Effect of Interferon Gamma as a Treatment for Post-aggressive Immunosuppression in Intensive Care Units, a Randomized Bayesian Double-blind Controlled Trial Versus Placebo

Inclusion Criteria: * Patient ≥ 18 years old * SOFA score for first 24 hours post-admission ≥ 6 * Mechanically ventilated at the time of inclusion (non-invasive ventilation (NIV) and high-flow nasal oxygen excluded) * mHLA-DR\< 8,000 AB/C measured between the 5th and 10th day after admission to the intensive care unit * Patient affiliated to a social security scheme * Written consent (relative/trusted person) Exclusion Criteria: * Patient with estimated life expectancy of less than 3 months * Patients with a predicted remaining stay in intensive care \< 72 hours * Patient with pre-existing immunosuppression: solid cancer active or in remission for \< 5 years, active hemopathy or in remission for \< 5 years, systemic disease (including in the absence of specific treatment), solid organ transplant or marrow allograft patient, patient suffering from a HIV infection * Patients with an expected prolonged duration of mechanical ventilation: comatose or vegetative patients (admission for severe stroke with Glasgow score \< 8, patient resuscitated from an arterial stroke,) patients with tracheotomy for ENT problems, patients suffering from muscular disease (e.g. myopathy), patients on long-term mechanical ventilation * Pregnant or breast-feeding women * Contraindication of Imukin (hypersensitivity to interferon gamma-1b or known hypersensitivity to related products, such as another interferon) * Patients on immunosuppressive therapy, including long-term corticosteroid therapy (\>2.5mg/d prednisone equivalent) * Patients with severe hepatic or renal insufficiency * Patient included in another interventional clinical trial * People under court protection and protected adults