Fifty-two patients with chronic myeloproliferative disorders (13 with polycythemia
vera; 23 with primary thrombocythemia; 6 with myelofibrosis and 10 with chronic granulocytic
leukemia) had low platelet levels of adenine nucleotides and serotonin and abnormal
uptake and storage of the amine. The storage pool deficiency was confined to the substances
contained in the platelet dense bodies, because α-granule and lysosome markers were
present in normal amounts. In chronic granulocytic leukemia the storage defect was
usually less marked but was accompanied by a decreased formation of thromboxane B2 and normal platelet aggregation in response to arachidonic acid. There was no clearcut
relationship of these biochemical abnormalities to prolongation of bleeding time or
to thrombotic and hemorrhagic symptoms. The defect was still present in 15 patients
after treatment had returned the cell counts to the normal range. Normal levels of
5HT and adenine nucleotides were observed in 8 patients whose platelet counts were
high after splenectomy for non-hematological reasons. These findings suggest that
biochemical abnormalities are related to the presence in the bone marrow of abnormal
clones, resulting in the production of defective platelets.
Key words
Thrombocytopathy - Storage pool deficiency - Platelet qualitative defects - Platelet
dense bodies - Serotonin metabolism
