The Role of Urinary Interleukin-8 Level in Diagnosis and Differentiation between Different Types of Urinary Tract Infection in Children

Abstract

Background: Interleukin (IL)-8 acts as a potent neutrophils chemotactant responsible for the migration of neutrophils into the infected renal tissue to protect against invading pathogens. The aim of our work was to identify the role of urinary IL-8 in the diagnosis and differentiation between different forms of urinary tract infections (UTI) and its role in detection of the effect of treatment. Materials and Methods: Fifty children with different forms of UTI were evaluated and classified into three groups: Group I included 20 children diagnosed as having pyelonephritis (age range 6 months–10 years), Group II included 15 children with acute cystitis (age range 1–12 years) and Group III included 15 children with asymptomatic bacteruria (age range 5 months–10 years) and group III was considered as the control group as bacteriuria was detected during routine urine examination. All groups were urine culture positive. Inflammatory markers including erythrocyte sedimentation rate, C-reactive protein, leukocyte count, and urinary IL-8, together with the results of ultrasonography and dimercaptosuccinic acid renal scintigraphy (DMSA) were evaluated in these children. The ratios of urinary IL-8 to creatinine (IL-8/Cr) before and after the treatment at 72 hours were compared with each other. Results: The initial urine IL-8 concentrations were significantly higher in group I than in group II and also higher than group III (all p < 0.001). After 72 hours the urinary IL-8 level significantly decreased in all groups studied (all p < 0.001). There were positive correlations between urine IL-8 concentrations and leukocyturia in children with acute pyelonephritis (r = 0.43, p < 0.001). In children with the lower UTI group, no correlations were found between urine IL-8 values and leukocyturia. Renal injury was found in 6 children with pyelonephritis detected by dimercaptosuccinic acid renal scintigraphy scanning and these 6 patients had the highest level of urinary IL-8 among those of the pyelonephritis group after 6 months. Conclusion: From this study it is concluded that the importance of urinary IL-8 as a non-invasive test in diagnosis and differentiation between different forms of UTIs in children (upper UTI from lower UTI and from those with asymptomatic bacteruria) and also its importance in detection of treatment efficacy.