Histopathological findings from the investigation of paediatric acute hepatitis of unknown aetiology, United Kingdom 2022.

In 2022, there were global reports of increased numbers of acute hepatitis not explained by hepatitis A-E virus infection in children. This manuscript summarises histopathology results from 20 patients in the United Kingdom who underwent liver transplant or had a liver biopsy as part of aetiological investigations. All available histopathological samples were reviewed centrally as part of the outbreak investigation. A working group comprised of infection specialists, hepatologists and histopathologists met virtually to review the cases, presentation, investigations and histopathology. All 20 liver samples had evidence of inflammation without significant interface activity, and submassive confluent pan-lobular or multilobular hepatocellular necrosis. Overall, the predominant histopathological findings were of acute nonspecific hepatitis with submassive hepatic necrosis and central vein perivenulitis and endothelitis. Histopathological findings were a poor indicator of aetiology.

Acute hepatitis of unknown aetiology in children: a clinical update on the recent outbreak with mechanistic insights.

Since April 2022, over 1000 children across 35 countries have developed episodes of acute hepatitis of unknown origin. At King's College Hospital, a total of 65 children were referred with acute hepatitis of unknown etiology, with 10 of these children presenting with acute liver dysfunction leading to acute liver failure. Multiple hypotheses have been proposed and continue to be investigated worldwide. In this review, we explore the current understanding of potential aetiologies for this outbreak. We further characterize the proposed immunological mechanisms of liver injury in these cases.

Outbreak of indeterminate acute liver failure in children with adenoviraemia - Not a new disease.

BACKGROUND & AIMS: In the year 2022, an outbreak of indeterminate acute hepatitis and indeterminate paediatric acute liver failure (ID-PALF) in association with adenoviraemia in immunocompetent children was reported in the UK. We postulate that this association is not a new disease in immunocompetent children. METHODS: Children with acute hepatitis during the outbreak who were referred to King's College Hospital, London for advice and management were included in the study. Data on the frequency of ID-PALF in 2022, as well as transplantation rates and the association with adenovirus infection, were obtained from electronic health records. The clinical presentation, histology and outcomes of children with ID-PALF and adenoviraemia in 2017-2021 were compared with those in 2022. RESULTS: From January to June 2022, 65 patients with acute hepatitis were referred. Ten children were admitted with ID-PALF. ID-PALF constituted 26% of all PALF cases in 2017-2021, in contrast to 58.8% during the 2022 outbreak. During the outbreak, adenoviraemia was present in 52% of children with acute hepatitis without liver failure (in whom adenoviraemia test results were available) and in 100% of ID-PALF cases. Adenoviraemia was seen in immunocompetent children in 6/13 (46%) of all ID-PALF cases between 2017-2019, with a clear absence of adenoviraemia in the 6 ID-PALF cases during 2020-2021. Compared to ID-PALF with adenoviraemia in 2017-2019 (n = 6), ID-PALF with adenoviraemia during the outbreak (n = 10) was associated with more frequent hepatic encephalopathy, hypotension requiring vasoactive medications and higher plasma ammonia levels (admission and peak), with similar native liver survival. CONCLUSIONS: The recent outbreak of ID-PALF with adenoviraemia in immunocompetent children does not appear to be a new disease, contrary to perception and other reports. The frequency of such cases over the years could be linked to background rates of adenovirus infections. IMPACT AND IMPLICATIONS: Indeterminate paediatric acute liver failure (ID-PALF) associated with adenoviraemia in immunocompetent children is not a new disease specific to 2022. The exclusive role of human adenovirus infection in the causation of this outbreak of acute hepatitis seems unlikely. Indeed, we provide histological data from explants in transplanted patients that do not support direct viral cytotoxicity. The disease is probably mediated by immunological injury directed towards adenovirus infection and/or adeno-associated virus-2.

Hepatic Dry Copper Weight in Pediatric Autoimmune Liver Disease.

