Rolling adhesion of HbSS RBCs onto immobilized ICAM-1 under flow conditions. The data shown are the mean percentages of adherent or rolling RBCs onto immobilized ICAM-1 and the mean rolling velocities under shear rates of 500, 1000, 2000, 3000, 4000, and 5000 s^−1. A mean of 100% of HbSS RBCs adhered to immobilized ICAM-1 (including rolling adhesion and firm adhesion). (A) The number of adherent RBCs to immobilized ICAM-1 decreased with increasing shear rates. Shown are mean percentages of adherent RBCs (n = 5). (B) Two overlapped frames, taken 1 second apart, extracted from a video depicting cell rolling behavior. (C) The number of rolling RBCs increased with increasing shear rates (n = 5). (D) The velocities of rolling RBCs on immobilized ICAM-1 increased with increasing shear rates (n = 5). Error bars represent ± SEM.