Background: Cryopreservation, a common method for storing human cells, has advantages when cells are used in retrospective studies of selected cell populations. Frozen lymphocytes can be used for tissue typing, for monitoring cell-mediated immunity, and for various immunological tests. Our report describes an efficient, simple and inexpensive method for cryopreservation of human acute leukemia cells.
Methods: Leukemia cells from 20 newly diagnosed cases were frozen at -80 degrees C after cryopreservation with 5% dimethysulfoxide and then assayed by flow cytometry for antigen expression determined by monoclonal antibodies at different time intervals.
Results: All cases had viability above 75% at presentation. After 4 weeks, 91% of pre-B ALL, 88% of T-ALL, 100% of AML, and 100% of biphenotypic aliquots had viability over 75%. Viability continued to be reliably above 75% at 6 weeks from cryopreservation.
Conclusion: We confirm that the method does not significantly alter the viability of cells and it preserved the antigenic expression of leukemia cells.