PRINCIPLES OF THERAPEUTIC INTERVENTION IN ALLERGIC INFLAMMATION - SIGNIFICANCE OF MODERN H1-ANTAGONISTS - EFFECT OF CETIRIZINE ON EOSINOPHIL GRANULOCYTES

The recent past has seen a fundamental change in our understanding of the pathogenesis of allergic inflammation. While tissue dwelling mast cells seem to be involved in early responses to allergen, T-lymphocyte s may perpetuate and orchestrate allergic inflammation through the rel ease of cytokines. As a consequence, eosinophils migrate into affected skin or mucosal tissue and contribute to local lesions associated wit h the late allergic response to allergen via secretion of a number of cytotoxic basic proteins and other mediators. In asthma, eosinophil-in duced bronchial epithelium disruption may be critical for airway hyper responsiveness and thus determine severity and chronic course of the d isease. Due to these underlying pathogenetic processes, the therapeuti c emphasis for allergic diseases has shifted towards an anti-inflammat ory treatment. Corticosteroids are the most effective anti-inflammator y agents known to date. However, potential side effects limit their ge neral use and drugs with anti-inflammatory actions such as the second generation H1 receptor antagonists may be considered as an alternative therapeutic option in certain allergic conditions. The clinical effec ts and the putative mode of action of this class of drugs with particu lar emphasis of the effects of cetirizine on eosinophils are discussed .