Enzyme immunoassay of anti-human acetylcholine receptor autoantibodies in patients with myasthenia gravis reveals correlation with striational autoantibodies.
Anti-acetylcholine receptor (AChR) autoantibodies are a marker of acquired myasthenia gravis (MG). Some of these antibodies cause muscle weakness. Striational autoantibodies (StrAb) also are a marker of MG. They are most prevalent in older patients and patients with thymoma. Here we describe a reproducible enzyme immunoassay (AChR-EIA) for detecting antibodies reactive with human muscle AChR, using antigens concentrated on plastic by prior sequential application of a biotinylated carrier, avidin, and biotinylated monoclonal IgG against AChR. There was significant correlation between values for antibodies assayed by AChR-EIA and by immunoprecipitation of AChR complexed with 125I-alpha-bungarotoxin. Unexpectedly, AChR-EIA and StrAb values also were significantly correlated. Further studies revealed a significant and unprecedented correlation for StrAb and AChR precipitating antibodies. A plausible explanation for these findings is that some StrAb may react with cytoskeletal proteins that associate and copurify with AChR. The AChR-EIA offers a nonradioactive method for detecting two autoantibodies that are relatively restricted to patients with acquired MG.
Sano
M
M
Department of Neurology, Mayo Clinic, Rochester, MN 55905.
Lennon
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VA
D000911:Antibodies, Monoclonal; D001323:Autoantibodies / Q000032:analysis*; D001360:Avidin; D001710:Biotin; D006801:Humans; D007124:Immunoenzyme Techniques; D009157:Myasthenia Gravis / Q000276:immunology*; D011137:Polystyrenes; D011950:Receptors, Cholinergic / Q000276:immunology*
D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D011137:Polystyrenes; D011950:Receptors, Cholinergic; D001360:Avidin; D001710:Biotin