Evidence of possible localized specific immunoglobulin E production in middle ear fluid as demonstrated by ELISA testing.

To determine whether IgE in the middle ear represents a passive transudate from the serum or may be produced within the middle ear itself, paired effusion and serum from 18 atopic children with otitis media with effusion were tested by micro-ELISA for specific IgE to 12 allergens. Elevated effusion concentrations of specific IgE were present in 83.3% (15 of 18) of atopic patients, but only 30% (64 of 214) of the serum antibodies appeared in the effusion. The data show that in atopic children with otitis media with effusion, there is no relation between a patient's serum and effusion level of IgE for specific antibodies (P < 0.001), suggesting that IgE in middle ear effusion is not a transudate but more likely reflects an active localized process in atopic patients.

Immunoglobulins and the immune system.

Lymphocytes play a major role in the sophisticated immune system of the human being. A group of lymphocytes that has undergone biologic processes to become plasma cells produces immunoglobulins, the molecules with the properties of antibodies. This article reviews the function of lymphocytes in the immune response and summarizes the current knowledge on the immunoglobins.

Correlation of a micro-ELISA assay with the skin test and the RAST assay in inhalant allergy.

Several modifications of a previously described micro-ELISA assay (IP Assay) for the diagnosis of IgE mediated disorders were developed to increase the assay sensitivity and specificity. The absorbance values in milliunits obtained in this assay were normalized with a computer algorithm. The results of this assay correlate well with those obtained with the RAST assay (normalized milliunits of absorbance versus bound radioactivity: r = 0.74 to 0.87). However, the IP assay detected allergen specific IgE antibodies in many sera for which the RAST assay gave negative results (from 13.3% to 28% for a variety of allergens). The converse was seen in fewer than one percent of tests. Further, in a series of 300 tests for a panel of ten allergens, the IP assay showed a higher degree of correlation with the intradermal skin test (82%) than the RAST assay (77.3%). The specificity of the IP and RAST assays were comparable. Data showing the stability of the polystyrene surface immunosorbent and the independence of the IP assay from high levels of total IgE antibodies are presented. The reasons for higher sensitivity of the IP assay than the RAST assay (and hence superior correlation with the skin test) are discussed.

A computerized micro-ELISA assay for allergen-specific IgE antibodies.

A computer-normalized micro-ELISA assay employing horseradish peroxidase and polystyrene microtiter plates (IP assay) for allergen-specific IgE antibodies is described. The specificity of the assay was confirmed by heat inactivation and multiple absorption experiments. Individual allergen blanks were used to account for the variability in the nonspecific binding among various allergens. The results obtained in milliunits of absorbance were normalized by a computer protocol using four reference sera. The coefficients of variation for the intraassay and interassay reproducibility ranged from 1.49 to 9.33% and 7.11 to 15.19%, respectively. Direct correlations between the results of the IP and the RAST assays (Absorbance vs. bound radioactivity) were excellent; the values for correlation coefficients for six pollens (June grass, Bermuda grass, Short ragweed, English plantain, Oak and Box elder), house dust mite, and two epidermal (cat and dog) allergens ranged from 0.88 to 0.99. Correlation between the two assays was lacking for the Alternaria and Penicillium mold allergens (r values: Alternaria 0.32, Penicillium 0.5). For sera from patients with a positive history and positive skin tests challenged with 11 allergens cited above, the IP assay detected low levels of specific IgE in many cases where the RAST assay was negative (from 10% for June grass to 48% for Alternaria and Penicillium mold antigens). The RAST positivity accompanied by the IP negativity, by contrast, was rarely seen. The superior sensitivity of the IP assay for specific IgE antibodies was achieved by lowering the background "noise" in the IP assay. This was attributed to the following factors: (1) use of individual allergen blanks; (2) 1:5 dilution of the serum sample that minimizes interference from high levels of total IgE antibodies and from allergen-specific IgG antibodies; (3) nonporous nature of the polystyrene immunosorbent surface; and (4) the use of a computer data reduction system to normalize the assay results.

Serum concentrations of allergen-specific IgG antibodies in inhalant allergy: effect of specific immunotherapy.

The occurrence of antibodies belonging to IgG class of immunoglobulins with specificity for short ragweed and Bermuda grass in the sera of nonatopic subjects and patients with inhalant allergy (at the time of initial diagnosis, following specific immunotherapy was investigated with an enzyme immunoassay. The intra-assay and inter-assay coefficients of variation for this assay ranged from 1.74%-4.62% and 3.18%-9.12%, respectively. IgG antibodies were found in the sera of the majority of nonatopic and all of atopic subjects. The differences in the concentration of these antibodies between these three groups were statistically significant (P less than 0.001). Specific immunotherapy resulted in a rise in the serum levels of allergen-specific IgG antibodies and, following an initial period of modest increase, a decrease in the level of allergen-specific IgE antibodies. Specific IgG response correlated with both the cumulative antigen dose and the clinical benefit that accrued from specific immunotherapy (P less than 0.001). The increase in the serum concentration of specific IgG was most pronounced in patients with high RAST scores at the time of initial diagnosis (P less than 0.001). The concentrations of short-ragweed specific IgG antibodies assayed with multiple samples in three patients with ragweed hay fever appeared not to be affected by the short-ragweed season to any significant degree. We conclude that direct enzyme immunoassay for allergen-specific IgE and IgG antibodies are useful in vitro monitors of immunologic responses to specific immunotherapy for inhalant allergy.