IL2 and COVID-19: In terms of the secretion of cytokines (IL-2, TNFα, INFγ), which are produced mainly by Th1 cells, but also by Ts cells and NK cells, we observed very low levels of IL-2 (almost within the normal ranges), and only slightly elevated TNFα and INFγ levels in the ICU COVID-19 patients, whereas increased levels of INFγ were characteristic of the non-ICU COVID-19 patients.