Fig. 1　Structure and mechanism of action of the AChR-Fc fusion protein. AChR-Fc is a fusion protein that contains the human AChR (acetylcholine receptor) structure and the Fc region of human IgG1. It is thought to have two mechanisms: neutralizing activity of AChR antibodies through the AChR structure and antibody-mediated cytotoxicity against AChR antibodyproducing pathogenic B cells via the Fc region. NMJ = neuromuscular junction