MFGE8 and systemic lupus erythematosus: Lupus-like autoimmune disease features were observed upon lack of the scramblase Xkr8, which regulates PS exposure of apoptotic cells or in milk fat globule epidermal growth factor 8 (Mfg-e8)-deficient mice lacking Mfg-e8, a PS-binding protein mediating integrin binding and engulfment (Lu and Lemke, 2001; Hanayama et al., 2004; Kawano and Nagata, 2018).