups and antiviral therapy should be made available in childhood to prevent long-term liver disease and spread of HCV. LAY SUMMARY: Chronic hepatitis C virus (HCV) infection is a global health problem, which can now be treated with potent direct-acting antiviral drugs. This study demonstrates that HCV infection in childhood causes serious liver disease in 32% of patients, a median of 33 years after infection, irrespective of age, mode and route of infection. Disease outcomes were better in patients treated before the development of advanced liver disease. Antiviral therapy should be made available in childhood to prevent long-term liver disease and the spread of HCV.

Long-term Effects of Cholestatic Liver Disease in Childhood on Neuropsychological Outcomes and Neurochemistry.

OBJECTIVES: Children with liver disease have increased risk of long-term cognitive deficits. We differentiated between the effects of chronic liver disease from that associated with transplantation by recruiting children with cholestatic liver disease (CLD) with and without transplantation. METHODS: Psychometric measures and magnetic resonance spectroscopy were obtained for 3 groups of children: stable liver disease without transplantation; CLD from birth with transplantation; and individuals healthy to 18 months of age, before transplantation for acute liver failure. RESULTS: Cognitive outcomes between children with different disease histories were significantly associated with the duration of liver disease but not the effects of transplantation, including that of immunosuppression. Lower intellectual ability was most frequently observed in the CLD group, whereas all of the acute liver failure group scored within the normal range. Myoinositol and glutamate/glutamine concentrations in cortex were significantly associated with disease duration across the cohort. Neurometabolite profiles in stable liver disease were consistent with subclinical encephalopathy. Impaired growth in early childhood was associated with later cognitive performance. CONCLUSION: Children with prolonged liver disease had the poorest cognitive outcomes despite successful transplantation, suggesting that prolonged cholestasis before transplantation adversely affects neurodevelopment, and reinforces the need for timely interventions.

Hepatopulmonary Syndrome in Children: A 20-Year Review of Presenting Symptoms, Clinical Progression, and Transplant Outcome.

Hepatopulmonary syndrome (HPS) in stable patients with cirrhosis can easily be overlooked. We report on the presenting symptoms, disease progression, and outcomes after liver transplantation (LT) in children with HPS. Twenty patients were diagnosed with HPS between 1996 and 2016. The etiologies were as follows: biliary atresia (n = 9); alpha-1-antitrypsin deficiency (n = 2); cryptogenic liver disease (n = 3); and others (n = 6). HPS presentations were as follows; dyspnea (n = 17) and pneumonia (n = 3). For diagnostic confirmation, the following techniques were used: technetium-99m-labeled macroaggregated albumin lung perfusion scan (n = 13) or contrast echocardiogram (n = 7). There were 16 patients listed for LT, with a median age at HPS diagnosis of 10 years and an average wait from listing to LT of 9 weeks. A marked rise in hemoglobin (Hb; median, 125-143.5 g/L) and modest decrease in oxygen saturation (SpO2 ; median 91% to 88% room air) were evident over this time. Patients' need for assisted ventilation (1 day), pediatric intensive care unit (PICU) stay (3 days), and total hospital stay (20 days) were similar to our general LT recipients-the key difference in the postoperative period was the duration of supplementary O2 requirement. Hb of ≥130 g/L on the day of LT correlated with a longer PICU stay (P value = 0.02), duration of supplementary O2 (P value = 0.005), and the need for the latter beyond 7 days after LT (P value = 0.01). Fifteen patients had resolution of their HPS after LT. The 5-, 10-, and 20-year survival rates were unchanged at 87.5%. None had a recurrence of HPS. In conclusion, HPS is a life-threatening complication of cirrhosis which usually develops insidiously. This combined with the often-stable nature of the liver disease leads to delays in diagnosis and listing for LT. Progressive polycythemia extends the need for supplementary O2 and PICU stay. We advocate screening for HPS with a combination of SpO2 and Hb monitoring to facilitate earlier recognition, timely LT, and shortened recovery periods.

Cystic Fibrosis-related Liver Disease: Research Challenges and Future Perspectives.

OBJECTIVES: Hepatobiliary complications are a leading cause of morbidity and mortality in cystic fibrosis (CF) patients. Knowledge of the underlying pathological aspects and optimal clinical management is, however, sorely lacking. METHODS: We provide a summary of the lectures given by international speakers at the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) monothematic conference on cystic fibrosis-related liver disease (CFLD) held in Paris in January 2016, to discuss the status of our current knowledge of liver disease in CF patients, to define the critical areas that need to be addressed, and to resolve actions to elucidate relevant mechanisms of disease to optimise future therapeutic options. CONCLUSIONS: The need for a universal consensus on the definition of CFLD to clarify disease stage and to identify relevant biomarkers to assess disease severity was highlighted. A deeper understanding of the pathophysiology and prognostic factors for the long-term evolution of CFLD is fundamental to move forward and has a strong bearing on identifying potential treatments. Novel experimental models and new treatment options under investigation are discussed and offer hope for the near future of CFLD.

