Why does a severe burn injury raise the neutrophil count?

1. Abnormally high neutrophil counts indicate infection or inflammation, and are also seen in burn patients and others under unusual stress. 2. A burn destroys the barrier function of the skin. 3. That opens a route for bacteria, which are exactly the pathogens neutrophils are best against. 4. Neutrophil proliferation therefore increases to meet the anticipated infection, giving leukocytosis. 5. The response is a marrow-driven increase in production, not a release of a stored skin pool, so the first option invents a reservoir. 6. Direct thermal acceleration of cell division is not the mechanism, so the second option is wrong. 7. Plasma loss does concentrate blood, but that would raise every cell count proportionately rather than produce a true neutrophil leukocytosis. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 18 "The Cardiovascular System: Blood", section 18.4 Leukocytes and Platelets_