Inclusion Criteria:  Adults (>18 years old) Clinical diagnosis of SARS-CoV2 infection with rtPCR confirmation Disease severity with the indication of immunomodulation therapy with interleukin-6 antagonist: acute respiratory failure that requires invasive, noninvasive ventilation , or high flow nasal oxygen therapy with the following parameters: FiO2 > 0,4, flow > 30L/min and C Reactive Protein > 75 mg/L  Exclusion Criteria:  The patient had previously been administered one of the following immunomodulating drug: anakinra, tocilizumab, sarilumab Presence of any condition or drug in the medical history that can lead to immunosuppression Suspicion of infection (active tuberculosis, bacterial, viral, fungal) or level of procalcitonine higher than 0,5 ng/ml at the enrollment of the patient Number of thrombocyte lower than 50 x 109 / L More than >120 hours passed between the admission to the ICU and the administration of interleukin-6 antagonist Administration of any of the following drugs the week before or during the study: fibrinolytic therapy, factor products (PCC, ATIII, FVIIa, FXIII), fibrinogen, desmopressin, tranexamic acid, blood products (FFP, thrombocyte concentrate) Pregnancy The patient or his legal guardian does not sign the consent