In particular, IL-1β, IL-6, and IL-10 are the three most elevated cytokines in severe cases.25,26 Our study also showed that cytokine levels, including IL2, IL-4, IL-6, IL-10, TNF-α and IFN-γ, are elevated in severe and critical COVID-19 cases, particularly IL-6 and IL-10, which showed a dramatic increase in levels.27 Here, IL2 is linked to COVID-19.