inclusion criteria: - adults aged > 18 years able to provide a valid informed consent to the study - documented covid-19 by direct testing (positive pcr), with lung infiltrates at imaging (chest-x ray or ct) and requirement of oxygen supplementation - less than 10 days form symptoms onset - cytokine storm, using the criteria developed at temple university (all of the three below criteria): - crp > 46 mg/l - ferritin > 250 ng/ml - one variable of each of the three clusters below - cluster 1 - albumin < 2.8 g/dl - lymphocytes <10.2 % of wbc - absolute neutrophil count > 11400/mm3 - cluster 2 - alt > 60 u/l - ast > 87 u/l - d-dimers > 4930 µg/l fibrinogen-equivalent-units (feu). - ldh >416 u/l - high sensitivity troponin > 1.09 ng/ml - cluster 3 - anion gap at arterial blood gas < 6.8 mm - chloride > 106 mm - potassium > 4.9 mm - bun:creatinine ratio > 29 - pao2/fio2 200-400 mmhg, while in oxygen therapy or continuous positive airway pressure (c-pap) - for women of childbearing potential and men: agreement to use contraception in the case of heterosexual intercourses before day 28 with a failure rate < 1% per year (bilateral tubal ligation, male sterilisation, hormonal contraceptives inhibiting ovulation, hormone-release or copper intrauterine devices). for men enrolled in the study, condom use is allowed.

inclusion criteria: - adults aged > 18 years able to provide a valid informed consent to the study - documented covid-19 by direct testing (positive pcr), with lung infiltrates at imaging (chest-x ray or ct) and requirement of oxygen supplementation - less than 10 days form symptoms onset - cytokine storm, using the criteria developed at temple university (all of the three below criteria): - crp > 46 mg/l - ferritin > 250 ng/ml - one variable of each of the three clusters below - cluster 1 - albumin < 2.8 g/dl - lymphocytes <10.2 % of wbc - absolute neutrophil count > 11400/mm3 - cluster 2 - alt > 60 u/l - ast > 87 u/l - d-dimers > 4930 µg/l fibrinogen-equivalent-units (feu). - ldh >416 u/l - high sensitivity troponin > 1.09 ng/ml - cluster 3 - anion gap at arterial blood gas < 6.8 mm - chloride > 106 mm - potassium > 4.9 mm - bun:creatinine ratio > 29 - pao2/fio2 200-400 mmhg, while in oxygen therapy or continuous positive airway pressure (c-pap) - for women of childbearing potential and men: agreement to use contraception in the case of heterosexual intercourses before day 28 with a failure rate < 1% per year (bilateral tubal ligation, male sterilisation, hormonal contraceptives inhibiting ovulation, hormone-release or copper intrauterine devices). for men enrolled in the study, condom use is allowed.