Prospective PTCTC trial of myeloablative haplo-BMT with posttransplant cyclophosphamide for pediatric acute leukemias.

Promising results have been reported for adult patients with high-risk hematologic malignancies undergoing haploidentical bone marrow transplant (haploBMT) with posttransplant cyclophosphamide (PTCy). To our knowledge, we report results from the first multicenter trial for pediatric and young adult patients with high-risk acute leukemias and myelodysplastic syndrome (MDS) in the Pediatric Transplantation and Cellular Therapy Consortium. Nine centers performed transplants in 32 patients having acute leukemias or MDS, with myeloablative conditioning (MAC), haploBMT with PTCy, mycophenolate mofetil, and tacrolimus. The median patient age was 12 years. Diagnoses included AML (15), ALL (11), mixed-lineage leukemia (1), and MDS (5). Transplant-related mortality (TRM) at 180 days was 0%. The cumulative incidence (CuI) of grade 2 acute graft-versus-host disease (aGVHD) on day 100 was 13%. No patients developed grades 3-4 aGVHD. The CuI of moderate-to-severe chronic GVHD (cGVHD) at 1 year was 4%. Donor engraftment occurred in 27 patients (84%). Primary graft failures included 3 patients who received suboptimal bone marrow grafts; all successfully engrafted after second transplants. The CuI of relapse at 1 year was 32%, with more relapse among patients MRD positive pre-BMT vs MRD negative. Overall survival rates at 1 and 2 years were 77% and 73%, and event-free survival rate at 1 and 2 years were 68% and 64%. There was no TRM or severe aGVHD, low cGVHD, and favorable relapse and survival rates. This successful pilot trial has led to a phase 3 trial comparing MAC haploBMT vs HLA-matched unrelated donor BMT in the Children's Oncology Group. This trial was registered at www.clinicaltrials.gov as #NCT02120157.

Lymphopenia in Patients with Single-ventricle Heart Disease after the Fontan Operation.

BACKGROUND: Lymphopenia is common in patients with Fontan circulation and no history of protein-losing enteropathy, but this phenomenon has not been significantly described in the literature. METHODS: We retrospectively identified patients with Fontan circulation who underwent catheterization between January 2003 and January 2013 at our center. Patients who had complete blood count with differential drawn within 12 months of the catheterization were included. Patients were excluded if complete blood count with differential was drawn in setting of possible infection or if there was history of protein-losing enteropathy (PLE). Possible associations between patient characteristics and absolute lymphocyte count (ALC) were examined. RESULTS: Fifteen patients were included. The median age at catheterization was 10.2 years (3.8-26.9) and median time from Fontan operation was 6.5 years (0.7-22.1). Twelve (80%) patients had undergone extracardiac Fontan and 9 (60%) had fenestration placed. The median time between complete blood count with differential and catheterization was 2 days (0-346). The median inferior vena cava (IVC) pressure was 13 mm Hg (7-20). The median ALC was 1.5 × 10(3) /µL (0.8-4.5). Four patients (26.7%) met criteria for lymphopenia with ALC < lower limit of normal and 7 (46.7%) patients had an ALC ≤ lower limit of normal. ALC was not associated with any hemodynamic variables but was associated with platelet count (rho = 0.5, P = .04), total white blood cell count (rho = 0.8, P ≤ .001), and absolute monocyte count (0.7, P = .002). CONCLUSIONS: In a cohort of patients with Fontan circulation and no history of protein-losing enteropathy who underwent catheterization, lymphopenia was common and positively associated with low platelet count. Thrombocytopenia has been shown to correlate with the degree of hepatic fibrosis in those with Fontan and, thus, hepatic fibrosis may underlie lymphopenia in these patients.

Characteristics of thawed autologous umbilical cord blood.

BACKGROUND: Autologous umbilical cord blood (AutoUCB) has historically been cryopreserved for potential use in hematopoietic transplantation. Increasingly, private AutoUCB banking is performed for therapies unavailable today. A Phase I trial using AutoUCB treatment for early pediatric Type 1 diabetes afforded us an opportunity to analyze characteristics of AutoUCBs. STUDY DESIGN AND METHODS: Twenty AutoUCBs from AABB-accredited private cord blood banks (CBBs) were evaluated for collection, processing, cryopreservation, and thaw characteristics. Using a standardized thaw-wash method, AutoUCBs were assessed for viable total nucleated cells (vTNCs), viable CD34+ (vCD34+), and colony-forming unit-granulocyte-macrophage counts. Postthaw %vTNC recoveries were compared against processing characteristics and analyzed according to processing method, cryopreservation volume, concentration, container, and length of storage. RESULTS: AutoUCB collection volumes (19.9-170 mL), cryopreserved TNC counts (7.6 × 10(7) -3.34 × 10(9)), %TNC processing recoveries (39%-100%), postthaw %vTNC recoveries (58%-100%), and %vCD34+ recoveries (26%-96%) varied widely. Regarding cell dose requirements, only 11% of evaluable AutoUCBs achieved the minimum TNC count of at least 9.0 × 10(8) to meet the National Cord Blood Inventory banking threshold, and only 50% met the minimum of 5.0 × 10(8) TNC count for Food and Drug Administration cord blood licensure eligibility. %vTNC recoveries correlated with %vCD34+ recoveries (R = 0.7; p = 0.03). Length of storage, cryopreservation volume, concentration, and container type did not affect postthaw %vTNC recoveries. CBB processing method, however, was associated with %vTNC postprocessing recoveries, with unmanipulated and plasma-depleted AutoUCBs having the highest postthaw %vTNC recovery, followed by RBC-depleted and density gradient-separated AutoUCBs. CONCLUSION: The high variability and low counts found in AutoUCB banking suggest that further standardization of characterization, collection, and processing procedures is needed.

