title: Clinical correlates of enzyme-immunoassay versus radioimmunoassay measurements of antibody against acetylcholine receptor in patients with myasthenia gravis.
abstract: Antibody against human nicotinic acetylcholine receptor [Ab(AcChR)] was measured in the sera obtained from 55 patients with myasthenia gravis (MG) using both radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA). By at least one assay, 91% of the patients had elevated Ab(AcChR). We found no correlation between the amount of Ab(AcChR) measured by RIA and that measured by ELISA. Patient subpopulations defined by ELISA- or RIA-measured Ab(AcChR) were associated with different disease durations. All of those who had high Ab(AcChR) levels by both assays had experienced symptoms for less than 2 years. 87% of those with high Ab(AcChR) levels by ELISA had had MG for less than 4 years. Those patients with high Ab(AcChR) only by RIA had a mean disease duration of over 8 years. With regard to correlations of Ab(AcChR) with patient age and sex, females under 50 years of age had high levels of Ab(AcChR) by RIA, but had lower levels by ELISA, whereas men over 50 had high Ab(AcChR) levels by ELISA. Using either assay, no relationship was established between concentrations of Ab(AcChR) and the patient's functional status, previous thymectomy, or current therapy. In this study, 16% of the MG patients with elevated Ab(AcChR) would have been considered within the non-disease range of Ab(AcChR) had only the RIA been performed, thus recommending the routine use of both assays for diagnostic purposes.
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001323:Autoantibodies / Q000032:analysis*; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000276:immunology* / Q000628:therapy; D011241:Prednisone / Q000627:therapeutic use; D011863:Radioimmunoassay; D011950:Receptors, Cholinergic / Q000276:immunology*; D012737:Sex Factors; D013997:Time Factors
chemical_list: D001323:Autoantibodies; D011950:Receptors, Cholinergic; D011241:Prednisone