E. Cabezudo et al., Leukapheresis components may be cryopreserved at high cell concentrations without additional loss of HPC function, TRANSFUSION, 40(10), 2000, pp. 1223-1227
BACKGROUND: The aim of this study was to assess the feasibility of freezing
mobilized peripheral blood progenitor cell (PBPC) components at higher cel
l concentrations than are classically recommended for bone marrow. This app
roach might have potential benefits, such as lower cost of processing and s
torage and less risk of the complications associated with the transfusion o
f large component volumes and large quantities of DMSO.
STUDY DESIGN AND METHODS: In the first phase, small aliquots of 19 apheresi
s components were cryopreserved at standard and higher cell concentrations
(Aliquots A and B, respectively). In the second phase, 21 apheresis compone
nts were split into two bags each and frozen at standard (Bag A) and high (
Bag B) cell concentrations. The differences in viability, cloning efficienc
y, and nucleated cell recovery in Bags A and B were examined. Finally, the
hematologic recovery of 10 patients who underwent autologous transplantatio
n with PBPC components frozen at high cell concentrations was analyzed.
RESULTS: The median cell concentration at freezing was 94 (57-100) x 10(6)
per mL and 291 (220-467) x 10(6) per mi for Aliquots A and B, respectively,
and 90.9 (45.4-92) x 10(6) per mi and 332 (171-582) x 10(6) per mt for Bag
s A and B, respectively. The viability was significantly lower in samples f
rozen at higher cell concentrations: 92 versus 83 percent (p = 0.001) and 8
7 versus 77 percent (p<0.001) for Aliquots and Bags A and B, respectively.
Significant differences were not observed in the recovery of total nucleate
d cells (102 vs. 101% and 98 vs. 105%) or the cloning efficiency after thaw
ing (13 vs. 16% and 27 vs. 23%) for Aliquots and Bags A and B, respectively
. The time to granulocyte engraftment greater than or equal to 0.5 x 10(9)
per L and platelet engraftment greater than or equal to 20 x 10(9) per L wa
s 9 (8-11) and 10.5 (7-21) days, respectively.
CONCLUSION: The cryopreservation of PBPC components at standard concentrati
ons and 3.3 (1.8-6.2)-fold cell concentrations has no adverse effect on the
function of HPCs after thawing.