...in mice reconstituted with low Rag1 expression, a block in development can be seen at the immature single positive to DP transition. ...the level of RAG1 expression in transduced stem cells and ...after transplantation and reconstitution in lymphocytes is a crucial determinant of outcome.
Background Severe combined immunodeficiency (SCID) represents congenital disorders characterized by a deficiency of T cells caused by arrested development in the thymus. Yet the nature of these ...developmental blocks has remained elusive because of the difficulty of taking thymic biopsy specimens from affected children. Objective We sought to identify the stages of arrest in human T-cell development caused by various major types of SCID. Methods We performed transplantation of SCID CD34+ bone marrow stem/progenitor cells into an optimized NSG xenograft mouse model, followed by detailed phenotypic and molecular characterization using flow cytometry, immunoglobulin and T-cell receptor spectratyping, and deep sequencing of immunoglobulin heavy chain (IGH) and T-cell receptor δ (TRD) loci. Results Arrests in T-cell development caused by mutations in IL-7 receptor α (IL7RA) and IL-2 receptor γ (IL2RG) were observed at the most immature thymocytes much earlier than expected based on gene expression profiling of human thymocyte subsets and studies with corresponding mouse mutants. T-cell receptor rearrangements were functionally required at the CD4− CD8− CD7+ CD5+ stage given the developmental block and extent of rearrangements in mice transplanted with Artemis-SCID cells. The xenograft model used is not informative for adenosine deaminase–SCID, whereas hypomorphic mutations lead to less severe arrests in development. Conclusion Transplanting CD34+ stem cells from patients with SCID into a xenograft mouse model provides previously unattainable insight into human T-cell development and functionally identifies the arrest in thymic development caused by several SCID mutations.
Background We recently demonstrated in a randomized, double-blind, placebo-controlled trial that intramyocardial bone marrow cell (BMC) injection is associated with improvements in myocardial ...perfusion and anginal symptoms in chronic myocardial ischemia patients. In the present study the results of the crossover phase of this trial, in which patients previously treated with placebo received autologous BMC injections are reported. This allows a unique intra-patient comparison on the effect of BMC versus placebo injection with elimination of patient-related confounding factors. Methods In 16 patients (14 male, 64 ± 10 years), who previously received intramyocardial placebo injections in the setting of a randomized trial, 100 × 106 BMC were injected using the NOGA-system. Canadian Cardiovascular Society angina score and quality of life were evaluated at baseline, 3 and 6 months. Tc-99m single photon emission computed tomography and magnetic resonance imaging were performed at baseline and 3 months to assess myocardial perfusion and left ventricular (LV) function. Results Canadian Cardiovascular Society score and quality of life improved significantly after BMC injection as compared to placebo ( P = 0.01 and P = 0.02, respectively). Single photon emission computed tomography revealed a significant greater improvement ( P = 0.03) in summed stress score after BMC injection as compared to placebo. LV end-systolic volume significantly decreased after BMC injection but not after placebo injection. LV end-diastolic volume and LV ejection fraction did not change. Conclusion Intramyocardial BMC injection in patients with chronic myocardial ischemia who previously received intramyocardial placebo treatment resulted in significant improvement in angina symptoms and myocardial perfusion. These results confirm the outcome of our previously reported randomized trial.
