IL7 and COVID-19: The involvement of CRS in the COVID-19 progression is evidenced by the increased pro-inflammatory factors [IL-6, IL-1, IL-2, IL-7, IL-10, granulocyte-colony stimulating factor, interferon-γ-inducible protein 10, monocyte chemoattractant protein 1, macrophage inflammatory protein-1 alpha, and TNF-α] observed in severe COVID-19 patients (10–12).