Semiquantitative measurement of acetylcholine receptor at the motor end-plate in myasthenia gravis

Objective The purpose of this study was to investigate whether this semiqua ntitative measurement of the motor end-plate acetylcholine receptors (AChRs ) can be used to confirm the diagnosis of myasthenia gravis (MG), and in pa rticular ocular MG, Methods Motor point biopsies were performed from the biceps brachii muscles . Measurement of AChRs was made in peroxidase-labeled alpha -bungarotoxin s tained muscle specimens. Patients Twenty patients with ocular MG, 37 with generalized MG, 5 with Lam bert-Eaton myasthenic syndrome, 3 with botulism, 8 with amyotrophic lateral sclerosis, and 8 controls were included in this study. Results AChRs were decreased in all patients with generalized MG and in 80% of ocular MG including patients without detectable circulating anti-AChR a ntibodies, as compared with the control subjects. Conclusion This method is useful to confirm the diagnosis of MG, in particu lar ocular MG without detectable anti-AChR antibodies.