CD4 and COVID-19: Because of its function as a proinflammatory cytokine and a myeloid cell growth factor, GM-CSF may be another important driver of the immunopathological sequelae of SARS-CoV-2 infection.69 Upon SARS-CoV-2 infection, CD4+ T lymphocytes are rapidly differentiated into pathogenic T helper (Th) 1 cells that produce IL-6 and GM-CSF, subsequently inducing CD14+CD16+ monocytes to secrete high levels of IL-6 and GM-CSF and worsen the cytokine storm.78 Hence, a monoclonal antibody against GM-CSF may be effective to attenuate the immunopathogenesis of COVID-19.