Immune system disorders can cause low activity or over activity of the immune system. Immune system over activity can cause the body to attack and damage its own tissues (autoimmune diseases). Immune deficiency diseases impair the body’s ability to fight invaders therefore causing vulnerability to infections.
In response to an unknown trigger, the immune system may produce antibodies that instead of fighting infections, attack the body’s own tissues. Treatment for autoimmune diseases generally focuses on reducing immune system activity.