CD276 and systemic lupus erythematosus: Proteomic analysis identified that Rapa-SLE-EVs are rich in various proteins involved in immune regulation and anti-inflammatory properties, including Indoleamine 2,3-dioxygenase 1 (IDO1), cathepsin G (CTSG), CD276, Milk Fat Globule EGF And Factor V/VIII Domain Containing (MFGE8), and Complex-related components (Fig. 9H).