Rolling of THP-1 cells on PMA-activated HUVEC was to a large extent mediated by L-selectin. P-selectin inhibition did not yield a blocking effect. After the addition of activated platelets (ratio 3:1), L- and P-selectin blocking resulted in an inhibition of rolling and a concomitant reduction of adhering monocytes. GPIIb/IIIa blockade resulted in reduced rolling, whereas GPIb inhibition reduced adhesion of complexes without affecting rolling of THP-1 cells in the presence of platelets (n = 4 for each condition, *P < .05).