English: Pathophysiological mechanisms of autoimmune diseases. Autoimmune diseases are multifactorial diseases, and their etiologies are not yet fully known. Their development depends on genetic susceptibility, environmental factors, hormonal factors, and immune dysregulation. These factors may influence, according to different mechanisms, the abnormal activation of potentially dangerous autoreactive cells. Other components are involved in enhancing the autoimmune process, including, antigen-presenting cells, inflammatory cells, and many chemical and soluble mediators such as vasoactive amines, nitric oxide, lipid mediators, growth factors, complement system, cytokines, etc. APC, antigen-presenting cell; IC, inflammatory cell; NO, nitric oxide.