During the first hour of incubation of the blood with LPS, platelets from WT mice underwent a shape change, extended pseudopodia and formed aggregates (Figure 2 ). Within this first hour, neither surface expression of PS on either platelets or leukocytes or numbers of platelet-or leukocyte-derived MV changed significantly in WT mice or dTLR4 mice (Table 1) . However, the number of platelets positive for leukocyte-specific antigen (defined by the platelet-gate on the flow cytometer, Figure 1 ) increased significantly in a time-dependent manner in blood of WT mice, but not dTLR4 mice (Figures 1) . Using the total leukocyte specific antibody (CD45-APC) to define total leukocytes, numbers of leukocytes positive for platelet-specific antigen did not increase significantly in either WT or dTLR4 mice ( Figure 1) .