Difficulty in enrolling new patients

Diffuse parenchymal lung diseases (DPLD) include a variety of respiratory conditions that affect either the pulmonary interstitium or the alveolar space . The etiological diagnosis of DPLD is often challenging, because of the large number of pathological entities involved, which share close clinical and radiological presentations. High resolution Chest CT, a key diagnostic procedure in DPLD, is subject to significant inter-observer analysis variations, so that the diagnosis sometimes requires a surgical or transbronchial lung biopsy sampling. This invasive procedure is not devoid of morbidity and may be impossible to perform in fragile patients. Therefore, the definite diagnosis of DPLD is usually achieved following a multi-disciplinary expert consensus, based on careful medical history, chest CT and bronchoalveolar lavage examinations.

Alveolar probe-based confocal laser endomicroscopy (pCLE) is a mini invasive endoscopic technique that allows distal lung microscopic imaging in vivo, during a flexible bronchoscopy performed under topical anaesthesia. Since 2006, Alveolar pCLE has been used in a monocentric clinical trial at the Rouen University Hospital in more than 200 patients and healthy volunteers. This allowed the first pCLE in-vivo description of normal pulmonary acinus, and confirmed the safety of the technique.

Inclusion Criteria:

• age ≥ 18
• signed written informed consent
• indication for a flexible bronchoscopy
• DPLD characterized by clinical and radiological data compatible with : idiopathic pulmonary fibrosis (IPF), acute or chronic hypersensitivity pneumonitis (HPS), sarcoidosis, or asbestosis.
• Initial histological confirmation of the disease is not required for the inclusion of the patient and the realisation of the alveolar bronchoscopy.
• non-smoking or smoking cessation >6 month
• Patient affiliated with, or beneficiary of a social security category

Exclusion Criteria:

• respiratory failure and contraindication for a flexible bronchoscopy (this item will stay at the appreciation of the physician, arterial blood gaz sampling being not required)
• bleeding disorder which would be not compatible with the realization of a flexible bronchoscopy
• history of pneumonectomy or non functional lung controlateral to the pCLE procedure
• patients for which a per-endoscopic distal lung cryobiopsy is forecasted during the first diagnostic bronchoscopy,
• patients for which the bronchoscopy needs a general anesthesia and mechanical ventilation during the procedure
• anticoagulant or platelet aggregation inhibitors that cannot be interrupted for the flexible bronchoscopy
• patients for which a follow up or an adequate work-up to achieve the final diagnosis will not be possible.
• patients for which a cryobiopsy is forecasted during the bronchoscopy
• pregnant and breast feeding women, or women of childbearing potential not taking adequate contraception
• Patients unable to understand informed consent
• Patient on major legal measure of protection
• Patients participating in an other interventional clinical trial at the inclusion date