Table 1.

Example of antibody-mediated diseases: clinical and experimental evidence for MG.

IN HUMANS:
Clinical features (weakness and fatigue) can be reversed by plasma exchange and other immunotherapies (21). IgG1 and IgG3 antibodies to the AChR are present in the majority of patients (22, 23). IgG and complement deposition are found at the neuromuscular junction (24). The thymus gland contains germinal centers and produces some of the AChR antibodies (25). Thymectomy leads to long-term clinical benefit, reducing the need for immunotherapies (26). Mothers can transfer pathogenic antibodies to the fetus or neonate, causing a transient form of MG (27) or rarely a severe neurodevelopmental disorder (arthrogryposis multiplex congenital) (28).
GENETIC CONDITIONS:
Genetic conditions caused by mutations in genes encoding AChRs cause similar clinical features but without evidence of autoimmunity. Genetic conditions can be modeled in transgenic mice [see (29)].
IN EXPERIMENTAL ANIMALS:
Injection of patient IgG into mice or other species leads to short-term clinical or electrophysiological evidence of the disease (16). Active immunization against purified AChRs leads to a more severe and prolonged model (30).

For a brief review of the history of research into myasthenia gravis, see Vincent (31). MG, myasthenia gravis; IgG, immunoglobulin G; AChR, acetylcholine receptor.