The immune monitoring of pediatric organ transplants : potential role of soluble CD30 plasma measurement and granzyme B enzyme-linked immunosorbent assay
(2009)
Files
Imprimaturversionencodage.pdf
Open Access - Adobe PDF
- 1.09 MB
Details
- Authors
- Supervisors
- Reding, Raymond
- Abstract
- (en) Over the last half century, kidney and liver transplantation have been recognized as the treatment of choice for children with end-stage renal or liver failure. Greater understanding of the molecular mechanism of rejection and tolerance, as well as development of reliable assays that can measure accurately the status of the immune response, not only would help clinicians customize the prescription of immunosuppressive drugs in individual recipients, but also might contribute to optimization of outcome in pediatric organ transplantation. In addition, despite improved immunosuppression (IS) protocols, infants still face a variety of chronic complications such as drug toxicity, infection, and malignancies. Thus, a major goal in organ transplantation is to define the optimal immunosuppressive load, according to the individual immunological profile of the transplant patient. Ideally, from a clinical perspective, the de novo donor-recipient encounter should be monitored in pre-transplantation and the immediate post-transplantation period, allowing the early diagnosis of ongoing rejection processes. In this thesis, we review the specificities of the immune system in infants; we then discuss the mechanisms of rejection and the terminology underlying the generic concept of “transplant tolerance”. This review focuses on the several immunological assays studied or under development in pediatric organ transplantation. We subsequently attempted to find predictive tests in order to evaluate the patient’s immunological risk of early rejection after organ transplantation. Forty pediatric patients (median age: 2.1 years, range: 4 months - 13 years) who received an orthotopic liver transplantation between 1994 and 2004 in the Pediatric Liver Transplant Program at Saint-Luc University Clinics in Brussels, Belgium, were included in this study. First, using antigen non-specific assays, we investigated the evolution of pre-transplant and post-transplant serum soluble CD30 (sCD30), interferon- gamma (IFN-γ) and interleukin-10 (IL-10) circulating levels in the recipients who developed acute rejection as compared to patients with early graft acceptance. The frozen serum of the patients was analyzed to measure sCD30, IL-10 and IFN-γ serum levels at pre-transplantation baseline (day 0) and post-transplantation at day 7. The delta value of serum sCD30 between day 0 and 7 was compared with the delta value of IFN-γ and of IL-10 circulating levels on the same day. This study showed that increased serum sCD30 could be correlated with increased IL-10 circulating levels, but not with IFN-γ levels in the post-transplantation period. Neither pre-transplantation sCD30, nor sCD30 at day 7 post-transplantation could be correlated with acute rejection in liver graft recipient. The monitoring of sCD30 might constitute a tool to assess the risk of acute rejection in renal transplant but, at least in our limited series, did not appear to constitute a useful marker for early immunological monitoring in liver allograft recipients. Next, we used the enzyme-linked immunosorbent (ELISPOT) as an antigen-specific assay to analyze the detailed kinetics of granzyme-B (GrB) producing cells before and during the early post-transplantation period. We also investigated the pre- and post-transplantation secretion of GrB in pediatric liver recipients who developed acute rejection compared to patients with graft acceptance. Peripheral blood mononuclear cells (PBMC) from pediatric recipients were serially tested for GrB-producing donor-reactive cells at baseline and at days 7, 14, 28 post-transplantation. This study demonstrated that single GrB ELISPOT pre-transplantation could not predict the occurrence of early post-transplant acute rejection; similarly, GrB frequencies at days 7, 14 and 28 could not be correlated with acute rejection in pediatric liver recipients. However, a kinetic analysis of these data demonstrated that GrB increased significantly at day 7 from baseline in the rejection group. Thus, a kinetic monitoring of GrB ELISPOT variation was found helpful to predict or confirm early rejection in the liver allograft recipients. In the future, further research should therefore be encouraged, to identify the role of sCD30 and GrB ELISPOT kinetic assays in combination with a number of techniques, e.g. regulatory T cell, proteomics transcriptional profiling, and DNA microarray assays. Accordingly, a multidisciplinary approach should be established through multicenter studies including assessment of dynamic profiles, so that ideal strategies can be identified for implemention in the immunological monitoring of kidney and liver transplant in pediatric recipients.
- Affiliations
Citations
Truong, Q. D. (2009). The immune monitoring of pediatric organ transplants : potential role of soluble CD30 plasma measurement and granzyme B enzyme-linked immunosorbent assay. https://hdl.handle.net/2078.5/128512