BACKGROUND: Detection of urinary cytokines in pauci-immune focal segmental necrotizing glomerulonephritis (FSNGN) may provide valuable information about disease pathogenesis and prognosis.METHODS: Epidermal growth factor (EGF), transforming growth factor (TGF-β1) and vascular endothelial growth factor (VEGF) were measured by ELISA, and Interleukins, monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein (MIP1β) by a multiplex cytokine assay, in 38 patients with FSNGN. Their levels were correlated with severity of histological findings and renal function outcome in short and long term.RESULTS: The percentage of crescents in renal biopsy had positive correlation with TGF-β1 (p=0.004) and IL-15 urinary excretion (p=0.01), and negative correlation with EGF (p=0.01). Increased urinary excretion of IL-6, IL-15, VEGF and MIP-1β was associated with poor renal function outcome, but increased levels of EGF, IL-2 and IL-9 predicted a favourable prognosis. In multiple regression analysis IL-6 and VEGF urinary levels were independent predictors of no-response at the acute phase (p=0.001 and p<0.0001, respectively), while, IL-6 was the only factor (p=0.03) predicted worse outcome at the end of follow-up (39.4±45 months).CONCLUSION: Increased urinary excretion of IL-6, IL-15, VEGF, TGF-β1, MCP-1 and MIP-1β and reduced EGF, IL-2, IL-9 may be associated with histological damage and influence response to treatment in pauci-immune FSNGN.