IL17A and psoriasis: found that intravenous administration of human gingiva-derived MSCs in mice (2 × 106 cells) can reduce the levels of pro-inflammatory cytokines including IFN-γ, TNF-α, IL-6, IL-17A, and IL-21 secreted by Th1 and Th17 cells and promote the increasing number of Treg cells in mouse psoriasis-like models (21).