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PubMed1978

The use of the radioallergosorbent test in the diagnosis of Hymenoptera anaphylaxis.

IgE antibody levels to Hymenoptera (honey bee, hornet, wasp or yellow jacket) venom or venom sac were measured in the serum of ninety-six patients with a history of immediate hypersensitivity reactions to these insect stings. Normal levels of IgE antibody were found in fourty-four of these patients tested. The severity of the systemic reaction was similar in those patients with normal and elevated IgE antibody levels, and the interval from the systemic reaction to antibody determination was also similar. In twelve patients with a definite reaction to honey bee venom, the IgE antibody was elevated in all and correlated with a positive venom skin test in nine out of the twelve. It is not possible to determine if the other patients with normal IgE antibody and a systemic reaction represent a false negative RAST value, loss of sensitivity to the Hymenoptera venom, or a lack of RAST sensitivity with some venom or venom sac antigens. Without the ready availability of venom skin tests to all Hymenoptera antigens or other in vitro tests, a definite assessment of insect anaphylaxis remains in doubt for the patient and physician.

Adolescent↗
PubMed1991

Estimation of IgE antibodies to the common allergens by reverse enzyme immunoassay. Comparison with the radioallergosorbent test.

A reverse enzyme immunoassay (REINA) is described, in which polystyrene microtiter wells are sensitized with murine monoclonal anti-human IgE, and then sequentially allowed to react with patient's serum, peroxidase-labeled allergens and substrate. The results obtained with the sera of patients allergic to Lolium perenne grass pollen, the tree pollens of Betula alba and Olea europea, the epithelia of cat and dog, the mite Dermatophagoides pteronyssinus, or to the foodstuffs cow's milk, chicken eggwhite or peanut were compared with the analytical data from the ratio allergosorbent test (RAST). The results show a good correlation between these two laboratory techniques.

Allergens↗
PubMed1982

Improvement of the radioallergosorbent test (RAST) sensitivity by using an antibody specific for the determinant D epsilon 2.

A technical modification was introduced by the manufacturer (Pharmacia) of a commercially available RAST, with the use of an anti-IgE antibody specific for the domain epsilon 2 of the IgE molecule. Results of the previous and of the new RAST were compared in 100 patients suffering from bronchial asthma or chronic rhinitis. When the same serum was assayed by both techniques, the new RAST technique disclosed a higher positivity in 26% of the comparisons. The new RAST improved the overall correlation between RAST and skin-tests by 6%: individually by 12% for house dust, 8% for Dermatophagoides pteronyssinus and 15% for animal danders. However, the level of correlation was decreased by 8% for the moulds. In patients with a total IgE concentration larger than 100 PRIST units, the new RAST allowed the demonstration of specific IgE in a number of cases twice as large as the previous technique. Thus, the modification of the RAST provides a more sensitive test, the results of which better correlate with those of other diagnostic methods.

Adolescent↗
PubMed1988

Evaluation of commercial imported fire ant extracts by crossed immunoelectrophoresis and radioallergosorbent test.

Imported fire ant whole-body extracts (IFAWBE) from three major U.S. commercial suppliers and a reference IFAWBE and imported fire ant venom (IFAV) preparation were compared by crossed immunoelectrophoresis and RAST-inhibition testing. Results of crossed immunoelectrophoretic studies showed major differences in antigen content between commercial preparations. IFAWBE and IFAV RAST-inhibition testing showed that no commercial extract had equivalent inhibitory activity to the reference IFAWBE. Reference IFAWBE reached 50% inhibition of IFAWBE and IFAV RAST at 52 and 492 micrograms/ml, respectively. IFAV gave 50% inhibition of IFAWBE and IFAV RAST at 5.9 and 58 micrograms/ml, respectively. Of the commercial extracts, only those from one supplier were able to reach 50% inhibition of the reference IFAWBE RAST, and no commercial extract from any supplier was able to reach 50% inhibition of IFAV RAST. Analysis of inhibition slopes and intercepts confirmed that there were both qualitative and quantitative differences among the commercial extracts and the reference IFAWBE and IFAV. Our findings suggest possible reasons why some individuals fail to respond to testing or immunotherapy with IFAWBE and show the urgent need for standardization of allergenic extracts for diagnosis and treatment of imported fire ant sensitivity.

