Cryopreservation of mononuclear cells before extracorporeal photochemotherapy does not impair their anti-proliferative capabilities.
OBJECTIVE
The clinical benefits of extracorporeal photochemotherapy (ECP) are well recognized, but its clinical use is limited by logistical difficulties, especially because of the need to perform repeated aphereses. The cryopreservation of mononuclear cells could allow maintenance of the ECP schedule while reducing the number of aphereses. The aim of this work was to assess whether previous cryopreservation impairs the immunomodulatory function of ECP-treated peripheral blood mononuclear cells (PBMC).


METHODS
Fresh or previously cryopreserved PBMC were exposed to ECP and added on day 0 into a mixed leukocyte reaction. Proliferation of alloreactive lymphocytes was measured by carboxyfluorescein succinimidyl ester (CFSE) dye dilution. Apoptosis was quantified by annexin-7AAD staining.


RESULTS
ECP-induced apoptosis was slightly increased in cryopreserved cells but the kinetics of apoptosis were similar to fresh cells. Lymphocytes stimulated in the presence of ECP-treated PBMC displayed a significant decrease in proliferation. The suppression was enforced when ECP-treated cells had been activated previously by allogeneic stimulation. Cryopreservation before ECP exposure did not impact apoptosis triggering or anti-proliferative properties of ECP-treated cells.


CONCLUSIONS
Cryopreservation before ECP does not impair the immunomodulatory effects of treated cells. These data warrant investigation of the clinical use of cryopreserved PBMC for ECP.
Merlin
Etienne
E
CHU Clermont-Ferrand, Centre Régional de Cancérologie et Thérapie Cellulaire Pédiatrique, Hôtel-Dieu, Clermont-Ferrand, France. e_merlin@chu-clermontferrand.fr
Hannani
Dalil
D
Veyrat-Masson
Richard
R
Chassagne
Jacques
J
Gabert
Fraçoise
F
Berger
Marc
M
Deméocq
François
F
Plumas
Joël
J
Kanold
Justyna
J
D017209:Apoptosis; D049109:Cell Proliferation; D002470:Cell Survival; D015925:Cryopreservation; D005452:Fluoresceins; D006801:Humans; D056747:Immunomodulation; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D008214:Lymphocytes; D017893:Photopheresis / Q000379:methods*
D005452:Fluoresceins