Chinese scientists have found that in severe cases, the coronavirus is a cause of serious disorders in the immune system, some cells are more active than others. The authors, who published in the journal Nature Medicine.

the Researchers analyzed the immune cells of the respiratory system, including those contained in the bronchi and alveoli in people with different severity COVID-19. Samples were taken from three patients with mild symptoms, six patients in serious or critical condition and three healthy.

critically ill patients in the fluid extracted from the lungs during the procedure, bronchoalveolar lavage, there was excessive number of monocytic macrophages that amplify the inflammatory response. Other types of cells, such as myeloid dendritic cells, plasmacytoid dendritic cells and T-lymphocytes, was at a lower level than patients with moderate COVID-19.

in severe disease, there is also a high level of cytokines produced by macrophages in the lungs. Thus, macrophages contribute to the intense inflammation in the bronchi and alveoli and the cytokine storm — an uncontrolled immune response that leads to disruption of body function and death of the patient.