RESUMEN
Objective To study the influences of long-term cryopreservation on nucleated cell viability,colony-form- ing units-granulocyte-macrophage(CFU-GM)-forming capability and Lymphocyte immune-phenotypes of pe- ripheral blood hematopoietic stem/progenitor cell(HS/PC)collections.Methods Fresh samples(n=12)were as control,frozen samples were divided into two groups:group 1(cryopreserved for 3-5 years,n=26)and group 2 (cryopreserved for 5-7 years,n=9).Flow cytometry(FCM)method based on 7 AAD or caspase-3staining was ap- plied to assess the degree of cell necrosis or apoptosis in cryopreserved and red-cell lytic collection samples.Lympho- cyte immune-phenotypes(CD3/CD4/CD8/CD19/CD16+56,CD4/CIM5RA/CIMSRO,CD8/CD28)were also de- tected by FCM.CFU-GM culture was done to study the hematopoietic activity.Results Percentages of necrosis and apoptosis cells of the control were both less than the groupl and group2(P