Role of the Fibroblast Activation Protein (FAP) as Biomarker of Fibrotic Lung Diseases

To evaluate the use of the fibroblast activation protein (FAP) as a biomarker of fibrotic lung disease (idiopathic pulmonary fibrosis (IPF) and non-IPF ILDs). The study will include both analysis of FAP expression in samples stored in the biobank of the department of Pneumology (BAL, blood, induced sputum and EBC) (cohort A) and lung FAPI uptake on PET/CT scans performed at the department of Nuclear Medicine:

* before and after the initiation of an antifibrotic therapy (IPF or PPF) (cohort B) * before and after the initiation of corticosteroid therapy in case of an acute exacerbation of ILD (cohort C) * before and after the initiation of an immunosuppressive drug in the context of non-IPF pulmonary fibrosis (cohort D). * before lung transplantation, surgery or biopsy to correlate with FAP expression determined by immunohistochemical analysis (IHC) (cohort E).

• Correlation between lung FAP expression and clinical evolution [Срок оценки: From date of inclusion for a period of 2 years]
• Comparison of different FAPi tracers [Срок оценки: From date of inclusion till the second FAPi PET/CT (maximum period of 4 weeks)]
• Comparison of different FAPi tracers [Срок оценки: From date of inclusion till the second FAPi PET/CT (maximum period of 4 weeks)]
• Correlation between lung FAPI uptake and corresponding FAP assessment in blood and BAL samples. [Срок оценки: From date of inclusion till last BAL sample taken, up to a maximum period of 2 years follow-up]
• Correlation between lung FAPI uptake and immunohistological evaluation of the FAP expression on lung samples (after lung transplantation, surgical lung biopsy or cryobiopsy) [Срок оценки: From date of inclusion until surgery, for a maximum period of 2 years]