Allergens↗
PubMed1987

Serum IgE antibodies to Trichophyton in patients with urticaria, angioedema, asthma, and rhinitis: development of a radioallergosorbent test.

A series of patients was identified who demonstrated immediate positive skin tests to intradermal Trichophyton extract. These skin responses did not correlate with other fungal skin tests and were present both in atopic and nonatopic patients. The individuals demonstrating positive immediate skin tests included patients with urticaria, angioedema, asthma, and/or rhinitis, as well as five of 34 normal control subjects. Most skin test positive individuals had a history of local fungal infection and clinical signs suggestive of fungal infection. By use of Trichophyton tonsurans extract linked to Sepharose as the immunosorbent, it was possible to measure IgE antibodies in 26/30 sera from skin test positive individuals. With strongly positive sera, RAST bound up to 30% of the radiolabeled anti-IgE added. The results confirm that most skin test positive individuals have IgE-mediated hypersensitivity to Trichophyton. These observations support the older view that absorption of dermatophyte allergen through the skin should be considered as a possible cause of allergic disease.

Angioedema↗
PubMed1981

Radioallergosorbent test with conjugates specific for 'minor' haptenic determinants in the diagnosis of IgE-mediated penicillin allergy in man.

Penicillamine-polylysine, benzylpenicillanyl-human serum albumin and ampicillin-polymers were coupled to CNBr-activated paper discs and used in addition to penicilloyl G and penicilloyl V discs in RAST investigations. Sera from sixty patients with case histories of penicillin allergy and with positive or negative skin tests to different penicillin determinants and from seventeen subjects with atopic diseases caused by allergens other than penicillin were tested. The penicilloyl-('major' determinant) specific RAST (Phadebas RAST Penicilloyl G and V) was positive in twenty out of twenty-four patients with positive skin tests to penicilloyl-polylysine, in eight out of twelve patients with sole skin reactivity to 'minor' determinants, and in five out of twenty-four patients with negative skin tests to all antigens used. The penicillamine-specific RAST was the only positive in vitro test in four patients with negative skin tests (two) or sole positive skin reactivity to 'minor' determinants (two), whereas benzylpenicillanyl and ampicillin-polymer discs added no more information than the penicilloyl structures in all patients tested. Antibodies specific to 'minor' determinants apparently show strong in vitro cross-reactivity with the penicilloyl determinant. It is, therefore, concluded that 'minor' determinant specific conjugates are of marginal importance for in vitro diagnosis of penicillin-allergic patients.

Benzeneacetamides↗
PubMed1982

A radioallergosorbent test (RAST) for Ascaris lumbricoides.

An antigen from Ascaris lumbricoides obtained from infected humans has been prepared which can be used for detecting immune response to Ascaris using the skin-prick test. A comparison of immune skin responses between this antigen and the commercial (Bencard) Ascaris suum antigen has been made and a RAST technique for the in vitro detection of specific IgE to Ascaris lumbricoides has been developed using the Lumbricoides antigen. A correlation between skin-prick test and RAST determinations and between RAST and total serum IgE antibodies has been demonstrated. The correlation of RAST results and serum IgE levels agreed with the division of the patients into two classes-allergic and non-allergic-on the basis of clinical criteria for allergy.

Antigens↗
PubMed1988

[Allergen analysis of mugwort pollen (Artemisia vulgaris) using crossed radioimmunoelectrophoresis and radioallergosorbent test inhibition].

It could be identified 43 antigens of mugwort pollen (Artemisia vulgaris), 31 migrating anodically and 12 cathodically, by means of crossed immunoelectrophoresis (CIE). Eleven antigens bound human IgE-antibodies in crossed radioimmunoelectrophoresis (CRIE). Two major allergens could be found, allergens 23 and 40.- The allergenic activity of mugwort pollen extract was examined by means of RAST-inhibition. Specificity of this reaction could be determined by a control trial with grass pollen extract.

