Investigation of Platelet Functions in Chronic Myeloproliferative Disorders by Optical and Luminesance Method.

Background: Bleeding and thrombosis are common causes of morbidity and mortality in patients with myeloproliferative disorders (MPD). Qualitative platelet abnormalities are frequently found in these patients and range from platelet hypofunction as demonstrated by defective invitro platelet aggregation, acquired storage pool disease and/or platelet membrane defects, in addition to enhanced platelet aggregation, increased plasma beta thromboglobulin levels or shortened platelet survival. In this study we aimed to perform platelet aggregation studies by optical method (on platelet rich plasma=PRP) and luminesance method (on whole blood) in chronic myeloproliferative disorders.

Methods:A total of twenty-five patients with MPD (17 chronic myeloid leukemia, 6 polycythemia vera, 2 essential thrombocytosis) were enrolled. Median age was 54,4 (29–76). Platelet aggregation was measured using the optic and luminesance method. The agonists used were adenosine diphosphate (ADP), arachidonic acid (AA) ristocetin and collagen. Platelets were considered to be hyperactive if at least one result (i.e. aggregation or ATP release with one agonist) was above the reference range, and hypoactive if at least one result (i.e. aggregation or ATP release) was below the reference range. Mixed hypo- and hyperactive platelets were considered present when at least one result (i.e. aggregation or ATP release) was below and above the reference range respectively.

Results:Platelet aggregation test results by two methods in myeloproliferative disorders were shown in Table 1. The percent for detection of platelet function abnormality by luminesance method was found to be higher than the optic method and a significant difference was shown between two methods (p<0,05).

Conclusion Our findings suggest that;1. Luminesance platelet aggregation study is more valuable than optic platelet aggregation study for invitro assessment of platelet function in patients with MPD. 2. The use of luminesance platelet aggregation study appears useful to select patients for antiplatelet therapy.

Platelet aggregation test results in myeloproliferative disorders (n=25)