DPP4 and viral infectious disease: Because of the observed involvement of IL22 in antiviral pathways, we analyzed the expression of genes which are involved in viral infections and clearance (Table S1) and found that IL22 inhibits the expression of several viral entry receptors, such as Ace2 (SARS-Cov-1 and 2), Tmprss2 (SARS-Cov-1 and 2), Dpp4 (MERS), Tnfrsf14 (HSV), and Cd46 (MV), while increasing the expression of antiviral proteins such as Rsad2, Apobec1 and 3, Irf9, Mx1, Isg20, and AoS (Fig. 7h).