TNF and psoriasis: Our results showed that significant attenuation of psoriasis symptoms including reduction in erythema, scaling, and skin thickness was observed in the following groups: IMQ + MSC, IMQ + MSC-2C preconditioned with IL-22+TNF-α cytokines, and IMQ + MSC-Exo 3C preconditioned with IL-17, IL-22, and TNF-α cytokines.