Immunity Markers in Intensive Care Patients and Ventilator-associated Pneumonia

Inclusion Criteria: * Patient over 18 years old * Patient admitted in the Intensive Care Unit of the CHIAP * Patient under mechanical ventilation * Patient with infectious pneumonia * Informed Consent Form (ICF) obtained from the patient or emergency ICF obtained from close relatives * Patient beneficiary of French social security, whatever the regime Exclusion Criteria: * Patient under 18 years old * Patient with severe neutropenia (neutrophils \< 0.5 G/L) * Patient under immunosuppressive treatment * Use of corticosteroids (intravenous or oral) prior to ICU admission * Use of therapeutic antibodies * Onco-hematological disease (e.g. lymphoma, leukemia...) under treatment or treated in the 5 years prior to inclusion * End of chemotherapy 6 months prior to inclusion * Patients with innate or acquired immune deficiency (e.g., severe combined immunodeficiency, HIV or AIDS, at any stage) * Patients with a decision to limit or discontinue active therapies, at the time of inclusion * Patients with an estimated ICU stay of less than 48 hours * Participation in an interventional study * Patient deprived of their liberty * Patient under tutorship or curatorship * Pregnant or breastfeeding woman