Analysis of engraftment kinetics in pediatric patients undergoing autologous PBPC transplantation.

We sought to analyze factors that affect the engraftment kinetics following autotransplantation with PBPC mobilized by filgrastim (G-CSF). Forty-six consecutive pediatric patients with hematologic malignancies (n = 23) or solid tumors (n = 23) underwent autologous PBPC transplantation after myeloablative therapy. PBPC were mobilized using G-CSF alone. All patients received G-CSF after PBPC infusion. Factors potentially influencing the neutrophil and platelet engraftment were examined using univariate and multivariate analysis. All patients experienced rapid hematopoietic recovery, with a median of 9 days (range 7-15) to achieve a neutrophil count of 0.5 x 10(9)/L and a median of 15 days (range 9-37) to achieve a platelet count of 20 x 10(9)/L. The most important predictive factor of both platelet (p = 0.002) and neutrophil (p = 0.0001) recovery was the number of CD34+ cells infused. Patients receiving > or =5 x 10(6)/kg CD34+ cells had a more rapid hematopoietic recovery (p < 0.001) than those receiving a lower cell dose. The CD34+ cell dose is the most important predictive factor for engraftment kinetics after PBPC transplantation. Although a minimal CD34+ cell dose could not be defined, a dose > or =5 x 10(6)/kg CD34+ cells may be optimal to ensure rapid neutrophil and platelet recovery.