34 research outputs found
T and NK Cells in IL2RG-Deficient Patient 50 Years After Hematopoietic Stem Cell Transplantation
No full textThe first successful European hematopoietic stem cell transplantation (HSCT) was performed in 1968 as treatment in a newborn with IL2RG deficiency using an HLA-identical sibling donor. Because of declining naive T and natural killer (NK) cells, and persistent human papilloma virus (HPV)-induced warts, the patient received a peripheral stem cell boost at the age of 37 years. NK and T cells were assessed before and up to 14 years after the boost by flow cytometry. The boost induced renewed reconstitution of functional NK cells that were 14 years later enriched for CD56dimCD27+ NK cells. T-cell phenotype and T-cell receptor (TCR) repertoire were simultaneously analyzed by including TCR Vβ antibodies in the cytometry panel. Naive T-cell numbers with a diverse TCR Vβ repertoire were increased by the boost. Before and after the boost, clonal expansions with a homogeneous TIGIT and PD-1 phenotype were identified in the CD27− and/or CD28− memory population in the patient, but not in the donor. TRB sequencing was applied on sorted T-cell subsets from blood and on T cells from skin biopsies. Abundant circulating CD8 memory clonotypes with a chronic virus-associated CD57+KLRG1+CX3CR1+ phenotype were also present in warts, but not in healthy skin of the patient, suggesting a link with HPV. In conclusion, we demonstrate in this IL2RG-deficient patient functional NK cells, a diverse and lasting naive T-cell compartment, supported by a stem cell boost, and an oligoclonal memory compartment half a century after HSCT.Pattern Recognition and Bioinformatic
The Wiskott-Aldrich syndrome protein is required for iNKT cell maturation and function
No full textThe Wiskott-Aldrich syndrome (WAS) protein (WASp) is a regulator of actin cytoskeleton in hematopoietic cells. Mutations of the WASp gene cause WAS. Although WASp is involved in various immune cell functions, its role in invariant natural killer T (iNKT) cells has never been investigated. Defects of iNKT cells could indeed contribute to several WAS features, such as recurrent infections and high tumor incidence. We found a profound reduction of circulating iNKT cells in WAS patients, directly correlating with the severity of clinical phenotype. To better characterize iNKT cell defect in the absence of WASp, we analyzed was(-/-) mice. iNKT cell numbers were significantly reduced in the thymus and periphery of was(-/-) mice as compared with wild-type controls. Moreover analysis of was(-/-) iNKT cell maturation revealed a complete arrest at the CD44(+) NK1.1(-) intermediate stage. Notably, generation of BM chimeras demonstrated a was(-/-) iNKT cell-autonomous developmental defect. was(-/-) iNKT cells were also functionally impaired, as suggested by the reduced secretion of interleukin 4 and interferon gamma upon in vivo activation. Altogether, these results demonstrate the relevance of WASp in integrating signals critical for development and functional differentiation of iNKT cells and suggest that defects in these cells may play a role in WAS pathology
Macrophage activation syndrome after autologous stem cell transplantation for systemic juvenile idiopathic arthritis
No full textOnce-Daily Intravenous Busulfan with Therapeutic Drug Monitoring Compared to Conventional Oral Busulfan Improves Survival and Engraftment in Children Undergoing Allogeneic Stem Cell Transplantation
No full textAbstractBecause of intra- and interindividual variability, bioavailability, and pharmacokinetics of busulfan (Bu) in children, oral busulfan without therapeutic drug monitoring (TDM) is assumed to be associated with higher graft failure rates as well as higher toxicity (eg, veno-occlusive disease [VOD]). This study compares the outcome of hematopoietic stem cell transplantation (HSCT) of 2 groups: 1) 30 patients who received myeloablation with once-daily intravenous (i.v.) dose-targeted busulfan (BUdtIV) based on TDM and 2) 30 patients who received the current practice of untargeted oral busulfan (BUPO). Patients received a 3-hour infusion of Bu at a first dose of 120 mg/m2 (age ≥1 year) or 80 mg/m2 (<1 year), or BUPO 1 mg/kg 4 times daily. Both regimens were continued for 4 days. The target area under the curve (AUC) was defined as 17,500 μg∗h/l. BUdtIV resulted in higher event-free survival (EFS) and survival rates compared to BUPO (EFS: 30% versus 83%, P < .001, survival: 53% versus 83%, P = .016). BUdtIV was associated with more cases of VOD. TDM was feasible in routine clinical practice. The results show that i.v. Bu using TDM is preferable over oral Bu in children undergoing allogeneic stem cell transplantation, especially in those at high risk for graft failure/relapse
