The Role of Interleukin 17 Cytokine Family in Inducing Allergic Inflammation in the Pulmonary Tract

IL-17 family is a group of proinfl ammatory cytokines produced by activated memory T-cells. These cytokines play an important role in the development of cellular and humoral mechanisms of immunological re-sponses lying at the basis of allergic disorders. The aim of this paper is to present the current knowledge on the role of interleukin 17 cytokine family in the pathogenesis of allergic disorders of the respiratory tract. IL-17A (as well as IL-17F) plays role in the development of airway hyperresponsiveness through activation of allergen-specific T-cells. Levels of IL-17A are elevated in sputum of asthmatic patients and correlate with airway hyperresponsiveness to methacholine. However, it remains fact, that the main effect of IL-17A in the pulmonary tract is recrutation of polymorphonuclear leukocytes, depending on CXC chemokine release from stromal cells. IL-17E evokes differ-ent immunological responses. This cytokine participates in the development of Th2-cell-dependent immunological response and the coexisting pathological tissue changes. These actions take place mainly through the induction of synthesis of the Th2 cell-derived cytokines (IL-4, IL-5, IL-13) and the development of eosinophilic infl ammation. It is thought, that the character of the immunological response evoked by different cytokines of IL-17 family depends on the differences between the spatial structure of their fragments including disulfi de bridges and that these differences determine their receptor interactions and biological functions.