Evaluation of solutions for the storage of granulocyte colony-stimulating factor-mobilized granulocyte concentrates

High cell counts in granulocyte colony-stimulating factor (G-CSF)-mobilized granulocytes are detrimental to concentrate storage. An eightfold dilution with autologous plasma improves storage, but this method is impractical. The purpose of this study was to identify an infusible solution that could be used in place of autologous plasma to dilute and store granulocytes.

Granulocytes collected from donors given dexamethasone (8 mg per os) and/or G-CSF (5 micrograms/kg subcutaneously [SQ]) were diluted eightfold in the following cell culture media: X-Vivo 10, Dulbecco's modified Eagle's minimal essential medium (DMEM) or Iscoves modified Dulbecco's medium (IMDM); or in the following infusible solutions: Plasma-Lyte A; Normosol R; lactated ringers, supplemented with 1% human serum albumin and 50 mM histidine (LRAH); or Plasma-Lyte A supplemented with 50 mM histidine buffer or 25 mM HEPES buffer plus 1% human serum albumin. The granulocytes were stored for 48 h at room temperature. White blood cell (WBC) counts, WBC viability and pH were measured after approximately 2 h, 24 h and 48 h of storage.

Cell counts, viability and pH were maintained after 2 h, 24 h and 48 h in cells stored in the three cell culture media. The pH fell slightly after 48 h to 6.86 +/- 0.10 in granulocyte concentrates diluted in LRAH, but fell to a greater extent after 24 h and 48 h, to 6.36 +/- 0.23 (48-h value) in granulocyte concentrates diluted in Plasma-Lyte A and to 6.40 +/- 0.19 (48-h value) in granulocyte concentrates diluted in Normosol R. The cell counts of concentrates diluted in LRAH were stable for 48 h, but fell in granulocyte concentrates stored in Plasma-Lyte A and Normosol R. Plasma-Lyte A supplemented with histidine maintained the pH of diluted granulocyte concentrates better than Plasma-Lyte A supplemented with HEPES; 6.91 +/- 0.10 and 6.65 +/- 0.11, respectively, after 24 h. Cell counts were maintained best in granulocyte concentrates diluted in Plasma-Lyte A supplemented with albumin and one or both of the buffers.

Culture media were best for granulocyte storage, but they are not approved for in vivo use. Infusible solutions are not buffered adequately and lack sufficient protein, but infusible solutions, such as lactated Ringer's solution or Plasma-Lyte A supplemented with buffers and albumin, hold promise as effective and licensable solutions for granulocyte storage.