title: Increased plasma levels of soluble CD40 ligand correlate with platelet activation markers and underline the need for standardized pre-analytical conditions.
abstract: OBJECTIVE
  To investigate whether sCD40L dosage might represent a useful tool to explore in vivo platelet function.
  
  
  METHODS
  sCD40L and sP-selectin levels and light transmission aggregometry (LTA) were analyzed in 69 healthy donors. Immunoassays were performed on platelet-depleted citrate plasma samples. The effects of in vitro aspirin treatment on the release of sCD40L were investigated in 15 subjects following platelet stimulation. The effects of a 1-month therapeutic course of low-dose aspirin on sP-selectin and sCD40L levels were also investigated.
  
  
  RESULTS
  A significant correlation was observed between sCD40L and sP-selectin (p<0.01). In vitro aspirin treatment remarkably decreased sCD40L levels following platelet activation by exogenous agonists. sCD40L directly correlated with LTA (Rho=0.62, p<0.0001). In vivo aspirin treatment significantly reduced both sP-selectin and sCD40L levels (both p<0.01) in a direct correlation (Rho=0.66, p<0.05).
  
  
  CONCLUSIONS
  Citrated plasma samples reflect sCD40L released from platelets, thus yielding the most valid estimates of in vivo circulating levels of this platelet activation markers.
authors.affiliation: Department of Laboratory Medicine and Advanced Biotechnologies, IRCCS San Raffaele, Rome, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Riondino
authors.forename: Francesca
authors.initials: F
authors.lastname: Martini
authors.forename: Francesca
authors.initials: F
authors.lastname: La Farina
authors.forename: Antonella
authors.initials: A
authors.lastname: Spila
authors.forename: Fiorella
authors.initials: F
authors.lastname: Guadagni
authors.forename: Patrizia
authors.initials: P
authors.lastname: Ferroni
mesh_terms: D000328:Adult; D000368:Aged; D001241:Aspirin / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D023201:CD40 Ligand / Q000097:blood*; D005260:Female; D006801:Humans; D007118:Immunoassay; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D019007:P-Selectin / Q000097:blood*; D015539:Platelet Activation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology
chemical_list: D019007:P-Selectin; D010975:Platelet Aggregation Inhibitors; D023201:CD40 Ligand; D001241:Aspirin