MP848URINARY INTERLEUKIN-6 AND INTERLEUKIN-8 EXCRETION IN CHILDREN WITH VESICOURETERAL REFLUX

Abstract

INTRODUCTION AND AIMS: Pyelonephritis is a leading cause of serious bacterial infections in children. Vesicoureteral reflux (VUR) predisposes to pyelonephritis development, and both can lead to permanent kidney damage, renal scarring (RS) and chronic renal failure. Experimental studies have shown that immune-inflammatory mechanisms are involved in the formation of RS. These data need to be confirmed in clinical research. The aim of the study was to assess urine interleukin-6 (uIL-6) and interleukin (uIL-8) levels in children with VUR, clinical information searching on immuno-inflamatory process which promotes to RS. METHOD(S): 43 patients aged from 3 month to 16 years with VUR were examined. These patients with VUR were divided into two groups: 18 with RS (1st group) and 25 children without RS (2nd group). None of them had had episode of pyelonephritis for a minimum of 6 months. 16 healthy children were included in control group. Urine concentrations of IL-6 and IL-8 were measured with commercially available ELISA (Vector-Best, catalog # A-8768, # A-8762, Russia), according to the manufacturer's instructions. To avoid dilution effects, urinary levels of IL-6 and IL-8 were determined as the ratio of cytokine to urinary creatinine (pg/mg) levels. Renal ultrasound, 99mTcdimercaptosuccinic acid scintigraphy (DMSA) and voiding cystourethrography were carried out in all patients. Statistical analyses were performed with StatSoft STATISTICA Version 8 (Tulsa, OK). Non-parametric variables are given as median (interquartile range). Differences between groups were tested using Mann-Whitney test. Multivariate regression modeling was performed to address the association between uIL-6, uIL-8 and other parameters. The clinical studies from which materials were obtained for the current study was approved by the Medical Ethics Committee of the Kharkiv National Medical University and conducted in accordance with the guidelines of the Declaration of Helsinki. All participants and/or their parents gave written informed consent. RESULT(S): The urine IL-6 levels were increased in the patients of the 1st and the 2nd groups, compared with controls ((4.96 (2.08; 11.20) and 10.30 (4.88; 17.70), compared with 1.76 (1.36; 1.92) pg/mg, respectively) (P<0.001)). The median urine IL-6 was significantly higher in patients of the 2nd group, than in children of the 1st group ((10.30 vs. 4.96), (P<0.05)). The urine IL-8 levels were elevated in the patients of the 2nd group, compared with controls ((12.27 (4.81; 29.44) and 4.39 (3.16; 5.68) pg/mg, respectively) (P<0.001)) and diminished in the patients of the 1st group, compared with control group ((4.08 (2.72; 4.22) and 4.39 (3.16; 5.68) pg/mg, respectively) (P<0.05)). Using multivariate regression modeling, significant correlates of uIL-6 and uIL-8 excretions included the grade of renal scars, the time passed since the last episode of pyelonephritis episode and age of patients (all P< 0.05). CONCLUSION(S): We found significant differences in children with VUR and with or without RS urine IL-6, IL-8. The determination of uIL-6 and uIL-8 levels can provide additional information about the status of the renal parenchyma status in children with VUR especially in places where other investigations are not available.