Mast cells are mesenchymal cells that occur in the connective tissue of most organs and serve as host defence . They have a varying shape that is influenced by the tissue microenvironment but generally shows prominent granules inside the cytoplasm on histological and electron microscopic examination. The granules contain preformed bioactive agents, e. g. hista-mine and the enzymes tryptase and/or chymase. According to the content of tryptase and/or chy-mase, mast cells are divided into a connective tissue type containing tryptase and chymase (MTC) and a mucosal type that contains only tryptase (MT). In the normal human conjunctiva mast cells only occur in the lamina propria and their majority (95%) are positive for tryptase and chymase. In allergic eye disease the number of Mt mast cells increases and they can occur inside the epithelium and tear film . They produce further signalling molecules such as cytokines  of the Thi and Th2 type that act in an immune modulatory way on various cell types including leukocytes and epithelial cells and influence the course of ocular allergy.
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Rosacea and Eczema are two skin conditions that are fairly commonly found throughout the world. Each of them is characterized by different features, and can be both discomfiting as well as result in undesirable appearance features. In a nutshell, theyre problems that many would want to deal with.