[The platelet defect in myeloproliferative disorder (author's transl)].

Platelets functions are very often impaired in myeloproliferative disorders and acute leukemias. The abnormalities may either results from plasmatic factor affecting the platelet function or from an intrinsic platelet defect. The mechanism of the platelet defect is still a subject to discussion: it may be an abnormal response of the platelet to the aggregating agent or an impaired release of nucleotides.