Determination of IgE complexes and of total IgE by latex immunoassay.
A sensitive immunoassay based on latex particle agglutination for the measurement of circulating IgE-containing complexes is described. In this method, the anti-IgE-coated particles are incubated with diluted serum and the resulting agglutination is quantified by turbidimetry or particle counting. In the latter version, the assay is fully automated in a continuous flow system. IgE-containing complexes were detected in all tested sera. Increased concentrations were observed in about 80% of the subjects with elevated serum IgE. However, high levels of IgE-complexes may also be found in subjects with a normal or even a very low serum concentration of IgE. The same latex immunoassay can be used for the determination of total IgE, after pepsin digestion of the gamma-globulin fraction of the serum. The results obtained correlate well with those found with a sandwich radioimmunoassay (r = 0.91, n = 83). The present method, however, yields a greater number of significantly positive results than the radioimmunoassay, probably because of its ability to detect IgE entrapped in circulating complexes.
D000936:Antigen-Antibody Complex / Q000032:analysis*; D002850:Chromatography, Gel; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007073:Immunoglobulin E / Q000032:analysis*; D007841:Latex Fixation Tests; D009391:Nephelometry and Turbidimetry; D010434:Pepsin A; D011863:Radioimmunoassay
D000936:Antigen-Antibody Complex; D007073:Immunoglobulin E; D010434:Pepsin A