Blood monocytes (including classical, nonclassical and intermediate monocytes), NK cells, and DCs are key during the early phase of endotoxemia because they are not only responsible for maintaining vascular homeostasis but also highly responsible for patrolling the bloodstream to recognize and phagocytize invading pathogens, resulting in the secretion of proinflammatory cytokines, such as IL-1β, TNF-α, IL-6, and IL-8 (58, –, 60). Here, IL6 is linked to serum lipopolysaccharide activity.