Oxidative stress, inflammation and disease activity biomarkers in lupus nephropathy.

Lupus nephropathy is a severe and frequent complication of systemic lupus erythematosus. Here, we assessed the biomarkers of oxidative stress, inflammation and disease activity in patients with lupus nephritis. Thirty-four patients with active lupus nephritis, 31 patients with inactive lupus nephritis and 20 lupus patients without renal damage (non-lupus nephritis) were studied. Oxidative stress biomarkers malonyldialdehyde, oxidized-to-total glutathione, catalase, superoxide dismutase and total antioxidant status were assessed, as well as inflammation biomarkers CRP, interleukin 6 and monocyte chemoattractant protein 1. Renal tubular disease biomarkers neutrophil gelatinase-associated lipocalin and β2-microglobulin were assessed, together with the classic disease activity biomarkers urinary protein/creatinine ratio, anti-dsDNA, anti-C1q antibody and complement proteins C3 and C4. Significant differences were found between active lupus nephritis and inactive lupus nephritis patients and between active lupus nephritis and non-lupus nephritis patients for all the assessed biomarkers (P < 0.05), except for catalase, superoxide dismutase and interleukin 6. There is an imbalance in the redox status in active lupus nephritis patients that would be involved in lipid peroxidation of the glomerular basal membrane that would alter its integrity and could also affect renal tubular function in these patients.