IL10 and COVID-19: Flow cytometric analysis of the T cell compartment in ex vivo stimulated PBMCs of COVID-19 patients revealed a subpopulation of IL-10 producing Treg cells that amounted to 2% of the total Treg population in healthy controls, to 6% in mild-moderate and to 10% in severe COVID-19 disease, notably, in the absence of other significant differences (115).