CXCL8 and diabetic kidney disease: 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.