Absence of Oligoclonal IgG Bands and Anti-Achr Antibodies in the Cerebrospinal Fluid of Patients with Myasthenia Gravis

Abstract

Myasthenia gravis (MG) is a neuromuscular disorder in which antibodies are directed against the nicotinic acetylcholine receptor (AChR) at the neuromuscular junction. Some investigators describe the existence of oligoclonal IgG bands and anti-AChR antibodies in the cerebrospinal fluid (CSF) of MG patients while other refuse it. This study was performed in 15 patients with clinical and electrophysiological diagnosis of MG. Oligoclonal IgG bands (OCB) and antibodies to the AChR from human skeletal muscle were determined in the serum and the CSF of the above MG patients. The last one was done in order to investigate any possible central nervous system (CNS) involvement. It was found that all the MG patients who had a high titre of anti- AChR antibodies in the serum (mean titre 29.2±24.3 nM, range 1.8 to 62 nM) did not present OCB and anti-AChR antibodies in their CSF. On the same time, in a group of 10 patients with a definite multiple sclerosis it was found that eight of them presented OCB in their CSF while the results were negative in another group of 10 patients without evidence of CNS disease. The last two groups served as control groups. Our findings are in accordance with the concept that MG is a pure neuromuscular disorder.