Clinical significance of urinary interleukin-6 in children with reflux nephropathy.
OBJECTIVE
We determined urinary interleukin-6 (IL-6) in children with reflux nephropathy to evaluate the clinical significance of this cytokine in the progression of renal injury.


METHODS
Enrolled in this study were 34 boys and 32 girls in whom 99mtechnetium dimercapto-succinic acid renal scan showed renal scarring. Vesicoureteral reflux had been corrected surgically at least 3 years before study entry. Urinary IL-6 was determined by enzyme-linked immunosorbent assay using spot urine samples. Simultaneously we measured serum creatinine, beta2-microglobulin, alpha1-microglobulin, urinary alpha1-microglobulin and albumin. In addition, IL-6 expression was assessed by immunohistochemical study in the scarred kidneys of 3 boys and 1 girl who underwent nephrectomy due to severe reflux nephropathy with little function on renal scan.


RESULTS
Urinary IL-6 was significantly higher in children with severe bilateral renal scarring than in those with mild scarring and normal controls. Urinary IL-6 correlated significantly with serum alpha1-microglobulin (Spearman test p <0. 03), beta2-microglobulin (p <0.003), creatinine (p <0.02) and urinary albumin (p <0.0001). Histological evaluation revealed that IL-6 was predominantly expressed in the tubules in and adjacent to fibrotic areas.


CONCLUSIONS
Our observations indicate that tubular IL-6 may be involved in the pathogenesis of tubulointerstitial injury in reflux nephropathy and urinary IL-6 may be a useful tool for monitoring the progression of reflux nephropathy.
Wang
J
J
Department of Urology and Second Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
Konda
R
R
Sato
H
H
Sakai
K
K
Ito
S
S
Orikasa
S
S
D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D018450:Disease Progression; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000652:urine*; D007684:Kidney Tubules / Q000737:chemistry / Q000473:pathology; D008297:Male; D011866:Radioisotope Renography; D019275:Radiopharmaceuticals; D019783:Technetium Tc 99m Dimercaptosuccinic Acid; D014718:Vesico-Ureteral Reflux / Q000175:diagnosis / Q000652:urine*
D015850:Interleukin-6; D019275:Radiopharmaceuticals; D019783:Technetium Tc 99m Dimercaptosuccinic Acid