Total blood MPs and cellular origin of MPs. Data are expressed as MP number per milliliter of platelet-free plasma and shown as mean ± SEM, and statistical analysis is presented in Table 1. In each panel, the clear bars (□) show data for healthy state, gray bars (▦) show data for steady state, and black bars (▪) show data for crisis. (A) Total MP number. (B) Endothelial-derived MP number. (C) MP number derived from red blood cells, platelets, and monocytes. Error bars represent SEM.