T-cells and their cytokines play an important role in the pathogenesis of idiopathic nephrotic syndrome (INS) in children. IL-17 secreted by activated CD4+ Tcells induces production of proinflammatory mediators, enhances T-cell-mediated immune responses and Th1 type reactions. The aim of the study was to evaluate IL-17 concentrations in serum and urine of children with INS and determine the possible role of this cytokine in the course of disease.
Patients and methods: 67 children with INS, aged 3 to 16 years (mean 9 +/- 4) and 15 normal controls were included in the study. The patients were divided into 2 groups according to activity of the disease: I (n=37)--INS in relapse, II (n=30)--INS in remission. Serum (s) and urinary (u) IL-17 were determined by immunoenzymatic method. In children with INS serum biochemical parameters, clearance of endogene creatinine and 24 hour proteinuria were measured.
Results: sIL-17 and uIL-17 concentrations (51.66 +/- 8.38 pg/mg and 56.29 +/-14.24 pg/mg creatinine (cr), respectively) were significantly higher (p<0.001) in group I compared with group II (35.7 +/- 10.18 pg/ml and 17.47 +/- 3.46 pg/mg cr) and normal controls (27.17 +/- 1.87 pg/ml and 13.91 +/- 1.22 pg/mg cr). UIL-17 correlated positively with sIL-17 (r=0.783, p<0.0001). A positive correlations between uIL-17 and sIL-17 and urinary protein excretion were found (r=0.58, r=0.42, respectively; p<0.05).
In conclusion: elevated serum and urinary IL-17 levels in children with relapse of nephrotic syndrome suggest the role of IL-17 in the pathophysiology of INS. IL-17 concentrations in serum and urine may reflect the disease activity of INS.