Five days after sepsis induction, when splenomegaly was present (Supplemental Figure 2A), we directly imaged the spleen using 2-photon intravital microscopy (2PIVM) (Supplemental Figure 2B) and fluorescent reporter mice (Pf4-Cre x mTmG, hereafter called Pf4-mTmG) to visualize MKs and platelets (1). Here, PF4 is linked to Sepsis.