Allergens↗
PubMed1983

Radioallergosorbent testing with p-tolyl monoisocyanate in toluene diisocyanate workers.

Sera from 149 occupationally exposed toluene diisocyanate (TDI) workers were tested by RAST with p-tolyl monoisocyanate human serum albumin (TMI-HSA). Of the seven positives, one had a history suggestive of TDI asthma and one had a rash which may have been TDI related. These results indicate that false positive RAST with TMI-HSA may occur in asymptomatic workers.

Asthma↗
PubMed1979

The radioallergosorbent test (RAST) in nasal polyposis.

The incidence of atopy among 64 adults undergoing polypectomy was 25 per cent. Among these atopic patients it was usual for the polyp IgE level to exceed that in the serum. Similarly, D. pteronyssinus-specific IgE was more commonly identified in polyp fluid by the RAST technique than in serum. However, this was not so for grass pollen-specific IgE, where serum and polyp fluid were equally positive. We conclude that there are atopic and non-atopic polyps.

Adult↗
PubMed1987

Lectins and the radioallergosorbent test.

An investigation into the possible role of lectin binding of IgE in RAST of legume and wheat extracts is reported. Lectins from pea, broad bean, lentil, jack bean, soybean, peanut, and wheat germ were coupled to RAST discs. The discs were pretreated with lectin-specific sugars in an attempt to inhibit RAST with sera from 11 sensitive patients. In all cases, RAST was almost unaffected by the inhibitory sugars, indicating that nonimmune binding of IgE by lectins in legume or wheat RAST was not significant when RAST was carried out with allergens bound to the usual paper discs. IgE contains binding sites for all the lectins examined, and five of the sera had high total IgE greater than 300 IU/ml. It is suggested that competition by IgG and other serum glycoproteins may explain the lack of effect by the added sugars. All sera contained endogenous glucose at a level of about 3 mmol/L that may have accounted for some self-inhibition of the lectin binding by pea, broad bean, lentil, and jack bean lectins. There was, however, significant immune binding of some of the lectins by specific IgE, and it is concluded that these lectins may be important in expression of IgE-mediated allergic responses.

Arachis↗
PubMed1980

The mini-RAST: Comparison with other varieties of the radioallergosorbent test for the measurement of immunoglobulin E antibodies.

In the performance of the RAST a variety of different solid-phase supports for allergens are utilized. In this study we coupled allergens to microcrystalline cellulose and reduced the quantities of solid-phase allergen tenfold and of anti-IgE fourfold. These reductions actually increased the sensitivity of the RAST for IgE antibodies to several allergens, including those derived from Alternaria tenuis and rye grass pollen. We have termed this procedure the mini-RAST to distinguish it from the procedure employing larger quantities of solid-phase allergen and anti-IgE, the maxi-RAST. We then compared three RAST procedures for the detection of IgE antibodies to ragweed allergens: the maxi-RAST, the mini-RAST, and the paper disk RAST, using both commercial paper disks and disks prepared in our laboratory. The maxi-RAST and the mini-RAST yielded similar results and both appeared more sensitive than the paper disk RAST for the detection of IgE antibodies to ragweed. The results indicate that the microcrystalline cellulose RAST can be significantly scaled down without a loss of its ability to detect IgE antibodies and with a considerable saving of valuable solid-phase allergens and anti-IgE.

Allergens↗
PubMed1992

Immunoassay of specific IgE: use of a single point calibration curve in the modified radioallergosorbent test.

