“GBS can affect anyone of any sex or age, but most often affects adults and people older than 50. GBS is not contagious or inherited and the exact cause is unknown.

Since the body’s own immune system does the damage, GBS is called an autoimmune disease (“auto” meaning “self”). Normally the immune system uses antibodies (molecules produced in an immune response) and special white blood cells to protect us by attacking infecting bacteria and viruses. In GBS, however, the immune system mistakenly attacks the healthy nerves. This attack may start as a fight against an infection. One possible reason for this is that some chemicals seen on bacteria and viruses resemble those on nerve cells. The immune system may not be able to distinguish bacteria and viruses from healthy nerve cells which also become targets of attack.”

(Guillain-Barré Syndrome | National Institute of Neurological Disorders and Stroke)