Acetylcholine receptor antibody characteristics in myasthenia gravis. I. Patients with generalized myasthenia or disease restricted to ocular muscles.

We have investigated anti-acetylcholine receptor (AChR) characteristics in three forms of generalized myasthenia gravis, which are distinguishable by their thymic pathology, age of onset, sex incidence and HLA antigen associations, and in restricted ocular myasthenia. Light chain, IgG subclass, avidity for denervated human AChR and reaction with various human and mammalian AChR preparations were examined in 9-12 patients from each group. Characteristics varied between individuals in each group but no significant differences were found in mean values between the three groups with generalized myasthenia. When antibody characteristics in ocular myasthenia were compared with those in generalized disease, however, differences were found particularly in relative reactivity with denervated, normal and ocular human AChR. The nature of the humoral response in ocular myasthenia thus differs from that in generalized myasthenia. The similarity in the humoral response between the three groups of generalized myasthenia suggests, on the other hand, that the distinguishing clinical features may reflect differing susceptibilities to diverse precipitating mechanisms.