Diseases caused by the action of the own immune system of the individual are called autoimmune diseases. The autoimmune diseases appear when the immune system makes antibodies or defense cells that attack cells, tissues and organs of its own body. The attacked cells or tissues are wrongly recognized as antigens by the immune system. Rheumatoid arthritis, lupus, scleroderma, vitiligo, pemphigus, type I diabetes mellitus, Crohn's disease (chronic inflammation of the gut), myasthenia gravis, Graves disease, Hashimoto's disease, etc., are all examples of autoimmune diseases.