The role of Th22 cells and IL-22 in the pathophysiology of PCC is not fully understood but IL-22-induced signaling pathway may switch from protective to pathogenic as COVID-19 progresses (95) due to although it acts on epithelial cells to promote tissue protection and regeneration, IL-22 may also elicit pro-inflammatory effects, contributing to disease pathology (96). This evidence concerns the gene IL22 and COVID-19.