TNF and focal segmental glomerulosclerosis: We demonstrate that inflammatory pathways including TNF, IL-17, NFkappa B, MAPK, and apoptotic signaling pathways are activated in the glomerular and tubulointerstitial compartments within 1–2 hours after the exposure of the kidney to the sera of FSGS patients undergoing kidney transplantation (Fig 2A) suggesting that these pathways are activated by one or more circulating factors present in the sera of patients with FSGS.