OBJECTIVES: Elevated hepatic dry copper weight is recognized in adults with autoimmune liver disease (AILD) and chronic cholestasis. We aim to review hepatic dry copper weight in pediatric AILD. METHODS: Retrospective review of pediatric AILD managed at our institution from 1999 to 2018, and 104 patients with hepatic dry copper weight assessment were included. RESULTS: Median age at presentation was 13.4 years (interquartile range, IQR, 11.7-14.9), 60% female, 54% autoimmune hepatitis, 42% autoimmune sclerosing cholangitis, and 4% primary sclerosing cholangitis. Histological features of advanced liver fibrosis in 68%. Median hepatic dry copper weight was 51.1 µg/g dry weight (IQR, 28.0-103.8). Elevated hepatic dry copper weight (>50 µg/g dry weight) was present in 51%, and was not associated with AILD subtype ( P = 0.83), age at presentation ( P = 0.68), or advanced fibrosis ( P = 0.53). Liver transplantation (LT) was performed in 10%, who had higher hepatic dry copper weight (148.5 µg/g dry weight [IQR, 39.5-257.3] vs 47.5 [IQR, 27.8-91.5], P = 0.04); however this was not associated with LT on multivariate analysis (hazard ratio 1.002, 95% CI 0.999-1.005, P = 0.23). In 8 (7.7%) patients ATP7B was sequenced and potentially disease causing variants were identified in 2 patients, both who required LT. CONCLUSIONS: Elevations in hepatic dry copper weight are common in pediatric AILD. Unlike in adults, it is not associated with AILD subtypes with cholestasis. Higher dry copper weight was detected in patients who required LT. While further work is needed to identify the significance of copper deposition in pediatric AILD, we recommend close monitoring of patients with elevated levels for progressive liver disease.

Liver Disease and Risk of Hepatocellular Carcinoma in Children With Mutations in TALDO1.

Mutations in the transaldolase 1 (TALDO1) gene have been described in a limited number of cases. Several organs can be affected and clinical manifestations are variable, but often include liver dysfunction and/or hepatosplenomegaly. We report 4 patients presenting with liver disease: 2 with early-onset hepatocellular carcinoma (HCC). Patients with cholestasis and mutations in TALDO1 were identified by next-generation sequencing. Clinical, laboratory, and histological data were collected. Four (1 male) patients were identified with variants predicted to be damaging in TALDO1. Three patients were homozygous (two protein truncating/one missense mutations), 1 one was compound heterozygous (two missense mutations). Median age at presentation was 4 months (range, 2-210 days) with jaundice (3), hepatosplenomegaly (3), and pancytopaenia (1). The diagnosis was corroborated by detection of minimal transaldolase enzyme activity in skin fibroblasts in two cases and raised urine polyols in the third. Three patients underwent liver transplantation (LT), 2 of whom had confirmed HCC on explanted liver. One patient suddenly died shortly after LT. The nontransplanted case has a chronic liver disease with multiple dysplastic liver nodules, but normal liver biochemistry and alpha-fetoprotein. Median follow-up was 4 years (range, 1-21). Conclusion: Transaldolase deficiency can include early-onset normal gamma-glutamyltransferase liver disease with multisystem involvement and variable progression. Patients with this disease are at risk of early-onset HCC and may require early LT.

Outcomes of adults who received liver transplant as young children.

BACKGROUND: Patient and graft survival 20-years after pediatric liver transplantation (pLT) are excellent. In children, attainment of normal growth, education and social adaptation to be an independent adult are equally important. This is particularly relevant for children who receive liver transplant at a young age, where infantile-onset liver disease, surgery and immunosuppression can adversely affect growth and neurodevelopment. The aim of this study was to evaluate the long-term physical and psychosocial outcomes of pLT recipients with normal graft function. We coin the term 'meaningful survival'. METHODS: We performed a cross-sectional study of pLT recipients who received transplants between 1985 and 2004. A 20-year evaluation of physical health (growth, renal function), mental wellbeing and social outcomes (substance abuse, adherence, education, employment) was performed. All patients included were considered to have normal graft function. FINDINGS: Eighty-four patients met study criteria. Median age at transplantation was 1.3 years (IQR 0·7-3·3 years), with median duration of follow-up of 20.2 years (18·0-23·5). At median of 20-years, 19 patients (23%) had chronic renal dysfunction and 3 patients (4%) had a BMI of >30 (mean 20·4). Evaluation of long-term psychosocial outcomes demonstrated 22 patients (26%) with mental health disorders. Substance abuse was lower than national average. 62 patients (74%) were in education, employment or training. Overall, only 26% of our cohort achieved a composite outcome of 'meaningful survival'. INTERPRETATION: This is the largest reported long-term study of biopsychosocial outcomes of pLT recipients with normal liver biochemistry, with follow-up upon completion of physical growth and senior school education. Importantly, despite normal liver function, many patients did not demonstrate 'meaningful survival'. We must refocus our efforts towards better understanding the long-term outcomes of children. A 'meaningful survival' rather than mere survival should be our goal. FUNDING: None.

