Mast cell anaphylaxis role

Table 1. Key concepts about the roles of mast cells in systemic anaphylaxis in mice and humans... 

It is generally accepted (based on clinical and in vitro studies) that mast cells (and basophils), IgE and FceRI are involved in most cases of allergen-induced anaphylaxis in humans. However, it is difficult to define the exact roles and relative importance of mast cells, basophils, and other potential effector cells (e.g monocytes/macrophages, dendritic cells) in either IgE-dependent or IgE-independent human anaphylaxis. Unlike in mice, we neither have access to mast cell- or basophil-deficient humans nor can we genetically manipulate human subjects to produce such phenotypes. 

The roles of potential effector cells other than mast cells and basophils (e.g. monocytes/ macrophages, dendritic cells) in IgE-dependent and IgE-independent anaphylaxis in mice and humans remain to be determined. 

Beta-agonists, indirectly via c-AMP, act on mast cell p2-receptors inhibiting the release of bronchoconstrictor mediators such as histamine. Slow-reacting substance of anaphylaxis (SRS-A), now known to be leukotriene D3 and D4 (Fig. 5-5), and eosinophil chemo-tactic factor of anaphylaxis (ECF-A) may also have their release inhibited by c-AMP. Leukotriene D, which is a mediator of hypersensitivity reactions, may still have an important role in causing asthmatic symptoms. In fact, it is 100 times more effective than histamine in producing vascular permeability. 

The proinflammatory actions of PAF and its elaboration by endothelial cells, leukocytes, and mast cells under inflammatory conditions are well characterized. PAF and PAF-like molecules are thought to contribute to the pathophysiology of inflammatory disorders, including anaphylaxis, bronchial asthma, endotoxic shock, and skin diseases. The plasma concentration of PAF is increased in experimental anaphylactic shock, and the administration of PAF reproduces many of its signs and symptoms, suggesting a role for the autacoid in anaphylactic shock. In addition, mice over expressing the PAF receptor exhibit bronchial hyperreactivity and increased lethality when... 

Mast cell A mast cell is derived from the myeloid stan cell and is part of the inunune system it contains many granules rich in histamine and heparin. Allhongh best known for their role in allergy and anaphylaxis, mast cells play an important protective role as well, being intimately involved in wound healing and defense against palhogens. 

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