Abnormal Results of Newborn Screening for SCID After Azathioprine Exposure In Utero: Benefit of TPMT Genotyping in Both Mother and Child
No full textTransplantation and immunomodulatio
Population Pharmacokinetic Modeling of Thymoglobulin (R) in Children Receiving Allogeneic-Hematopoietic Cell Transplantation: Towards Improved Survival Through Individualized Dosing
No full textBackground and Objectives To prevent graft-versus-host disease and rejection in hematopoietic cell transplantation (HCT), children receive Thymoglobulin (R), a polyclonal antibody acting mainly by depleting T cells. The therapeutic window is critical as over-exposure may result in delayed immune reconstitution of donor T cells. In this study, we describe the population pharmacokinetics of Thymoglobulin (R) as a first step towards an evidence-based dosing regimen of Thymoglobulin (R) in pediatric HCT. Methods Serum active Thymoglobulin (R) concentrations were measured in all pediatric HCTs performed between 2004 and 2012 in two pediatric HCT centers in The Netherlands. Population pharmacokinetic analysis was performed using NONMEM (R) version 7.2. Results A total of 3,113 concentration samples from 280 pediatric HCTs were analyzed, with age ranging from 3 months to 23 years old. The cumulative Thymoglobulin (R) dose was 10 mg/kg in 94 % of the patients given in 4 consecutive days. A model incorporating parallel linear and concentration-dependent clearance of Thymoglobulin (R) was identified. Body weight [for linear clearance (CL) and central volume of distribution] as well as lymphocyte count pre-Thymoglobulin (R) infusion (for CL) were important covariates. As such, the current dosing regimen results in higher exposure in children with a higher bodyweight and/ or a lower lymphocyte count pre-Thymoglobulin (R) infusion. Conclusion This model can be used to develop an individual dosing regimen for Thymoglobulin (R), based on both body weight and lymphocyte counts, once the therapeutic window has been determined. This individualized regimen may contribute to a better immune reconstitution and thus outcome of allogeneic HCT
Introducing Newborn Screening for Severe Combined Immunodeficiency (SCID) in the Dutch Neonatal Screening Program
No full textThe implementation of newborn screening for severe combined immunodeficiency (SCID) in the Netherlands is a multifaceted process in which several parties are involved. The Dutch Ministry of Health adopted the advice of the Dutch Health Council to include SCID in the Dutch newborn screening program in 2015. As newborn screening for SCID is executed with a new, relatively expensive assay for the Dutch screening laboratory, an implementation pilot study is deemed instrumental for successful implementation. A feasibility study was performed in which the practicalities and preconditions of expanding the newborn screening program were defined. Cost-effectiveness analysis (CEA) indicated that SCID screening in the Netherlands might be cost-effective, recognizing that there are still many uncertainties in the variables underlying the CEA. Data and experience of the pilot study should provide better estimates of these parameters, thus enabling the actualization of CEA results. Prior to the implementation pilot study, a comparison study of two commercially available SCID screening assays was performed. A prospective implementation pilot study or so-called SONNET study (SCID screening research in the Netherlands with TRECs) started in April 2018 and allows the screening for SCID of all newborns in three provinces of the Netherlands for one year. Based on the results of the SONNET study, the Dutch Ministry of Health will make a final decision about national implementation of newborn screening for SCID in the Netherlands
An evaluation of the TREC assay with regard to the integration of SCID screening into the Dutch newborn screening program
