Ristocetin-induced platelet agglutination in four Chinese patients with Glanzmann's thrombasthenia

We studied the degree of Ristocetin-induced platelet agglutination in 4 Chinese patients with Glanzmann's thrombasthenia. At Ristocetin concentrations of 1.2-2.0 mg/ml (final concentration) variable, abnormal responses were observed. The most notable feature in 3 of 4 patients studied was the phenomenon of dose dependent, cyclic platelet agglutination-disagglutination. However, this phenomenon could be reproduced in only one of the 2 patients who were investigated on 2 separate occasions. Variable, but often characteristic responses of thrombasthenic platelets to different concentrations of Ristocetin are a useful additional diagnostic marker for this disease.