Mast cells are resident cells found in several types of tissues throughout the body. They are also known as mastocytes and are seen particularly in association with blood vessels and nerves. Being intimately involved in defense against pathogens and wound healing, mast cells play an important role in allergy and anaphylaxis.
The History:
Paul Ehrlich discovered mast cells in 1878. Mr. Ehrlich described them first in his doctoral thesis on the basis of their unique staining characteristics and large granules. He named him “Mastzellen” which in Greek means “I feed” because he mistakenly believed that mast cells existed to nourish the surrounding tissues.
Mast Cells and Basophils:
Mast cells are closely related to basophil granulocytes or basophils. Basophils are a class of white blood cells in blood. They represent about 0.01% to 0.3% of circulating white blood cells. Apparent similarities between basophils and mast cells led many scientists to speculate that mast cells are same as basophils that are “homed in” on tissues. But later it was cleared that each one is generated by different precursor cells in the bone marrow and thus are different.
Role of mast cells in the body: Mast Cells and Allergy
Mast cells and basophils play a key role in inflammatory and immediate allergic reactions. When activated a mast cell is able to release its characteristic granules and various other hormonal mediators into the interstitium (fluid surrounding the tissue). Basophils and mast cells release potent inflammatory mediators such as proteases, histamines, cytokines, chemotactic factors and metabolites of arachidonic acid that act on connective tissues, smooth muscles, the vasculature, mucous glands and inflammatory cells.
Mast cells react only after activation. They remain inactive until an allergen (allergy causing substance) binds to IgE which is already attached to the cell. Once allergen is bind the release of mediators cause clustering of the inter-cellular domains of the cells leading to activation of mast cells.
