4. Molecular Mimicry/Innocent Bystander Theory
The precise mechanism of action regarding Guillain Barre Syndrome is not fully understood. However, what we do have are several different theories and potential explanations.
One of the most common is that molecules on some nerves appear very similar (chemically) to molecules found on harmful microorganisms. When the body becomes infected with these microorganisms, it essentially fools the body into believing that the nerves are that same harmful invader: they then begin to attack the myelin.
Very often, Guillain Barre Syndrome is preceded by a viral or bacterial infection, which helps to explain this possibility. It may also be the case that the antibodies are created to fight something called campylobacter jejuni – a bacterial infection that attacks axons.