Increased platelet CD36 constitutes a common marker in myeloproliferative disorders.
The distribution of the major platelet membrane glycoproteins (GP), Ib, IX, IIb-IIIa and IV (or CD36), which play important roles as receptors for adhesive molecules in haemostasis and thrombosis, was studied in 34 patients with myeloproliferative disorders (MPD): 13 had essential thrombocythaemia (ET), 12 had polycythaemia vera (PV) and nine had chronic myelogenous leukaemia (CML). Only occasionally were modifications of the numbers of GPIb or GPIIb-IIIa measured using the binding of specific radiolabelled antibodies to platelets. In contrast, 2-3-fold increases of the total CD36 content and the surface CD36 expression were measured in almost all patients studied, using a radioimmunoassay and the direct binding of the radiolabelled antibody, FA6-152, to the platelet surface, respectively. These results indicate that the abnormality affected both the external and internal CD36 pools. Therefore platelet CD36 may be a useful tool for the diagnosis and the follow-up of MPD patients. Surface CD36 has been proposed as a platelet receptor for thrombospondin, an adhesive glycoprotein that is released from platelets upon activation and promotes aggregate formation. Despite a 2-fold increase of CD36 molecules, resting and thrombin-activated platelets from ET patients expressed the same amount of thrombospondin as normal platelets, suggesting that there is not a direct correlation between the CD36 expression and thrombospondin binding either spontaneously or after activation.
Thibert
V
V
INSERM U353 Hôpital Saint-Louis, Paris, France.
Bellucci
S
S
Cristofari
M
M
Gluckman
E
E
Legrand
C
C
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001792:Blood Platelets / Q000378:metabolism*; D018955:CD36 Antigens / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D008875:Middle Aged; D009196:Myeloproliferative Disorders / Q000097:blood* / Q000378:metabolism; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000378:metabolism; D019699:Thrombospondins
D018955:CD36 Antigens; D008562:Membrane Glycoproteins; D019038:Platelet Glycoprotein GPIb-IX Complex; D019699:Thrombospondins