Two cases of DCDC2-related neonatal sclerosing cholangitis with developmental delay and literature review.

Ciliopathies are a group of clinical and molecular heterogeneous conditions with pleiotropic manifestations affecting the central nervous system, renal, liver, skeletal, and ocular systems. Biallelic pathogenic variants in DCDC2 cause a ciliopathy primarily presenting with neonatal sclerosing cholangitis (NSC). Pathogenic variants in DCDC2 have further been reported in the context of nephronophthisis and non-syndromic recessive deafness. Polymorphisms in DCDC2 have also been associated with dyslexia and DCDC2 has a role in neuronal development. We report on two unrelated patients with DCDC2-related NSC with additional central nervous system impairment manifesting as microcephaly, global developmental delay, and axial hypotonia. Histological findings of our patients can mimic biliary atresia or congenital hepatic fibrosis. We further show that transmission electron microscopy in patients with NSC does not always show absence of primary cilia. Hence patients with DCDC2 pathogenic variants should also undergo an evaluation of neuromotor development. Review of all reported patients further reveals a risk for supra-aortic arterial aneurysms.

Infantile ATP7B-Related End-Stage Liver Disease: An Exceptional Wilson Disease Phenotype From Consecutive Generations.

Wilson disease (WD) is a rare autosomal recessive disorder of copper metabolism typically presenting after 3 years of age. We describe a girl presenting with neonatal cholestasis rapidly progressing to end-stage liver disease. She presented hepatosplenomegaly, neurological impairment, Coombs-negative hemolytic anemia, central hypothyroidism. A patient-parents whole exome sequencing identified a homozygous state for ATP7B mutations causing WD in the proband (p.Gln7fs/p.His1069Gln) and her mother (p.His1069Gln/p.His1069Gln), who was then confirmed to have cirrhotic WD. A causative role of copper toxicity due to ATP7B loss of function was indicated by the presence of extrahepatic features of WD, consistent tests of copper metabolism-including a 7-fold increase in liver copper-and similarity of patient's liver gene expression profile and ultrastructure with that of WD models. This exceptionally early presentation could result from the combination of the ATP7B impairment and the intrauterine copper overload due to maternal undiagnosed WD.

Cholestasis Due to USP53 Deficiency.

OBJECTIVES: Although a number of genetic forms of cholestasis have been identified, the genetic etiology of disease remains unidentified in a subset of cholestasis patients. METHODS: Whole exome sequencing (WES) was performed in DNA from patients diagnosed with cholestasis, at different points on the continuum from progressive familial intrahepatic cholestasis to benign recurrent intrahepatic cholestasis, in whom no disease mutations in known cholestasis genes had been identified. Candidate genes were then assessed in a larger patient sample, by targeted next-generation sequencing (NGS). Disease features at presentation and follow-up were collected from available medical records. RESULTS: By WES, we identified 3 patients with homozygous mutations in USP53. Screening of USP53 in a larger set of patients identified 4 additional patients with homozygous mutations in USP53. Six of the 7 patients had deletion mutations, and 1 had a missense mutation; 3 of the patients were siblings, all bearing a deletion that also disrupted neighboring MYOZ2. Age of onset ranged from early infancy to adolescence. Cholestasis tended to be biochemically mild and intermittent, and responsive to medication. Liver fibrosis was, however, present in all 4 patients who were biopsied, and splenomegaly was apparent in 5 of 7 at last ultrasound. CONCLUSIONS: Two groups recently identified patients with liver disease and mutation in USP53. We have now identified biallelic mutation in USP53 in 7 further patients with cholestasis, from 5 families. Most individuals had evidence of chronic liver disease, and long-term follow-up is recommended.

