Abstract
Mast cells have been recognized as cells playing an important role in the pathophysiology not only of allergic and immunological diseases but also of various other diseases. They participate in physiological and pathological processes through the production and release of biologically active substances such as preformed and newly generated mediators or cytokines.
The skin is one of the major target organs of IgE-mediated hypersensitivity disorders. The various mediators and/or cytokines are released from skin after mast cell activation in IgE-mediated anaphylactic reaction. The activated skin mast cells release not only histamine but also other mediators such as PGD2 and LTB4. These mediators contribute to pathogenesis of mast cell-related disorder such as urticaria and atopic dermatitis. In addition, it has been known that human mast cells are able to produce a variety of cytokines such as IL 4, IL-5, IL 6, TNF-α and IFN-γ. These cytokines may have an important role in skin inflammation.
It has been known that an increase in number of mast cells are observed in several skin diseases. An increase in number of mast cells at the sites of lesions may affect the pathophysiology of the diseases. The results of our studies show that keratinocytes may produce some factor which induces expression of unknown factor, different from SCF, for mast cell growth on fibroblast membrane. The mast cell growth observed in our studies may be due to a novel mechanism of mast cell proliferation and differentiation. This may be important in mast cell related skin disorders.
