Patients who required intensive care unit admission because of COVID-19 showed a higher percentage of GM-CSF+ CD4+ T cells, suggesting excessive activation of the immune response by G-CSF may promote the development of lung injury.50 Therefore, although G-CSF may reduce hospitalization from neutropenic complications, it carries a theoretical risk of promoting pulmonary injury and aggravating the COVID-19 course.22,50 Given the absence of clinical data to resolve this, evidence is needed to clarify how GM-CSF modulates the global risk of patients. Here, CD4 is linked to COVID-19.