Preventing secondary infections in ICU patients with sustained immune suppression using interferon-gamma

Inclusion Criteria:

* Adult patient hospitalized in the ICU for at least 1 week
* Expected length of stay in the ICU greater than 10 days at screening
* At least 1 episode of multiple organ failure, defined as a SOFA ≥ 6 (excluding the respiratory component when related to a neurological failure), during the first 1 week of ICU hospitalization
* Immunosuppression defined as an mHLA-DR \< 8000 Ab/c and a lymphopenia \< 1000/mm3 within a 96 hours time window
* Patient or the legal representative giving consent must be able to understand the trial in its entirety
* Patient affiliated to the social security system
* For female participants of childbearing potential, agreement to use dual methods of contraception until Day 90
* For male participants with female partners of childbearing potential, agreement to use barrier method of contraception until Day 90.

Exclusion Criteria:

* Uncontrolled secondary infections ongoing at the time of screening
* Participation in another research clinical trial within 30 days
* Chemotherapy / radiation therapy within the last 6 weeks
* Apache II ≥ 30 at screening
* History of autoimmune disease
* Organ or bone marrow transplant
* History of hematologic malignancy
* History of hepatitis C
* HIV stage C within the last 12 months
* Patients under legal protection
* History of or ongoing tuberculosis
* Chronic hepatitis B
* Patients receiving immunosuppressive medications including patient receiving a steroid dose greater than 1mg/kg/day of prednisone equivalent for more than 1 week and patient that have been on corticosteroid for more than 3 months
* Patient with thrombocytopenia below 50,000/mm3
* Patient with traumatic brain and spinal injury
* Pregnancy or breast feeding
* Subjects with a history hypersensitivity to interferon gamma or excipient (Mannitol, Sodium succinate dibasic hexahydrate, Succinic acid, polysorbate 20), known latex hypersensitivity or other interferon
* Hepatic cytolysis with AST/ALT \> 5 times ULN (local laboratory)
* Suspected acute pancreatitis with lipase or amylase \> 3 times ULN (local laboratory)
* Severe chronic renal failure (eGFR\<10 ml/min/1.73m2 CKP-EPI method)
* Acute ECG abnormality such as myocardial infarction or any acute life-threatening ECG abnormalities (e.g: ventricular fibrillation, ventricular tachycardia…)
* Mental state rendering the person giving consent incapable of understanding the trial
* Patient deprived of liberty by judicial or administrative decision
* Patient being the investigator, or any member of the team or relative of the investigator directly involved in the trial, including assistant doctors, pharmacists, nurses, trial coordinators