No full textNewborn screening of severe combined immunodeficiency through the detection of T-cell receptor excision circles will provide the opportunity of treating before the occurrence of life-threatening infections. With the EnLite Neonatal TREC assay (PerkinElmer) and end-point PCR, 39 samples (3.0%) of 1295 heel prick cards of the Dutch newborn screening program required a retest after initial analysis. After retest, 21 samples (1.62%) gave TREC levels below cut-off. A significant reduction in TREC levels was observed in heel prick cards stored for three months (n=33) and one year (n=33). Preterm newborns (n=155) showed significantly lower TREC levels and a higher retest-rate than full-term newborns. Peripheral blood spots of 22 confirmed SCID patients and 17 primary immunodeficiency patients showed undetectable or low TREC-levels. These findings suggest that the EnLite Neonatal TREC assay is a suitable method for SCID-screening in the Netherlands, thereby providing guidance in the decisions concerning implementation into the Dutch progra
Individualised dosing of anti-thymocyte globulin in paediatric unrelated allogeneic haematopoietic stem-cell transplantation (PARACHUTE): a single-arm, phase 2 clinical trial
No full textBackground: Anti-thymocyte globulin, which is used in the conditioning of haematopoietic stem-cell transplantation (HSCT) to prevent graft-versus-host disease (GVHD) and graft failure, has highly variable pharmacokinetics. Overexposure to anti-thymocyte globulin leads to poor CD4+ T-cell immune reconstitution, which is associated with inferior overall survival. We hypothesised that individualised anti-thymocyte globulin dosing would promote CD4+ immune reconstitution, while still preventing GVHD and graft failure. Methods: We report the results of a prospective, single-arm, phase 2 clinical trial done at the University Medical Center Utrecht and the Princess Máxima Center for Pediatric Oncology (Utrecht, Netherlands) to investigate individualised dosing of anti-thymocyte globulin for unrelated allogeneic HSCT in paediatric patients. Anti-thymocyte globulin dosing was based on bodyweight, absolute lymphocyte counts before the first dose, and the stem-cell source, with cumulative doses ranging from 2–10 mg/kg. Patients younger than 18 years receiving a first HSCT with a T-cell repleted graft for any indication and a Lansky/Karnofsky performance status of at least 70% were eligible for inclusion. The primary endpoint was CD4+ immune reconstitution (>0·05 × 109 CD4+ T-cells per L twice within 100 days [±3] after transplantation). The primary endpoint needed to be met in 38 of 53 evaluable patients (no death, relapse, or graft failure before day 100). Toxicity was registered according to Common Terminology Criteria for Adverse Events criteria version 4.0. The study is registered with the Dutch Trial Register, NL4836. Findings: Between July 1, 2015, and Aug 22, 2018, 58 patients were included in the study, of whom 51 were evaluable for the primary endpoint. Median follow-up was 25·6 months (IQR 15·0–37·0) and median age was 7·4 years (IQR 2·8–13·2). 29 (50%) of 58 patients were female. CD4+ immune reconstitution was reached in 41 (80%, 95% CI 67–90, in survival analysis) of 51 evaluable patients, hence the study met its primary endpoint. There was no difference in CD4+ immune reconstitution between patients who received different stem-cell sources (87% [95% CI 61–96] in cord blood, 77% [54–89] in bone marrow [p=0·62]). The most common grade 3–5 adverse events were infections (32 [50%] patients had grade 3, two [3%] patients had grade 4, and seven [11%] patients had fatal events) and immunological disorders (seven [11%] patients had grade 3, three [5%] patients had grade 4, and five [8%] patients had fatal events). Two (3%) of 64 patients died of GVHD, which might be indirectly related to the intervention. Interpretation: Individualised dosing of anti-thymocyte globulin led to a significant improvement in early CD4+ immune reconstitution without increasing GVHD and graft failure incidence. Promotion of early CD4+ immune reconstitution by individualising anti-thymocyte globulin dose might improve outcomes of allogeneic HSCT. Funding: Sanofi
Gut microbiota structure in the course of pediatric allo-HSCT
No full textEffect of selective and total gut decontamination treatments on gut microbiota structure in the course of pediatric allogenic HSCT, as determined via 16S rRNA gene amplicon sequencing
