title: Gravity sedimentation of granulocytapheresis concentrates with hydroxyethyl starch efficiently removes red blood cells and retains neutrophils.
abstract: BACKGROUND
  Transfusion of granulocytapheresis concentrates can be limited by the volume of incompatible donor red blood cells (RBCs) in the component. Efficient reduction of RBCs in granulocyte units would result in safe transfusion of RBC-incompatible units.
  
  
  METHODS
  Granulocyte concentrates were collected by continuous-flow apheresis from granulocyte-colony-stimulating factor (G-CSF) and dexamethasone-stimulated volunteer donors, with 6% hydroxyethyl starch (HES) added continuously during apheresis as a RBC sedimenting agent to enhance granulocyte collection efficiency. After collection, the component was placed in a plasma extractor for 4 hours. A sharp line of demarcation between the starch-sedimented RBCs and the granulocyte-rich supernatant developed, and the supernatant was transferred to a sterilely docked transfer pack. RBC reduction and white blood cell recovery were determined.
  
  
  RESULTS
  Gravity sedimentation was performed on 165 granulocyte concentrates. Mean sedimentation time was 267 minutes (range, 150-440 min). RBC depletion was 92% (range, 71%-99%) with mean residual RBC content of 3.2 +/- 1.4 mL. Twelve percent of components contained less than 2 mL of RBCs. Mean granulocyte and platelet (PLT) recoveries were 80 and 81%, respectively. There were no transfusion reactions or signs of hemolysis after transfusion of 66 RBC-incompatible granulocyte concentrates (RBC volume, 1.6-8.2 mL). The remaining concentrates were used for topical or intrapleural applications.
  
  
  CONCLUSIONS
  RBCs were significantly reduced and granulocytes and PLTs effectively retained in G-CSF/steroid-mobilized granulocyte components collected with HES and processed by gravity sedimentation. This procedure allows safe transfusion of RBC-incompatible sedimented granulocyte units and may be used to expand the pool of available granulocyte donors for specific recipients.
authors.affiliation: Department of Transfusion Medicine, Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland 20892-1184, USA. bryantb2@cc.nih.gov
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Bryant
authors.forename: Yu Ying
authors.initials: YY
authors.lastname: Yau
authors.forename: Phyllis J
authors.initials: PJ
authors.lastname: Byrne
authors.forename: David F
authors.initials: DF
authors.lastname: Stroncek
authors.forename: Susan F
authors.initials: SF
authors.lastname: Leitman
mesh_terms: D001782:Blood Donors; D004912:Erythrocytes / Q000166:cytology*; D006112:Gravitation; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000737:chemistry*; D007937:Leukapheresis; D017708:Leukocyte Transfusion; D009504:Neutrophils / Q000166:cytology*; D010952:Plasma Substitutes / Q000737:chemistry*
chemical_list: D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes