Freezing human platelets with 6 percent dimethyl sulfoxide with removal of the supernatant solution before freezing and storage at -80 degrees C without postthaw processing.
BACKGROUND
Platelets (PLTs) can be frozen with 6 percent dimethyl sulfoxide (DMSO) at -80 degrees C for up to 2 years. This method has been modified by concentrating the PLTs and removing the supernatant before freezing.


METHODS
High-yield leukoreduced PLTs stored at 22 degrees C for up to 5 days were divided into three equal volumes: one was frozen with 6 percent DMSO at -80 degrees C, thawed, washed, and resuspended in plasma (old method with DMSO); the second was treated with 6 percent DMSO, concentrated to remove the supernatant DMSO, frozen at -80 degrees C, thawed, and diluted with 0.9 percent NaCl (new method with DMSO); and the third was treated with 0.9 percent NaCl without DMSO, concentrated to remove the supernatant solution, frozen at -80 degrees C, thawed, and diluted with 0.9 percent NaCl (new method without DMSO).


RESULTS
Freeze-thaw-wash recovery of PLTs frozen by the old method with DMSO was 74 +/- 2 percent with 5 percent PLT microparticles. Freeze-thaw recovery was 94 +/- 2 percent with 7 percent PLT microparticles (new method with DMSO) and 69 +/- 9 percent with 15 percent PLT microparticles (new method without DMSO). Total DMSO in washed PLTs was 400 and 600 mg in PLTs concentrated before freezing. In vivo recovery of PLTs frozen by the new method with DMSO and transfused into normal volunteers was 30 percent and the life span was 7 days.


CONCLUSIONS
Concentrating PLTs before freezing simplified the procedure by eliminating postthaw washing. PLTs frozen by this method had more PLTs with reduced GPIb and increased annexin V binding than those frozen by the old method.
Valeri
C Robert
CR
Naval Blood Research Laboratory, Boston, MA 02118, USA. navblood@nbrl.org
Ragno
Gina
G
Khuri
Shukri
S
D000094902:Blood Banking / Q000379:methods; D001792:Blood Platelets / Q000166:cytology* / Q000187:drug effects; D001793:Blood Preservation / Q000379:methods*; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents; D004121:Dimethyl Sulfoxide; D005615:Freezing; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010976:Platelet Count; D010983:Plateletpheresis
D003451:Cryoprotective Agents; D004121:Dimethyl Sulfoxide