IL22 and psoriasis: For example, in mouse psoriasis models RORγt positive ILC3 account for the production of the proinflammatory IL-17A and the potent keratinocyte growth factor IL-22 (Pantelyushin et al., 2012) and levels of this cell type are increased in human psoriatic skin (Cai et al., 2011; Villanova et al., 2014).