IL2 and COVID-19: Most of the data supporting this hypothesis in COVID-19 come from an early paper that observed high levels of the cytokines interleukin-2 (IL-2), IL-7, IL-10, granulocyte colony-stimulating factor (G-CSF), Interferon γ-induced protein 10 (IP-10), monocyte chemoattractant protein 1 (MCP1), macrophage inflammatory protein–1α (MIP-1α), and tumor necrosis factor α (TNFα) in a small cohort of patients with COVID-19 being cared for in the intensive care unit (ICU).