Urinary Interleukin-8 as a Biomarker for Steroid Resistance in Childhood Onset Nephrotic Syndrome

Abstract

Background Nephrotic syndrome (NS) is one of the commonest pediatric renal disorders. Minimal change disease (MCD) is the commonest cause of childhood NS followed by focal segmental glomerulosclerosis (FSGS). The majority of MCD children respond to corticosteroid therapy, but some are steroid-dependent or steroid-resistant, while the majority of patients with FSGS are steroid resistant. Recently, it has been proposed that changes in the cytokine and chemokine profile of NS patients may contribute to proteinuria and glomerular damage Aim of this study To investigate the relation between interleukin 8 (CXCL8/IL8) and the response to steroid therapy in pediatric nephrotic syndrome. Patients and methods Sixty-five patients with NS were included. They were divided into two groups according to response to steroids group 1: steroid sensitive NS (40 patients) group 2: steroid resistant NS (25 patients) and each group include two subgroups (during disease activity and during remission). Serum and urine CXCL8/IL8 levels were measured by quantitative sandwich enzyme immunoassay technique. Results During activity serum CXCL8/IL8 levels were significantly higher in SRNS [median, IOR = 293(11-296)] as compared to SSNS [114.3(5.8-296)] , p .04. Similarly, urinary CXCL8/IL8 levels were significantly higher in SRNS [187(61.8-210.3)] as compared to SSNS [40.6(24.4-80)] , p.04. During the remission, urinary CXCL8/IL8 levels were significantly higher in SRNS [ 38(21.8-57)] as compared to SSNS [2.4(.0-9.8)] , p .03. Conclusions Urinary CXCL8/IL8 levels were significantly higher in SRNS than SSNS patients and can be a reliable marker for steroid resistance of childhood onset nephrotic syndrome