BACKGROUND: Transplantation of allogeneic peripheral blood stem cells (PBSCs) may have advantage over bone marrow transplantation with regards to the speed of hematopoietic and immunologic recovery. Recently to overcome the need for multiple leukaphereses to collect enough PBSCs for autologous transplantation, large volume leukaphereses (LVL) are used to process multiple blood volumes per session. Experience with this technique in healthy individuals after mobilization with colony stimulating factor (CSF) is limited. We have investigated the efficacy and safety of LVL for the collection of G-CSF and GM-CSF mobilized PBSCs from healthy donors. METHODS: This study was done on 40 healthy donors who were mobilized with G-CSF and GM-CSF for allogeneic peripheral blood stem cells transplantation (allo-PBSCT). After 5 days of mobilization treatment, PBSCs were collected by LVL with Fenwal CS-3000 Plus (Baxter Co, USA). In LVL, heparin was administered in addition to ACD-A. Patients underwent of LVL procedures daily to obtain a target cell dose of >or= 4x10(8)/kg MNCs and >or= 6x10(6)/kg CD34+ cells. RESULTS: 66 LVL procedures were done on 40 donors. Of these donors, 31 (77.5%) reached the collection target with one leukapheresis. The product per LVL contained a mean 5.79+/-2.47 10(8)MNCs/kg and 11.6+/-10.62x10(6) CD34+ cells/kg respectively. Mean percentages of MNC were 79.88+/-22.15% and collection efficiencies of MNCs were inversely related to the starting MNC count (r=-0.536, P<0.001). After LVL, although none of the donors exhibited bleeding complications, platelets decreased from 187.4+/-52.68x10(3)/microL to 74.88+/-13.7x10(3)/microL and activated partial thromboplastin time (APTT) prolonged from 29.13+/-3.77 seconds to 67.51+/-54.26 seconds. CONCLUSION: We conclude that LVL after mobilization treatment with G-CSF and GM-CSF in normal healthy donors was tolerable and efficient methods for PBSCs collection, but long-term risk of adverse effects in normal donors needs to be carefully addressed by individual institutions as well as national and international registries.