Role of epithelium in pathogenesis of chronic rhinosinusitis with nasal polyps: cells and mediators

Chronic rhinosinusitis with nasal polyps is a heterogeneous disease characterized by local inflammation of the upper airways. Inflammation in chronic rhinosinusitis with nasal polyps is divided into 3 main endotypes with different pathophysiology and various forms of inflammation: T1, T2, and T3. Epithelial barrier dysfunction is a common feature in chronic rhinosinusitis induced by endotype-specific cytokines directly and indirectly. The sinonasal epithelium not only functions as a passive barrier but also is an active immunological organ with innate and adaptive components. Violation of the delicate balance of intercellular interactions in the sinonasal epithelium leads to the development of inflammation. The nasal polyp tissue contains numerous populations of immune cells that secrete many different cytokines and chemokines and interact with each other and with cells of the sinonasal epithelium. The most common is the T2 endotype, which is characterized by inflammation of the corresponding type. Inflammatory mediators such as cytokines, chemokines, and their receptors, are potential therapeutic targets for biologics (specific monoclonal antibodies). Several of these drugs have been clinically tested and are already being used in clinical practice. Further studies are aimed at detailing the pathogenetic mechanisms of nasal polyposis, studying the influence of genetic factors on the predisposition to the development of various endotypes, and creating new effective and safe biological preparations for various endotypes of nasal polyposis.