Long-term hematopoietic engraftment after autologous peripheral blood progenitor cell transplantation in pediatric patients: Effect of the CD34+cell dose

Background and Objectives: We analyzed the relationship between long-term h ematopoietic recovery and the number of CD34+ cells infused in order to det ermine the optimal dose of CD34+ cells for rapid and stable engraftment. Pa tients and Methods: Between November 1993 and December 1998, 96 consecutive autologous transplantations were performed in 92 pediatric patients with d ifferent malignancies. Peripheral blood progenitor cells (PBPC) were mobili zed by G-CSF alone (12 mug/kg/day s.c., Neupogen(R); Amgen, Thousand Oaks, Calif., USA) and collected using a Cobe Spectra blood cell separator (Cobe, Denver, Cole., USA) through a central venous catheter with double lumen. T he CD34+ cell contents of apheresis products were assessed by means of flow cytometric analysis using an Epics Elite Row cytometer (Coulter, USA). Resu lts: The median number of CD34+ cells infused was 3.2 x 10(6)/kg (range 0.1 7-44.4). The median times for short-term engraftment (neutrophil count >0.5 x 10(9)/l and platelet count >20 x 10(9)/l) was 9 (range: 7-16) and 13 day s (range: 7-91), respectively. The median times for long-term engraftment ( platelet count >50 x 10(9)/I and >100 x 10(9)/I) was 21 (range: 10-249) and 45 days (range: 12-288). When the infused CD34(+) cell dose was greater th an or equal to5 x 10(6)/kg (median 7.99, range 5.01-44.4), there was a stat istically significant increase in the rate of short- and long-term hematopo ietic recovery compared to patients transplanted with a lower number of CD3 4+ cells (p < 0.0001). The earlier recovery in the high CD34+ cell group re sulted in less transfusional support, fewer days on intravenous antibiotics and shorter hospitalization. Conclusions: This study confirms that G-CSF-m obilized PBPC provide rapid short- and longterm hematopoietic engraftment i n pediatric patients undergoing autologous transplantation if a CD34+ cell dose <greater than or equal to>5.0 x 106/kg is infused. As this PBPC dose s eems to have clinical and potentially economic implications, it should be c onsidered the optimal dose for apheresis. Copyright (C) 2000 S. Karger AG. Basel.