In patients given high-dose chemotherapy, with or without radiation, for the treatment of hematologic cancer, allogeneic peripheral-blood cells used for hematopoietic rescue restore blood counts faster than allogeneic bone marrow, without increasing the risk of graft-versus-host disease.

Disease status and prior treatment influence the ability to mobilize PBSC. CD34 cell dose is an important predictor of engraftment kinetics after PBSC transplant, regardless of disease or mobilization technique. The use of postinfusion CSF improves neutrophil recovery, but at low CD34 doses can delay platelet recovery.

Factors affecting mobilization and engraftment were analysed in 54 patients undergoing transplant using autologous PBSCs mobilized with high-dose recombinant granulocyte stimulating factor (rhG-CSF). Patients received 5-7 d of rhG-CSF, 16 micrograms/kg/d, administered subcutaneously. PBSCs were harvested by leukapheresis using automated continuous-flow blood cell separators beginning on day 4 of rhG-CSF, processing 10 litres of whole blood, for 2-6 consecutive days. Transplants were performed for the following diseases: breast cancer (n = 22), non-Hodgkin's lymphoma (n = 18), multiple myeloma (n = 7) and other (n = 7). Engraftment was rapid with patients reaching a neutrophil count of 1 x 10(9)/l a median of 12 d (range 9-22) after transplant. Platelets > 20 x 10(9)/l independent of transfusion support were achieved a median of day 10 (range 7-60) after infusion. Multiple factors potentially influencing engraftment were examined using a Cox regression model. The number of CD34+ cells per kg was highly correlated with the time to achievement of granulocyte and platelet recovery (P < 0.012, 0.0001). The use of a post-infusion growth factor and a radiation preparative regimen was important for neutrophil recovery, and a diagnosis of breast cancer was important for platelet recovery. In an analysis by linear regression of the logarithm of CD34+ cells collected, lower age, marrow without disease, no prior radiation, and lower number of prior chemotherapy regimens, were important factors influencing larger numbers of CD34+ cells in collections.