Peripheral blood-derived stem cell collections for use in autologous transplantation after high dose chemotherapy: An alternative approach

Peripheral blood-derived hematopoietic stem cells (PBHSC) can be utilized to reconstitute hematopoiesis in patients after high dose myeloablative chemotherapy. We have performed PBHSC reinfusion in 18 patients who have or had a history of tumor involving the bone marrow or a hypocellular bone marrow. The PBHSC were collected by continuous flow leukapheresis and subsequently cryopreserved. A median of 31.9 x 10⁹ (range 18 x 10⁹ - 67.2 x 10⁹) mononuclear cells or a median of 4.85 x 10⁸ mononuclear cells/kg (range 2.7 x 10⁸ - 11.0 x 10⁸) were collected. Fifteen patients had in vitro assays of granulocyte-monocyte colony-forming cells (CFU-GM) performed with a median of 2.7 x 10⁴ (range 0-11.5 x 10⁴) CFU-GM/kg. To date, of the 18 patients collected, all have undergone high dose chemotherapy and PBHSC reinfusion. For the evaluable patients, granulocyte recovery (>500 x 10⁶/ml) has occurred in a median of 15 days and platelet recovery (>15 x 10⁹/ml without transfusion support) has occurred in a median of 43 days. Four patients have had prolonged thrombocytopenia and still require platelet transfusion at 80+, 97+, 124+, and 270+ days. PBHSC collection is safe and effective for hematopoietic reconstitution after high dose chemotherapy in the majority of patients; however incomplete hematopoietic reconstitution has been observed in 4/18 evaluable patients. This procedure required further investigation.