Semiquantitative Measurement of Acetylcholine Receptor at the Motor End-plate in Myasthenia Gravis

Abstract

Objective: The purpose of this study was to investigate whether this semiquantitative measurement of the motor end-plate acetylcholine receptors (AChRs) can be used to confirm the diagnosis of myasthenia gravis (MG), and in particular ocular MG. Methods: Motor point biopsies were performed from the biceps brachii muscles. Measurement of AChRs was made in peroxidase-labeled α-bungarotoxin stained muscle specimens. Patients: Twenty patients with ocular MG, 37 with generalized MG, 5 with Lambert-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 antibodies, as compared with the control subjects. Conclusion: This method is useful to confirm the diagnosis of MG, in particular ocular MG without detectable anti-AChR antibodies.