Chapter 5 The immunopathogenesis of myasthenia gravis

Abstract

Myasthenia gravis (MG) is a human autoimmune disease. Autoantibodies against neuromuscular antigens play a key role in the pathogenesis of MG, and the detection and monitoring of these antibodies is essential for the clinical management of myasthenic patients. This chapter reviews the immunopathogenesis of MG. The chapter provides an overview of some fundamental principles of immunology, and then addresses the role of antibodies, T cells, immunogenetic aspects, and thymus. The relevant animal models of MG, the risk factors of MG and associations with other immunological diseases are discussed. Complement system mediates destruction of the postsynaptic membrane of the neuromuscular junction. The detection of autoantibodies against acetylcholine receptor (AChR) is a key element for making the diagnosis of autoimmune MG. CD4+ helper T cells are crucially involved in the immunopathogenesis of MG. MG is associated with other autoimmune diseases (e.g., rheumatoid arthritis, thyroid disease) pointing to a general autoimmune predisposition of MG patients conferred by unknown genes. The thymus is thought to play an important role in MG pathogenesis. Patients with thymic tumors carry a markedly increased risk of developing myasthenia gravis. The features of experimental autoimmune myasthenia gravis (EAMG) vary with the species and strain, source of AChR, use of adjuvants, and immunization schedules. Epidemiological data indicates that the prevalence of late onset MG is increasing. If aging is an independent risk factor for the development of MG is yet to be determined.