Platelet aggregation in children with acute lymphoblastic leukemia during induction of remission therapy.
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.
Jaime-Pérez
José Carlos
JC
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
Cantú-Rodríguez
Olga Graciela
OG
Herrera-Garza
José Luis
JL
Gómez-Almaguer
David
D
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
D000900:Anti-Bacterial Agents; D014662:Vasoconstrictor Agents; D012310:Ristocetin; D000244:Adenosine Diphosphate; D003094:Collagen; D004837:Epinephrine