PERIPHERAL-BLOOD PROGENITORS MOBILIZED BY G-CSF (FILGRASTIM) AND REINFUSED AS UNPROCESSED AUTOLOGOUS WHOLE-BLOOD SHORTEN THE PANCYTOPENIC PERIOD FOLLOWING HIGH-DOSE MELPHALAN IN MULTIPLE-MYELOMA

Growth factor granulocyte colony-stimulating factor (G-CSF; filgrastim ) is effective at progenitor release into the peripheral blood. After high-dose chemotherapy haematopoietic reconstitution occurs after rein fusion of these peripheral blood progenitor cells (PBPC). However, the collection by leukapheresis and further processing of PBPC are very t ime consuming and expensive. We have studied the transplantation poten tial of a small volume of unprocessed autologous whole blood after G-C SF mobilisation. Six patients with plasma cell disorders received G-CS F 1O mu g/kg sc during 6 days. Subsequently 11 of whole blood was coll ected by phlebotomy, kept unprocessed at room temperature and reinfuse d 24 h after high-dose melphalan 140 mg/m(2). CFU-GM content was 845 p er ml blood (median, range 320-3472) and CD34(+) cells rose to a media n percentage of 0.9 (range 0.4-2.0). Haematological recovery was signi ficantly faster in the study group compared with the control group of 20 patients who received the same dose of melphalan without reinfusion of PBPC. The neutrophil count reached 0.5 x 10(9)/l at a median of 12 .5 days after infusion of PBPC vs 38 days in the control group (p = 0. 0003). The platelet count reached 20 X 10(9)/l after a median of 23.5 days vs 38 days (p = 0.0218). The shortened recovery was reflected by less transfusions, less antibiotic use and shortening of hospital stay (19 days vs 43 days, p = 0.0003). We conclude that this easy techniqu e of mobilisation and collection of PBPC is very effective for hasteni ng haematologic recovery after high-dose chemotherapy.