Heterogeneity in storage pool deficiency: studies on granule-bound substances in 18 patients including variants deficient in alpha- granules, platelet factor 4, beta-thromboglobulin, and platelet-derived growth factor

with storage pool deficiency (SPD) have been found previously to have diminished amounts of substances that are stored in platelet-dense granules (storage pool ATP and ADP, calcium. and serotonin) and impaired platelet aggregation responses. In these studies on 1 8 patients with SPD. we measured. in addition to these dense granule substances, platelet factor 4 (PF4). /1-thromboglobulin (/ITG). heparin-neutralizing activity (HNA). fibrinogen. and platelet-derived growth factor (PDGF). In addition, we quantified the number of a-granules. dense granules. and mitochondria in their platelets. Our findings demonstrated several defects that GRANULE