Cryopreservation of red blood cells: effect of freezing on red cell quality and residual lymphocyte immunogenicity.
OBJECTIVE
To investigate treatment with glycerol/washing as a potential substitute for freeze-thawing in the production of leucocyte depleted red cell concentrates for patients with a history of non-haemolytic reactions following transfusion.


METHODS
The standard procedure of treatment with glycerol/-80 degrees C freezing/thawing/washing was compared with a similar procedure in which freezing was omitted. The quality of the resulting red cell products was assessed in relation to: (1) standard red cell biochemical parameters; (2) leucocyte and lymphocyte subset composition using flow cytometry with fluorescent labelled monoclonal antibodies; and (3) immunogenicity of the residual lymphocytes in mixed lymphocyte culture.


RESULTS
Compared with red cells subjected to the standard freeze-thaw technique, red cells undergoing the non-freezing procedure and suspended in additive solutions had significantly better biochemical preservation after 21 days of storage (p < 0.001). Both procedures removed an average 98% of the initial leucocytes at the expense of 18-20% of the red cells. The non-freezing procedure resulted in higher residual concentrations of HLA class II bearing lymphocytes (p < 0.01), but not higher numbers of dendritic cells. Both procedures were equally effective in annulling the residual lymphocytes' ability to act as stimulator cells in one-way mixed lymphocyte culture.


CONCLUSIONS
The non-freezing procedure produces a superior product for the provision of red cells to patients with granulocyte antibodies. These products may also offer a lower risk of HLA alloimmunisation to previously unexposed patients.
Farrugia
A
A
Red Cross Blood Bank, South Melbourne, Australia.
Shea
N
N
Knowles
S
S
Holdsworth
R
R
Piouronowski
H
H
Portbury
D
D
Romeo
A
A
D001793:Blood Preservation / Q000379:methods*; D015925:Cryopreservation; D003713:Dendritic Cells; D004912:Erythrocytes; D005990:Glycerol; D006454:Hemoglobins / Q000032:analysis; D000949:Histocompatibility Antigens Class II / Q000097:blood; D006801:Humans; D007958:Leukocyte Count; D016131:Lymphocyte Subsets; D011188:Potassium / Q000097:blood
D006454:Hemoglobins; D000949:Histocompatibility Antigens Class II; D005990:Glycerol; D011188:Potassium