PATHOLOGY

Detailed explanation-1: -Histamine is a major secretory product of the mast cell and is recognized for its role in the regulation of vasodilation and bronchoconstriction (115, 116). Histamine also regulates functions of monocytes and macrophages (117, 118), eosinophils (117, 118), T cells (119), neutrophils, and endothelial cells (120, 121).

Detailed explanation-2: -Histamine is a major preformed mediator released by mast cells and it strongly increases vascular permeability.

Detailed explanation-3: -Histamine is a vasodilatory substance released during anaphylaxis.

Detailed explanation-4: -Activated basophils and mast cells release both overlapping and unique sets of inflammatory mediators, including histamine, proteoglycans, lipid mediators, proteases, chemokines, growth factors and cytokines [9].