Dictionary of Allergies .. Basophils and late-phase reactions

The allergic inflammatory response is composed of two main phases-the early and the late. The early phase initiates when an allergen activates the tissue resident mast cell, triggering the release of a variety of granule-stored and newly formed mediators. As the inflammatory response progresses, blood borne inflammatory cells-in particular, eosinophils-are recruited into the inflamed tissue. Eosinophil activation and consequent release and production of several pro-inflammatory mediators results in the late phase reaction [1]. Experimental investigations of antigen-induced inflammation in vivo have released both immediate reactions and so-called late-phase reactions in all organs studied. The immediate hypersensitivity reaction is driven by mast cells while the late-phase reaction, which occurs hours later, is driven, in part, by basophil mediators [2].

Mast cells in patients with allergic rhinitis and asthma produce Th2 type cytokines, induce IgE synthesis in B cells and can autoactivate itself via the mast cell-IgE-FcepsilonRI cascade. In addition, mast cells upregulate the production of a variety of cytokines/chemokines in epithelial cells and fibroblasts and induce the recruitment of basophils, T cells and eosinophils into sites of allergic inflammation as well as their own intraepithelial accumulation [3].

References
Minai-Fleminger Y, Levi-Schaffer F. Mast cells and eosinophils: the two key effector cells in allergic inflammation. Inflamm Res. 2009 May 8.

2. Massay W. A. and Lichtenstein L.M.: Role of Basophils in Human Allergic Disease. Int Arch Allergy Immunol. 99:184-188:1992.

3. Pawankar R. Mast cells in allergic airway disease and chronic rhinosinusitis. Chem Immunol Allergy. 2005;87:111-29.