inclusion criteria: hospitalized patients, sars-cov-2 pcr positive, within 8 days from the onset of the symptoms (immunosuppressed patients are excluded from the time limit when they become chronic carriers of the virus), who have: * pneumonia or/and sato2 ≤94% on room air or/and respiratory rate ≥24breaths/min and * lymphopenia cd3+≤650/μl or/and alc≤1000/microl and * increased values of d-dimers (≥2χ) or/and ferritin (\>1000ng/ml) or/and crp (≥3χ) or/and ldh (≥2χ)

inclusion criteria: hospitalized patients, sars-cov-2 pcr positive, within 8 days from the onset of the symptoms (immunosuppressed patients are excluded from the time limit when they become chronic carriers of the virus), who have: * pneumonia or/and sato2 ≤94% on room air or/and respiratory rate ≥24breaths/min and * lymphopenia cd3+≤650/μl or/and alc≤1000/microl and * increased values of d-dimers (≥2χ) or/and ferritin (\>1000ng/ml) or/and crp (≥3χ) or/and ldh (≥2χ)

inclusion criteria: hospitalized patients, sars-cov-2 pcr positive, within 8 days from the onset of the symptoms (immunosuppressed patients are excluded from the time limit when they become chronic carriers of the virus), who have: pneumonia or/and sato2 ≤94% on room air or/and respiratory rate ≥24breaths/min and lymphopenia cd3+≤650/μl or/and alc≤1000/microl and increased values of d-dimers (≥2χ) or/and ferritin (>1000ng/ml) or/and crp (≥3χ) or/and ldh (≥2χ)

inclusion criteria: hospitalized patients, sars-cov-2 pcr positive, within 8 days from the onset of the symptoms (immunosuppressed patients are excluded from the time limit when they become chronic carriers of the virus), who have: pneumonia or/and sato2 ≤94% on room air or/and respiratory rate ≥24breaths/min and lymphopenia cd3+≤650/μl or/and alc≤1000/microl and increased values of d-dimers (≥2χ) or/and ferritin (>1000ng/ml) or/and crp (≥3χ) or/and ldh (≥2χ)