title: Leukocyte apoptosis in whole blood involves platelet-dependent coaggregation.
abstract: BACKGROUND
  Activated leukocytes and platelet-leukocyte interaction are involved in the pathogenesis of thrombotic and inflammatory events. Because apoptosis is a prerequisite for the successful resolution of an inflammatory response, we investigated the amount of apoptotic peripheral blood leukocytes (PBLs) in whole blood and their possible functional relation with the platelet-leukocyte interaction by a flow cytometric assay using APO 2.7 antibody for the detection of apoptosis
  
  
  METHODS
  Thirty healthy subjects volunteered for the study. PBL apoptosis in seven volunteers was induced by phorbol 12-myristate 13-acetate or while standing at rest.
  
  
  RESULTS
  Apoptosis was observed in all types of leukocytes (0.7% neutrophils, 1.5% monocytes, and 0.3% lymphocytes). Apoptosis was found predominantly in platelet and leukocyte coaggregates (<1% of nonaggregated leukocytes vs. 9% of platelet and leukocyte coaggregates). This phenomenon was even more pronounced after induction of leukocyte apoptosis in vitro (66% of platelet and leukocyte coaggregates).
  
  
  CONCLUSIONS
  Apoptosis and platelet-leukocyte interaction seemed to be closely related phenomena, and apoptotic leukocytes seemed to trigger adhesion and, hence, activation of platelets. Because platelet-leukocyte interaction is involved in the pathogenesis of thrombotic events, apoptotic leukocytes may constitute an additional prothrombotic trigger.
authors.affiliation: German Diabetes Research Institute, Heinrich-Heine-University, Duesseldorf, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Hartz
authors.forename: B
authors.initials: B
authors.lastname: Menart
authors.forename: D
authors.initials: D
authors.lastname: Tschoepe
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D001792:Blood Platelets / Q000502:physiology*; D002449:Cell Aggregation / Q000187:drug effects / Q000502:physiology; D005434:Flow Cytometry; D006801:Humans; D007962:Leukocytes / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D010974:Platelet Aggregation; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D013755:Tetradecanoylphorbol Acetate