Blood stem cell procurement: donor safety issues

Allogeneic transplantation of rhG-CSF-mobilized peripheral blood stem cells (PBSCs) is now being increasingly performed, but safety considerations for hematologically normal PBSC donors have not been fully addressed. Experience in this area is rapidly accumulating, however, and on the basis of currently available data, a consensus is gradually emerging on several issues: (1) rhG-CSF treatment and PBSC collection seem to have an acceptable short-term safety profile in normal donors. There is a need for continued safety monitoring, however. (2) rhG-CSF doses up to 10 microg/kg/day show a consistent dose-response relationship with the mobilization (and collection) of CD34+ progenitor cells, and this dose is acceptable for routine clinical use. Whether higher doses are superior (or cost-effective) remains to be determined, and they may produce more severe side-effects. The potential risks of marked leukocytosis (arbitrarily defined as a leukocyte count of more than 70 x 10(9)/l) have been a concern, and rhG-CSF dose reduction is performed by many centers to maintain leukocyte counts below this level. (3) Transient post-donation cytopenias, involving granulocytes, lymphocytes and platelets, may occur and are at least partly related to the leukapheresis procedure. These are generally asymptomatic and self-limited; follow-up blood counts are not necessarily required. Reinfusion of autologous platelet-rich plasma should be considered for donors with expected post-donation thrombocytopenia (platelet count <80-100 x 10(9)/l). (4) Donors should meet the eligibility criteria which apply to donors of apheresis platelets, with the exception that pediatric (as well as elderly) donors may also be considered. There is insufficient information at this time to clearly establish definite contraindications for PBSC collection in a hematologically normal donor. Potential contraindications include the presence of inflammatory, autoimmune or rheumatologic disorders, as well as atherosclerotic or cerebrovascular disease. (5) The creation of an International PBSC Donor Registry is desirable to facilitate monitoring the long-term effects of the procedure. Individual institutions or donor centers are encouraged to establish their own PBSC donor follow-up system, preferably with a standardized approach to data collection.