title: Cryopreservation of red blood cells: effect of freezing on red cell quality and residual lymphocyte immunogenicity.
abstract: 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.
authors.affiliation: Red Cross Blood Bank, South Melbourne, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Farrugia
authors.forename: N
authors.initials: N
authors.lastname: Shea
authors.forename: S
authors.initials: S
authors.lastname: Knowles
authors.forename: R
authors.initials: R
authors.lastname: Holdsworth
authors.forename: H
authors.initials: H
authors.lastname: Piouronowski
authors.forename: D
authors.initials: D
authors.lastname: Portbury
authors.forename: A
authors.initials: A
authors.lastname: Romeo
mesh_terms: 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
chemical_list: D006454:Hemoglobins; D000949:Histocompatibility Antigens Class II; D005990:Glycerol; D011188:Potassium