TNF and psoriasis: In addition, subcutaneous injection of the fused exosomes significantly upregulated the expression of M2 macrophage biomarker, arginase-1 (Arg-1), and reduced the levels of pro-inflammatory cytokines, including IL-1β, IL-6 and TNF-α in lesional skin, resulting in attenuation of the psoriasis-like skin inflammation [100].