| Abstract: | Abstract: Platelet function and the clinical course of the disease were prospectively investigated in 29 patients with myeloproliferative disorders. Serial determinations (median: 5 investigations per patient within 17 months) of platelet aggregation, plasma and intraplatelet concentrations of β-thromboglobulin (βTG) and platelet factor 4 (PF4), and of fibrino-peptide A (FPA) plasma levels were carried out. In the chronic phase of polycythaemia vera, patients with thrombohaemorrhagic complications during the study period had higher platelet count, more severe platelet aggregation defects, and increased plasma levels of βTG and FPA compared to patients without complications. However, thrombohaemorrhagic complications were not predicted by changes in these parameters in the individual patient during the chronic disease phase. When patients with chronic myelogenous leukaemia entered blast crisis, bleeding complications were related to thrombocytopenia, impaired platelet function and low intraplatelet concentrations of βTG and PF4. Cytoreduction by chemotherapy in the chronic phase of CML did not alter βTG and PF4 plasma levels, whereas treatment of polycythaemia rubra vera by venesection favourably influenced platelet α-granule secretion and increased intraplatelet concentrations of βTG and PF4. |