Biliary atresia and other cholestatic childhood diseases: Advances and future challenges.

Biliary Atresia and other cholestatic childhood diseases are rare conditions affecting the function and/or anatomy along the canalicular-bile duct continuum, characterised by onset of persistent cholestatic jaundice during the neonatal period. Biliary atresia (BA) is the most common among these, but still has an incidence of only 1 in 10-19,000 in Europe and North America. Other diseases such as the genetic conditions, Alagille syndrome (ALGS) and Progressive Familial Intrahepatic Cholestasis (PFIC), are less common. Choledochal malformations are amenable to surgical correction and require a high index of suspicion. The low incidence of such diseases hinder patient-based studies that include large cohorts, while the limited numbers of animal models of disease that recapitulate the spectrum of disease phenotypes hinders both basic research and the development of new treatments. Despite their individual rarity, collectively BA and other cholestatic childhood diseases are the commonest indications for liver transplantation during childhood. Here, we review the recent advances in basic research and clinical progress in these diseases, as well as the research needs. For the various diseases, we formulate current key questions and controversies and identify top priorities to guide future research.

The transmembrane protein meckelin (MKS3) is mutated in Meckel-Gruber syndrome and the wpk rat.

Meckel-Gruber syndrome is a severe autosomal, recessively inherited disorder characterized by bilateral renal cystic dysplasia, developmental defects of the central nervous system (most commonly occipital encephalocele), hepatic ductal dysplasia and cysts and polydactyly. MKS is genetically heterogeneous, with three loci mapped: MKS1, 17q21-24 (ref. 4); MKS2, 11q13 (ref. 5) and MKS3 (ref. 6). We have refined MKS3 mapping to a 12.67-Mb interval (8q21.13-q22.1) that is syntenic to the Wpk locus in rat, which is a model with polycystic kidney disease, agenesis of the corpus callosum and hydrocephalus. Positional cloning of the Wpk gene suggested a MKS3 candidate gene, TMEM67, for which we identified pathogenic mutations for five MKS3-linked consanguineous families. MKS3 is a previously uncharacterized, evolutionarily conserved gene that is expressed at moderate levels in fetal brain, liver and kidney but has widespread, low levels of expression. It encodes a 995-amino acid seven-transmembrane receptor protein of unknown function that we have called meckelin.

Biliary disease progression in childhood onset autoimmune liver disease: A 30-year follow-up into adulthood.

Background & Aims: Long-term follow-up studies of paediatric onset autoimmune liver disease (AILD) are invaluable in helping better understand the clinical course of disease. In day-to-day practice clinicians struggle with disease definitions whilst patients and parents lack clear prognostic information. Methods: The clinical progression of 159 patients with childhood onset AILD between June 1990 and December 2013 was reviewed, capturing data up to adulthood (ending May 2021). Results: Presentation with autoimmune hepatitis (AIH) was dominant (n = 119); biliary presentations accounted for 25%. During follow up, biliary disease progression confirmed by cholangiography and/or liver histology was observed frequently: 19.8% (20/101) patients with childhood onset AIH type 1 (AIH-1) developed biliary features by adulthood and of these 50% phenotypically transitioned to primary sclerosing cholangitis (PSC); the remaining transitioned to an overlap disease phenotype. No patients with AIH type 2 developed biliary progression. Two-thirds of patients with overlap features (14/21) in childhood had phenotypically progressed to PSC by adulthood. Approximately 43% (6/14) of AIH-1 patients requiring a liver transplant in adulthood had explant evidence of biliary disease compared with 11% (1/9) in childhood, whereas 35.7% (5/14) of patients had histology diagnostic of PSC in their explant liver and 7.1% (1/14) had overlap features. All patients with biliary phenotypes (PSC, autoimmune sclerosing cholangitis, overlap) who required a transplant (n = 18) were found to have explant histology consistent with PSC. Twelve of 14 patients with biliary progression developed ulcerative colitis during follow-up with 92% progressing to PSC. Conclusions: Three decades of follow-up demonstrated how children presenting with AILD had a significant risk of clinical transformation to PSC. Biliary progression was significantly associated with the development of inflammatory bowel disease. Impact and implications: Childhood onset autoimmune liver disease remains very impactful for patients and families. Disease nomenclature can however be confusing. Long-term follow up studies as children become adults is important to help understand how and why disease behaves over time. Understanding more about the long-term course of childhood autoimmune liver disease will help patients, families and doctors striving to improve care and reduce poor clinical outcomes. We followed over 150 patients with childhood onset autoimmune liver diseases into adulthood. We found that amongst patients with classical autoimmune hepatitis, 1 in 5 developed biliary disease over time, mostly consisting of primary sclerosing cholangitis. This was associated with developing inflammatory bowel disease. Our study design was retrospective and has relevant limitations. Defining phenotypes of autoimmune liver diseases is difficult and there is insufficient consensus, especially between adult and childhood physicians. Our data confirms the critical importance of careful long-term follow-up of patients, including safe transition to adult care, as well as robustly demonstrates, using real-world data, how disease nature can change over time. Our study affirms the need for investment in prospective cohort studies.

