Human Recombinant Interferon Gamma in the Treatment of Ventilator-acquired Pneumonia in ICU Patients

Inclusion Criteria: * adult patients hospitalized in intensive care unit * under mechanical ventilation for more than 5 days * having a first episode of VAP (with a Clinical Pulmonary Infectious Score (CPIS score) \>6) * treated with antibiotics for less than 24 hours * with monocyte HLA-DR \< 8000 AB/C * written informed consent signed by the patient's trusted support person, or in the absence of the patient's representative and taking into account the agreement of the relative obtained by telephone emergency certificate completed and signed by the investigator * membership of a social security scheme Exclusion Criteria: * inability to administer the first dose of treatment in the study within 48 hours of the start of antibiotic therapy (antibiotic therapy for VAP) * Noradrenaline \> 0.25 mcg/kg/min * Immunosuppression, defined by: * solid tumor with chemotherapy in the last 3 months * progressive metastatic disease * hematological disease * solid organ transplantation * HIV infection (AIDS stage or not) * corticosteroid therapy at any dose for more than 3 months * ≥ 1 mg/kg of Prednisone equivalent for more than 7 days * immunosuppressive therapy * Head and/or cervical spine trauma : with a predictable impact on the duration of mechanical ventilation (left to the investigator's judgement), the investigator will assess whether the patient meets the following neurological criteria for extubation during their recovery: * A level of consciousness assessed as 0 or 1 on the Richmond Agitation-Sedation Scale (RASS) * FiO2 \<40% * PEEP level \<5 cmH2O * A FR/Vt ratio \<105 * Effective cough * Response to simple commands * Administration of noradrenaline \< 0.2 mcg/kg/min * Cardiocirculatory arrest * Burn patient * Cirrhosis with Child B or C score * Infection with Aspergillus spp. * Refusal to participate * Patient participating in another interventional research in progress or including an exclusion period still in progress at pre-inclusion (excluding interventional research of 2° not interfering with the endpoints of the study according to the judgment of the principal investigator) * Lack of social coverage * Patient under curatorship or guardianship * Pregnant or breastfeeding women * Patient admitted to intensive care for SARS-Cov2 pneumonia * Known allergy to latex * Hypersensitivity to the active substance (interferon gamma-1b) or known hypersensitivity to related products, such as another interferon, or to any of the following excipients: Mannitol, Disodium succinate hexahydrate, Succinic acid, polysorbate 20 * Existence of chronic heart disease with FeVG\<45% * Major hepatic impairment (total bilirubin\>60 mg/L or 102 mcmol/L, equivalent to 3 SOFA points) * thrombocytopenia \<50000/mm3 (equivalent to 3 SOFA points) AST and/or ALT \> 5N Lipase \> 3N Severe chronic renal failure (creatinine clearance MDRD\< 10 ml/min/1.73m2) * Thrombocytopenia \<50,000/mm3 (equivalent to 3 SOFA points) * Respiratory failure requiring home oxygen therapy * Persons under court protection