title: The effect of gamma irradiation on the quality of apheresis platelets during storage for 7 days.
abstract: BACKGROUND
  This study compares the quality of gamma-irradiated versus nonirradiated platelet (PLT) concentrates (PCs) during storage for 7 days as assessed by various in vitro methods. A new technique, free oscillation rheometry (FOR), which measures clotting time and coagulum elasticity, was also used to evaluate the PLT function.
  
  
  METHODS
  Single-donor PLTs were collected by apheresis technique (n = 20). The PLTs from each donor were divided into two PCs, one gamma-irradiated with 25 Gy and the other used as a nonirradiated control. Blood gases, metabolic variables, and swirling were analyzed from Day 0. Samples taken on Days 1, 5, and 7 were also analyzed for hypotonic shock response (HSR), P-selectin, and glycoprotein (GP)Ib expression by flow cytometry and coagulation by FOR.
  
  
  RESULTS
  Swirling, HSR, and the percentage of GPIb-expressing cells were well maintained for 7 days of storage. pH was always within accepted range (6.4-7.4). Glucose decreased and lactate increased during the storage period (p < 0.05). P-selectin expression increased during storage (p < 0.05). The FOR clotting time remained constant, whereas the build-up of elasticity was slower after storage (p < 0.05). No difference was found between irradiated and nonirradiated PCs.
  
  
  CONCLUSIONS
  The results indicate a well-preserved quality of gamma-irradiated apheresis PLTs during storage for 7 days as assessed by in vitro methods, with no difference compared to nonirradiated PLTs.
authors.affiliation: Department of Clinical Immunology and Transfusion Medicine, University Hospital, Linköping, Sweden.
authors.forename: Nahreen
authors.initials: N
authors.lastname: Tynngård
authors.forename: Monika
authors.initials: M
authors.lastname: Studer
authors.forename: Tomas L
authors.initials: TL
authors.lastname: Lindahl
authors.forename: Marie
authors.initials: M
authors.lastname: Trinks
authors.forename: Gösta
authors.initials: G
authors.lastname: Berlin
mesh_terms: D000704:Analysis of Variance; D015415:Biomarkers / Q000378:metabolism; D001777:Blood Coagulation; D001781:Blood Component Removal; D001784:Blood Gas Analysis; D001792:Blood Platelets / Q000166:cytology* / Q000378:metabolism / Q000528:radiation effects*; D001793:Blood Preservation / Q000379:methods*; D048429:Cell Size; D002470:Cell Survival / Q000528:radiation effects; D005720:Gamma Rays; D006801:Humans; D019007:P-Selectin / Q000378:metabolism; D010976:Platelet Count; D017713:Platelet Transfusion
chemical_list: D015415:Biomarkers; D019007:P-Selectin