- age <18 years - pregnant or breast-feeding woman or with positive pregnancy test result - pao2/fio2 ≤100 mmhg / mechanical ventilation - severe organ failure - not expected to survive for >7 days - hemodynamically unstable in the preceding 10 hours (map ≤65 mmhg, or sap <90 mmhg, dap <60 mmhg, vasoactive agents are required) - patient on ecmo - patient in other therapeutic clinical trial within 30 days before enrolment - chronic immunosuppression: current autoimmune diseases or patients who received immunotherapy within 30 days before enrolment - hematologic malignancy (lymphoma, leukemia, multiple myeloma) - other patient characteristics (not thought to be related to underlying covid-19) that portend a very poor prognosis (e.g, severe congestive heart failure( nyha class iii or iv, ef less than 30%,) liver cirrhosis , chronic kidney disease stave iv, v(e gfr<30 ml/min), chronic obstructive lung disease: gold c,d : ≥2 exacerbations or ≥1 that required hospitalization, fev1<50%, gold 3,4) - atopic patients suffering from allergies

- age <18 years - pregnant or breast-feeding woman or with positive pregnancy test result - pao2/fio2 ≤100 mmhg / mechanical ventilation - severe organ failure - not expected to survive for >7 days - hemodynamically unstable in the preceding 10 hours (map ≤65 mmhg, or sap <90 mmhg, dap <60 mmhg, vasoactive agents are required) - patient on ecmo - patient in other therapeutic clinical trial within 30 days before enrolment - chronic immunosuppression: current autoimmune diseases or patients who received immunotherapy within 30 days before enrolment - hematologic malignancy (lymphoma, leukemia, multiple myeloma) - other patient characteristics (not thought to be related to underlying covid-19) that portend a very poor prognosis (e.g, severe congestive heart failure( nyha class iii or iv, ef less than 30%,) liver cirrhosis , chronic kidney disease stave iv, v(e gfr<30 ml/min), chronic obstructive lung disease: gold c,d : ≥2 exacerbations or ≥1 that required hospitalization, fev1<50%, gold 3,4) - atopic patients suffering from allergies