Assessment of Interleukin-15 (IL-15) Concentration in Children with Cystic Kidney Disease.

Cystic kidney disease is characterized by progressive structural remodeling of renal parenchyma and altered cellular signaling. Inflammatory mediators may contribute to disease biology; however, data on interleukin-15 (IL-15) in pediatric cystic kidney disorders remain limited. The aim of this study was to assess serum and urinary IL-15 concentrations in children with cystic kidney disease and to evaluate their association with renal function. Methods: This study included 47 children with cystic kidney disease and 41 controls without renal cystic disease or other systemic, inflammatory, or immunological disorders. Serum and urinary IL-15 concentrations were measured using an enzyme-linked immunosorbent assay (ELISA). Renal function was assessed using the estimated glomerular filtration rate (eGFR). Statistical analyses included non-parametric comparisons, logistic regression, and receiver operating characteristic (ROC) curve analysis. Results: Children with cystic kidney disease demonstrated significantly elevated serum and urinary IL-15 concentrations compared with controls. IL-15 levels were not associated with eGFR and did not differ between cystic disease subtypes. In logistic regression analysis, IL-15 remained significantly associated with disease status. ROC analysis suggested high diagnostic ability of serum and urinary IL-15. Conclusions: IL-15 concentrations are increased in children with cystic kidney disease independently of current renal function. These findings suggest that IL-15 may reflect early inflammatory or epithelial signaling rather than established functional impairment.