Tehran University of Medical Sciences Immunology and Genetics Journal 2645-4831 7 4 2024 12 22 203 212 Maryam Keyfari Alamdari Cancer Immunology Project Interest Group (CIP), Universal Scientific Education and Research Network (USERN), Tehran, Iran; School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Sara Hemmati Cancer Immunology Project Interest Group (CIP), Universal Scientific Education and Research Network (USERN), Tehran, Iran; School of Medicine, Tehran University of Medical Sciences, Tehran, Iran 2025 02 17 2025 02 17 As a pro-inflammatory cytokine, IL-17 is important in the immune system against fungal and bacterial infections. The IL-17 cytokine family consists of six members that exert their effects by cooperating with five receptors that form the IL-17 receptor family. Although IL-17 is mainly a defensive factor, at times, overexpression of this cytokine will lead to inflammatory and damaging outcomes. Pneumonia is a lower airway disease that can be caused by different agents. In this condition, IL-17 is secreted from different cells and can fight against infection or otherwise lead to progression of the disease. This article reviews the IL-17 role in pneumonia and different inflammatory pathways that it can affect. https://igj.tums.ac.ir/index.php/igj/article/view/184 https://igj.tums.ac.ir/index.php/igj/article/download/184/157