FEASIBILITY OF A PB CD34(+) CELL TRANSPLANTATION PROCEDURE USING STANDARD LEUKAPHERESIS PRODUCTS IN VERY SMALL CHILDREN

To evaluate the feasibility and efficacy of CD34(+) cell immunoselecti on from routine peripheral blood stem cell (PBSC) harvests in very sma ll children a prospective study was performed in 15 children with adva nced neuroblastoma weighing 20 kg or less, Products of two consecutive leukaphereses carried out on a COPE Spectra separator after G-CSF alo ne mobilization were pooled for immunoselection on Ceprate column, The median number of CD34(+) cells and total CFU-GM collected were respec tively 5.9 x 10(6)/kg (range 2.3-23.4) and 126.9 x 10(4)/kg (range 52. 9-559.9). After separation the median number of CD34(+) cells in the a dsorbed fraction was 2.6 x 10(6)/kg (range 1-9.8) with a median purity of 54% (range 21-82) and a median of 95.7-fold (range 35-250) enrichm ent, Thirteen patients underwent autografts with CD34(+) PBSCs after a busulfan 600 mg/m(2) + melphalan 180 mg/m(2) preparative regimen, The median number of days to achieve an absolute granulocyte count of 0.5 x 10(9)/l and a platelet count of 20 x 10(9)/l were respectively, 12 (range 10-24) and 35 (range 25-43), The median number of platelet tran sfusions was nine (range 2-15). We conclude that safe and effective im munoselection and transplantation of CD34(+) PBSC can be accomplished in children with low body mass.