ICAM-1 overexpression is due to SS RBC-MPs rather than PLT-MPs. The percentage of ICAM-1⁺ cells (A) and their MFIs (B) were increased with SS RBC-MPs compared with the condition with PLT-MPs of the same SS patients (n = 9). The dashed lines represent the control level (without MPs) at 4 hours. *P < .05, **P < .01 vs SS PLT-MPs, paired Student t test.