title: Platelet products prepared by different methods of sedimentation undergo platelet activation differently during storage.
abstract: BACKGROUND
  The activation marker CD40 ligand (CD40L) has recently been demonstrated to be released from the cytoplasm of platelets (PLTs) during storage. CD40L may be associated with some adverse transfusion reactions including febrile responses and transfusion-related acute lung injury. CD62P has been traditionally measured to assess PLT activation. This study compares the surface levels of CD40L and CD62P and accumulation of the soluble forms of these activation markers in the plasma of stored PLTs, prepared by PLT-rich plasma (PRP) or buffy coat (BC) methods and with two apheresis instruments.
  
  
  METHODS
  Individual PLT concentrates (PCs) were prepared in 100 percent plasma from a pool of two ABO-identical whole-blood units. Apheresis PLTs (APs) were prepared in 100 percent plasma using one of two commercially available cell separators (Amicus, Baxter Healthcare; and Trima, Gambro BCT). Surface expression of CD40L and CD62P was measured by flow cytometry, and secretion of soluble CD40L (sCD40L) and soluble CD62 (sCD62) was measured by enzyme-linked immunosorbent assay during 7 days of PLT storage.
  
  
  RESULTS
  Secretion of sCD40L was greater in Amicus APs than in Trima APs during the first 3 days of storage. It was also greater in the PRP-PC preparations than in BC-PC preparations through the first day of storage. Surface expression of CD40L was low in all PLT preparations. Secretion of sCD62P was greater in Amicus APs than in Trima APs during the entire storage period and greater in PRP-PC than in BC during the first 5 days of storage. The percentage of CD62P-positive PLTs was greater in Amicus units than Trima units and greater in PRP-PC than BC-PC preparations during the first 5 and 3 days of storage, respectively.
  
  
  CONCLUSIONS
  The kinetics of the secretion of CD40L are influenced by the method used to prepare PLTs for storage. The patterns for CD40L membrane association and secretion are different than those observed for CD62P during storage.
authors.affiliation: The American Red Cross Biomedical Services, Holland Laboratory, Blood Components Development, Rockville, Maryland 20855, USA. skripcha@usa.redcross.org
authors.forename: Andrey
authors.initials: A
authors.lastname: Skripchenko
authors.forename: James
authors.initials: J
authors.lastname: Kurtz
authors.forename: Gary
authors.initials: G
authors.lastname: Moroff
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Wagner
mesh_terms: D001781:Blood Component Removal / Q000009:adverse effects / Q000379:methods*; D001792:Blood Platelets / Q000166:cytology / Q000378:metabolism*; D001793:Blood Preservation / Q000009:adverse effects / Q000379:methods*; D023201:CD40 Ligand / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D007700:Kinetics; D019007:P-Selectin / Q000097:blood; D015539:Platelet Activation
chemical_list: D019007:P-Selectin; D023201:CD40 Ligand