title: Effect of storage of red blood cells on alloimmunization.
abstract: BACKGROUND
  Red blood cells (RBCs) undergo changes during storage. Various studies have suggested a higher risk of adverse and often multifactorial clinical outcomes associated with older-stored RBCs. Our aim therefore was to examine if storage of transfused RBCs is also associated with the risk of RBC-specific alloantibody formation.
  
  
  METHODS
  A two-center retrospective case-referent study was performed where case patients and control subjects were sampled from all consecutive patients who had received their first and subsequent RBC transfusions in one of the two centers only. Cases were defined as patients who developed a first RBC alloantibody. Control subjects were patients without detectable RBC alloantibodies, who were matched to the case patients regarding number of RBC transfusions. Binary logistic regression analysis was used to examine the association between storage time of RBCS and the occurrence of alloimmunization.
  
  
  RESULTS
  A total of 144 cases and 286 controls were selected for our study, who had received a total 5478 RBC units. Comparing patients receiving units stored shorter than a certain number of days versus older units (with various storage periods up to 4 weeks) did not reveal an association or a trend between alloimmunization risk and storage time categories.
  
  
  CONCLUSIONS
  Our findings suggest that storage times of transfused RBCs between 1 and 4 weeks do not affect the risk of alloimmunization.
authors.affiliation: Center for Clinical Transfusion Research, Sanquin Blood Supply, Leiden, The Netherlands; Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands; Jon J. van Rood Center for Clinical Transfusion Research, Leiden University Medical Center, Leiden, The Netherlands; Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands; Blood Transfusion, Pediatric and Point of Care, Clinical Chemistry and Hematology Laboratory, University Medical Center Utrecht, Utrecht, The Netherlands; Puget Sound Blood Center Research Institute, Seattle, Washington.
authors.forename: Saurabh
authors.initials: S
authors.lastname: Zalpuri
authors.forename: Henk
authors.initials: H
authors.lastname: Schonewille
authors.forename: Rutger
authors.initials: R
authors.lastname: Middelburg
authors.forename: Leo
authors.initials: L
authors.lastname: van de Watering
authors.forename: Karen
authors.initials: K
authors.lastname: de Vooght
authors.forename: James
authors.initials: J
authors.lastname: Zimring
authors.forename: Johanna G
authors.initials: JG
authors.lastname: van der Bom
authors.forename: Jaap Jan
authors.initials: JJ
authors.lastname: Zwaginga
mesh_terms: D000328:Adult; D000368:Aged; D001793:Blood Preservation; D017707:Erythrocyte Transfusion / Q000009:adverse effects*; D004912:Erythrocytes / Q000502:physiology*; D005260:Female; D006801:Humans; D007518:Isoantibodies / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D007518:Isoantibodies