Allogeneic hematopoietic cell transplantation for refractory myasthenia gravis.

OBJECTIVE: To describe a patient with intractable myasthenia gravis (MG) who was treated with a matched sibling peripheral blood stem cell transplantation.

DESIGN: Case report. Patient A 17-year-old boy with MG diagnosed at 11 months of age who was previously treated with pyridostigmine, intravenous immunoglobulin, corticosteroids, thymectomies, azathioprine, mycophenolate mofetil, plasmaphereses, rituximab, and high-dose cyclophosphamide.

RESULTS: The patient underwent a reduced-toxicity conditioning with intravenous busulfan, fludarabine, and alemtuzumab, followed by a peripheral blood stem cell infusion from his HLA-matched sibling. Before transplantation, the patient was receiving frequent plasmaphereses, intravenous immunoglobulin, and pyridostigmine. He had ophthalmoplegia, oropharyngeal and limb muscle involvement, and limited mobility. At 40 months posttransplantation, his oropharyngeal and skeletal muscle weakness has completely resolved, he is not taking any medications for MG, and he is an avid athlete. However, his ophthalmoplegia persists, and his anti-acetylcholine receptor antibody levels remain elevated.

CONCLUSIONS: Following allogeneic hematopoietic stem cell transplantation, the presence of anti-acetylcholine receptor antibodies was not sufficient for inducing symptoms of MG. This confirms that additional immune mechanisms are important in pathogenesis of this disease. Allogeneic transplantation may be a therapeutic option for patients with severe, refractory MG. However, little is known about the long-term efficacy of allogeneic transplantation for this disease, and long-term follow-up is warranted.