Broos CE, et al. - The lung-draining mediastinal lymph nodes (MLN) are currently widely used to diagnose sarcoidosis. Herein, researchers sought to investigate if T helper 17.1 (Th17.1) cells are also increased in the MLN of sarcoidosis patients and if frequencies of the Th17.1 cells at diagnosis may correlate with disease progression. In sarcoidosis MLN vs in control MLN, higher proportions of Th17.1 cells were detected. Moreover, in patients developing chronic disease vs those undergoing resolution within 2-year clinical follow-up, significantly higher broncho-alveolar lavage fluid (BALF) Th17.1 cell proportions were detected. Overall, Th17.1 cell proportions in pulmonary sarcoidosis can be assessed as diagnostic and/or prognostic marker in clinical practice and could serve a new therapeutic target.