For assessment of CCL21 expression in proteinuric kidney disease we chose a non-immunological model of podocyte injury, rat PAN nephrosis, since it is directly induced by a podocyte toxin, does not require activation of the immune system and is representative of human focal segmental glomerulosclerosis, a common human proteinuric nephropathy29, 30. The gene discussed is CCL21; the disease is focal segmental glomerulosclerosis.