[Pathomechanisms of autoantibody production against the nervous system]

In immune-mediated neurological disorders, the production of autoantibodies against the nervous system occurs mainly because of impaired immune tolerance. In myasthenia gravis (MG), the thymus shows pathologic alterations, particularly in anti-AChR antibody-positive patients. Further, resection of the thymus induces a clinical recovery. The MG thymus contains all the elements, including AChR antigens, AChR-specific T cells, and antigen-secreting B cells, that are required to initiate and sustain autoantibody production. Central tolerance, established by the repertoire selection of immature T lymphocytes in the thymus, is impaired in MG patients who are positive for anti-AChR antibodies. Recent evidence suggests that chronic inflammation elicited by viral infection is important for the production of AChR antibodies. Antibodies against ganglioside are crucial for the diagnosis of Guillain-Barre syndrome (GBS). Molecular mimicry between the lipooligosaccharides of Camplylobacter jejuni and gangliosides of the peripheral nerve causes the production of antibodies. However, less than 1 in 1000 patients infected with C. jejuni develop GBS. This fact suggests that some host factors might influence the production of antibodies. A recent hypothesis suggests that transient impairment of peripheral tolerance due to infection may play a crucial role in GBS pathogenesis. In summary, autoantibody production might correlate with the impairment of immune tolerance as well as with innate immunity.