CSF3 and lymphopenia: Indeed, on the development of a respiratory infection, the immune system produces inflammatory markers such as granulocyte colony stimulating factor, tumor necrosis factor-alpha, interferon gamma, interleukin- (IL-) 6, and IL-8 by endothelial cells and lymphoid cells activating neutrophils and promoting their proliferation, thus, the hypothesis of the role of neutrophilia and lymphopenia in the death of patients with COVID-19 [33].