SC-EVs regulate Th17/Treg balance such as inhibition the differentiation of activated CD4+ T cells into Th17 cells, downregulation pro-inflammatory IL-17, promotion differentiation of Tregs (31, 51, 74, 76, 94) (Table 1) and CTLA-4+ Tregs (74), upregulation anti-inflammatory TGF-β, and inhibition aberrant inflammatory responses in stroke (31), type 1 diabetes (51, 76), and chronic periodontitis (94). Here, IL17A is linked to type 1 diabetes mellitus.