the roles of t helper 1, t helper 17 and regulatory t cells in the pathogenesis of sarcoidosis

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-il17/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.