Bi-phasic CD34+ cell mobilization of a syngeneic donor during prolonged G-CSF delivery.

Abstract

G-CSF administration over 10 days and neutrophil cytapheresis have been reported in the literature, but the kinetics of CD34+ cells in this situation is unclear. A 42-year-old female underwent syngeneic transplantation for metastatic breast cancer. The recipient was in critical condition peri-transplant, therefore the donor received G-CSF for 13 days, during which eight cytaphereses for both PBPC and neutrophils were performed. Two peaks in CD34+ cells were noted; the first on Day 5 and the second on Days 10-13 of G-CSF administration; a total of 11.6 x 10(6)/kg CD34+ cells and 38.11 x 10(8)/kg neutrophils were infused. The recipient's ANC exceeded 0.1 x 10(9)/L on Day +3. To our knowledge, this is the longest reported cytapheresis of CD34+ cells from a normal donor The bi-phasic pattern in the cytapheresis product is also of interest. It is an unusual pattern that suggests a profound and complicated alteration in the marrow progenitor cell pool. If substantiated, this finding may offer an alternative cytapheresis schedule for donors.