Phenotypic variation and long-term outcome in children with congenital hepatic fibrosis.

BACKGROUND AND OBJECTIVE: Congenital hepatic fibrosis (CHF) and Caroli syndrome are frequently associated with renal cystic diseases. They have a variable clinical course, and the natural history is not well defined despite molecular advances. Our study describes the clinical manifestations and long-term outcome in children with this disorder. METHODS: A retrospective case review of children with CHF at a single centre diagnosed on the basis of clinical features, radiological and endoscopic evidence of portal hypertension (PHT), and compatible histopathological findings. Children were categorised based on hepatic phenotype-group 1 (Caroli syndrome) and group 2 (CHF). Hepatobiliary as well as renal manifestations were recorded at presentation, and their evolution followed up until transplant or last follow-up. RESULTS: There were 40 children (22 boys) with a median age of 1.3 years at clinical presentation. Fourteen of 40 (35%) children presented in the neonatal period with primarily renal disease, of whom 11 (78%) had Caroli syndrome (P = 0.02). Significant PHT with oesophageal varices was seen in 86%, with no difference in the incidence of gastrointestinal bleeding and varices between Caroli syndrome and CHF. Cholangitis developed in 10 of 40 (25%) and was more common in the Caroli syndrome group (P = 0.009). A higher proportion of children with Caroli syndrome developed chronic kidney disease (CKD) stage 3 and above as compared with CHF (85% vs 42%; P = 0.007). Twelve of 21 (57%) and 8 of 19 (42%) children in the Caroli syndrome and CHF groups required either combined liver-kidney or isolated liver transplant, with the most common indication for renal transplantation being end-stage renal disease (CKD5d) with or without advanced PHT or cholangitis. All 14 (100%) children with neonatal presentation developed CKD5d and required combined liver-kidney transplant before 14 years of age, whereas 77% of children presenting beyond the neonatal period survived without liver-kidney transplant (P < 0.001). Neonatal presentation was the best predictor of the need for transplant. CONCLUSIONS: Caroli syndrome is more likely to present in the neonatal period and these patients are more likely to develop CKD5d. CKD stage 3 or above with recurrent cholangitis is more common in Caroli syndrome presenting beyond the neonatal period and adds to the significant morbidity in these patients. Children presenting in the neonatal period have a more severe phenotype and should be considered early for combined liver-kidney transplant.

Vitamin D deficiency and insufficiency after pediatric liver transplantation.

Vitamin D deficiency and insufficiency are increasingly recognized in the general population, including healthy children. There is also an increasing emphasis on the importance of vitamin D status following pediatric liver transplantation and specifically its relationship to metabolic bone disease and growth retardation. Vitamin D insufficiency has also been associated with multiple immunological and metabolic disorders in adults. To our knowledge, this has not been systematically evaluated in children undergoing liver transplantation to date. Between October 2004 and August 2008, serum 25-(OH)-vitamin D levels were measured in 199 children who had undergone liver transplantation at Birmingham Children's Hospital. Potential factors contributing to vitamin D levels were evaluated. Additionally, we evaluated a possible relationship between vitamin D levels and immunological phenomena and metabolic complications. Median 25-(OH)-vitamin D level was 19.5 ng/mL (range: 4.4-71.4 ng/mL). A total of 105 children (53%) had insufficient vitamin D levels and 28 children (14%) showed vitamin D deficiency. The only factors found to be associated with vitamin D deficiency were season of sample, ethnicity, and PTH levels. Vitamin D deficiency was more prevalent during the first year after transplantation. We did not find a significant relationship between vitamin D levels and graft function or any other immunological and metabolic complications. Vitamin D insufficiency and deficiency are common in children after liver transplantation, especially in winter and spring and in non-white patients. Initial post-transplant period and high PTH are significantly associated with vitamin D deficiency. Vitamin D status should be monitored following pediatric liver transplantation and vitamin D supplementation provided as required.

