Determination of IgE-containing immune complexes in human sera. Evaluation of polyethylene glycol precipitation of monomeric and complex IgE and of the detectability of IgE in the complexes

A sensitive and reproducible method for the determination of subnanogram quantities of immunoglobulin E (IgE)

An immunoradiometric assay for immunoglobulin E (IgE) using high adsorption polystyrene test tubes as the solid phase (the 'Maxisorp' assay) is described. The sensitivity of the method was found to be 50 pg IgE/ml and the within-assay reproducibility was 3-7%. The accuracy was estimated by means of a comparison between the Maxisorp assay and paper radioimmunosorbent test (PRIST) and a correlation coefficient of 0.98 (P less than 0.001) was obtained. We conclude that the Maxisorp assay is a fast and reliable assay for IgE determination in cord blood, cell culture supernatants and other highly diluted IgE preparations.

Clinical and immunological aspects of a case of monoclonal hyper-IgE. Isolation of IgE-protein, estimation of basophil cell bound IgE and histamine release

A case of monoclonal IgE type lambda with IgE levels about 1 mg/ml has been followed for 6 years. Except for a slight asthma no signs of malignancies, parasitic infestations or other known diseases compatible with hyper-IgE have been found. By the combination of fractional ammonium sulphate precipitation, gel filtration, chromatofocusing, and subtraction affinity chromatography the IgE protein was isolated in an immunochemically pure and homogeneous form. Immunofluorescence of bone marrow cells showed about 1% IgE plasma cells. The amount of basophil bound IgE was 42 ng/10(6) cells, and histamine release from basophils challenged with anti-IgE was not different from that in atopic control persons, indicating a within-allergic-patients normal amount of IgE receptors. The protein-A reactivity was 0.4% equivalent to well-known IgE myeloma proteins. No antigen specificity of the IgE protein was found. Only a few cases of asymptomatic hyper-IgE are known, and it cannot be ruled out that this represents a premyeloma condition, since a similar case terminated in a malignant lymphoma.