SARS-CoV-2: a storm is raging

Abstract

The pandemic coronavirus infectious disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is rapidly spreading across the globe. In this issue of the JCI, Chen and colleagues compared the clinical and immunological characteristics between moderate and severe COVID-19. The authors found that respiratory distress on admission is associated with unfavorable outcomes. Increased cytokine levels (IL-6, IL-10, and TNF-α), lymphopenia (in CD4+ and CD8+ T cells), and decreased IFN-γ expression in CD4+ T cells are associated with severe COVID-19. Overall, this study characterized the cytokine storm in severe COVID-19 and provides insights into immune therapeutics and vaccine design.

Keywords: COVID-19.

Figure 1. Cytokine storm and T cell lymphopenia is associated with COVID-19 severity.

SARS-CoV-2 infection causes COVID-19. Compared with uninfected individuals (left panel), moderate COVID-19 cases exhibit an increase in IL-6 and a decrease in total T lymphocyte counts, particularly CD4⁺ T cells and CD8⁺ T cells (middle panel). Severe COVID-19 cases have further increased production of IL-6, IL-2R, IL-10, and TNF-α, while total T lymphocytes, particularly CD4⁺ T cells and CD8⁺ T cells, and IFN-γ–expressing CD4⁺ T cells markedly decrease (right panel). The level of cytokine storm and T cell lymphopenia is associated with pulmonary damage, respiratory distress, and unfavorable outcome. ARDS, acute respiratory distress syndrome; CRP, C-reactive protein; LDH, lactate dehydrogenase.