FIGURE 2.

Severe SARS-CoV-2 infection: summary of aberrant activation of leukocytes and cytokine production contributing to a cytokine storm and pathology. Conceptual model of observations associated with severe SARS-CoV-2 infection. The activation of monocytes/macrophages and lymphocyte subsets in blood are likely to be major sources of cytokine release, together with the infiltration of leukocytes into lung tissue. Alveolar injury is shown to be associated with cell infiltrates, the release of neutrophil extracellular traps (NETs), hyperplasia of type II pneumocytes, among others, all of which could result in ARDS, lung insufficiency and a cytokine storm (exacerbated if combined with a superimposed bacterial infection). COVID-19/bacterial pneumonia image provided by: Dr. Ana S. Kolansky, University of Pennsylvania. Figure is made with BioRender (https://app.biorender.com/)