Neuronal ganglionic acetylcholine receptor autoimmunity.

We have developed and validated an assay to detect serum antibodies specific for the ganglionic AChR. The assay uses ganglionic AChR solubilized from membranes of the human neuroblastoma cell line (IMR-32) as antigen. The ganglionic AChR is radiolabeled by complexing with 125I-epibatidine. Among patients with acquired dysautonomia, seropositivity is highly associated with the diagnosis of idiopathic or paraneoplastic autonomic neuropathy and can distinguish these disorders from other forms of autonomic dysfunction. Ganglionic AChR binding antibodies are detectable in 50% of patients with subacute autoimmune autonomic neuropathy (AAN). These patients often have a high antibody value (>0.2 nmol/L). Lower values (0.05-0.20 nmol/L) are found in approximately 10% of patients with limited AAN.