Increased transmigration of G-CSF-mobilized peripheral blood CD34+ cells after overnight storage at 37 degrees C

G-CSF-mobilized PBPCs are utilized in allogeneic and autologous PBPC transplants. Homing, adhesion, and transmigration of hematopoietic CD34+ cells are required for successful engraftment. Hematopoietic CD34+ cells undergo directional migration toward the CXCR4 receptor ligand stromal-derived factor-1 (SDF-1). Limited data are available on the effects of liquid storage and cryopreservation on PBPC CD34+ cells.

Magnetic-assisted cell sorting (MACS)-selected CD34+ cells were assayed for retention of in vitro transmigration and phenotypic changes of unit-matched liquid-stored and cryopreserved PBPC samples from healthy donors. Studies evaluated whether transmigration of CD34+ cells in Iscove's modified Dulbecco's medium plus 1 percent HSA alone or in medium supplemented with SCF or allogeneic plasma was affected by overnight incubation at 37 degrees C, relative to nonincubated conditions.

Transmigration was maintained during liquid storage at 1 to 6 degrees C during a 2-day period and in unit-matched cryopreserved-thawed samples that had been initially liquid stored. Overnight incubation at 37 degrees C of MACS-selected unit-matched liquid-stored or cryopreserved-thawed CD34+ cells resulted in substantially increased transmigration, in particular with noncoated filters chemoattracted with the chemokine SDF-1.

CD34+ cell transmigration was comparable between liquid-stored and cryopreserved samples, and both demonstrated similar increases after overnight incubation at 37 degrees C.