[The importance of microRNAs in the development of systemic autoimmune disorders].

MicroRNAs (miRNAs) are 18-25 nucleotide long, single stranded, endogenous, non-coding small RNAs playing an important role in regulating gene expression at posttranscriptional level. miRNAs control approximately 90% of protein-coding genes, and play a central role in various biological processes including immune cell lineage commitment, differentiation, proliferation, apoptosis and maintenance of immune homeostasis. Changes in the expression of certain miRNAs may lead to the development of many diseases, including systemic autoimmune diseases. In this study, we summarize the biogenesis of miRNAs, their role in regulation of the immune system, and review the latest research findings in systemic lupus erythematosus, primary Sjögren's syndrome, rheumatoid arthritis and systemic sclerosis. In the future, miRNAs may help not only in establishing diagnosis and prognosis but potentially serve as targets for modern therapeutic approaches in autoimmune diseases. Orv Hetil. 2019; 160(15): 563-572.