Described as a proinflammatory cytokine produced by CD4 memory T cells (e.g., Th1, Th17, Th22), IL-22, a member of the IL-10 family, have been found to be significantly elevated in patients with psoriasis compared to healthy controls (Boniface et al., 2007; Lo et al., 2010; Shimauchi et al., 2013; Dudakov et al., 2015; Gordon et al., 2019; Wawrzycki et al., 2019). Here, IL10 is linked to psoriasis.