title: Biochemical and cellular changes in leukocyte-depleted red blood cells stored for transfusion.
abstract: BACKGROUND
  To evaluate biochemical and cellular changes associated with the storage of leukocyte-depleted red blood cells (RBCs).
  
  
  METHODS
  We investigated 10 leukocyte-depleted RBC units, randomly chosen from volunteer donors. Every week an aliquot was collected for laboratorial evaluation, which included complete cell blood count, glucose-6-phosphate dehydrogenase (G6PD) activity, extracellular sodium, potassium and pH, membrane-bound hemoglobin (MBH), band 3 profile, and quantification of RBC membrane proteins composition.
  
  
  RESULTS
  We observed an increase in mean cell volume (from 91.86 ± 4.65 fl to 98.10 ± 5.80 fl, day 0 vs. day 21; p < 0.05), red cell distribution width, percentage of macrocytic RBCs, reticulocyte hemoglobin content and a decreased percentage of microcytic RBCs, mean cell volume concentration and G6PD activity. The extracellular concentration of sodium decreased, and that of potassium increased significantly over time. RBC membrane composition revealed an increase in spectrin/ankyrin ratio after 21 days (from 4.84 ± 0.99 to 5.27 ± 0.94, day 0 vs. day 21; p < 0.05). At day 35, a decrease in ankyrin (from 6.44 ± 1.70% to 5.49 ± 1.96%, day 0 vs. day 35; p < 0.05), in protein 4.1/band 3, protein 4.2/band 3, and ankyrin/band 3 ratios and in band 5 was observed.
  
  
  CONCLUSIONS
  Our data show that leukocyte-depleted RBCs present changes in the RBC morphology, membrane protein composition, enzymatic activity, and extracellular electrolyte concentration and pH.
authors.affiliation: Serviço de Patologia Clínica, Laboratório de Hematologia, Centro Hospitalar S. João, Porto, Portugal.
authors.forename: Diana
authors.initials: D
authors.lastname: Nogueira
authors.affiliation: Departamento de Ciências Biológicas, Laboratório de Bioquímica, Faculdade Farmácia, Universidade do Porto, Porto, Portugal ; UCIBIO @ REQUIMTEUniversidade do Porto, Porto, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Rocha
authors.affiliation: Serviço de Imunohemoterapia, Centro Hospitalar S. João, Porto, Portugal.
authors.forename: Estela
authors.initials: E
authors.lastname: Abreu
authors.affiliation: Departamento de Ciências Biológicas, Laboratório de Bioquímica, Faculdade Farmácia, Universidade do Porto, Porto, Portugal ; UCIBIO @ REQUIMTEUniversidade do Porto, Porto, Portugal.
authors.forename: Elísio
authors.initials: E
authors.lastname: Costa
authors.affiliation: Departamento de Ciências Biológicas, Laboratório de Bioquímica, Faculdade Farmácia, Universidade do Porto, Porto, Portugal ; UCIBIO @ REQUIMTEUniversidade do Porto, Porto, Portugal.
authors.forename: Alice
authors.initials: A
authors.lastname: Santos-Silva
keywords: Leukocyte depletion; Membrane proteins; RBC; Red cell aging; Transfusion