Autoimmune autonomic ganglionopathy: Bench to Bedside

Autoimmune autonomic ganglionopathy (AAG) presents as severe generalized sympathetic and parasympathetic autonomic failure. This disorder is also known as acute pandysautonomia or idiopathic subacute autonomic neuropathy. The most disabling manifestations are orthostatic hypotension (OH) and gastrointestinal dysmotility. An autoimmune pathogenesis was suggested by the subacute onset, frequent association with antecedent viral illness, occasional association with cancer or other autoimmune disorders, and spontaneous recovery in some patients. Many cases have a rapid onset, but others have a chronic progressive course. Clinical and experimental observations demonstrate that AAG is an antibody-mediated disorder. (1) AAG patients have high levels of serum antibodies specific for the neuronal AChR in autonomic ganglia. This ganglionic AChR mediates fast synaptic transmission in all autonomic ganglia. Ganglionic AChR antibodies found in AAG patients are distinct from muscle AChR antibodies found in patients with MG. (2) Ganglionic AChR antibody levels correlate with severity of autonomic deficits. Patients with high antibody levels have a combination of OH, dry eyes and dry mouth, Adies pupil, gastroparesis, and neurogenic bladder. (3) Induction of ganglionic AChR antibodies in rabbits by immunization leads to experimental AAG which reproduces many of the cardinal features of the human disease. (4) Passive transfer of ganglionic AChR antibodies to mice causes transient autonomic failure. In electrophysiological studies, ganglionic AChR antibodies produce a reduction in ganglionic AChR current in cultured neuroblastoma cells and inhibit synaptic transmission in isolated autonomic ganglia. AAG is an antibody-mediated channelopathy that produces a severe, but treatable, form of autonomic failure.