Chronic graft versus host disease (cGVHD) is a multisystem alloimmune and autoimmune disorder characterized by immune dysregulation, immunodeficiency, impaired organ function, and decreased survival. cGVHD is characterized by the development of features reminiscent of various autoimmune or immunologic disorders, such as scleroderma, Sjogren's syndrome, chronic immunodeficiency, and bronchiolitis obliterans. cGVHD typically involves the skin and dermal appendages, mouth, eyes, genitalia, gastrointestinal tract, liver, lungs, musculoskeletal system, and hematopoietic system. More rarely, cGVHD can involve the heart or kidneys, or manifest as vasculitis, serositis, or myasthenia gravis (MG). These unusual manifestations are rare and other causes such as drug toxicity and postirradiation effects should be considered.
Myasthenia gravis is an autoimmune disease resulting from the production of autoantibodies that bind to the acetylcholine receptor (anti-AchR Ab) of the neuromuscular endplate. This binding causes impaired transmission at the neuromuscular junction, leading to skeletal muscle weakness and fatigue. Despite the fact that approximately 20% of patients with cGVHD show anti-AchR Ab, the frequency of clinically apparent MG after hematopoietic stem cell transplantation (HSCT) is relatively low. There are only a few case reports describing MG following HSCT in the literature. MG has been reported as far out as 9 years following HSCT and only one patient has developed MG without evidence of cGVHD. MG has been reported in children as well as adults and there appears to be no gender predilection.