Search

Purpose: To characterize the relationship between CD34+ collection efficiency and blood volumes processed in pediatric patients undergoing autologous peripheral blood stem cell (PBSC) collection. Methods: Retrospective 8-year (2001–2009) study of pediatric patients (n = 79) with neuroblastoma and central nervous system (CNS) tumors undergoing first day of autologous PBSC harvest using MNC program on the COBE Spectra (Caridian BCT, Lakewood, CO) was performed. Patients undergoing 0 to 2.9 BV (standard volume), 3 to 6 BV (large volume), and greater than 6 BV (ultra large volume) harvests were evaluated for CD34+ collection efficiency, diagnosis (neuroblastoma vs. nonneuroblastoma), disease type (primary vs. relapse), mobilization regimen, granulocyte colony stimulating factor (GCSF) dose, and apheresis complications. Results: CD34+ collection efficiencies (CE) for neuroblastoma patients were 67%, 50%, and 53% for standard (n = 14), large (n = 9), and ultra large (n = 5) volume harvests, respectively. Similarly, patients with nonneuroblastoma diagnoses had CD34+ CE of 63%, 55%, and 65% for low (n = 19), large (n = 27), and ultra large (n = 5) volume harvests, respectively. Weight, granulocyte colony stimulating factor (G-CSF) stimulation, type of mobilization, and apheresis complications (normalized by run time) were similar between the standard, large, and ultra large volume groups in patients with either neuroblastoma or nonneuroblastoma diagnoses. Conclusions: CD34+ collection efficiency in pediatric autologous PBSC collection on the first day of harvest does not decrease with higher numbers of blood volumes processed in patients with either neuroblastoma or nonneuroblastoma primary disease. These results indirectly indicate bone marrow CD34+ cell mobilization occurs with longer apheresis procedures in pediatric patients. J. Clin. Apheresis, 2011. © 2011 Wiley-Liss, Inc.

EBV-associated tumors in the immune deficient host express type II and III latency antigens including latent membrane protein 1 (LMP1) and LMP2, which can serve as potential targets for immunotherapy. Several studies have documented the safety and efficacy of LMP-specific T cells for patients with EBV-associated malignancies, but clinical applications may be limited by the time to generate LMP-specific T cell products as well as the availability of an appropriate donor source. We hypothesize that the administration of “off the shelf” third party LMP-specific cytotoxic lymphocytes (LMP-CTLs) will rapidly restore EBV-specific T-cell immunity and prevent relapse in patients with post-transplant lymphoproliferative disease PTLD post solid organ transplant (SOT). To develop the third party T cell bank, we manufactured healthy donor-derived LMP-specific T cells from eligible donors with a wide range of HLA types in our good manufacturing practices (GMP) facility. This T-cell bank is for several clinical trials including a proposed multicenter Children's Oncology Group (COG) trial (ANHL1522) for patients with PTLD after SOT. Currently, 15 LMP-specific T-cell products have been manufactured from healthy donors and released for third-party use using autologous monocytes and lymphoblastoid cell lines (LCL), transduced with an adenoviral vector expressing ΔLMP1 and LMP2. T-cell products were active against LMP2 (mean:172 SFU/1×10^5 cells; range:13-655), LMP1 (33; 1-322), and LCL (87; 0-424) as determined by IFN-γ ELISPOT assay. Epitope mapping of LMP-specific T cells using IFN-γ ELISPOT assay demonstrates that these products recognize a broad epitope repertoire within LMP1 and LMP2. At the time of cryopreservation, the T-cell products comprised a mean of 45% CD8+ T-cells, 35% CD4+ T-cells, and 9% NK cells. No B cells or monocytes were detected in the final products. Thus far, one patient with NK/T cell non-Hodgkin Lymphoma received third party LMP-specific T cells achieving a very good partial response. No infusion-related toxicities were observed, and LMP-specific T cells were detectable post-infusion. Thus, third party LMP-specific T cells appear to be a safe and promising therapeutic modality for patients with EBV-associated lymphomas, and a third party bank will make this therapeutic more readily available to patients with PTLD post-SOT.