Conclusion:
The clinical, immunological, and pathologic features of COVID-19 have
something in common with SARS and MERS. All the viruses can cause
lymphopenia and influenza-like symptoms in the early stage. SARS and
COVID-19 do not lead to the elevation of TNF-α, but the increase of IL-6
and IL-10 is more common in COVID-19. The IL-6 plays a crucial role in
the pathologic of COVID-19, including the chemotaxis of neutrophils and
lymphocyte necrosis. Importantly, COVID-19 is more able to cause
cytotoxic lymphocytes exhaustion.