BV2-derived EVs expressing the cytokine IL-4, delivered in a mouse model of multiple sclerosis, propagated an anti-inflammatory response, upregulating microglia and macrophage expression of chitinase 3-like 3 (ym1) and arginase (arg-1), which reduced neuroinflammation with protective effects on tissues (Casella et al., 2018). Here, ARG1 is linked to multiple sclerosis.