URINARY PROTEOMIC ANALYSIS PROVIDES DIFFERENT PATTERNS BETWEEN LUPUS PATIENTS WITH AND WITHOUT NEPHRITIS: RESULTS OF A MULTICENTER STUDY IN 124 PATIENTS

PV034 / #275 Poster Topic: AS04 - Biomarkers Background/Purpose Lupus nephritis is a common and serious manifestation in lupus patients. Biopsy is the gold standard to identify different patterns of disease, being not always accessible and with potential complications. A need emerges to identify biomarkers that reflect disease pathology in a noninvasive manner. Urine investigation by proteomics could in theory provide new biomarkers to better classify these patients. The objective of the study is to compare urine from lupus patients with and without nephritis using proteomics in order to find potential biomarkers of the disease Methods Multicentric and prospective proteomics study was conducted in 24-hour urine samples from SLE patients with and without renal involvement. The analysis has been performed by label free nLC MS/MS in 2 batches that included class I, II, III, IV and V nephropathology. SLE patients has been diagnosed according to the 2019 EULAR/ACR Classification Criteria. Limma test statistics were made using Prostar v.1.34.6 Results 124 samples of patients from 5 hospitals were collected and from those 109 was analyzed. There were no differences between groups according to race, gender and age (Table 1). 803 proteins were identified. 178 proteins were increased in lupus without nephritis and 190 in patients with nephritis. Making a different analysis by batches, results, it is confirmed that there is a linear correlation between proteins in patients with and without renal involvement (Figure 1). Proteins increased in urine of nephritis patients includes transport proteins as afamin but also others involved in B cell activation: Fc receptor-like protein 5, enzymes like beta-ala-his dipeptidase, immunoglobulin heavy constant gamma 4 involved in antibacterial humoral response and complement activation (Table 2). Table 1. Figure 1. Table 2. Conclusions This study shows different patterns of proteomic profile in lupus patients with renal involvement and opens a new field of investigation for better understanding of the disease and find potential biomarkers of different types and severity of nephritis. Funding: GSK-funded study.