Association of Complement and Inflammatory Biomarkers with Diabetic Nephropathy.

Objective. To investigate the association between complement and inflammatory biomarkers with diabetic nephropathy (DN) in type 2 diabetes mellitus (T2DM). Methods. Plasma and urinary complement and inflammatory biomarkers were measured in 115 T2DM patients assigned to one of two groups: with DN (n=48) and without DN (n=67). Results. The plasma and urinary levels of C3a, C4d, C5a, sC5b-9 and MBL (mannan-binding lectin) were significantly higher in T2DM patients with DN compared to T2DM patients without DN. The plasma levels of IL-10 and INF-gamma, as well as the urinary levels of INF-gamma and TNF-alpha in T2DM patients with DN, were significantly higher than T2DM patients without DN. Both urinary MBL and INF-gamma were independent risk factors for DN within T2DM patients (OR, 2.35 (95% CI 2.28-2.64) and 1.17 (95% CI 1.15-1.18); P=0.000 and 0.016, respectively). The area under the receiver-operating-characteristic-curve for urinary MBL was 0.89, with sensitivity 91% and specificity 83% for DN. The area under the receiver-operating-characteristic-curve for INF-gamma was 0.84, with sensitivity 86% and specificity 79% based on cutoff values of 1.42 ng/mg and 5.15 pg/mg, respectively. Conclusion. This study suggests that urinary INF-gamma and MBL levels are independent risk factors with a high predictive power for DN in T2DM patients.