| Summary: | Myasdienia gravis (MG) is an antibody-mediated autoimmune disease causing muscle weakness and fatigue. Over 80% of patients with generalised MG have IgG autoantibodies (mostly IgUlj to the native muscle acetylcholine receptor (AChR) at the neuromuscular junction (NM]). AChR-antibody-positive MG (AChR-MG) patients often benefit from thymectomy. Their thymus usually has epithelial hyperplasia and the thymus is thought to be the site of autoimmunisation against AChR. Of the remaining 15-20% of patients with generalised MG, a variable proportion (0-50%) have autoantibodies to muscle-specific kinase, MuSK (MuSKMG), which are predominantly IgG4. These patients usually have more severe disease, which does not respond to thymectomy, but their thymic pathology has not been studied in detail. The remaining patients have no detectable autoantibodies against AChR or MuSK (seronegative MG, SNMG), but have similar disease to AChR-MG, although tending to be milder, and it is not clear whether the thymus is also abnormal.
|
|---|
