TNF and psoriasis: found that intradermal administration of EVs derived from UC-MSCs stimulated by IFN-γ (IFNγ-sEVs) (150 μg) in mice can effectively reduce the symptom of psoriasis through decreasing the levels of pro-inflammatory cytokines including IL-17A, IFN-γ, IL-6, and TNF-α and Th17 cells and increasing the population of Th2 cells in both spleen and skin in psoriasis (74) (Figure 2).