miRNA-21 is regarded as both an abundant and highly conserved member of the microRNA (miRNA) family. It is expressed in virtually every cell and is responsible for critical regulatory actions that are important in health and disease. This microRNA has been shown to potentially have a role in the pathogenesis of several immune-related disorders, including autoimmune diseases, such as Multiple sclerosis and systemic lupus erythematosus, as two prominent examples of diseases that might be involved. In the current research, we looked at the role of miRNA-21, regarded as one of the most significant pathogenic miRNAs with a role in the development of autoimmune illness.