CD34(+) cell enrichment for autologous peripheral blood stem cell transplantation by use of the CliniMACS device

Several devices for selection of CD34(+) peripheral blood stem cells (PBSC) have been used during the last years for reducing tumor cell contamination of the graft. The new CliniMACS system (magnetic-activated cell separation system by Miltenyi Biotech GmbH, Bergisch-Gladbach, Germany) was recently approved for clinical use in Europe. To evaluate its purging efficiency and engraftment data in the autologous transplant, PBSC from 28 adult patients with various malignant diseases (non-Hodgkin's lymphoma, n = 17; chronic l ymphocytic leukemia, n = 5; multiple myeloma, n = 4; acute lymphocytic leuk emia, n = 1; medulloblastoma, n = 1) were mobilized by chemotherapy and gra nulocyte colony-stimulating factor (G-CSF) (10 mu g/kg per day). Thirty leu kapheresis products from 28 patients with a median of 4.4 x 10(8) nucleated cells/kg body weight (bw)(range 0.6-10.8 x 10(8)/kg bw) and a median of 7. 1 x 10(6) CD34(+) cells/kg bw (range 2.8 to 18.8 x 10(6)/kg bw) were select ed using the Cobe spectra cell separator (Cobe BCT Inc., Lakewood, CO). Aft er the CliniMACS procedure, the median yield of CD34(+) selected cells was 4.5 x 10(6)/kg (range 2.2 11.1 x 10(6)/kg bw) with a median recovery of 69. 5% (range 46.9-87.3%) and a median purity of 97.7% (range 89.4-99.8%). The procedure did not alter viability of selected cells, which was tested by pr opidium iodide staining. So far, purified PBSC were used for autologous tra nsplantation in 15 out of 28 patients after total body irradiation and/or h igh-dose chemotherapy. Median time to reach an absolute neutrophil count > 500/mu l was 12 days (range 10-18 days), platelet recovery >50,000/mu l occ urred at day +16 (range 11-22). With a median follow-up time of 12 months ( range 3-19), 5 patients died of relapse. We confirmed the feasibility and s afety of the CliniMACS CD34(+) cell enrichment procedure in adult patients with autologous PBSC transplantation.