Mutations in VPS33B, encoding a regulator of SNARE-dependent membrane fusion, cause arthrogryposis-renal dysfunction-cholestasis (ARC) syndrome.

ARC syndrome (OMIM 208085) is an autosomal recessive multisystem disorder characterized by neurogenic arthrogryposis multiplex congenita, renal tubular dysfunction and neonatal cholestasis with bile duct hypoplasia and low gamma glutamyl transpeptidase (gGT) activity. Platelet dysfunction is common. Affected infants do not thrive and usually die in the first year of life. To elucidate the molecular basis of ARC, we mapped the disease to a 7-cM interval on 15q26.1 and then identified germline mutations in the gene VPS33B in 14 kindreds with ARC. VPS33B encodes a homolog of the class C yeast vacuolar protein sorting gene, Vps33, that contains a Sec1-like domain important in the regulation of vesicle-to-target SNARE complex formation and subsequent membrane fusion.

Case report: Acute liver failure in children and the human herpes virus 6-? A factor in the recent epidemic.

The 2022 worldwide epidemic of acute hepatitis and liver failure in young children has led to a focus on unusual causes for childhood acute hepatitis. In the UK epidemic, human herpes virus subtype 6B (HHV-6B) was detected along with adenovirus subtype-41F in severely affected children, especially in those requiring liver transplantation (LT). The lifting of COVID lock-down measures has coincided with the rise in these common childhood infections with a higher than expected rate of systemic complications. The sudden exposure of young children to common childhood infections from which they were protected during the pandemic may have induced an abnormal immune mediated response potentiated by multiple pathogen exposure. Primary HHV-6 infection is one such common childhood infection. Classically known as Roseola infantum due to the appearance of a widespread erythematous rash on fever subsidence (exanthema subitem), it has a peak incidence of 6-12 months of age and almost all children will have been infected by age 2. It is the virus most frequently associated with febrile convulsions but the more serious complications of hepatitis and liver failure are rare. We report on the historic cases of three female infants who had suspected primary HHV-6B infection, acute hepatitis and rapid progression to acute liver failure (ALF) requiring LT. Appearances of their native liver were identical to those described in children in the recent hepatitis epidemic. Deteriorating clinical trajectories of recurrent graft hepatitis and rejection-like episodes followed and all three succumbed to graft failure with HHV-6B detected posthumously in their liver allografts. Our case series and the serious complications observed with the recent rise in common childhood infections is a reminder that these routinely encountered pathogens can be deadly especially in the young immunologically untrained. We advocate for HHV-6 to be screened for routinely in children with acute hepatitis and the use of effective HHV-6 anti-viral prophylaxis to prevent recurrence post-transplant.

Diagnosing Acute Cellular Rejection after Paediatric Liver Transplantation-Is There Room for Interleukin Profiles?

BACKGROUND: The current gold standard to diagnose T-cell-mediated acute rejection (TCMR) requires liver histology. Using data from the ChilSFree study on immune response after paediatric liver transplantation (pLT), we aimed to assess whether soluble cytokines can serve as an alternative diagnostic tool in children suspected to have TCMR. METHODS: A total of n = 53 blood samples obtained on the day of or up to 3 days before liver biopsy performed for suspected TCMR at median 18 days (range 7-427) after pLT in n = 50 children (38% female, age at pLT 1.8 (0.5-17.5) years) were analysed for circulating cytokine levels using Luminex-based Multiplex technology. Diagnostic accuracy of cytokine concentrations was assessed using a multivariable model based on elastic net regression and gradient boosting machine analysis. RESULTS: TCMR was present in 68% of biopsies. There was strong evidence that patients with TCMR had increased levels of soluble CXCL8, CXCL9, CXCL10, IL-16, IL-18, HGF, CCL4, MIF, SCGF-ß, and HGF before biopsy. There was some evidence for increased levels of sCD25, ICAM-1, IL-6, IL-3, and CCL11. Diagnostic value of both single cytokine levels and a combination of cytokines and clinical markers was poor, with AUROCs not exceeding 0.7. CONCLUSION: Patients with TCMR showed raised levels of cytokines and chemokines reflective of T-cell activation and chemotaxis. Despite giving insight into the mechanisms of TCMR, the diagnostic value of soluble cytokines for the confirmation of TCMR in a clinical scenario of suspected TCMR is poor.

