FACTORS INFLUENCING YIELDS OF PROGENITOR CELLS FOR ALLOGENEIC TRANSPLANTATION - OPTIMIZATION OF G-CSF DOSE, DAY OF COLLECTION, AND DURATIONOF LEUKAPHERESIS

Mobilization of hematopoietic progenitor cells by G-CSF was attempted on 89 occasions in 85 healthy donors. Three dose ranges of G-CSF were chosen for analysis: low (4-7.4 mu g/kg), intermediate (7.5-10 mu g/kg ) and high (>10 mu g/kg). A target blood level for apheresis of 20 x 1 0(6)/L CD34+ cells was reached by day 3 in 75 patients (84%) and by da y 4 in all but 1 (99%). Target yields above 2.5 x 10(6)/kg for 75 unma nipulated transplants were exceeded in a single collection in 73 donor s (97%). Correlation of CD34+ cell yields to blood CD34+ cell level be fore leukapheresis was moderate only (r(2) = 0.32). There was close li near correlation between processed volume and cumulative CD34+ cell yi eld, with a median r(2) value of 0.98 (range 0.74-1.00). Yields of CD3 4+ cells achieved on day 3 were significantly lower after the high dos e than after the intermediate G-CSF dose (21 +/- 3 versus 29 +/- 6 x 1 0(6)/L blood processed, p = 0.03). After the low dose of G-CSF, yields on day 4 were higher than on day 3 (48 +/- 10 versus 22 +/- 4 x 10(6) /L blood processed, p = 0.01). There was no difference between day 3 a nd day 4 yields with the intermediate G-CSF dose. In 73 of 93 (78%) le ukaphereses, the CD34+ cell yield was more than 100% of the estimated intravascular CD34+ cells at the beginning of collection and ranged up to 342%. These data indicate that a daily dose of 7.5-10 mu g/kg G-CS F, given as a multiple of 300 and 480 mu g ampoules, is a convenient r egimen giving adequate yields from a single collection on day 3 or 4 i n most donors. Measuring blood CD34+ cell levels is of limited value i n predicting yields, but monitoring CD34+ cell yields during leukapher esis may help to minimize unnecessary or inefficient collection.