Liver histology in children with glycogen storage disorders type VI and IX.

BACKGROUND: Glycogen storage diseases (GSD) type VI and IX are caused by liver phosphorylase system deficiencies and the two types are clinically indistinguishable. AIM: As the role of liver biopsy is increasingly questioned, we aim to assess its current value in clinical practice. METHODS: We retrospectively reviewed children with diagnosis of GSD VI and IX at a paediatric liver centre between 2001 and 2018. Clinical features, molecular analysis and imaging were reviewed. Liver histology was reassessed by a single histopatologist. RESULTS: Twenty-two cases were identified (9 type VI, 9 IXa, 1 IXb and 3 IXc). Features at presentation were hepatomegaly (95%), deranged AST (81%), short stature (50%) and failure to thrive (4%). Liver biopsy was performed in 19 patients. Fibrosis varied in GSD IXa with METAVIR score between F1-F3 and ISHAK score of F2-F5. METAVIR score was F2-F3 in GSD VI and F3-F4 in GSD IXc. Hepatocyte glycogenation, mild steatosis, lobular inflammatory activity and periportal copper binding protein staining were also demonstrated. CONCLUSIONS: Although GSD VI and IX are considered clinically mild, chronic histological changes of varying severity could be seen in all liver biopsies. Histopathological assessment of the liver involvement is superior to biochemical parameters, but definitive classification requires a mutational analysis.

Clinical management of sickle cell liver disease in children and young adults.

Liver involvement in sickle cell disease (SCD) is often referred to as sickle cell hepatopathy (SCH) and is a complication of SCD which may be associated with significant mortality. This review is based on a round-table workshop between paediatric and adult hepatologists and haematologists and review of the literature. The discussion was prompted by the lack of substantial data and guidance in managing these sometimes very challenging cases. This review provides a structured approach for the diagnosis and management of SCH in children and young adults. The term SCH describes any hepatobiliary dysfunction in the context of SCD. Diagnosis and management of biliary complications, acute hepatic crisis, acute hepatic sequestration and other manifestations of SCH are discussed, as well as the role of liver transplantation and haemopoietic stem cell transplantation in the management of SCH.

Hepatic perivascular epithelioid cell tumours in children with tuberous sclerosis.

Perivascular epithelioid cell tumours are a novel histological description of mesenchymal tumours consisting of perivascular and epithelioid cells. Angiomyolipomas are one of the commoner types of this tumour group. They are typically associated with the inherited condition tuberous sclerosis (TS). In TS they are often seen arising in the kidneys and brain, although much more rarely can be seen in the liver. While usually thought of as benign tumours there is little evidence to predict whether they will progress to malignancy. Currently, there is no recommended best management strategy between resection and surveillance. We report two patients with TS seen in our centre with these described PEComa liver lesions histologically, however only one required a resection. On review of the literature, features such as increased size, rapid growth and vascular invasion would be concerning for possible malignant potential and therefore merit resection, as well as significant symptoms.

Mutations in Myosin 5B in Children With Early-onset Cholestasis.

OBJECTIVES: Mutations in Myosin 5B (MYO5B) are known to be associated with microvillous inclusion disease (MVID) a genetic cause of neonatal intractable diarrhoea. More recently, they have been reported in children with cholestasis but without typical gastrointestinal symptoms of MVID. We describe our series of children with cholestasis and mutations in MYO5B. METHODS: Clinical, laboratory, and histological data were collected from patients with cholestasis and pathogenic mutations in MYO5B, found by next generation sequencing (NGS) but with minimal gastrointestinal disease. RESULTS: Six patients (3 boys) were identified. Median age at presentation was 19 months (range, 3-92). Presenting features were jaundice, pale stools, pruritus, and failure to thrive. Patients 5 and 6 had intractable diarrhoea until the age of 3 and 7 years, respectively, but currently are on full enteral diet with no intestinal symptoms. Median values for serum total bilirubin were 55 µmol/L (2-500), alanine aminotransferase 73I IU/L (32-114), γ-glutamyltransferase 7 IU/L (7-10), and serum bile acids 134 µmol/L (18-274). Three patients underwent 1 or more types of biliary diversion for symptom control. Median follow-up was 5 years (2-22). At most recent follow-up, they all reported pruritus while on antipruritics. Patient 1 had a liver transplant. CONCLUSIONS: We identified 6 patients, with mutations in MYO5B, early-onset cholestasis and pruritus, with variable response to biliary diversion without typical MVID.

