With an autoimmune disorder, the body's immune system attacks itself. The exact cause is unknown. GBS can occur at any age. It is most common in people of both sexes between ages 30 and 50. GBS often follows a minor infection, such as a lung infection or gastrointestinal infection. Most of the time, signs of the infection have disappeared before the symptoms of GBS begin. GBS damages parts of nerves. This nerve damage causes tingling, muscle weakness, and paralysis. GBS most often affects the nerve's covering. This damage is called demyelination. It causes nerve signals to move more slowly. Damage to other parts of the nerve can cause the nerve to stop working altogether. GBS may occur with viral infections as follows: AIDS, herpes simplex, mononucleosis, systemic lupus erythematosus, Hodgkin disease, severe illness.