Urine interleukin-6 and interleukin-8 in children with acute pyelonephritis, in relation to DMSA scintigraphy in the acute phase and at 1-year follow-up.

The relationship between urine interleukin-6 (IL-6) and interleukin-8 (IL-8)/creatinine quotients and 99mTc-dimercaptosuccinic acid (DMSA) scintigraphy, performed within 10 days of acute first-time pyelonephritis and after 1 year, was studied in 41 children. The urine IL-6 and IL-8/creatinine quotients were also related to the urine N-acetyl-beta-D-glucosaminidase (NAG) and albumin/creatinine quotients. Presence of DMSA uptake defects, reflecting local inflammation, in children in the acute phase of pyelonephritis, were associated with elevated urine IL-6/creatinine quotients (median 27 pg/mumol); in children without DMSA changes there was no increase in quotients (median non-detectable) (P < 0.05). Persistent DMSA changes at the 1-year follow-up, probably reflecting renal scarring, were only seen in children with increased urine IL-6/creatinine quotients in the acute phase (P < 0.01). No correlation was found between urine IL-8 and DMSA uptake defects. Vesicoureteral reflux (VUR) at 6-8 weeks did not correlate with the urine cytokine levels in the acute phase. The urine excretion of NAG and albumin, reflecting renal dysfunction, was associated with values of both urine IL-6 and IL-8/creatinine quotients, but not with DMSA defects or VUR. Thus, the initial urine IL-6/creatinine quotients might be used as an indicator of risk for persistent renal damage in acute pyelonephritis.