title: Cryopreservation of mononuclear cells before extracorporeal photochemotherapy does not impair their anti-proliferative capabilities.
abstract: 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.
authors.affiliation: CHU Clermont-Ferrand, Centre Régional de Cancérologie et Thérapie Cellulaire Pédiatrique, Hôtel-Dieu, Clermont-Ferrand, France. e_merlin@chu-clermontferrand.fr
authors.forename: Etienne
authors.initials: E
authors.lastname: Merlin
authors.forename: Dalil
authors.initials: D
authors.lastname: Hannani
authors.forename: Richard
authors.initials: R
authors.lastname: Veyrat-Masson
authors.forename: Jacques
authors.initials: J
authors.lastname: Chassagne
authors.forename: Fraçoise
authors.initials: F
authors.lastname: Gabert
authors.forename: Marc
authors.initials: M
authors.lastname: Berger
authors.forename: François
authors.initials: F
authors.lastname: Deméocq
authors.forename: Joël
authors.initials: J
authors.lastname: Plumas
authors.forename: Justyna
authors.initials: J
authors.lastname: Kanold
mesh_terms: 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*
chemical_list: D005452:Fluoresceins