In 22 cases of chronic ITP, the platelet 5-HT storage organelles were counted by examination
of platelets loaded with mepacrine and correlated with the size and volume of the
platelets. Statistical analysis showed that the mean volume and the number of granules
increased in ITP without increase in the mean number of granules per unit volume.
A strong correlation was found between platelet long diameter and number of dense
bodies in controls (44 healthy subjects) (r = 0.94; y = 2.826 × – 0.699) and in ITP
(r = 0.92; y = 2.587 × + 0.06). This study demonstrated in chronic ITP the presence
both of platelets without granules and others rich in granules. These anomalies were
present no matter what the count of platelets and did not change the mean values for
granules and for ADP in most cases. Most platelets remain morphologically normal.
Keywords
I. T. P - Platelet dense bodies