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

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 alpha-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.