Figure 2.

The immunological drama mastered by SARS-CoV-2. The alveolar macrophages act as first sentinels in the airways. The innate arm of immunity shows overzealous activation during severe cases of SARS-CoV-2.After confronting SARS-CoV-2, macrophage inflammasome-mediated release of IL-1βinduces a robust host response visible during immunopathology. At the same time, they induce vigorous expression of IFN-α/β that add on to the cytokine storm. Inside the alveolus, the DCs also stimulate expression of TNF-α, IL-2 and IL-6 through TLR signaling. The cytopathic effect of SARS-CoV-2 can be seen in the epithelial damage. Also, the infected cells, exerting their “by stander” effect, also induce IFN-α/β. Subsequent interaction of virus/antigens with IMMs further augments in the concentration of inflammatory cytokines. Th1 activation also charges a set of cytokines to add up to cytokine storm. The cytokine storm exerts damaging effect in alveolar tissue. The extravasation of circulating neutrophils and monocyte under the existing cytokine stimulation manifests in edema and deposition of debris in the alveolus. The condition of ARDS is conspicuously registered.