Release reaction in Glanzmann's Thromboasthenia

MESCHENGIESER S; SCHATTNER M; LAZZARI MA

Estocolmo, Suecia.

Congreso; IX Congress of the International Society on Thrombosis and Hemostasis; 1983

Six patiens with Glanzmann's Thromboasthenia have been studied. Diagnosis was established by prolonged bleeding time, decreased platelet retention and a characteristic platelet aggregation. Simultaneous recording of aggregation and secretion was performed using a Lumi aggregometer. Aggregation induced by ADP and epinephrine was completely absent in all the cases. Aggregation induced by low doses of collagen was absent in 5 cases and markedly reduced in one. Platelet aggregation induce by high doses of collagen was absent in one case and reduced in the other five cases. Ristocetin and Bovine FVIII induced aggregation only showed first wave of agrgegation in all the patients. Platelet aggregation induced by arachidonic acid was absent in one case and diminished in the other five while PGH2 analogue induced aggregation was markedly reduced. ATP release induced by ADP, epinephrine, ristocetin and Bovine FVIII was absent in all the cases while collagen (1 ìg/mL) was normal in only one and with collagen (8 ìg/mL) it was diminished in all the patients. ATP release induced by arachidonic acid and PGH2 analogue was normal. Various aggregating agents expose fibrinogen receptor by different activating mechanisms. This receptor is likely to be situated on the glycoprotein IIb/IIIa complex, deficient in thromboasthenic platelets. Our results suggest that interaction and cooperation between different receptors is needed for any aggregating agent, whatever the mechanism involved, to achieve aggregation, and that probably thromboxane receptor has different locus on which aggregating agents produce independent platelet responses: aggregation and secretion.