A total of 33 leukaphereses were performed with the IBM continuous flow
centrifuge on 28 normal healthy donors for the purpose of obtaining increased yields
of granulocytes for infusion into leukopenic recipients. The pretreatment of donors within
a 10- to 12-hour period prior to pheresis with a double dose of dexamethasone and the
addition of hydroxyethyl starch to the input line of the continuous flow centrifuge,
significantly increased the total quantity and efficiency of granulocyte collected as compared
to a donor group receiving a single dose of dexamethasone in addition to hydroxyethyl
starch. A mean of 25.5 x 10^9 total granulocytes were collected in addition to an
efficiency of 2.11 x 10^9 granulocytes harvested per liter of blood processed in the doubledose-
treated donors, in contrast to 19.6 x 10^9 total granulocytes collected and an efficiency
of 1.82 x 10^9 granulocytes harvested per liter of blood processed in the single dose donor
group. The results of the present study demonstrate that elevated quantities of granulocytes
can be collected from normal donors by scheduling a double dose of dexamethasone prior
to the pheresis procedure.