Seamless Management of Juvenile Autoimmune Liver Disease: Long-Term Medical and Social Outcome.

OBJECTIVES: To report baseline features and long-term medical/social outcomes of juvenile autoimmune liver disease, including autoimmune hepatitis (AIH) and autoimmune sclerosing cholangitis (ASC), managed in a single tertiary center. STUDY DESIGN: Retrospective study of children diagnosed in 2000-2004 with AIH/ASC followed up to date. Patients with abnormal cholangiogram were classified as ASC. Presentation and outcome features were compared. RESULTS: Eighty-three children were included (42 female, median age 12.1 years [8.5-14.1 years], AIH = 54, ASC = 29). Most (65%) had antinuclear and/or anti-smooth muscle autoantibodies; 6% presented with acute liver failure; 29% had histologic evidence of cirrhosis. The 1999 and simplified International Autoimmune Hepatitis Group criteria failed to diagnose up to 26% of patients with AIH and 48% with ASC, and the proposed the European Society for Pediatric Gastroenterology, Hepatology and Nutrition criteria were accurate. Response to treatment was excellent with 95% achieving normal transaminase levels. During follow-up, 31% had at least 1 relapse episode; 3 patients with AIH developed cholangiopathy and 5 patients with ASC developed progressive bile duct injury. At last follow-up (median of 14.5 years, 10.4-16.8), 99% were alive, 11 underwent transplantation and 1 is listed for transplant. Five-, 10-, and 15-year transplant-free survival rates were 95%, 88%, and 83%; patients with ASC and those relapsing being more likely to require transplant. Social outcome was excellent with 93% in employment/education. CONCLUSIONS: Seamless management of juvenile autoimmune liver disease leads to excellent clinical and social outcomes. Despite good response to immunosuppressive treatment, patients with ASC have a worse prognosis than those with AIH. Diagnostic models developed for adults are unsatisfactory to correctly diagnose juvenile autoimmune liver disease.

Liver neoplasms in methylmalonic aciduria: An emerging complication.

Methylmalonic aciduria (MMA) is an inherited metabolic disease caused by methylmalonyl-CoA mutase deficiency. Early-onset disease usually presents with a neonatal acute metabolic acidosis, rapidly causing lethargy, coma, and death if untreated. Late-onset patients have a better prognosis but develop common long-term complications, including neurological deterioration, chronic kidney disease, pancreatitis, optic neuropathy, and chronic liver disease. Of note, oncogenesis has been reported anecdotally in organic acidurias. Here, we present three novel and two previously published cases of MMA patients who developed malignant liver neoplasms. All five patients were affected by a severe, early-onset form of isolated MMA (4 mut0 , 1 cblB subtype). Different types of liver neoplasms, that is, hepatoblastoma and hepatocellular carcinoma, were diagnosed at ages ranging from infancy to adulthood. We discuss pathophysiological hypotheses involved in MMA-related oncogenesis such as mitochondrial dysfunction, impairment of tricarboxylic acid cycle, oxidative stress, and effects of oncometabolites. Based on the intriguing occurrence of liver abnormalities, including neoplasms, we recommend close biochemical and imaging monitoring of liver disease in routine follow-up of MMA patients.

Chronic Cholangiopathy Associated with Primary Immune Deficiencies Can Be Resolved by Effective Hematopoietic Stem Cell Transplantation.

