Literature Review All human bodies have an immune system, which is a complex network of cells and organs that protect the body from germs and other foreign substances. One mistake can make the body unable to distinguish between foreign substances and the body's own cells. When this happens, the body produces autoantibodies that mistakenly attack the body's cells. When a foreign substance invades your body (like a cold virus or a bacterium on a thorn that bites your skin), your immune system attacks it. Try to identify, kill and get rid of invaders that could harm you. But sometimes problems with the immune system cause it to mistake the body's healthy cells as invaders and then repeatedly attack them. This is called an autoimmune disease. Polymyositis It has been documented that the exact cause of this disease is unknown but may be caused by environmental factors. 1 The Mayo Clinic also stated that an autoimmune disease occurs when autoantibodies attack the body's own tissues. Their hypothesis is that an unknown event in the body triggers the onset of polymyositis...