Long‐term cryopreservation of red cells from patients with sickle cell disease

Twelve units of red cells (RBCs) from patients with sickle cell disease were glycerolized and frozen for periods of 1 to 3 years. The freeze-thaw hemolysis (mean 11.6% +/- 2.1% SEM) and in vitro process recovery (mean 74.4% +/- 3.7% SEM) were similar to those of sickle RBCs frozen for shorter periods of time. There was a weak positive correlation between duration of frozen storage and cell losses during deglycerolization. The adenosine triphosphate and 2,3-diphosphoglycerate levels of the thawed RBCs were within an acceptable range (mean 3.4 +/- 0.2 mumol/g Hb and 18.0 +/- 0.8 mumol/g Hb, respectively). Long-term cryopreservation of sickle (Hb SS) RBCs opens the possibility of exploring autologous transfusion to treat sickle cell disease patients during anemic episodes that are not due to sickling.