BAFF/APRIL LEVELS IN PATIENTS AFFECTED BY SYSTEMIC LUPUS ERYTHEMATOSUS AND SJOGREN SYNDROME

Background: Elevated serum levels of BAFF and APRIL are a characteristic of autoimmune diseases such as systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS). These cytokines both belong to the tumor necrosis factor (TNF) superfamily and are crucial for the survival, maturation, and differentiation of B cells. Objectives: to study BAFF and APRIL in patients affected by systemic lupus erythematosus and Sjogren syndrome. Methods: seventy patients, (50 SLE, 20 SS) and 30 healthy subjects were enrolled in this study. All subjects were evaluated for laboratory data (ESR, CRP, Immunoglobulin G, A and M) and autoantibodies (ANA; ENA-SSA, -SSB, -Sm). For patients, disease activity and damage indexes were assessed at the time of enrollment in the study with the use of SLEDAI and SLICC and SSDAI and SSDDI for SLE and SS, respectively. BAFF and APRIL were determined by commercial sandwich ELISA kit (Bender MedSystem). Statistical analysis has been performed with software Prism (Graphpad Instat, version 5.00 - GraphPad Software, San Diego California USA). Results: APRIL levels were higher among SLE and SS patients compared to controls (p0.0001, and p0.004, respectively). BAFF levels in SLE were significantly higher than in SS (p0.001). We found higher BAFF levels in SLE and SS compared to controls (p0.0003 and p0.01, respectively). Among SLE patients APRIL correlated with SLEDAI (r0.3,p0.002), SLICC (r0.5,p0.001), ESR (r0.3,p0.005) and CRP (r0.04,p0.001). Among SS patients APRIL correlated with SSDAI (r0.4,p0.02), SSDDI (r0.4,p0.01), IgG (r0.5,p0.01), ESR (r0.6,p0.01) and CRP (r0.6,p0.02); BAFF correlated with SSDDI (r0.4,p0.02). Conclusion: In this study we showed higher BAFF and APRIL levels in patients with SLE and SS respect to controls; moreover, we found a positive correlation between disease activity and damage indexes and BAFF/APRIL levels in SLE and SS patients suggesting a role in the strong activation of the immune system in patients with active disease. References: 1. Chu VT, Systemic activation of the immune system induces aberrant BAFF and APRIL expression in B cells in patients with systemic lupus erythematosus. Arthritis Rheum. 2009 Jul;60(7):2083-93. 2. Candon S, Quantitative assessment of antibodies to ribonucleoproteins in primary Sjögren syndrome: correlation with B-cell biomarkers and disease activity. Ann Rheum Dis. 2009 Jul;68(7):1208-12. Epub 2008 Aug 19. Disclosure of Interest: None declaredCitation: Annals of the Rheumatic Diseases, volume 69, supplement 3, year 2010, page 574Session: SLE, Sjögren's and APS – clinical aspects (other than treatment) (Poster Presentations )