Increased urine interleukin-6 concentrations correlate with pyelonephritic changes on 99mTc-dimercaptosuccinic acid scans in neonates with urinary tract infections.

Interleukin (IL)-6 and -8 are important inflammatory cytokines in bacterial infections. Their serum and urine concentrations were measured in 27 neonates with urinary tract infection (UTI) at onset and the second week of therapy, as well as in 23 control neonates. Escherichia coli was isolated in 89% of cases. 99mTc-dimercaptosuccinic acid (99mTc-DMSA) scans were performed between the 10th and 90th days after UTI and showed pyelonephritic changes in 15 neonates (56%). Increased IL-6 and IL-8 concentrations were found in urine but not in serum within the first 24 h after presumptive diagnosis of UTI (P=.036 and.010, respectively), suggesting that the neonatal urinary tract can respond to uropathogens by producing inflammatory cytokines. Urine concentrations of IL-6 correlated with findings of renal changes in 99mTc-DMSA scans (P=.012) and thus may serve as a marker of renal parenchymal outcome. All neonates exhibited undetectable urine cytokine levels during the second week of therapy.