The roles of mast cells in allergic inflammation and mast cell-related disorders

ABSTRACT

Mast cells, which are major effector cells in allergic reactions, are found in the perivascular spaces of most tissues and contain pro-inflammatory and vasoactive mediators. These mediators are released after IgE receptor cross-linking induced by allergens or other stimuli, including anaphylatoxins (C3a and C5a), aggregated IgG, certain drugs, venoms, and physical stimuli (pressure and temperature changes), as well as cytokines and neuropeptides. The excess release of these mediators can cause variable allergic symptoms and signs, such as bronchospasm, itching, flushing, nausea, vomiting, diarrhea, abdominal pain, vascular instability, and anaphylaxis. Furthermore, mast cell disorders may involve either excessive proliferation of mast cells or abnormal mast cell reactivity. Mast cell disorders can be broadly divided into 3 types: primary, secondary, and idiopathic. All of these disorders present with signs and symptoms of mast cell activation and differ in severity and involvement of various organ systems. The best characterized primary disorder is mastocytosis. Systemic and cutaneous forms of the disease are well described. Secondary disorders include typical allergic diseases and some types of urticarial diseases. In this article, the biochemical characteristics of mast cells and the role of mast cells in allergic inflammation, as well as the classification, diagnosis, and management of mast cell-related disorders, will be reviewed.