Genetic landscape of pediatric acute liver failure of indeterminate origin

BACKGROUND AND AIMS

Pediatric acute liver failure (PALF) is a life-threatening condition. In Europe, the main causes are viral infections (12%-16%) and inherited metabolic diseases (14%-28%). Yet, in up to 50% of cases the underlying etiology remains elusive, challenging clinical management, including liver transplantation. We systematically studied indeterminate PALF cases referred for genetic evaluation by whole-exome sequencing (WES), and analyzed phenotypic and biochemical markers, and the diagnostic yield of WES in this condition.

APPROACH AND RESULTS

With this international, multicenter observational study, patients (0-18 y) with indeterminate PALF were analyzed by WES. Data on the clinical and biochemical phenotype were retrieved and systematically analyzed.

RESULTS

In total, 260 indeterminate PALF patients from 19 countries were recruited between 2011 and 2022, of whom 59 had recurrent PALF. WES established a genetic diagnosis in 37% of cases (97/260). Diagnostic yield was highest in children with PALF in the first year of life (41%), and in children with recurrent acute liver failure (64%). Thirty-six distinct disease genes were identified. Defects in NBAS (n=20), MPV17 (n=8), and DGUOK (n=7) were the most frequent findings. When categorizing, the most frequent were mitochondrial diseases (45%), disorders of vesicular trafficking (28%), and cytosolic aminoacyl-tRNA synthetase deficiencies (10%). One-third of patients had a fatal outcome. Fifty-six patients received liver transplantation.

CONCLUSIONS

This study elucidates a large contribution of genetic causes in PALF of indeterminate origin with an increasing spectrum of disease entities. The high proportion of diagnosed cases and potential treatment implications argue for exome or in future rapid genome sequencing in PALF diagnostics.

Early steroids after pediatric liver transplantation protect against T-cell-mediated rejection: Results from the ChilSFree study

Steroid-free immunosuppression protocols gained popularity in pediatric liver transplantation (pLT) after the introduction of IL-2-receptor blockade for induction therapy. We analyzed the clinical and immunologic outcome data of the multicenter prospective observational ChilSFree study to compare the impact of steroid-free versus steroid-containing immunosuppressive therapy following pLT in a real-life scenario. Two hundred forty-six children [55.3% male, age at pLT median: 2.4 (range: 0.2-17.9) y] transplanted for biliary atresia (43%), metabolic liver disease (9%), acute liver failure (4%), hepatoblastoma (9%), and other chronic end-stage liver diseases (39%) underwent immune monitoring and clinical data documentation over the first year after pLT. Patient and graft survival at 1 year was 98.0% and 92.7%, respectively. Primary immunosuppression was basiliximab induction followed by tacrolimus (Tac) monotherapy (55%), Tac plus steroid tapering over 3 months (29%), or cyclosporine and steroid tapering (7%). One center used intraoperative steroids instead of basiliximab followed by Tac plus mycophenolate mofetil (7% of patients). N = 124 biopsy-proven T-cell-mediated rejections were documented in n = 82 (33.3%) patients. T-cell-mediated rejection occurred early (median: 41 d, range: 3-366 d) after pLT. Patients initially treated with Tac plus steroids experienced significantly fewer episodes of rejection than patients treated with Tac alone (chi-square p <0.01). The use of steroids was associated with earlier downregulation of proinflammatory cytokines interferon (IFN)-γ, Interleukin (IL)-6, CX motif chemokin ligand (CXCL)8, IL-7, and IL-12p70. Both primary immunosuppression with Tac plus steroids and living donor liver transplantation were independent predictors of rejection-free survival 1 year after pLT on logistic regression analysis. Adjunctive steroid therapy after pLT leads to earlier suppression of the post-pLT proinflammatory response and significantly reduced rejection rates during the first year after pLT (15.9%). Fifty-one percent of patients initially treated without steroids remain steroid-free over the first 12 months without rejection.

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-β, 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.

Systematic review of response criteria and endpoints in autoimmune hepatitis by the International Autoimmune Hepatitis Group

BACKGROUND & AIMS

Autoimmune hepatitis (AIH) has been well characterised and codified through the development of diagnostic criteria. These criteria have been adapted and simplified and are widely used in clinical practice. However, there is a need to update and precisely define the criteria for both treatment response and treatment.

METHODS

A systematic review was performed and a modified Delphi consensus process was used to identify and redefine the response criteria in autoimmune hepatitis.

RESULTS

The consensus process initiated by the International Autoimmune Hepatitis Group proposes that the term 'complete biochemical response' defined as 'normalization of serum transaminases and IgG below the upper limit of normal' be adopted to include a time point at 6 months after initiation of treatment. An insufficient response by 6 months was a failure to meet the above definition. Non-response was defined as '<50% decrease of serum transaminases within 4 weeks after initiation of treatment'. Remission is defined as liver histology with a Hepatitis Activity Index <4/18. Intolerance to treatment was agreed to stand for 'any adverse event possibly related to treatment leading to potential drug discontinuation'.

