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

Plasma immune signatures can predict rejection-free survival in the first year after pediatric liver transplantation

BACKGROUND & AIMS

After pediatric liver transplantation (pLT), children undergo life-long immunosuppression since reliable biomarkers for the assessment of rejection probability are scarce. In the multicenter (n = 7) prospective clinical cohort "ChilSFree" study, we aimed to characterize longitudinal dynamics of soluble and cellular immune mediators during the first year after pLT and identify early biomarkers associated with outcome.

METHODS

Using a Luminex-based multiplex technique paired with flow cytometry, we characterized longitudinal dynamics of soluble immune mediators (SIMs, n = 50) and immune cells in the blood of 244 patients at eight visits over 1 year: before, and 7/14/21/28 days and 3/6/12 months after pLT.

RESULTS

The unsupervised clustering of patients based on SIM profiles revealed six unique SIM signatures associated with clinical outcome. From three signatures linked to improved outcome, one was associated with 1-year-long rejection-free survival and stable graft function and was characterized by low levels of pro-inflammatory SIMs (CXCL8/9/10/12, CCL7, SCGF-β, sICAM-1), and high levels of regenerative (SCF, TNF-β) and pro-apoptotic (TRAIL) SIMs (all, p <0.001, fold change >100). Of note, this SIM signature appeared 2 weeks after pLT and remained stable over the entire year, pointing towards its potential as a novel early biomarker for minimizing or weaning immunosuppression. In the blood of these patients, a higher frequency of CD56bright natural killer cells (p <0.01), a known hallmark also associated with operationally tolerant pLT patients, was detected. The concordance of the model for prediction of rejection based on identified SIM signatures was 0.715, and 0.795, in combination with living-related transplantation as a covariate, respectively.

CONCLUSIONS

SIM blood signatures may enable the non-invasive and early assessment of rejection risks in the first year after pLT, paving the way for improved clinical management.

IMPACT AND IMPLICATIONS

ChilSFree represents the largest pediatric liver transplant (pLT) cohort with paired longitudinal data on soluble immune mediators (SIMs) and immune phenotyping in the first year after pLT. SIM signatures allow for the selection of rejection-free patients 2 weeks after pLT independently of patient diagnosis, sex, or age. The SIM signatures may enable the non-invasive and early assessment of rejection risks, paving the way for minimization or withdrawal of immunosuppression after pLT.

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.

Innate immune cell dysfunction and systemic inflammation in children with chronic liver diseases undergoing transplantation

Advanced liver diseases (ALD) can affect immune function and compromise host defense against infections. In this study, we examined the phenotypic and functional alterations in circulating monocyte and dendritic cells (DCs) in children with ALD undergoing liver transplantation (LT). Children were stratified into 2 clusters, C1 (mild) and C2 (severe), on the basis of laboratory parameters of ALD and compared with healthy pediatric controls. Children in C2 had a significant reduction in frequencies of nonclassical monocytes and myeloid DCs. Children in C2 displayed monocyte and DC dysfunction, characterized by lower human leucocyte antigen DR expression and reduced interleukin 12 production, and had an increased incidence of infections before and after LT. Children in C2 demonstrated immune dysregulation with elevations of pro- and anti-inflammatory cytokines in plasma. Alterations of innate immune cells correlated with multiple laboratory parameters of ALD, including plasma bile acids. In vitro, monocytes cultured with specific bile acids demonstrated a dose-dependent reduction in interleukin 12 production, similar to alterations in children with ALD. In conclusion, a cohort of children with ALD undergoing LT exhibited innate immune dysfunction, which may be related to the chronic elevation of serum bile acids. Identifying at-risk patients may permit personalized management pre- and post-transplant, thereby reducing the incidence of infection-related complications.

Long-term liver allograft fibrosis: A review with emphasis on idiopathic post-transplant hepatitis and chronic antibody mediated rejection

Liver transplantation (LT) is a life-saving surgical procedure and the current standard of care for most patients with end stage liver disease. With improvements in organ preservation techniques, perioperative care, and immunosuppression, there is better patient and graft survival following LT, and assessment of the liver allograft in long-term survivors is becoming increasingly important. Recurrent or de novo viral or autoimmune injury remains the most common causes of chronic hepatitis and fibrosis following liver transplantation in adults. However, no obvious cause can be identified in many adults with controlled recurrent disease and the majority of pediatric LT recipients, as they have been transplanted for non-recurrent liver diseases. Serial surveillance liver biopsies post LT have been evaluated in several adult and pediatric centers to identify long-term pathological changes. Pathological findings are frequently present in liver biopsies obtained after a year post LT. The significance of these findings is uncertain as many of these are seen in protocol liver biopsies from patients with clinically good allograft function and normal liver chemistry parameters. This narrative review summaries the factors predisposing to long-term liver allograft fibrosis, highlighting the putative role of idiopathic post-LT hepatitis and chronic antibody mediated rejection in its pathogenesis.

Role of Innate Immunity in Pediatric Post-transplant Idiopathic Liver Fibrosis

Pediatric post-transplant idiopathic liver fibrosis is an unexplained graft fibrosis that occurs in symptom-free children without acute rejection and surgical complications. Despite a lack of consensus on the subject, the development of pediatric post-transplant idiopathic liver fibrosis is believed to be the result of multiple potential factors, including ischemia-reperfusion injury, allogeneic acute and chronic rejection, viral hepatitis recurrence, opportunistic infection, and drug-induced liver damage. Among them, there is growing evidence that innate immunity may also have a unique role in this progression. This study reviews the features of pediatric post-transplant idiopathic liver fibrosis and discusses current studies illustrating the potential mechanisms of liver allograft tolerance induced by intrahepatic innate immunity, the role of components including Toll-like receptors (TLRs), interferons (IFN), dendritic cells (DC), natural killer cells (NK cells), NKT cells, neutrophils, and Kupffer cells, as well as their possibly relevant role in the development of pediatric post-transplant idiopathic liver fibrosis.

Factors influencing harmonized health data collection, sharing and linkage in Denmark and Switzerland: A systematic review

INTRODUCTION

The digitalization of medicine has led to a considerable growth of heterogeneous health datasets, which could improve healthcare research if integrated into the clinical life cycle. This process requires, amongst other things, the harmonization of these datasets, which is a prerequisite to improve their quality, re-usability and interoperability. However, there is a wide range of factors that either hinder or favor the harmonized collection, sharing and linkage of health data.

OBJECTIVE

This systematic review aims to identify barriers and facilitators to health data harmonization-including data sharing and linkage-by a comparative analysis of studies from Denmark and Switzerland.

METHODS

Publications from PubMed, Web of Science, EMBASE and CINAHL involving cross-institutional or cross-border collection, sharing or linkage of health data from Denmark or Switzerland were searched to identify the reported barriers and facilitators to data harmonization.

RESULTS

Of the 345 projects included, 240 were single-country and 105 were multinational studies. Regarding national projects, a Swiss study reported on average more barriers and facilitators than a Danish study. Barriers and facilitators of a technical nature were most frequently reported.

CONCLUSION

This systematic review gathered evidence from Denmark and Switzerland on barriers and facilitators concerning data harmonization, sharing and linkage. Barriers and facilitators were strictly interrelated with the national context where projects were carried out. Structural changes, such as legislation implemented at the national level, were mirrored in the projects. This underlines the impact of national strategies in the field of health data. Our findings also suggest that more openness and clarity in the reporting of both barriers and facilitators to data harmonization constitute a key element to promote the successful management of new projects using health data and the implementation of proper policies in this field. Our study findings are thus meaningful beyond these two countries.