An overactive immune system comprises the other end of immune dysfunction, causing autoimmune disorders. Here, the immune system fails to properly distinguish between self and non-self, and attacks part of the body.

The immune system can go awry and attack parts of you, any part of you. For example in multiple sclerosis the immune system is attacking the myelin sheath. In rheumatoid arthritis the immune system is attacking the synovial membrane between the joints. The immune system can attack any organ or any system.

There’s no organ or bodily system excluded from potential attack. Your finest weapon can become your greatest enemy. Like any other part of the body, defects can arise in the immune system. The onset of an autoimmune disease would require a combination of several factors going wrong at the same time.

Cited as possibilities are, genetic predisposition, hormonal influences, enzyme abnormalities, stress, diet, ultraviolet light and micro-organisms like bacteria and viruses. Although some autoimmune disorders result from genetic defects, immunologists believe that the majority of autoimmune diseases result when the layers of tolerance inducing mechanisms fail to eliminate self-reactive cells in genetically normal individuals.

Genetic inheritance is not the central determinant for autoimmune diseases for most people. For reasons not fully understood, about 75% of autoimmune diseases on average occur in women. Hormones are thought to play a role as symptoms can improve or change depending on hormone activity.