CONCLUSIONS

These definitions provide a simple and reproducible framework to define treatment response and non-response, irrespective of the therapeutic intervention. A consensus on endpoints is urgently required to set a global standard for the reporting of study results and to enable inter-study comparisons. Future prospective database studies are needed to validate these endpoints.

LAY SUMMARY

Consensus among international experts on response criteria and endpoints in autoimmune hepatitis is lacking. A consensus on endpoints is urgently required to set a global standard for the reporting of study results and to enable the comparison of results between clinical trials. Therefore, the International Autoimmune Hepatitis Group (IAIHG) herein presents a statement on 5 agreed response criteria and endpoints: complete biochemical response, insufficient response, non-response, remission, and intolerance to treatment, which can be used to guide future reporting.

Immune Status in Children Before Liver Transplantation-A Cross-Sectional Analysis Within the ChilsSFree Multicentre Cohort Study

Background: Both, markers of cellular immunity and serum cytokines have been proposed as potential biomarkers for graft rejection after liver transplantation. However, no good prognostic model is available for the prediction of acute cellular rejection. The impact of underlying disease and demographic factors on immune status before pediatric liver transplantation (pLTx) is still poorly understood. We investigated expression of immune markers before pLTx, in order to better understand the pre-transplant immune status. Improved knowledge of the impact of pre-transplant variables may enhance our understanding of immunological changes post pLTx in the future.

Methods: This is a cross-sectional analysis of data from the ChilSFree study, a European multicentre cohort study investigating the longitudinal patterns of immune response before and after pLTx. Immune cell counts and soluble immune markers were measured in 155 children 1–30 days before pLTx by TruCount analysis and BioPlex assays. Results were logarithmised due to skewed distributions and then compared according to age, sex, and diagnosis using t-tests, ANOVAs, and Tukey post-hoc tests. The association between immune markers at time of pLTx and patients' age was assessed using a fractional polynomial approach. Multivariable regression models were used to assess the relative contribution of each factor.

Results: Sex had no effect on immune status. We found strong evidence for age-specific differences in the immune status. The majority of immune markers decreased in a log-linear way with increasing age. T and B cells showed a sharp increase within the first months of life followed by a log-linear decline in older age groups. Several immune markers were strongly associated with underlying diagnoses. The effects of age and underlying disease remained virtually unchanged when adjusting for each other in multivariable models.

Discussion: We show for the first time that age and diagnosis are major independent determinants of cellular and soluble immune marker levels in children with end-stage liver disease. These results need to be considered for future research on predictive immune monitoring after pLTx.

Effects of plasma transfusions on antithrombin levels after paediatric liver transplantation

BACKGROUND AND OBJECTIVES

Thrombotic complications affect 3-10% of patients after liver transplantation (LT), leading to potentially life-threatening complications. In the days following LT, antithrombin (AT) is decreased longer than pro-coagulant factors, thus favouring a pro-thrombotic profile. Plasma transfusions are given empirically in some centres to correct AT levels following LT. We assessed the effect of plasma transfusion on AT levels after paediatric LT.

MATERIALS AND METHODS

Prospective single-centre observational study in 20 consecutive paediatric LT recipients over a 24-month period. Plasma was administered twice daily (10 ml/kg/dose) according to an existing protocol. AT levels were measured once daily, immediately prior to and one hour after the morning plasma transfusion. Sample size was calculated based on a non-inferiority hypothesis.

RESULTS

The median age and weight were 11.6 years (IQR 2.8; 14.7) and 40 kg (IQR 12.75; 44.8), respectively. We collected 85-paired blood samples. The median AT level prior to plasma transfusion was 58%. The median difference in AT levels before and after plasma transfusion was 4.2% (P = 0.001). Changes in AT levels after plasma transfusion were not correlated with baseline AT levels (R = 0.19) or patient weight (R = 0.18).

CONCLUSION

Plasma transfusions only marginally increase AT levels in children after LT. Therefore, prophylactic plasma transfusions probably do not seem to confer an advantage in the routine management of paediatric LT patients. Randomized controlled trials are needed to identify the optimal anticoagulation strategy in this specific population.

