inclusion criteria: * age \> 18 years * hospitalized for covid-19 confirmed by reverse transcriptase-polymerase chain reaction (rt-pcr) or scanner * patients with pao2/fio2 between 100 and 200 mmhg requiring non invasive ventilation or high flow oxygen * at least two biological results suggesting a cytokine storm or hyperinflammatory condition state among : c-reactive protéine (crp)\>50mg/l, procalcitonin (pct)\>1µg/l, fibrinogen\>5g/l, d-dimer \>1000ng/ml, ferritin \> 800ng/ml during the last 72 hours. * treatment with corticosteroids (at least 2 intakes of dexamethasone 6 mg or equivalent with another form of corticosteroids) * patient affiliated to a social security or similar scheme * information and written consent from the patient or if not possible from a confident person

inclusion criteria: * age \> 18 years * hospitalized for covid-19 confirmed by reverse transcriptase-polymerase chain reaction (rt-pcr) or scanner * patients with pao2/fio2 between 100 and 200 mmhg requiring non invasive ventilation or high flow oxygen * at least two biological results suggesting a cytokine storm or hyperinflammatory condition state among : c-reactive protéine (crp)\>50mg/l, procalcitonin (pct)\>1µg/l, fibrinogen\>5g/l, d-dimer \>1000ng/ml, ferritin \> 800ng/ml during the last 72 hours. * treatment with corticosteroids (at least 2 intakes of dexamethasone 6 mg or equivalent with another form of corticosteroids) * patient affiliated to a social security or similar scheme * information and written consent from the patient or if not possible from a confident person

inclusion criteria: - age > 18 years - hospitalized for covid-19 confirmed by reverse transcriptase-polymerase chain reaction (rt-pcr) or scanner - patients with pao2/fio2 between 100 and 200 mmhg requiring non invasive ventilation or high flow oxygen - at least two biological results suggesting a cytokine storm or hyperinflammatory condition state among : c-reactive protéine (crp)>50mg/l, procalcitonin (pct)>1µg/l, fibrinogen>5g/l, d-dimer >1000ng/ml, ferritin > 800ng/ml during the last 72 hours. - treatment with corticosteroids (at least 2 intakes of dexamethasone 6 mg or equivalent with another form of corticosteroids) - patient affiliated to a social security or similar scheme - information and written consent from the patient or if not possible from a confident person

inclusion criteria: - age > 18 years - hospitalized for covid-19 confirmed by reverse transcriptase-polymerase chain reaction (rt-pcr) or scanner - patients with pao2/fio2 between 100 and 200 mmhg requiring non invasive ventilation or high flow oxygen - at least two biological results suggesting a cytokine storm or hyperinflammatory condition state among : c-reactive protéine (crp)>50mg/l, procalcitonin (pct)>1µg/l, fibrinogen>5g/l, d-dimer >1000ng/ml, ferritin > 800ng/ml during the last 72 hours. - treatment with corticosteroids (at least 2 intakes of dexamethasone 6 mg or equivalent with another form of corticosteroids) - patient affiliated to a social security or similar scheme - information and written consent from the patient or if not possible from a confident person