MICROANATOMY

Detailed explanation-1: -Mast cells and basophils represent the most relevant source of histamine in the immune system. Histamine is stored in cytoplasmic granules along with other amines (e.g., serotonin), proteases, proteoglycans, cytokines/chemokines, and angiogenic factors and rapidly released upon triggering with a variety of stimuli.

Detailed explanation-2: -Mast cells are multifunctional bone marrow-derived tissue-dwelling cells that are the major producer of histamine in the body.

Detailed explanation-3: -Interestingly, it has been demonstrated that eosinophil-derived MBP directly activates the release of histamine and LTC4 from human basophils [15, 25].

Detailed explanation-4: -So, the correct answer is ‘Basophils’.

Detailed explanation-5: -In this report, we show that eosinophils express histamine H4, but not H3 receptors. Since mast cells are the major producers of histamine and both mast cells and eosinophils are known effector cells in allergic reactions, the possible role of mast cells in the recruitment of eosinophils via histamine was investigated.