Platelet CD36 expression levels correlate with activation response to oxLDL. (A) PRP from 4 different healthy subjects expressing high, medium, low, or no platelet CD36 were incubated with oxLDL 50 μg/mL for 30 minutes and then stimulated with low-dose ADP (2μM). Aggregation was assessed turbidometrically with a dual-chamber aggregometer. Tracings show representative aggregometry curves from triplicate assays performed on platelets from 2 CD36 null donors and from 5 or more donors from each of the 3 other groups. oxLDL at this concentration by itself did not effect platelet aggregation. (B) Washed platelets from 7 normal healthy subjects with levels of CD36 expression ranging from 0 to more than 12 000 molecules/platelet were incubated with oxLDL 50 μg/mL for 30 minutes, and platelet α-granule release was quantified by flow cytometry using anti–P-selectin IgG. The graph plots mean fluorescence intensity of anti–P-selectin binding against surface expression of CD36 and shows a correlation coefficient (r²) of 0.87.