Cytokine administration to normal apheresis donors

Allotransplantation of cytokine-mobilized peripheral blood stem cells (PBSCs) and granulocyte transfusions are now being increasingly performed, with rhG-CSF being the cytokine most commonly employed. Safety and efficacy issues related to the use of cytokines in normal apheresis donors have not been fully addressed, although experience in this area is accumulating. A consensus has gradually built up over the following points. 1) rhG-CSF treatment and PBSC/granulocyte collection seem to have an acceptable short- term safety profile in normal donors, with adverse events largely limited to self-limiting bone pain, headache, fatigue and myalgias. The need for continued safety monitoring is recognized, however. 2) rhG-CSF doses up to 10 mg/kg/day (for 3-5 days) show a consistent dose-response relationship with the mobilization/collection of CD34+ progenitor cells. Whether higher doses are superior (or cost-effective) is unclear, and they may produce more severe side effects. The potential risks of marked leucocytosis (arbitrarily defined as a WBC count > 70 x 10⁹/L) have been a concern, and rhG-CSF dose reduction is often performed to maintain WBC counts below this level. 3) Transient post-donation cytopenias, involving granulocytes, lymphocytes and platelets, may occur and are at least partly related to the leucapheresis procedure. These are generally asymptomatic and self-limited. Reinfusion of autologous platelet-rich plasma should be considered for donors with expected post- donation thrombocytopenia (platelet count < 80-100 x 10⁹/L). 4) Donors should generally meet the eligibility criteria for plateletpheresis donors, and paediatric donors may also be considered. Any deviation from these criteria should have appropriate documentation. 5) There is insufficient information at this time to clearly establish definite contraindications for PBSC collection in a haematologically normal donor. Donor age itself should not necessarily be a contraindication to PBSC donation. 6) The creation of an International PBSC Donor Registry is desirable to facilitate monitoring the long-term effects of the procedure.