Isolation and transplantation of highly purified autologous peripheral CD34+ progenitor cells: purging efficacy, hematopoietic reconstitution and long-term outcome in children with high-risk neuroblastoma

Abstract

Summary:We have investigated the purging efficacy of positive selection of autologous mobilized CD34 ϩ peripheral stem cells in 22 children with high-risk neuroblastoma. CD34 ϩ cell selection was performed using the method of magnetic-activated cell sorting (MACS). The median purity of the CD34 ϩ cells post selection was 97.6% (range 81.7-99.7). For detection of contaminating neuroblastoma cells before and after CD34 ϩ selection, the chimeric anti-disialoganglioside GD2 antibody delta ch 14.18 was used. Prior to positive selection, various numbers of contaminating neuroblastoma cells were found in 17 patients. After positive CD34 ϩ cell selection, low numbers of neuroblastoma cells were only detectable in four patients. In 18 patients, high-dose chemotherapy was performed and the isolated CD34 ϩ cells were reinfused. In all patients, a rapid neutrophil recovery was seen with a median time to reach 0.5 × 10 9 /l neutrophils of 12 days (range 8-24 days). Nine of the 18 patients are free of progression with a median followup of 55 months (range 45-70 months). Two patients are alive with relapse, six patients died due to progression or relapse and one patient died due to secondary AML 10 months after transplant while in remission from neuroblastoma. In summary, we show that, through a highly effective positive selection method, a high purging efficacy can be obtained without compromising the hematopoietic reconstitution capacity of the graft. Bone Marrow Transplantation (2002) 29, 731-736.

Tumour cell contamination of autologous stem cells grafts in high-risk neuroblastoma: the good news?

“…Myeloablative therapy consisted of melphalan, etoposide, and carboplatin; some patients also had high-dose mIBG therapy, given as described . Of the 24 patients, 21 received posttransplant immunotherapy with an antibody (ch14.18) to the tumour-associated disialoganglioside GD2 (Handgretinger et al, 2002). All transplants were given between January 1996 and February 1998.…”

“…All 24 CD34 þ stem cell grafts were examined for the presence of contaminating neuroblastoma cells by immunofluorescence with the chimeric anti-GD2 antibody delta ch14.18 (Handgretinger et al, 2002). This technique can detect contamination as low as one neuroblastoma cell in 10 5 normal cells.…”

Peripheral blood stem cell mobilization by granulocyte colony-stimulating factor alone and engraftment kinetics following autologous transplantation in children and adolescents with solid tumor

“…Autologous hematopoietic stem cell transplantation is increasingly performed for the treatment of various pediatric and adolescent cancers, 1,2 and currently most centers use peripheral blood stem cells (PBSC) as the source of stem cells to support high-dose chemotherapy. The advantages of PBSC include rapid hematopoietic recovery following transplantation, and less of a potential for tumor cell contamination of the grafts.…”

Hourly monitoring of circulating CD34+ cells to optimize timing of autologous apheresis in pediatric patients

“…Samples were incubated for 20 min in the dark at room temperature. Erythrocytes were counted by erylysis reagent (8.29 g NH 4 Cl, 1 g KHCO 3 , 37.2 mg EDTANa 2 , distilled water, pH 7.3-7.4) and for buffering, DPBSBuffer (Bio Whittaker Europe) was used. Samples with a WBC counts greater than 20 000/ml were first diluted to 10 000/ml with buffer.…”

“…Nevertheless, high doses of CD34 þ cells (45 Â 10 6 cells/kg) seem to improve the clinical outcome. 3,4 A major consideration is that apheresis procedures bear risks and are not always well tolerated, especially in small children. Therefore, a minimum of aphereses with a maximum yield of CD34 þ cells should be strived for.…”