Elevated urinary IL-36α and IL-18 levels are associated with diabetic nephropathy in patients with type 2 diabetes mellitus.

BACKGROUND:Inflammatory cytokines have been reported to be pathogenic factors for the development and progression of diabetic nephropathy (DN). Interleukin (IL)-36α is a newly discovered member of the IL-1 cytokine family that has been implicated in animal models of renal impairment. However, little is known about the role of IL-36α in DN in humans. The purpose of the present study was to assess the levels of IL-36α and IL-18 in type 2 diabetic patients (T2DM) patients with and without DN. METHODS:Subjects were divided into 3 groups: Control (N.=20), T2DM without DN (N.=30), and T2DM with DN (N.=30). Urinary IL-36α and IL-18 levels were assessed using ELISA. Correlation analysis was performed to determine the association of the IL levels with clinical markers of T2DM and DN. RESULTS:IL-36α and IL-18 levels were significantly elevated in T2DM patients with DN, when compared to T2DM patients without DN (P<0.0001, P=0.0025, respectively) and controls (P<0.0001, for both). IL-36α levels showed a positive correlation with urinary albumin excretion (r=0.754, P<0.0001), HbA1c (r=0.433, P=0.0168), fasting plasma glucose (r=0.433, P=0.0168) and negative correlation with glomerular filtration rate (r=-0.852 P<0.0001). CONCLUSIONS:The results highlighted the association of IL-36α with DN. However, further extensive studies are suggested for evaluating the association.