Which cell type produces histamine as part of an allergic response and heparin as an anticoagulant?

• A. Fibroblast Cells
• B. Leucocytes
• C. Histiocytes
• D. Mast Cells

Answer: (D)

Mast cells play a key role in allergic responses by storing and releasing mediators from their granules. When an allergen triggers IgE on the mast cell surface, degranulation occurs and histamine is released. Histamine causes dilation of blood vessels and increases permeability, leading to redness, swelling, and itching, and can also trigger airway constriction in sensitized individuals. Mast cells also release heparin, an anticoagulant, which helps prevent clotting at the inflamed site and supports the movement of immune cells into the tissue. Other cells like fibroblasts, leucocytes, or histiocytes don’t ordinarily store and release these two mediators in this combination, so mast cells fit this description best.