Platelet CD62 expression and PDCFAB secretion in patients undergoing PTCA and treatment with abciximab

Aims To investigate a correlation of the platelet activation marker CD62 an d secretion of the growth factor PDGF from platelets in coronary patients u nder therapy with the GPIIb/IIIa-inhibitor abciximab. Methods Flow cytometric assessment of fibrinogen binding (GPIIb/IIIa-bindin g site) and CD62 expression, as well as PDGF release of human platelets (im munoassay) and platelet aggregation with 20 muM ADP and 2 mug ml(-1) collag en were evaluated in nine patients with stable coronary artery disease. Pat ients were undergoing elective balloon angioplasty and were treated with as pirin (100 mg day(-1)), heparin (ACT < 220 s) and abciximab (bolus and infu sion over 12 h). Blood samples were obtained before initiation of abciximab therapy (under aspirin and heparin) (1), 3 h after angioplasty under abcix imab (II) and 12 h after termination of abciximab infusion (III). Results Compared with sample I before abciximab therapy, fibrinogen binding was reduced to 37% (+/-34 s.d., P<0.05) (II) and 55% (+/-40 s.d., P<0.05) (III). Reduced fibrinogen binding also led to a significant reduction of th e aggregation response to ADP (down to 37% +/- 20) and collagen (down to 0% ,). Mean fluorescence intensity of CD62-expression was 78 units (+/-20 s.d. ) (I), 72 units (+/-14 s.d.) (II) and 64 units (+/-12 s.d., P<0.05) (III). PDGF release from isolated, washed platelets was 99 (+/-33 s.d.) ng/10(9) p latelets at (I), 82 (+/-31 s.d.) ng/10(9) platelets and 96 (+/-30 s.d.) ng/ 10(9) platelets. Conclusions The results indicate that despite a strong reduction of GPIIb/I IIa-binding and platelet aggregation, CD62 as a marker of platelet secretio n and the secretion product PDGF were only slightly reduced under abciximab treatment. No direct correlation between CD62 expression and PDGF release could be demonstrated.