TREM1 and Sepsis: Immunohistochemical markers considered suitable for this purpose include: E-selectin [30], VLA-4, and ICAM-1 (CD54) [31], all adhesion molecules involved in leukocytic attraction and migration through the endothelial barrier towards the inflammatory compartment; lactoferrin (LF) [32], an iron-binding protein whose role is to take iron from bacteria in order to limit their growth; TNF-α [34], one of the major pro-inflammatory mediators; CCR2 and CX3CR1 [37], involved in leukocytic chemotaxis; PCT [38], whose expression is up-regulated during sepsis; CD15 [40] and TREM-1 [41].