Donor hypernatremia before procurement and early outcomes following pediatric liver transplantation

The demand for transplantable organs far outweighs the supply. Recently, efforts have been made to increase the donor pool by adopting extended criteria for livers, including those from hypernatremic donors. Currently, there is no clear evidence that the use of organs from hypernatremic donors has detrimental effects on pediatric liver transplantation (LT) recipients. Our aim was to use the Scientific Registry of Transplant Recipients database to evaluate the effects of donor hypernatremia on 30-day outcomes in pediatric LT recipients. We performed an analysis of 2325 children who underwent whole or partial LT between 2005 and 2010. First, we sought to determine a donor sodium threshold for increased mortality following pediatric LT. Second, we examined rates of mortality and graft failure at 30 days after LT in patients receiving grafts from hypernatremic donors compared to patients receiving grafts from normonatremic donors. Hypernatremia was defined as a donor sodium level of ≥160 µmol/L. The primary outcome measure was mortality at 30 days after transplant. The secondary outcome measure was graft failure at 30 days after transplant. There was no threshold sodium level for increased 30-day mortality following pediatric LT. Mean recipient ages/weights, Pediatric End-Stage Liver Disease/Model for End-Stage Liver Disease scores, and mean cold and warm ischemia times were similar between the 2 study groups. There were no significant differences in mortality rates (3.9% versus 4.5%; P = 0.87) and graft failure rates (2.2% versus 1.9%; P = 1.00) in patients receiving grafts from hypernatremic donors compared to patients receiving grafts from normonatremic donors at 30 days after LT. In conclusion, donor hypernatremia just before procurement does not appear to have negative effects on mortality and graft failure rates at 30 days following pediatric LT.

[KidsETransplant--a serious game for children with liver disease or liver transplant]

In Switzerland all children's liver transplants are centralized at the University Hospitals of Geneva (HUG) since 1989. Approximately 150 children have received transplants since then, and their survival rate is higher than 90%--one of the highest in Europe. Maximizing the chances of long-term success requires that patients comply with follow-up treatment, something which mandates a sound understanding of their medical condition. The KidsETransplant project aims to help the child--and his family--to understand better his state of health. To this end, our tool offers secured, unrestricted access to the patient's medical record, with a view to both increase patient autonomy and improve communication with healthcare professionals. This paper describes KidsETransplant, as well as its implemented evaluation process.

Hepatic neoplasms in children: a focus on differential diagnosis

Paediatric hepatic neoplasias are rare, accounting for 1-4% of all solid childhood tumors. Liver tumors in children can be classified into benign or malignant; some of the benign lesions can have the potential of malignant transformation. Two-thirds of liver tumors in children are malignant. Hepatoblastoma accounts for two-thirds of malignant liver tumors in children. Other liver malignancies in children include sarcomas, germ cell and rhabdoid tumours, and hepatocellular carcinoma. Benign tumors of the liver in children include vascular tumours, hamartomas, adenomas, and focal nodular hyperplasia. The histology and anatomy of a paediatric liver tumour guides the treatment and prognosis. Although benign and malignant liver masses share some clinical manifestations, treatment and prognosis differ.

Liver involvement in children with ciliopathies

Abnormalities in primary cilia lead to diseases called ciliopathies. Multiple organ involvement is the norm since primary cilia are present in most cells. When cholangiocyte cilia are abnormal, ductal plate malformation ensues leading to such conditions as congenital hepatic fibrosis, Caroli disease or syndrome, or other fibrocystic disease.

Ornithine transcarbamylase deficiency: a possible risk factor for thrombosis

Ornithine transcarbamylase (OTC) deficiency is the most common urea cycle defect. Thromboembolic complications have not heretofore been linked with this diagnosis. We describe four patients with neonatal-onset OTC deficiency who developed vascular thromboses. One patient had arterial thrombosis; the rest developed venous thromboses. Multiple pro-thrombotic risk factors were identified. Low plasma arginine levels were observed in all patients at the time of thrombosis. Arginine deficiency and the resultant nitric oxide insufficiency may contribute to thrombotic risk. Careful normalization of plasma arginine and citrulline levels and increased surveillance for thrombotic complications should be considered in patients with OTC deficiency.

Biliary atresia and orthotopic liver transplantation. 11 years of experience in Geneva

Biliary atresia (BA) is a congenital malformation or an evolutive inflammatory process which, without treatment, leads to cirrhosis, hepatic failure and death within two years of birth. The literature gives a survival rate of 60% at five years and 25% to adulthood after an initial operation performed for BA. 30% of children do not survive beyond two years of age. BA has become the most frequent indication for liver transplantation (LT) in children. With LT, survival expectancy is 90%. Results of the operation designed for BA remain unsatisfactory, and seem to depend on the age of the infants, as well as on other factors such as liver histology, and centre experience. Since 1989, onset of the paediatric hepatic transplantation program in Geneva, to July 2000, 20 children have been referred for initial treatment of BA, and 26 for possible hepatic transplantation after initial treatment done in another centre. The aim of the current study is to analyse our own results of the initial operation and to present the results of liver transplantation in this particular group of patients. All the patients with a BA are included in this study. The initial operation for BA yielded 43% favourable outcome at five years and the survival in this group following LT reached 91.3% survival. The importance of the age of the patient at time of initial operation is underlined.