In accordance with the research published on January 24, 2020, Huang and his colleague found the cytokines and chemokines were elevated in the COVID-19 patients, and made the comparison between ICU and non-ICU patients, which revealed the higher IL-2, IL-7, IL-10, TNF-α, GCSF, IP10, MCP1, MCP1A levels in the ICU patients. Here, IL2 is linked to COVID-19.