title: Platelet aggregation in children with acute lymphoblastic leukemia during induction of remission therapy.
abstract: BACKGROUND
  Development of thromboembolytic events is a major complication during induction of remission therapy (IRT) for acute lymphoblastic leukemia (ALL) of childhood. Increased in vitro platelet aggregation in response to drugs employed at this stage has been documented. To investigate the presence of an in vivo platelet agonist effect, we studied changes in aggregation patterns of patients with ALL receiving IRT.
  
  
  METHODS
  Platelets from 22 children with a new diagnosis of ALL were obtained during IRT once the platelet count reached >100 x 10(9)/L. Platelets were stimulated with adenosine diphosphate (ADP), collagen, ristocetin, and epinephrine. Platelet responses were evaluated by optical aggregometry.
  
  
  RESULTS
  Percentages of platelet aggregation in ALL patients were as follows: ADP, 89+/-22; collagen, 90+/-24; ristocetin, 84+/-26, and epinephrine, 81+/-20. Percentages in healthy individuals were ADP: 98+/-12; collagen: 105+/-10; ristocetin: 100+/-15, and epinephrine, 98+/-8.
  
  
  CONCLUSIONS
  Platelet aggregation with classical agonists was diminished during IRT for ALL of childhood, although it remained within the normal lower limit for age. Considerable heterogeneity in platelet reactivity existed, probably reflecting the presence of several pharmacologically altered platelet subpopulations. No apparent clinical correlation of aggregometric changes was documented.
authors.affiliation: Departamento de Hematología, Facultad de Medicina, Hospital Universitario Dr. José E. González, Universidad Autónoma de Nuevo León, Av. Madero y Gonzalitos, Col. Mitras Centro, 64460 Monterrey, Nuevo León, Mexico. carjaime@hotmail.com
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Jaime-Pérez
authors.forename: Olga Graciela
authors.initials: OG
authors.lastname: Cantú-Rodríguez
authors.forename: José Luis
authors.initials: JL
authors.lastname: Herrera-Garza
authors.forename: David
authors.initials: D
authors.lastname: Gómez-Almaguer
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000293:Adolescent; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D003094:Collagen / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D007223:Infant; D008297:Male; D015539:Platelet Activation; D010974:Platelet Aggregation; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000097:blood* / Q000188:drug therapy; D012074:Remission Induction; D012310:Ristocetin / Q000494:pharmacology; D013997:Time Factors; D014662:Vasoconstrictor Agents / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D014662:Vasoconstrictor Agents; D012310:Ristocetin; D000244:Adenosine Diphosphate; D003094:Collagen; D004837:Epinephrine