To detect CXCR4 expression in fibrotic kidneys, kidney biopsies from normal nephrectomy specimens and patients with diabetic kidney disease (DKD) and kidney fibrosis and kidneys from 3 mechanistically distinct mouse models of kidney fibrosis, including streptozotocin-induced (STZ-induced) DKD, UUO, and FA nephropathy, were collected. Here, CXCR4 is linked to diabetic kidney disease.