Autoimmune disease is an inflammatory disorder in which the body's own immune system attacks normal cells. This disease can cause decreased and abnormal immunity, which ultimately leads to tissue damage or organ dysfunction. It can be divided into organ-specific autoimmune diseases and systemic autoimmune disease based on clinical manifestations.
The pathogenesis of autoimmune diseases is not fully understood yet. It is estimated that approximately 5 to 8% of the world's population are threatened by autoimmune diseases. Organ-specific autoimmune diseases include chronic lymphocytic thyroiditis, hyperthyroidism, pulmonary hemorrhagic nephritis syndrome, insulin-dependent diabetes mellitus, primary biliary cirrhosis, pernicious anemia with chronic atrophic gastritis, ulcerative colitis, acute idiopathic polyneuritis, myasthenia gravis, multiple sclerosis and so on. Systemic autoimmune diseases include systemic lupus erythematosus, rheumatoid arthritis, systemic vasculitis, pemphigus, dermatomyositis, mixed connective tissue disease, autoimmune hemolytic anemia, and the like.
Mesenchymal stem cells have non-specific immunomodulatory ability, which functions through secreted soluble cytokines and forms a comprehensive network of regulation through signal transduction. The immune microenvironment can also enhance immunomodulatory effects of mesenchymal stem cells. Such effects together with involvement or promotion of various damage repairs are the theoretical basis for treatment of autoimmune diseases.
Autoimmune diseases are manifested as tissue or organ damage. Application of some powerful immunosuppressive drugs plays an important role in the treatment of many autoimmune diseases. However, there are no ideal drugs or treatments that can both simultaneously regulate immune function and promote immune damage repair. The discovery and application of immunomodulatory effects of mesenchymal stem cells have opened up new thoughts on treatment of autoimmune diseases. Infusion of mesenchymal stem cells in patients with systemic lupus erythematosus alone can significantly alleviate clinical symptoms and improve the function of affected organs. Since mesenchymal stem cells themselves have low immunogenicity and do not require HLA matching in clinical treatment, non-HLA-matched mesenchymal stem cells have been clinically applied to the treatment of graft-versus-host disease and have achieved good results. Other studies have shown that allogeneic BMSCs are superior to autologous BMSCs.
Some countries have approved BMSCs for the treatment of autoimmune diseases: US, Canada, and Japan approved use of bone marrow stem cells to treat graft-versus-host disease; US and EU approved treatment of Crohn's disease using mesenchymal stem cells. In addition, a number of clinical trials are underway, which is expected to bring hope to patients with autoimmune diseases.