Lipidomics in autoimmune diseases with main focus on systemic lupus erythematosus.

Autoimmune diseases (AID) are a heterogeneous group of disorders that have in common a chronic inflammation and dysregulation of the immune system. Systemic lupus erythematosus (SLE) is one of the most frequent systemic autoimmune diseases characterized by autoimmune phenomena in multiple organs. The tests used for evolution and prognosis assessment are either non-specific or non-sensitive, impairing an adequate therapeutics. To face this drawback, lipidomics is being used to provide more knowledge and insights regarding autoimmune disorders. Through lipidomic approaches using MS, it is possible to identify and quantify the level of lipid molecular species in the biological system and this could be useful to identify biomarkers and to better understand the pathophysiology of autoimmune diseases. There are some evidence that lipids and oxidized lipids can play a key role in AID pathogenesis. Although this field has been scarcely explored, there are some studies that reported variations on the lipid profile at a molecular level using lipidomic approaches based on MS in SLE. The results gathered herein showed changes mainly in the level of phospholipids, with decrease of some plasmenyl lipids, fatty acids, with reduction of PUFA, and sphingolipids, with changes in fatty acyl chain composition. These changes may be the result of lipids` modifications due to oxidation and increase of ROS. Some alterations can be associated with changes in membrane of lymphocytes and with the deregulation of the immune system. Thus, exploring the knowledge from modern lipidomic approaches in the study of the role of lipids and oxidized lipids, in oxidative stress and in inflammatory diseases, could contribute for the identification of new lipid biomarkers. Lipid biomarkers are promising tools to prognosis and treatment monitoring, tailored for the best therapeutic response and highest safety to ensure better patient care and to be used for personalized medicine.