The serum levels of the CXCR2 ligands, CXCL1 and CXCL8, were also significantly increased in DKD patients (Fig. S1A, S1C), and line regression showed that CXCL1 (Fig. S1B) and CXCL8 (Fig. S1D) were positively correlated with UACR. Here, CXCR2 is linked to diabetic kidney disease.