Long-term Outcome of Asymptomatic Patients With Graft Fibrosis in Protocol Biopsies After Pediatric Liver Transplantation.

BACKGROUND: The histological prevalence of allograft fibrosis in asymptomatic children after liver transplantation (LT) is well documented. However, long-term graft and patient survival remain unclear. This retrospective multicenter study aims to determine the prevalence of allograft fibrosis and analyze the long-term outcome for patients transplanted in childhood. METHODS: We reviewed clinical data of children who had undergone 10-y protocol liver biopsies. We excluded patients with autoimmune hepatitis, primary sclerosing cholangitis, hepatitis B or C, and retransplantation. In total, 494 patients transplanted in childhood across 12 international transplant centers were included. We evaluated the development of fibrosis by comparing the results with biopsies obtained 5 and 15 y post-LT. Histological findings were correlated with graft and patient survival up to 20 y post-LT. RESULTS: In the 10-y biopsies, periportal or pericentral fibrosis was observed in 253 patients (51%), 87 (18%) had bridging fibrosis, 30 (6%) had cirrhosis, and 124 (25%) had no fibrosis. The prevalence and stage of graft fibrosis significantly progressed from 5 to 10 y. At 10 y, the severity of fibrosis correlated significantly with inflammation. Patients with graft cirrhosis in the 10-y biopsy were more likely to die or require retransplantation subsequently ( P = 0.027). CONCLUSIONS: At 10 y post-LT, most patients transplanted in childhood developed fibrosis, based on the protocol liver biopsies. Although mild-to-moderate graft fibrosis did not largely affect patient or graft survival up to 20 y post-LT, this progressive fibrosis finding has substantial implications for developing cirrhosis and portal hypertension in adult care.

Paediatric acute hepatitis of unknown aetiology: a national investigation and adenoviraemia case-control study in the UK.

BACKGROUND: An increase in acute severe hepatitis of unknown aetiology in previously healthy children in the UK in March, 2022, triggered global case-finding. We aimed to describe UK epidemiological investigations of cases and their possible causes. METHODS: We actively surveilled unexplained paediatric acute hepatitis (transaminase >500 international units per litre) in children younger than 16 years presenting since Jan 1, 2022, through notifications from paediatricians, microbiologists, and paediatric liver units; we collected demographic, clinical, and exposure information. Then, we did a case-control study to investigate the association between adenoviraemia and other viruses and case-status using multivariable Firth penalised logistic regression. Cases aged 1-10 years and tested for adenovirus were included and compared with controls (ie, children admitted to hospital with an acute non-hepatitis illness who had residual blood samples collected between Jan 1 and May 28, 2022, and without known laboratory-confirmed diagnosis or previous adenovirus testing). Controls were frequency-matched on sex, age band, sample months, and nation or supra-region with randomised selection. We explored temporal associations between frequency of circulating viruses identified through routine laboratory pathogen surveillance and occurrence of cases by linear regression. SARS-CoV-2 seropositivity of cases was examined against residual serum from age-matched clinical comparison groups. FINDINGS: Between Jan 1 and July 4, 2022, 274 cases were identified (median age 3 years [IQR 2-5]). 131 (48%) participants were male, 142 (52%) were female, and one (<1%) participant had sex data unknown. Jaundice (195 [83%] of 235) and gastrointestinal symptoms (202 [91%] of 222) were common. 15 (5%) children required liver transplantation and none died. Adenovirus was detected in 172 (68%) of 252 participants tested, regardless of sample type; 137 (63%) of 218 samples were positive for adenovirus in the blood. For cases that were successfully genotyped, 58 (81%) of 72 had Ad41F, and 57 were identified as positive via blood samples (six of these were among participants who had undergone a transplant). In the case-control analysis, adenoviraemia was associated with hepatitis case-status (adjusted OR 37·4 [95% CI 15·5-90·3]). Increases in the detection of adenovirus from faecal samples, but not other infectious agents, in routine laboratory pathogen surveillance correlated with hepatitis cases 4 weeks later, which independently suggested an association (ß 0·06 [95% CI 0·02-0·11]). No association was identified for SARS-CoV-2 antibody seropositivity. INTERPRETATION: We observed an association between adenovirus 41F viraemia and paediatric acute hepatitis. These results can inform diagnostic testing recommendations, clinical management, and exploratory in vitro or clinical studies of paediatric acute hepatitis of unknown aetiology. The role of potential co-factors, including other viruses and host susceptibility, requires further investigation. FUNDING: None.