Interest in immunoassay standardization has prompted development of specific IgE assays reporting results related to the international IgE reference. To examine the single point calibration curve employed in the modified RAST assay (MRT) to convert MRT counts to IgE units, independent dilutions of a 25 kU/L total IgE reference and nine allergic sera (three each for short ragweed, cat, and timothy) were made in horse serum and assayed. In a log-log plot, the single point curve was, by definition, linear over its entire range; the dilution curve was curvilinear because of reagent system saturation, which was at 7 kU/L. Curves were not parallel (P less than .001). Allergen-specific dilution curves showed saturation points at values similar to or less than the total IgE system. The linear portions of these curves paralleled the total IgE dilution curve but not the single point curve. This lack of parallelism would have resulted in varying magnitudes of error in estimation of IgE antibody levels in the upper and lower assay ranges, and would imply a lower detection limit for IgE than that which the assay actually has. Modified RAST assay is not appropriate in research or a clinical situation in which accurate quantitative results are needed. Modified RAST assay would furthermore be an inappropriate means of assigning units to proposed reference preparations for standardization.

Allergens↗
PubMed1982

Particle counting immunoassay of immunoglobulin E antibodies after their elution from allergosorbents by pepsin: an alternative to the radioallergosorbent test.

The absorption of specific antibodies on allergen-coated cellulose discs, followed by pepsin digestion to release the IgE Fc" fragment, which is then assayed by particle counting immunoassay (PACIA), is a new practical and reliable method to quantitate IgE antibodies and to standardize allergens. The coefficient of variation of repeated assays does not exceed 12.8% and the correlation coefficient with RAST was r = 0.96. Some discrepancies could be explained by differences in the antiserum specificities and the presence of anti-IgE autoantibodies. The determination of IgE antibodies by PACIA offers the following advantages: (1) no radioisotopes; (2) stability of reagents, since antibody-coated latex particles and the standards keep their activity for more than 1 yr; (3) low cost of reagents due to ease of preparation --PACIA does not require purified antibodies to measure IgE but only F(ab')2 fragments of the IgG fraction of the anti-IgE antiserum to coat latex; (4) avoidance of nonspecific absorption of the labeled anti-IgE on the solid phase; (5) prevention by elution of the inaccuracies observed in RAST at very high titers of IgE antibodies; (6) expression of the results in international units per milliliter to calculate the ratio of specific IgE Ab vs total IgE, with a high ratio suggesting that the patient is sensitive to a few allergens; (7) standardization of allergenic extracts; and (8) the particular specificity of the anti-IgE antiserum directed against a heat- and protease-resistant fragment of IgE.

Allergens↗
PubMed1986

Detection of antibodies to proteases used in laundry detergents by the radioallergosorbent test.

Two proteases, Esperase and Alcalase, derived from Bacillus licheniformis and B. subtilis, respectively, are used in laundry products. In testing for the prevalence of IgE antibodies to these enzymes in sera among 300 laundry product workers, we experienced two problems in the establishment of a reliable RAST for these antigens. The first problem was the propensity of the allergen, Esperase, to undergo autolysis, suggesting that solid-phase Esperase might also lose reactivity through degradation. Treatment of Esperase with phenylmethylsulfonyl fluoride stabilized the enzyme and permitted the synthesis of a stable solid-phase antigen. The second problem was the finding that sera reactive with Esperase in the RAST were also reactive with Savinase, an enzyme from B. licheniformis to which the workers were not exposed. Immunochemical analyses of the three enzymes with specific rabbit antisera by gel diffusion and by two-site immunoradiometric assay demonstrated that they were not cross contaminated to any appreciable extent. RAST inhibition demonstrated that solid-phase Esperase possessed unique allergenic determinants in that the reactivity of IgE antibodies was inhibited by low concentrations of Esperase and only by very high concentrations of Alcalase and Savinase. In contrast, the reactivity of solid-phase Alcalase was occasionally inhibited equally well by Esperase and Alcalase. Most strikingly, the reaction of IgE antibodies with solid-phase Savinase was always inhibited by comparable quantities of Esperase, Alcalase, and Savinase. Thus, the establishment of the RAST for these proteases appears to require the use of phenylmethylsulfonyl fluoride to retard autolysis, and the results must be interpreted with caution because IgE antibodies in certain sera demonstrate cross-reactivity with Alcalase and Savinase.

Antibodies↗