Recent studies suggest that the JAK/STAT signaling pathway constitutes a new step in the clinical and therapeutic progress of sarcoidosis. Further investigations are necessary to identify the most suitable patients to receive treatment targeting this pathway, in particular in cases of severe sarcoidosis refractory to the various therapeutic lines.

The investigators hypothesize that the JAK/STAT signaling pathway constitutes a new step in the clinical and therapeutic progress of sarcoidosis, in particular in cases of severe sarcoidosis refractory to the various therapeutic lines. The main objective of this proposal is to evaluate the presence and stage of activation of the JAK/STAT pathway in PBMCs from inactive and active sarcoidosis patients. The second objective will be to determine the role of the JAK/STAT pathway in the formation and maintenance of granulomas and their association with the severity of sarcoidosis and fibrogenesis.

Inclusion Criteria:

• Patients with a diagnosis of mediastinopulmonary sarcoidosis made according to ATS / ERS / WASOG criteria
• Or patient suspected of having mediastino-pulmonary sarcoidosis, without any other probable causal factor identified on the usual standard examination at the time of the sample with the need for diagnostic confirmation at the end of the study according to the criteria of the ATS / ERS / WASOG
• Sarcoidosis with stage 1 to 4 pulmonary involvement
• Patients who had a chest CT scan in the 6 months preceding the sample. Examination carried out as part of routine care

Exclusion Criteria:

• Pregnancy.
• Opposition expressed to participation in the study.
• Patients on State Medical Aid.

Patients with mediastino-pulmonary sarcoidosis receiving or not receiving treatment for their sarcoidosis. Subjects treated for their sarcoidosis (corticosteroids and/or immunosuppressants) are not excluded because of two recent cases reported of multi-treated patients in which an involvement of the JAK/STAT pathway was demonstrated.