RESUMO
Myasthenia gravis is an autoimmune disease, which leads to load-dependent weakness of voluntary skeletal muscles with recovery of function after resting. The disease is caused by autoantibodies directed against the postsynaptic nicotinic acetylcholine receptors (AChR) leading to a reduction of neuromuscular transmission. Muscles and nerves are not affected. Disorders of the thymus play a role in the pathogenesis of AChR antibody-positive myasthenia. The clinical symptoms include exercise-induced fatigue either of the ocular muscles alone (ocular myasthenia) or striated skeletal muscle and the ocular, facial and bulbar musculature (generalized myasthenia). Treatment of myasthenia gravis involves administration of acetylcholine esterase inhibitors and immunosuppressive drugs. A myasthenic crisis is characterized by life-threatening complications with severe weakness, swallowing difficulties and respiratory failure, which requires intensive care treatment.
Assuntos
Inibidores da Enzima Conversora de Angiotensina/administração & dosagem , Técnicas de Diagnóstico Neurológico , Imunossupressores/administração & dosagem , Miastenia Gravis/diagnóstico , Miastenia Gravis/terapia , Diagnóstico Diferencial , Medicina Baseada em Evidências , Humanos , Resultado do TratamentoRESUMO
Little is known about pathogenesis -- and especially about involvement of CD8(+) T-cells -- in late-onset myasthenia gravis (LOMG). Remarkably, outstanding CD8(+) TCRVbeta-subset expansions were found in 64% and 72% of recent onset LOMG or thymoma-associated MG (vs. 16% with early-onset MG (p<0.0002); 21% in older controls (p<0.001)). In LOMG, ~25% of the expanded cells initially showed a naïve CD62L(+hi)/CD45RA(+) recent thymic emigrant (RTE)-like phenotype. These expansions associated significantly with IgG antibodies against cytomegalovirus (p<0.036), IL-12 and/ or IFN-alpha2 (p<0.03). The CD8(+) TCRVbeta expansions were stable over 5years, but RTE markers declined.