Platelet function in the Chediak-Higashi syndrome.

Platelet function studies were performed on two patients with the Chediak-Higashi syndrome, one of whom had a history of easy bruising unrelated to thrombocytopenia. Both patients had prolonged bleeding times, abnormal platelet aggregation, and a defect of platelet storage granules, manifested by reduced platelet ADP, an increased ATP/ADP ratio, increased adenine nucleotide specific radioactivity after 3H-adenine labeling, and decreased platelet uptake of radioactive 5-hydroxytryptamine. These findings confirm preliminary data in animals with the Chediak-Higashi syndrome, provide and explanation for impaired primary hemostasis in these patients, and illustrate another disorder in which platelet storage-pool deficiency occurs.