OBJECTIVES: To investigate effects and outcome of hematopoietic stem cell transplantation (HSCT) on sclerosing cholangitis, in pediatric patients with different primary immunodeficiencies (PIDs). STUDY DESIGN: From databases in 2 tertiary centers for immunodeficiencies and liver disease, we have identified children with PIDs and sclerosing cholangitis, who have paired clinical, radiologic, and histologic information before and after HSCT and studied their clinical progress and outcome. RESULTS: Seven of 13 children (53.8%) died at a median interval of 4 months (range, 3 months-5 years) after HSCT. However, 6 surviving children (46.2%) with different PIDs and less severe cholangiopathies showed an improvement in markers of liver injury within months of successful unrelated reduced intensity conditioning HSCT. The repeated native liver biopsy, performed in 4 patients at a median of 96 (range, 4-144) months post-HSCT, showed a considerable improvement. Biochemical markers of liver function in the survivors completely normalized after a median of 13 months (range, 2-48). All patients continue to have a mildly dilated extrahepatic biliary system on ultrasonography with no intrahepatic ductal changes on magnetic resonance cholangiography after a follow-up of median 18 years (range, 2-20). CONCLUSIONS: Effective HSCT has the potential to improve biochemical and histologic features of cholangiopathy in children with PIDs, presumably by clearance of chronic infection following establishment of immune competence. However, careful patient selection is critical as advanced liver injury is often associated with serious complications and mortality.

Autoimmune pancreatitis in children: A single centre experience in diagnosis, management and long term follow up.

OBJECTIVES: Autoimmune pancreatitis (AIP) is a rare form of chronic pancreatitis and data is limited in the paediatric population. We aim to describe in detail a cohort of paediatric patients with AIP including their presentation, investigations that led to their diagnosis, management and long-term follow up. METHODS: We retrospectively reviewed the data of 6 patients diagnosed with AIP over an 10-year period. Data including demographics, clinical information, laboratory parameters, serological markers, radiological and histological findings as well as longitudinal follow up were collected. RESULTS: Out of the six patients, one was diagnosed with definitive Type 1 AIP, two with definitive Type 2 AIP, two with probable Type 2 AIP and one with suspected Type 2 AIP. Median time of follow up was 3.9 years (range 2.6-10.1). 4 patients had pancreatic biopsies with 2 of these patients showing granulocytic epithelial lesions (GELs). 4 patients received steroids and two of them developed ulcerative colitis. Azathioprine was commenced on the patient with Type 1 AIP to help her wean off steroids that caused significant side effects on her. Only two patients developed exocrine insufficiency. CONCLUSIONS: The long term follow up of our cohort of paediatric AIP shows good prognosis. More follow up data on patients with AIP is needed to help further characterize and define the disease.

Reduced Hepatocellular Expression of Canalicular Transport Proteins in Infants with Neonatal Cholestasis and Congenital Hypopituitarism.

OBJECTIVE: To assess whether prolonged neonatal cholestasis, described in congenital hypopituitarism and septo-optic dysplasia (SOD), is associated with altered expression of selected canalicular ectoenzymes and canalicular transport proteins. STUDY DESIGN: Children with congenital hypopituitarism (n = 21), SOD (n = 18), and cholestasis seen in our center over 26 years were reviewed. Histopathologic findings in archival liver biopsy specimens were assessed (n = 10) and in those with low/normal levels of serum γ-glutamyltransferase (GGT) activity despite conjugated hyperbilirubinemia, expression of canalicular ectoenzymes and canalicular transport proteins was evaluated immunohistochemically. RESULTS: Patients presented at a median age of 8 weeks (range 3-20 weeks) with median total bilirubin 116 µmol/L (45-287 µmol/L), GGT 95 IU/L (25-707 UI/L), and serum cortisol 51 nmol/L (17-240 nmol/L). All but 3 had low free thyroxin (median 9.6 pmol/L [6.8-26.9]) with increased thyroid-stimulating hormone levels (median 5.95 mU/L [<0.1-9.24]). Liver histologic features included moderate-to-severe intralobular cholestasis with nonspecific hepatitis, giant-cell transformation of hepatocytes, and fibrosis. In all, immunohistochemical staining for canalicular ectoenzymes and canalicular transport proteins revealed a degree of reduced expression, associated with normal serum GGT values in 6 of the 10 patients, and another 6 nonbiopsied infants with cholestasis also had low/normal serum GGT activity. Sequencing of ABCB11 and ATP8B1 performed in 6 of the biopsied patients did not identify pathogenic mutations. Following replacement therapy, biochemical evidence of hepatobiliary injury resolved in all children within a median period of 6 months. CONCLUSION: Hepatobiliary involvement in congenital hypopituitarism associated with SOD has a good prognosis, but its etiology remains uncertain. Immunohistochemical expression of canalicular transport proteins was reduced in available liver samples.