Chimeric antibody receptors (CARs): driving T-cell specificity to enhance anti-tumor immunity.

Adoptive transfer of antigen-specific T cells is a compelling tool to treat cancer. To overcome issues of immune tolerance which limits the endogenous adaptive immune response to tumor-associated antigens, robust systems for the genetic modification and characterization of T cells expressing chimeric antigen receptors (CARs) to redirect specificity have been produced. Refinements with regards to persistence and trafficking of the genetically modified T cells are underway to help improve the potency of genetically modified T cells. Clinical trials utilizing this technology demonstrate feasibility, and increasingly, antitumor activity, paving the way for multi-center trials to establish the efficacy of this novel T-cell therapy.

A high throughput microelectroporation device to introduce a chimeric antigen receptor to redirect the specificity of human T cells.

It has been demonstrated that a chimeric antigen receptor (CAR) can directly recognize the CD19 molecule expressed on the cell surface of B-cell malignancies independent of major histocompatibility complex (MHC). Although T-cell therapy of tumors using CD19-specific CAR is promising, this approach relies on using expression vectors that stably integrate the CAR into T-cell chromosomes. To circumvent the potential genotoxicity that may occur from expressing integrating transgenes, we have expressed the CD19-specific CAR transgene from mRNA using a high throughput microelectroporation device. This research was accomplished using a microelectroporator to achieve efficient and high throughput non-viral gene transfer of in vitro transcribed CAR mRNA into human T cells that had been numerically expanded ex vivo. Electro-transfer of mRNA avoids the potential genotoxicity associated with vector and transgene integration and the high throughput capacity overcomes the expected transient CAR expression, as repeated rounds of electroporation can replace T cells that have lost transgene expression. We fabricated and tested a high throughput microelectroporator that can electroporate a stream of 2 x 10(8) primary T cells within 10 min. After electroporation, up to 80% of the passaged T cells expressed the CD19-specific CAR. Video time-lapse microscopy (VTLM) demonstrated the redirected effector function of the genetically manipulated T cells to specifically lyse CD19+ tumor cells. Our biomedical microdevice, in which T cells are transiently and safely modified to be tumor-specific and then can be re-infused, offers a method for redirecting T-cell specificity, that has implications for the development of adoptive immunotherapy.

Autologous umbilical cord blood transfusion in very young children with type 1 diabetes.

OBJECTIVE: Interest continues to grow regarding the therapeutic potential for umbilical cord blood therapies to modulate autoimmune disease. We conducted an open-label phase I study using autologous umbilical cord blood infusion to ameliorate type 1 diabetes. RESEARCH DESIGN AND METHODS: Fifteen patients diagnosed with type 1 diabetes and for whom autologous umbilical cord blood was stored underwent a single intravenous infusion of autologous cells and completed 1 year of postinfusion follow-up. Intensive insulin regimens were used to optimize glycemic control. Metabolic and immunologic assessments were performed before infusion and at established time periods thereafter. RESULTS: Median (interquartile range [IQR]) age at infusion was 5.25 (3.1-7.3) years, with a median postdiagnosis time to infusion of 17.7 (10.9-26.5) weeks. No infusion-related adverse events were observed. Metabolic indexes 1 year postinfusion were peak C-peptide median 0.50 ng/ml (IQR 0.26-1.30), P = 0.002; A1C 7.0% (IQR 6.5-7.7), P = 0.97; and insulin dose 0.67 units * kg(-1) * day(-1) (IQR 0.55-0.77), P = 0.009. One year postinfusion, no changes were observed in autoantibody titers, regulatory T-cell numbers, CD4-to-CD8 ratio, or other T-cell phenotypes. CONCLUSIONS: Autologous umbilical cord blood transfusion in children with type 1 diabetes is safe but has yet to demonstrate efficacy in preserving C-peptide. Larger randomized studies as well as 2-year postinfusion follow-up of this cohort are needed to determine whether autologous cord blood-based approaches can be used to slow the decline of endogenous insulin production in children with type 1 diabetes.