LARGE-VOLUME LEUKAPHERESIS MAXIMIZES THE PROGENITOR-CELL YIELD FOR ALLOGENEIC PERIPHERAL-BLOOD PROGENITOR DONATION

We have investigated the efficiency and safety of large volume leukaph eresis (LVL) for the collection of granulocyte colony-stimulating fact or (G-CSF)-mobilized peripheral blood progenitor cells (PBPCs) from he althy donors. In six apheresis sessions in four healthy individuals on a COBE-BCT Spectra(TM) cell separator (median processed volume 3.5 x total blood volume, TBV, range 3.3-4.4 x TBV), harvested cells were co llected sequentially into three single bags. The collection bags were changed after processing 33%, 66%, and 100% of the prospective apheres is volume, allowing analysis of PBPCs collected at different periods d uring one harvest. Mononuclear cells (MNCs), CD34+ cells, CD34+ subset s, and lymphocyte subsets were determined in each bag. Substantially m ore PBPCs were harvested than were in the circulation before G-CSF adm inistration preceding LVL (median 171%, range 69-267%), reflecting pro genitor release during the procedure. In donors 1 and 3, the CD34+ cel l yields decreased in the third bag to 53% and 42% of that collected i n the first bag, whereas the progenitor cell yields in donors 2 and 4 were stable or rose during the procedure, achieving in the third bag 1 57% and 105% of the number of CD34+ cells collected in the first bag. Minor changes were found in the subsets of CD34+ cells, lymphocytes, a nd monocytes collected at different periods during a single harvest. L VL was well tolerated. Reversible thombocytopenia developed in all cas es. No late effects attributable to LVL or G-CSF were found in the 4 d onors and 16 other healthy individuals who have undergone LVL in our i nstitution. We conclude that LVL is safe and maximizes PBPC yields for allogeneic transplantation.