Serum and urine interleukin-6 and transforming growth factor-beta1 in young infants with pyelonephritis.

BACKGROUND

Cytokines are involved both in the acute response during pyelonephritis and in the progression to renal scarring. The aim of the present study was to assess the pro-inflammatory interleukin-6 (IL-6) and the anti-inflammatory pro-fibrotic transforming growth factor-beta1 (TGF-beta) in very young infants with pyelonephritis.

METHODS

Serum and urine concentrations of IL-6 and TGF-beta1 were determined by enzyme immunoassay in infants with acute pyelonephritis before antibiotic treatment and in infants with non-renal fever. IL-6 was studied in 12 infants with pyelonephritis and in eight with non-renal fever (median ages, 2 months for both groups). TGF-beta1 was studied in 11 infants with pyelonephritis and in nine with non-renal fever (median ages, 2 and 4 months, respectively).

RESULTS

No significant differences were documented in serum concentrations of IL-6 and TGF-beta1 between patients and controls. Urine IL-6 levels were significantly higher in infants with pyelonephritis than in controls (medians, 147 and 21.4 pg/ml, respectively; P = 0.0106). The urine levels of TGF-beta1 were lower in infants with pyelonephritis than in controls, although not significantly (medians, 6.12 and 11.0 ng/ml, respectively; P = 0.0705).

CONCLUSIONS

Our findings confirm the implication of IL-6 but not of TGF-beta1 in the pathogenesis of the early stages of pyelonephritis in young infants. Tauhe role of the pro-fibrotic TGF-beta1 in the development of renal scarring deserves further investigation.