Which cell type primarily mediates the early phase of acute inflammation?

• A. Eosinophils
• B. Neutrophils
• C. Lymphocytes
• D. Basophils

Answer: (B)

Neutrophils are the first responders in acute inflammation. When tissue is injured, resident cells release chemotactic signals such as IL-8, C5a, and leukotriene B4 that rapidly recruit neutrophils from the bloodstream to the site. These cells are specialized for immediate defense: they quickly phagocytose bacteria and debris and release enzymes and reactive oxygen species to kill invaders. Their short lifespan means they dominate the early phase, typically within the first day or so, before monocytes differentiate into macrophages to continue cleanup and repair.

Eosinophils, basophils, and lymphocytes have other roles. Eosinophils are more involved in defense against parasites and allergic reactions; basophils (and mast cells) contribute to vascular changes via histamine release but are not the main early phagocytes; lymphocytes drive adaptive immune responses and are more prominent in later, especially chronic, inflammation.