“Myasthenia gravis (MG) is an autoimmune disorder caused by antibodies targeting different components of the neuromuscular junction, resulting in fatigable muscle weakness affecting ocular, bulbar and limb districts. Aside from idiopathic forms, it can also present as part of chronic Graft-versus-Host disease (GVHD), occurring in less than 1% of patient who underwent allogenic hemopoietic stem cell transplantation (HSCT).
A 56-years-old male with a history of myelodysplasia treated with bone marrow transplantation two years before, was admitted to neurology ward for a sudden onset of binocular diplopia and convergent strabismus in the left eye. On examination, right palpebral ptosis appeared on prolonged up-gaze. Brain imaging (CT/MRI) was negative. Anti-acetylcholine receptor antibodies were absent, but the patient exhibited a strong response to Prednisone 25 mg and Pyridostigmine 120 mg daily, so a diagnosis of seronegative ocular MG was made. On chest CT and spirometry signs of moderate-grade pulmonary GVHD subsequently emerged, so the patient was treated with Ruxolitinib, with benefit on respiratory symptoms. Six months later, he was neurologically asymptomatic, except for slight fatigable ptosis, and started slow steroid tapering.
MG is a rare manifestation of GVHD, whose severity can range from mild forms to life-threatening myasthenic crisis. Underlying mechanisms are poorly understood, but likely imply an alloreactive T cells-mediated thymic dysfunction and immune tolerance breakdown.
Attention should be paid in transplanted patients who exhibit neurological signs on NMJ disfunction, and prompt search for additional recognized manifestations of chronic GVHD should be carried out, in order to rapidly start appropriate treatment.”