Searching for Diagnostic/Prognostic Biomarkers in SLE With Renal Involvement by Proteomic Techniques

Objective: To search for potential biomarkers obtained by non-invasive methods (24-hour urine collection) that distinguish between patients diagnosed with systemic lupus erythematosus with or without renal involvement, patients with non-autoimmune renal disease and healthy donors. Lupus nephritis is one of the most common and severe complications of systemic lupus erythematosus, causing from asymptomatic mild proteinuria to rapidly progressive glomerulonephritis with kidney failure. To date, kidney biopsy (an invasive medical procedure with associated risks and complications) is essential for making a definitive diagnosis, assessing the severity of the damage and deciding on the best treatment. In relation to this, the identification of biomarkers using a non-invasive biological sample could help to classify population groups, and this would be a great step forward in the clinical setting. In this research project, we propose to conduct a case and control study. For this, we will first carefully classify the study groups, using clinical data on patients and by testing a pool of peptides described in the scientific literature in each of the sample groups, using solid phase extraction combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Subsequently, we will carry out multivariate principal component analysis on the data collected, and calculate corresponding receiver operating characteristic curves, to enable us to identify the masses corresponding to peptides with potential as biomarkers. We will then use classification algorithms to select sets of masses that would allow us to distinguish the population groups, and generate statistical classifiers for assessing the level of confidence in the model and its subsequent validation.