Peripheral blood progenitor cells (PBPC) were mobilized and harvested in 200 patients treated for non‐Hodgkin's lymphoma (n = 148), Hodgkin's disease (n = 22) and multiple myeloma (n = 30). The variables predicting the collection of a minimal (>2.5 × 106/kg) or a high (>10 × 106/kg) CD34+ cell count were analysed. Patients were mobilized with haemopoietic growth factors following either standard chemotherapy (n = 49) or high‐dose cyclophosphamide, given alone (n = 55) or combined with high‐dose VP16 (n = 86). 10 patients received haemopoietic growth factors only. The first mobilization resulted in a PBPC harvest with enough CD34+ cells in 179/200 patients (90%). High‐dose cyclophosphamide, with or without VP16, did not mobilize a higher progenitor cell yield than standard chemotherapy. When performing multiple regression analysis in the 190 patients who received chemotherapy‐containing mobilization, only the number of previous chemotherapy regimens and the exposure to fludarabine predicted for a failure to collect a minimal PBPC count (P = 0.06 and 0.0008 respectively). The target to collect a high CD34+ cell count was negatively associated with the number of previous chemotherapy regimens (P = 0.002). When only non‐Hodgkin's lymphoma patients were considered for multivariate analysis, low‐grade histology with fludarabine appeared to be associated with poor PBPC cell yield (P = 0.08 and 0.005 respectively). This data confirms that PBPC harvest should be planned early in the disease course in transplant candidates, and can be obtained after a standard course of chemotherapy.

Optimal numbers of CD34+ cells to be reinfused in patients undergoing peripheral blood progenitor cell (PBPC) transplantation after high-dose chemotherapy are still unknown. Hematologic reconstitution of 168 transplantations performed in patients with lymphoproliferative diseases was analyzed according to the number of CD34+ cells reinfused. The number of days from PBPC reinfusion until neutrophil recovery (>1.0 × 109/L) and unsustained platelet recovery (>50 × 109/L) were analyzed in three groups defined by the number of CD34+ cells reinfused: a low group with less than or equal to 2.5 × 106 CD34+ cells/kg, a high group with greater than 15 × 106 CD34+cells/kg, and an intermediate group to which the former two groups were compared. The 22 low-group patients had a significantly delayed neutrophil (P < .0001) and platelet recovery (P < .0001). The 41 high-group patients experienced significantly shorter engraftment compared with the intermediate group with a median of 11 (range, 8 to 16) versus 12 (range, 7 to 17) days for neutrophil recovery (P = .003), and a median of 11 (range, 7 to 24) versus 14 (range, 8 to 180+) days for platelet recovery (P< .0001). These patients required significantly less platelet transfusions (P = .002). In a multivariate analysis, the amount of CD34+ cells reinfused was the only variable showing significance for neutrophil and platelet recovery. High-group patients had a shorter hospital stay (P = .01) and tended to need fewer days of antibotic administration (P = .12). In conclusion, these results suggest that reinfusion of greater than 15 × 106 CD34+ cells/kg after high-dose chemotherapy for lymphoproliferative diseases further shortens hematopoietic reconstitution, reduces platelet requirements, and may improve patients' quality of life.

No abstract