بررسی غلظت سرمی و ادراری اینترلوکین-6 (IL-6) در کودکان مبتلا به عفونت دستگاه ادراری: افتراق پیلونفریت از سیستیت حاد

    Background & Aim: Pyelonephritis is one of the most serious and common infectious diseases in children. Its renal infection and scarring is the leading cause of end stage renal disease (ESRD) in some parts of the world including Iran. Serum and urinary levels of interleukin-6 (IL-6) have been reported to be high in acute pyelonephritis by some of the previous studies. This study was conducted to examine whether serum and urinary IL-6 is high and can be used as a screening test for acute pyelonephritis.Patients and Method: This prospective, analytical, cross-sectional study was conducted on 40 children with fever, clinical signs and symptoms of urinary tract infection and positive urinary culture who were referred to Ali Asghar Children's Hospital in 2008. Regarding the results of DMSA scan in these children, urinary and serum concentrations of IL-6 were compared in two groups of cystitis (n=20) and pyelonephritis (n=20). For data analysis, independent t-test, Mann-Whitney U-test, Wilcoxon rank, correlation and Receiver Operating Characteristics Curve (ROC) analysis were used. Results: The mean of baseline urinary concentration of IL-6 was significantly higher in children with pyelonephritis [11.53 (SD=9.51) pg/dl] than the ones with cystitis [4.00 (SD=2.18) pg/dl] (P=0.002). Also, the mean of serum concentration of IL-6 in acute phase of the disease was significantly higher in children with pyelonephritis [15.59 (SD=8.40) pg/dl] than the ones with cystitis [3.21 (SD=4.58) pg/dl] (P<0.001). The optimal cut-point of 6.60 pg/dl for urinary concentration of IL-6 has the sensitivity and specificity of 70% and 95% to differentiate acute pyelonephritis patients from acute cystitis respectively. In addition, serum concentration of 9.25 pg/dl has the sensitivity and specificity of 80% and 95% to differentiate  these two groups of children. Conclusion: It seems that urinary and serum concentrations of IL-6 possess a high diagnostic value to differentiate  pyelonephritis from cystitis and could be used as an important index to diagnose upper urinary tract infection from the lower one in the acute phase of the disease among children.