P30 A custom-made microarray for detection of autoantibodies in systemic lupus erythematosus

Background Systemic Lupus Erythematosus (SLE) is a heterogeneous autoimmune disease associated with chronic inflammation with progressive organ degeneration. Early diagnosis intervention is crucial to improve overall disease course. Anti-dsDNA antibodies are the most sensitive serological biomarkers for SLE. The available diagnostic methods, however, identify different antibody subpopulations against dsDNA leading to varying performance. Thus, a serological biomarker profile specific to aid timely diagnosis and sensitive for disease activity of SLE remains an important clinical unmet need. In this study a microarray was developed that enabled a simple and rapid characterization of the serological profile of SLE patients. In this microarray it was possible to analyze up to 90 autoantibodies in Methods A microarray was developed by spotting autoantigens in an arrayed fashion onto the surface of maxisorp plastic slides. Binding of each antigen was optimized regarding concentration and spotting buffer. The assay was performed by incubating diluted serum on the array followed by incubation with a fluorescent-labeled anti-human IgG antibody. Fluorescence intensities were measured with a laser scanner and the resulting images analyzed with an image analysis software. The microarray performance was compared to single analytes on EliA™ (Phadia AB, Uppsala, Sweden). For technical evaluation serum from 160 SLE patients and 313 healthy blood donors were measured. Results Overall, there was strong correlations between microarray and EliA results for relevant biomarkers. The mean CV% between productions, lots and assays were 11, 8 and 7%, respectively. Conclusions The developed microarray showed good technical performance and is a promising tool for the characterization of the serological profile of SLE patients. Furthermore, it has been applied in a clinical study as a discovery tool for new autoantibodies and patterns of autoantibodies with promising results.