Elevated interleukin-18 levels in the urine of nephrotic patients.
OBJECTIVE
The etiology of minimal-change nephritic syndrome (MCNS) is obscure. It has been speculated that T cells play a role in the pathogenesis of MCNS. Interleukin (IL)-18, a novel immunoregulatory cytokine with potent inferon-gamma-inducing activities, may play an important role in T-helper type 1-mediated immune responses. To examine further the possible role of IL-18 in nephrotic syndrome (NS), in the present study we measured IL-18 levels in the urine in different clinical stages of MCNS. The aim of this study was to investigate the involvement of IL-18 in MCNS.


METHODS
Urine samples were obtained from 20 MCNS patients. The disease controls included 20 patients with IgA nephropathy. The samples were assayed for IL-18 protein by a sandwich enzyme-linked immunosorbent assay.


RESULTS
Compared with normal controls, significantly increased urinary levels of IL-18 were detected in MCNS patients with the NS. The urinary IL-18 (uIL-18) levels correlated with the degree of proteinuria in MCNS patients. Moreover, when individual MCNS patients were followed through their clinical illness, uIL-18 levels were increased during the active phase and decreased as the patients went into remission.


CONCLUSIONS
These results indicate that uIL- 18 is detectable in a subgroup of patients with active NS and correlates to their disease activity in patients with MCNS. Our findings support the notion that IL-18 may play a role in the pathophysiology of NS.
Matsumoto
K
K
Department of Medical Technology, College of Medical Sciences, Saitama Prefectural University, Koshigaya, Japan.
Kanmatsuse
K
K
D000328:Adult; D003165:Complement System Proteins / Q000032:analysis; D005260:Female; D005922:Glomerulonephritis, IGA / Q000503:physiopathology / Q000652:urine; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D020382:Interleukin-18 / Q000652:urine*; D007678:Kidney Glomerulus / Q000276:immunology; D008297:Male; D009404:Nephrotic Syndrome / Q000188:drug therapy / Q000503:physiopathology* / Q000652:urine; D011239:Prednisolone / Q000627:therapeutic use; D011507:Proteinuria / Q000503:physiopathology
D007070:Immunoglobulin A; D020382:Interleukin-18; D003165:Complement System Proteins; D011239:Prednisolone