MAG抗体

Myelin-associated glycoprotein (MAG) is a transmembrane glycoprotein predominantly located in the periaxonal Schwann cell membrane of myelinated nerves, playing a critical role in maintaining myelin-axon adhesion and stabilizing nerve conduction. Structurally, MAG belongs to the immunoglobulin (Ig) superfamily and interacts with specific axonal components, such as gangliosides (e.g., GD1a, GT1b), to mediate glial-axonal signaling. Autoantibodies targeting MAG are strongly associated with immune-mediated peripheral neuropathies, particularly a rare subtype of chronic inflammatory demyelinating polyneuropathy (CIDP) or IgM paraproteinemic neuropathy. These antibodies, often IgM class, bind to carbohydrate epitopes (e.g., HNK-1) on MAG, triggering complement-mediated damage or disrupting myelin-axon interactions, leading to demyelination and progressive sensorimotor deficits. MAG antibody testing (via ELISA or immunohistochemistry) aids in diagnosing these neuropathies, though positivity is not disease-specific. Clinically, MAG antibody-associated neuropathies typically present with distal weakness, tremors, and ataxia, progressing over years. Treatment focuses on immunosuppression (e.g., rituximab, IVIG) to reduce antibody production or activity. Research continues to clarify MAG's pathophysiological role and optimize therapeutic strategies for antibody-mediated nerve injury.