Autoimmune diseases such as rheumatoid arthritis or systemic lupus erythematosus are caused by the inability of the immune system to distinguish between self and non-self-structures of the body leading to chronic inflammation and tissue damage. The causes of autoimmunity are complex and involve a combination of genetic, environmental, and hormonal factors and the dysregulation of immune cells. Our laboratory studies the role of different immune cells in the pathogenesis of autoimmune diseases with the ultimate goal to develop new treatment targets.