Department of Veterinary Anatomy, College of Veterinary and Animal Sciences, G B Pant University of Agriculture and Technology, Pantnagar, 263145 (Uttarakhand).
Mast cells are highly granulated tissue dwelling cells, widely distributed throughout the body in connective tissues and at mucosal surfaces. They are derived from undifferentiated precursor cells released in blood from bone marrow precursors expressing the CD34 molecule. Besides, they also originate from undifferentiated mesenchymal connective tissue and migrate into the blood and subsequently into the tissues, where they undergo final maturation. Mast cells are classified into two types in humans and rodents on the basis of types of proteases contained in their exocytotic granules i.e. mucosal mast cells and connective tissue mast cells. The mucosal mast cells are somewhat similar in size with basophils, where as connective tissue mast cells are larger. The mast cell releases a large number of pro-inflammatory and immunoregulatory mediators after activation induced by either immunoglobulin Edependent or immunoglobulin E-independent mechanisms. Mast cells have been most widely studied in the context of allergic reactions and parasite infections, but there are now compelling evidences that they are important players in innate and acquired immunity and also serve critical protective and homeostatic functions. Mast cell plays vital role in Type I hypersensitivity reaction and inflammation like many forms of cutaneous and mucosal allergy, asthma, eczema, itch (from various causes) and allergic rhinitis, allergic conjunctivitis, pulmonary disease and lung fibrosis. They participate not only in several chronic inflammatory conditions, helminithic parasitosis, fibrosis, and in some solid tumor reactions, but also in physiological situations, such as wound healing. Mast cells are associated with the autoimmune disorders, rheumatoid arthritis, and multiple sclerosis, involved in the recruitment of inflammatory cells to the joints and this activity is dependent on antibodies and complement components. Mastocytosis is a rare condition featuring proliferation of mast cells. It exists in a cutaneous and a systemic form, with the former being limited to the skin and the latter involving multiple organs. A mastocytoma is a mast cell tumor, often seen in dogs and cats. Agents like certain hormones, some drugs, stressor and physical agents, allergy, diet, age, sex and reproduction affect the mast cell production.
Mast cell, allergy, immunology, mastocytoma
