ALLOGENEIC BLOOD STEM-CELL TRANSPLANTATION - CONSIDERATIONS FOR DONORS

Allogeneic transplantation of cytokine-mobilized peripheral blood stem cells (PBSCs) is now being increasingly performed, but safety conside rations for hematologically normal PBSC donors have not been fully add ressed. Progenitors are generally mobilized for collection from normal donors using recombinant human granulocyte colony-stimulating factor (rhG-CSF). Although the short-term safety profile of rhG-CSF seems acc eptable, experience remains limited and its optimal dose and schedule have not been defined. Minimal data exist regarding long-term safety o f rhG-CSF, primarily derived from experience in patients with chronic neutropenia or cancer. An ''ad hoc'' workshop was recently convened am ong a group of investigators actively involved in the field of allogen eic stem cell transplantation to discuss the safety issues pertaining to normal PBSC donors. There was agreement on the following points: (1 ) On the basis of available data, it appears that rhG-CSF treatment an d PBSC collection have an acceptable short-term safety profile in norm al donors. However, the need for continued safety monitoring was recog nized. (2) rhG-CSF doses up to 10 mu g/kg/d show a consistent dose-res ponse relationship with the mobilization (and collection) of CD34(+) p rogenitor cells, and this dose is acceptable for routine clinical use. Whether higher doses are superior (or cost effective) remains to be d etermined, and they may produce more severe side effects. The potentia l risks of marked leukocytosis (arbitrarily defined as a leukocyte cou nt of more than 70 x 10(9)/L) have been a concern, and rhG-CSF dose re duction is performed by many centers to maintain leukocyte counts belo w this level. (3) Transient post donation cytopenias, involving granul ocytes, lymphocytes, and platelets, may occur and are at least partly related to the leukapheresis procedure. These are generally asymptomat ic and self-limited; follow-up blood counts are not necessarily requir ed. Reinfusion of autologous platelet-rich plasma should be considered for donors with expected postdonation thrombocytopenia (platelet coun t < 80 to 100 x 10(9)/L). (4) Donors should meet the eligibility crite ria which apply to donors of apheresis platelets, with the exception t hat pediatric donors may also be considered. Any deviation from these criteria should have supporting documentation. There is insufficient i nformation at this time to clearly establish definite contraindication s for PBSC collection in a hematologically normal donor. Potential con traindications include the presence of inflammatory, autoimmune, or rh eumatologic disorders, as well as atherosclerotic or cerebrovascular d isease. (5) The creation of an International PBSC Donor Registry is de sirable to facilitate monitoring the long-term effects of the procedur e. Individual institutions or donor centers are encouraged to establis h their own PBSC donor follow-up system, preferably with a standardize d approach to data collection. (C) 1997 by The American Society of Hem atology.