Biomarkers in Systemic Lupus Erythematodes

Abstract

A biomarker is defined as a genetic, biological, biochemical or molecular event, whose alterations correlate with the pathogenesis and/or manifestations of a disease and can be evaluated qualitatively and/or quantitatively in laboratories. Biomarkers are used for diagnosis, assessment of activity and better understanding of the pathogenesis of SLE (systemic lupus erythematodes). Biomarkers in SLE are conditionally subdivided into markers of genetic susceptibility, markers of diagnosis and markers of disease activity. Recent genetic studies of SLE have focused on correlating SLE (susceptibility, disease spectrum and severity) with polymorphisms of hypothetical candidate genes. These include genes coding for mannose-binding lectin (MBL), cytokines (IL-6, IL-10, IL-21, TNF-α and osteopontin), chemokines (MCP-1), cytokine receptors/antagonists (type II TNF-α receptor and IL-1 receptor antagonist), Fcγ receptors (FcγRIIa, FcγRIIb, FcγRIIIa, and FcγRIIIb), IFNα, programmed death protein-1 (PD-1; also known as PDCD-1) and other cell surface receptors (cytotoxic T lymphocyte antigen-4 (CTLA-4) involved in the pathogenesis of SLE. Biomarkers for diagnostic are anti-dsDNA, erythrocyte-bound C4d/Erythrocyte-CR1 and platelet-bound C4d. Markers of disease activity are complement components, cytokines, soluble cytokine receptors IL-2R, TNFR, IL-1Ra, soluble molecules expressed on the cell surface − BLyS (BAFF), CD27, CD154, endothelial dysfunction markers − sICAM, sVCAM, thrombomodulin, circulating endothelial cells, acute-phase proteins − CRP, ferritin. Genetic testing for biomarkers in SLE patients is currently being introduced in the Rheumatology Clinic to “Sv. Ivan Rilski” Multiprofile University Hospital for Active Treatment, Sofia, Bulgaria. Its performance is expected to help solve multiple unmet needs in SLE patients – precise diagnosis, identification and prediction of the timing of disease flares, clinical assessment and adequate treatment approach.