Which statement about basophils is true?

Which statement about basophils is true?

• A. They release histamine
• B. They represent about 50-70% of white blood cells
• C. They are the most abundant white blood cells
• D. They become macrophages in tissues

Answer: (A)

Basophils are specialized players in allergic and inflammatory responses, and their key role is to release mediators stored in their granules when activated. The most notable of these is histamine, which dilates blood vessels and increases permeability, helping to drive the symptoms of an allergic reaction and to recruit other immune cells to the site of exposure. Basophils are a very small fraction of circulating white blood cells, not the majority or a large percentage, so statements claiming they’re common or the most abundant are incorrect. They do not become macrophages in tissues; macrophages originate from monocytes that migrate into tissues and differentiate there. Because releasing histamine is a defining action of basophils in their function, that statement is true.

Basophils are specialized players in allergic and inflammatory responses, and their key role is to release mediators stored in their granules when activated. The most notable of these is histamine, which dilates blood vessels and increases permeability, helping to drive the symptoms of an allergic reaction and to recruit other immune cells to the site of exposure. Basophils are a very small fraction of circulating white blood cells, not the majority or a large percentage, so statements claiming they’re common or the most abundant are incorrect. They do not become macrophages in tissues; macrophages originate from monocytes that migrate into tissues and differentiate there. Because releasing histamine is a defining action of basophils in their function, that statement is true.