Scientists investigate why ventilators may worsen lung infections

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Patient who has given his non-opposition (or non-opposition obtained from close relative of ventilated patients, who will be informed as soon as possible). * Adult patient * Group 1: patient with: * Acute pneumonitis defined by: Signs and acute symptoms of pneumonia (new or worsening within the last 7 days), at least 2 of which are: * Coughing * Purulent sputum * Dyspnea * Chest pain * Temperature \< 35°C or ≥ 38°C And a new pulmonary radiological infiltrate (x-ray or CT scan on admission) * Not acquired under mechanical ventilation * Complicated from ARDS according to the new Berlin definition, Chest x-ray finding bilateral parenchymal opacities not fully explained by pleural effusions, nodules or atelectasis. Respiratory distress not explained by cardiac dysfunction or overfilling. An echocardiogram will be performed in case of diagnostic uncertainty. PaO2/FiO2 report \< 300 and PEP ≥ 5 cmH2O * Requiring the use of MV. * With a diagnostic BAL performed within 72 hours of the start of the MV * Group 2: Patients: * No fever during the last 15 days (reported or measured ≥ 37.8°C). * Not under MV, * Undergoing BAL for a reason other than acute infection (e.g. chronic interstitial syndrome, nodule or lung mass). Exclusion Criteria: * Patient not affiliated to the national health insurance system * Major under judicial protection * Pregnant, parturient or breastfeeding woman * Known primary or secondary immune deficiency (radiotherapy, chemotherapy, immunosuppressive therapy or systemic corticosteroid therapy (\>10mg/day prednisone equivalent for more than 7 days) within 6 months before inclusion, HIV infection, primary cellular immune deficiency) * Patients with treatment known to modulate mitochondrial function, biogenesis and/or mitophagia (chloroquine, hydroxychloroquine, rapamycin, carbamazepine, resveratrol, metformin, sildenafil) * Patients with pulmonary fibrosis or cystic fibrosis known to be associated with mitochondrial alterations