inclusion criteria: * aged between 18 and 65. * rt-pcr positive for sars-cov-2 (berlin protocol). * moderate to severe acute respiratory insufficiency (100 mmhg \<pao2/fio2 ≤ 200 mmhg). * confirmatory diagnosis of pulmonary injury by chest teleradiography or computed axial t tomography. * being under standard therapy for covid-19. * informed consent signed by the patient or a legally acceptable representative (in the case of the legal representative, informed consent could be obtained by a phone call or email with the subsequent written confirmation).

inclusion criteria: * aged between 18 and 65. * rt-pcr positive for sars-cov-2 (berlin protocol). * moderate to severe acute respiratory insufficiency (100 mmhg \<pao2/fio2 ≤ 200 mmhg). * confirmatory diagnosis of pulmonary injury by chest teleradiography or computed axial t tomography. * being under standard therapy for covid-19. * informed consent signed by the patient or a legally acceptable representative (in the case of the legal representative, informed consent could be obtained by a phone call or email with the subsequent written confirmation).

inclusion criteria: - aged between 18 and 65. - rt-pcr positive for sars-cov-2 (berlin protocol). - moderate to severe acute respiratory insufficiency (100 mmhg <pao2/fio2 ≤ 200 mmhg). - confirmatory diagnosis of pulmonary injury by chest teleradiography or computed axial t tomography. - being under standard therapy for covid-19. - informed consent signed by the patient or a legally acceptable representative (in the case of the legal representative, informed consent could be obtained by a phone call or email with the subsequent written confirmation).

inclusion criteria: - aged between 18 and 65. - rt-pcr positive for sars-cov-2 (berlin protocol). - moderate to severe acute respiratory insufficiency (100 mmhg <pao2/fio2 ≤ 200 mmhg). - confirmatory diagnosis of pulmonary injury by chest teleradiography or computed axial t tomography. - being under standard therapy for covid-19. - informed consent signed by the patient or a legally acceptable representative (in the case of the legal representative, informed consent could be obtained by a phone call or email with the subsequent written confirmation).

inclusion criteria: men and women. 2. aged between 18 and 65. 3. rt-pcr positive for sars-cov-2 (berlin protocol). 4. moderate to severe acute respiratory insufficiency (100 mmhg <pao2/fio2 ≤ 200 mmhg). 5. confirmatory diagnosis of pulmonary injury by chest teleradiography or computed axial tomography. 6. being under standard therapy for covid-19. 7. informed consent signed by the patient or a legally acceptable representative (in the case of the legal representative, informed consent could be obtained by a phone call or email with the subsequent written confirmation). -

inclusion criteria: men and women. 2. aged between 18 and 65. 3. rt-pcr positive for sars-cov-2 (berlin protocol). 4. moderate to severe acute respiratory insufficiency (100 mmhg <pao2/fio2 ≤ 200 mmhg). 5. confirmatory diagnosis of pulmonary injury by chest teleradiography or computed axial tomography. 6. being under standard therapy for covid-19. 7. informed consent signed by the patient or a legally acceptable representative (in the case of the legal representative, informed consent could be obtained by a phone call or email with the subsequent written confirmation). -