Defective platelet aggregation and increased platelet turnover in patients with myelofibrosis and other myeloproliferative diseases.

In 9 patients with myeloproliferative diseases (MPD) (6 with myelofibrosis, MF, 1 with Ph1 positive chronic granulocytic leukaemia, CGL, 1 with primary eosinophilia, PE, 1 with pre-leukaemia syndrome, preL) collagen, epinephrine, and ADP-induced aggregation, N-ethylmaleimide-induced malondialdehyde (MDA) production, beta-thromboglobulin (beta-TG) plasma levels, and platelet turnover were studied. Collagen-induced aggregation was found to be normal in 7 patients, absent in 1, and reduced in 1. In all but 3 patients, aggregation with ADP was markedly reduced. Epinephrine-induced aggregation was decreased in 7 patients. No difference was found between mean MDA production in MPD (3.21 +/- 0.50 nmol/10(9) PLTs) and in control group of 21 normal subjects (3.04 +/- 0.26 nmol/10(9) PLTs). Mean beta-TG levels were significantly higher (P less than 0.01) in MPD patients (165.00 +/- 28.29 ng/ml) than in healthy controls (81.76 +/- 14.63 ng/ml). Mean platelet production half-time was significantly shorter in MPD (2.48 +/- 0.24 d) than in the control group (3.43 +/- 0.17 d), after adjustment for age by covariance analysis (P less than 0.005). Our data do not indicate an abnormal prostaglandin synthesis and are consistent with the hypothesis that a disseminated intravascular platelet aggregation might take place in MPD patients.