Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 15 4 2016 08 30 334 339 EN Esmaeil Mortaz Department of Immunology, Medical School, Shahid Beheshti University of Medical Sciences, Tehran, Iran AND Chronic Respiratory Diseases Research Center and National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Department of Immunology, Shahid Beheshti University of Medical Sciences, Tehran, Iran AND Airways Disease Section, National Heart and Lung Institute, Imperial College London, London, UK Fatemeh Rezayat Department of Immunology, Medical School, Shahid Beheshti University of Medical Sciences, Tehran, Iran Davar Amani Department of Immunology, Medical School, Shahid Beheshti University of Medical Sciences, Tehran, Iran Arda Kiani Chronic Respiratory Diseases Research Center and National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Department of Immunology, Shahid Beheshti University of Medical Sciences, Tehran, Iran Johan Garssen Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, The Netherlands Ian Adcock Airways Disease Section, National Heart and Lung Institute, Imperial College London, London, UK Aliakbar Velayati Mycobacteriology Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran 2015 11 19 2016 02 21 Sarcoidosis is a systemic granulomatous disorder of unidentified etiology, with a heterogeneous clinical presentation. It is characterized by a reduced delayed-type hypersensitivity to tuberculin and common antigens. The balance between Th1, Th17 and Regulatory T(Treg) cells controls T-cell proliferation and activation.The Th17/Treg ratio in the peripheral blood and bronchoalveolar lavage fluidis increased in patients with active sarcoidosis. Amplified IL-17A expression in granulomas and the presence of IL-17A+, IL-17A+IL-4+ and IL-17A+IFN-γ+ memory T helper cells in the circulation and BAL indicate Th17 cell involvement in granuloma induction and/or maintenance in sarcoidosis. Sarcoidosis should therefore be considered as a Th1/Th17 multisystem disorder and anti-IL-17/Th17 approaches that control and reduce IL-17Amay be an option, therefore, for the treatment of sarcoidosis.Here we provide a short overview as to the role of Th17 cells as critical cells in the pathogenesis of sarcoidosis. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/695 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/695/649