The present study investigated the safety, feasibility, and potential efficacy of autologous bone marrow cell injection in patients with chronic myocardial infarction and severe left ventricular (LV) ...dysfunction. In 15 patients (63 ± 9 years; 14 men) bone marrow was aspirated from the iliac crest. Using the NOGA system (Biosense-Webster, Waterloo, Belgium), 94 ± 14 × 106 bone marrow–derived mononuclear cells were injected into the infarction border zone. Bone marrow cell injection was performed without periprocedural complications in all patients. At 2.5 months, 1 patient died from worsening heart failure. New York Heart Association class improved from 3.5 ± 0.5 at baseline to 2.7 ± 0.8 at 3 months (p <0.01) and 2.9 ± 0.8 at 6 months (p <0.01 vs baseline). LV ejection fraction (technetium-99m tetrofosmin single-photon emission computed tomography) increased from 23 ± 8% to 27 ± 9% at 3 months (p = 0.02) and regional wall thickening improved from 12.8 ± 5.9% to 15.3 ± 7.2% at 3 months (p = 0.02). Injected myocardial segments displayed a significant improvement in regional wall thickening (6.6 ± 6.3% vs 11.7 ± 7.0% at 3 months, p <0.01) and perfusion score (3.5 ± 0.7 vs 3.0 ± 0.9 at 3 months, p = 0.02) and a trend toward an improved fluorine-18 fluorodeoxyglucose score (2.9 ± 0.9 vs 2.6 ± 1.0 at 3 months, p = 0.06). Regional wall thickening (16.5 ± 8.9% vs 19.1 ± 9.1% at 3 months, p = NS), perfusion score (1.8 ± 0.4 vs 1.7 ± 0.5 at 3 months, p = NS), and fluorodeoxyglucose score (1.7 ± 0.4 vs 1.6 ± 0.4 at 3 months, p = NS) did not improve in noninjected myocardial segments. In conclusion, bone marrow cell injection in patients with chronic myocardial infarction and severe LV dysfunction is safe and feasible and appears to be associated with a decrease in heart failure symptoms and an improved LV function.
Summary Background Severe graft-versus-host disease (GVHD) is a life-threatening complication after allogeneic transplantation with haemopoietic stem cells. Mesenchymal stem cells modulate immune ...responses in vitro and in vivo. We aimed to assess whether mesenchymal stem cells could ameliorate GVHD after haemopoietic-stem-cell transplantation. Methods Patients with steroid-resistant, severe, acute GVHD were treated with mesenchymal stem cells, derived with the European Group for Blood and Marrow Transplantation ex-vivo expansion procedure, in a multicentre, phase II experimental study. We recorded response, transplantation-related deaths, and other adverse events for up to 60 months' follow-up from infusion of the cells. Findings Between October, 2001, and January, 2007, 55 patients were treated. The median dose of bone-marrow derived mesenchymal stem cells was 1·4×106 (min–max range 0·4–9×106 ) cells per kg bodyweight. 27 patients received one dose, 22 received two doses, and six three to five doses of cells obtained from HLA-identical sibling donors (n=5), haploidentical donors (n=18), and third-party HLA-mismatched donors (n=69). 30 patients had a complete response and nine showed improvement. No patients had side-effects during or immediately after infusions of mesenchymal stem cells. Response rate was not related to donor HLA-match. Three patients had recurrent malignant disease and one developed de-novo acute myeloid leukaemia of recipient origin. Complete responders had lower transplantation-related mortality 1 year after infusion than did patients with partial or no response (11 37% of 30 vs 18 72% of 25; p=0·002) and higher overall survival 2 years after haemopoietic-stem-cell transplantation (16 53% of 30 vs four 16% of 25; p=0·018). Interpretation Infusion of mesenchymal stem cells expanded in vitro, irrespective of the donor, might be an effective therapy for patients with steroid-resistant, acute GVHD. Funding Swedish Cancer Society, Children's Cancer Foundation, Swedish Research Council, Cancer Society in Stockholm, Cancer and Allergy Foundation, Karolinska Institutet, Istituto Superiore di Sanità, European Union, Regione Lombardia, Fondazione CARIPLO, Associazione Italiana Ricerca contro il Cancro, Compagnia di San Paolo Torino, Progetto CARIGE Cellule Staminali, European Commission, Ministero dell'Università e della Ricerca Scientifica e Tecnologica, Ricerca Finalizzata Regione Liguria 2005 Assistenza Domiciliare, Dutch Programme for Tissue Engineering.
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