IgG from "seronegative" myasthenia gravis patients binds to a muscle cell line, TE671, but not to human acetylcholine receptor.

Journal article

Antibodies to acetylcholine receptor (AChR) are found in 85% of patients with myasthenia gravis (seropositive MG [SPMG]) and are thought to be pathogenic; but in 15% of MG patients, the standard immunoprecipitation test for anti-AChR is negative (seronegative MG [SNMG]). Here, we used a novel approach, fluorescence-activated cell sorting analysis, to measure binding of SPMG and SNMG IgG antibodies to rhabdomyosarcoma cell lines that express human adult (TE671-epsilon) or fetal (TE671-gamma) AChR, and to human embryonic kidney (HEK) fibroblasts that express adult human AChR (HEK-AChR). We found that whereas most SPMG antibodies bind to all three cell lines, IgG from 8 of 15 SNMG sera/plasmas bind to the surface of both TE671 cell lines but not to HEK-AChR cells. These results indicate that SNMG antibodies bind to a muscle surface antigen that is not the AChR, which strongly supports previous studies that suggest that SNMG should be considered a distinct subtype of MG.

Authors: Blaes, F; Beeson, D; Plested, P; Lang, B; Vincent, A

• Publication status: Published
• Journal: Annals of neurology
• Volume: 47
• Issue: 4
• Pages: 504-510
• Publication date: 2000-04-01
• DOI: 10.1002/1531-8249(200004)47:4<504::aid-ana14>3.3.co;2-h
• EISSN: 1531-8249
• ISSN: 0364-5134
• Language: English
• Keywords: Antibody Specificity; Myasthenia Gravis; Transfection; Fetus; Humans; Adult; Muscle Neoplasms; Rhabdomyosarcoma, Embryonal; Immunoglobulin G; Flow Cytometry; Kidney; Autoantibodies; Receptors, Cholinergic; Tumor Cells, Cultured