Platelet activation and thrombosis: studies in a patient with essential thrombocythemia.
Recent advances permit the detection of activated platelets using specific monoclonal antibodies and flow cytometry. Nevertheless, there are few reports in which activated platelets have been studied over a period of time in patients at risk for thrombosis. Our patient S.D. has essential thrombocythemia and a prothrombotic state manifested in two major thrombotic episodes involving the portal vein and a mesenteric artery. Investigation revealed both spontaneous aggregation and hyperaggregability in response to ADP and the presence of activated platelets in platelet-rich plasma as revealed by flow cytometry. Interestingly, the activated platelets were recognized by an anti-RIBS ("receptor-induced binding site") monoclonal antibody that recognized bound fibrinogen but not by antibodies reactive with antigens whose presence on the platelet surface was secretion dependent. Treatment with aspirin inhibited spontaneous platelet aggregation but had little effect on the activated platelet profile. A change of therapy to ticlopidine suppressed expression of platelet activation markers. Treatment with ticlopidine has continued for 1 year so far without further thrombotic complications.
Nurden
P
P
Laboratoire d'Hémobiologie, URA 1464 CNRS, Hôpital Cardiologique, Pessac, France.
Bihour
C
C
Smith
M
M
Raymond
J M
JM
Nurden
A T
AT
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology; D001241:Aspirin / Q000494:pharmacology / Q000627:therapeutic use; D001792:Blood Platelets / Q000276:immunology; D004198:Disease Susceptibility; D005260:Female; D005340:Fibrinogen / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D008638:Mesenteric Arteries; D008641:Mesenteric Vascular Occlusion / Q000097:blood / Q000209:etiology*; D015539:Platelet Activation / Q000187:drug effects; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000187:drug effects / Q000378:metabolism; D011169:Portal Vein; D018048:Receptors, Purinergic P2 / Q000187:drug effects; D013162:Splenic Vein; D013920:Thrombocythemia, Essential / Q000097:blood* / Q000150:complications / Q000188:drug therapy; D013927:Thrombosis / Q000097:blood / Q000209:etiology* / Q000517:prevention & control; D013988:Ticlopidine / Q000627:therapeutic use
D000911:Antibodies, Monoclonal; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D018048:Receptors, Purinergic P2; D000244:Adenosine Diphosphate; D005340:Fibrinogen; D013988:Ticlopidine; D001241:Aspirin