C. Gotti et al., DETECTION OF ANTIBODY CLASSES AND SUBPOPULATIONS IN MYASTHENIA-GRAVISPATIENTS USING A NEW NONRADIOACTIVE ENZYME-IMMUNOASSAY, Muscle & nerve, 20(7), 1997, pp. 800-808
To investigate the presence of antibodies in myasthenia gravis (MG) pa
tients, we have developed a new reproducible and sensitive enzyme immu
noassay (EIA-AChR), in which a beta subunit-specific monoclonal antibo
dy (mAb 73) immobilizes fetal calf acetylcholine receptors (AChRs). We
tested 92 MG patients (42 with positive and 50 with negative antibody
titers), 60 healthy controls. and 40 controls with other autoimmune d
iseases. EIA-AChR detected immunoglobulin G (IgG) titers in all of the
seropositive samples, with a significant correlation between these an
d those obtained using the traditional immunoprecipitation method. Mor
eover, 5 seronegative patients at immunoprecipitation assay were posit
ive at EIA-AChR. EIA-AChR was also useful in revealing: (1) a seroposi
tive patient subpopulation with generalized MG who had Abs directed ag
ainst alpha-Bungarotoxin binding sites; and (2) patients with IgM dire
cted against fetal calf AChR (detected in 13 seronegative and 16 serop
ositive WIG patients, and in 6 of the patients with other autoimmune d
iseases). (C) 1997 John Wiley & Sons, Inc.