Although STZ administration induced persistent hyperglycemia, repeated administration of human umbilical cord-derived cultured CD34+ cells markedly improved urinary albumin excretion and renal pathology, including mesangial matrix expansion, interstitial fibrosis, PTC loss, and glomerular macrophage infiltration, in rats with STZ-induced diabetic nephropathy. The gene discussed is CD34; the disease is diabetic kidney disease.