Abstract
Aim: To determine the role of IL-17 and IL-6 in the pathogenesis of SLE as biomarkers of disease activity and predictors of remission and outcome of therapy in patients with active lupus nephritis.
Methods: The study was carried out on 72 SLE female patients and 70 sex- and age-matched normal healthy subjects as controls. SLE disease activity was assessed in all patients with (SLEDAI-2k scores). Plasma levels of IL-6, and IL-17 were measured by enzyme linked immunosorbent assay and their levels were correlated with clinical manifestations of the disease and (SLEDAI-2k). ROC curve analysis was performed to determine the validity of both cytokines in prediction of activity and remission of active lupus nephritis.
Results: SLE patients were found to have significantly higher levels of IL-17 (p < 0.001) and IL-6 (p < 0.001), in relation to normal subjects. Active group of patients had higher levels of both cytokines than the inactive one (P < 0.001). Elevated serum levels of both cytokines were associated with active lupus nephritis, anemia and positively correlated with SLEDAI-2k scores (P = 0.025 for IL-17 and P < 0.001 for IL-6). There was a significant positive correlation between IL-6 and IL-17 serum concentrations during periods of disease activity (r = 0.497, P = 0.005) as well as during remission (r = 0.662, P < 0.001). ROC curve analysis for IL-6 and IL-17, as predictor of disease activity reviled, optimal cutoff level of 12.3 pg/ml and 19.7 pg/ml, with AUC = 0.93, and 0.95, for both cytokines respectively, while as predictors of remission of active lupus nephritis, provide a cutoff value of IL-6 at 20.8 pg/ml, with AUC 0.80, and a cutoff value of IL-17 at 27.0 pg/ml, with AUC 0.82.
Conclusion: In conjunction with their major role in pathogenesis of SLE, baseline serum levels of IL-6 and IL-17 can be used as sensitive biomarkers for disease activity, as well as predictors of remission of lupus nephritis. (C) 2015 Elsevier Ltd. All rights reserved.