Thymic mast cells: From morphology to physiology

This minireview summarizes some of our results on the structure, origin, and functions of thymic mast cells, as well as their role in stress-induced thymic atrophy. A comparison of the thymic mast cells with the connective tissue and mucosa mast cells is carried out. The morphological and cytochemical similarity of thymic and mucosa mast cells has been proven. The mechanisms of neuro-mast cell interaction, as well as the features of intercellular signaling are analyzed. Another aspect of the review is related to the assessment of thymic mast cell functions in stress-induced atrophy. It is hypothesized that the main function of these cells under stress is to regulate the T-cell emigration. The role of the thymus as an endocrine gland is also discussed. Probably, its endocrine function is mainly associated with the thymic mast cells which are regulated by the nervous system. Regardless of their localization and despite their hemopoietic origin, all mast cells are an important addition to the nervous system. They are a unique combination of both receptor and effector cells located in all organs and tissues. The mast cells supply the central nervous system with information about any local changes in tissue homeostasis and enhance local nervous influences. At the same time, mast cells are extremely important for neuro-immune communication as well as their mutual control on local defense reactions and mucosa conditions