The Third Euromyasthenia Conference; Meeting Report and Update on Myasthenia Research

Abstract

Understanding of myasthenia gravis (MG) has been advanced by a series of clinical and basic breakthroughs since the early recognition that it mimics curare poisoning and can likewise be treated with anti-cholinesterase drugs¹, which established that it is a defect in nerve-muscle transmission. The subsequent identification² of high affinity α-neurotoxin probes led to efforts to purify and characterise their targets-the nicotinic acetylcholine receptors (AChR)-initially from detergent extracts of the AChR-rich electric organs of the electric ray (Torpedo). When the resulting product was used to immunise rabbits, they developed typical myasthenic signs that were also cleared by anti-cholinesterases³. This was dramatic support for Simpson's earlier prediction⁴ that MG would prove to be autoimmune, and was rapidly confirmed by the ready detectability of autoantibodies to human muscle AChR in 85590% of MG patients⁵. In the 1980s, the Torpedo, human and other AChR genes have been cloned and sequenced⁶, and so, for over a decade, MG has been one of the best defined autoimmune diseases. We are thus in a phase of consolidation, with several groups focusing on how the antibodies cause AChR loss, on the immunogenetics and cellular immunology of MG patients, on the possible involvement of the thymus in initiating the response and on the AChR-specific T cells that are widely believed to be crucial for its induction. Most groups are striving towards the ultimate goal of selectively extinguishing a specific autoantibody response⁷