Studies of skin test on diagnosis of nasal allergy induced house dust and mites

Skin test, radioallergosorbent test (RAST) and nasal provocation test were carried out on 392 patients to detect house dust (HD) and mites as causative allergens. This study was undertaken to evaluate the difference between the results of skin test, RAST and nasal provocation test. The results were as follows: 1. The frequency of positive intradermal test to mites was high regardless of age. But possibility of false positive results existed and this possibility increased with the patient's age. 2. RAST to mites was significantly higher than that to HD. In diagnosing HD allergy, measuring RAST to mites was more useful than measuring that to HD. 3. In pediatric patients, it could be assumed that measuring RAST to mites was the most applicable technique for diagnosing HD and mites as causative allergens. 4. The combination of intradermal test to HD and scratch test to mites was considered to be a useful screening skin test in diagnosing HD allergy. 5. Both the end point and reaction criteria of intradermal test were significantly correlated with the results of RAST and nasal provocation test.     

Comparison of a multi-allergen dipstick IgE assay to skin-prick test and RAST

A multi-allergen dipstick enzyme immunoassay 'Quidel Allergy Screen' (QAS) has recently been developed commercially for measuring IgE antibodies against nine allergens (house dust 1, house dust 2, Dermatophagoides pteronyssinus, D. farinae, Japanese cedar, ragweed, cat dander, sweet vernal grass, and egg white) at one time. To assess whether this assay is useful in screening allergen-specific IgE antibody, we compared the titres of IgE antibodies against the nine allergens measured by QAS to those in the skin-prick test and by RAST in 93 atopic asthmatics and 22 normal subjects. We found a good overall agreement between the results of the skin-prick test and the results of QAS (sensitivity = 47.1-81.4%, specificity = 84.5-100%, and agreement = 78.9-88.9%). The sensitivities against house dust 1, D. pteronyssinus, and D. farinae ranged from 77.2 to 81.4%. However, the sensitivities against house dust 2, Japanese cedar, ragweed, and cat dander were low (47.1-68.8%). We also found a good overall agreement between the results of RAST and the results of QAS, except for egg white (sensitivity = 46.2-94.4%, specificity = 87.4-100%, and agreement = 77.4-96.5%). The sensitivities against house dust 1 and 2, D. pteronyssinus, D. farinae, and Japanese cedar ranged from 86.0 to 94.4%. The sensitivities against ragweed, cat dander, and sweet vernal grass were low (46.2-52.6%). There were strong correlations between the titres of RAST and the titres of QAS except cat dander and egg white (r = 0.701-0.924 for the seven allergens). Thus, we conclude that QAS is useful in screening IgE antibodies against multiple allergens at one time. However, because the sensitivities against some allergens tested were low, further improvement of some allergen preparations seems to be necessary in the assay.     

Comparison of a new specific IgE assay Quidel allergy screen to skin prick test, intradermal test, and RAST

Quidel Allergy Screen (QAS), an enzyme-linked immunosorbent assay, has been developed for measuring IgE antibodies against 9 allergens (HD 1, HD 2, Mite 1, Mite 2, Japanese cedar, ragweed, cat dander, sweet vernal grass, and egg white) at the same time. To determine whether this assay is useful in screening allergen-specific IgE antibody, we compared the titers of IgE antibodies against the 9 allergens measured by QAS to the obtained in skin prick tests, in intradermal tests and by RAST in 93 atopic asthmatics and 25 normal subjects. We found a good agreement between the reactivity of skin prick tests and the reactivity of QAS. There was a significant correlation between the threshold doses of intradermal tests and the titers of QAS. We also found a good agreement between the reactivity of RAST and the reactivity of QAS, and a strong correlation between the titers of RAST and the titers of QAS. Thus, it is concluded that QAS is useful in screening IgE antibodies against multiple allergens simultaneously.     

Evaluation of Oriton IgE, a new kit for measurement of allergen specific IgE antibodies]

To determine whether Oriton IgE kit, a new kit for the measurement of allergen-specific IgE antibodies, is useful in screening allergen-specific antibody, we measured the titers of IgE antibodies against 11 different allergens (house dust 2, Dermatophagoides farinae, Japanese cedar, ragweed pollen, egg white, milk, cat epithelium, dog epithelium, Candida, Alternaria and Aspergillus) with the Oriton IgE kit, and the results were compared to those of intradermal tests and RAST in 103 allergic patients and 10 normal subjects. There was a clear correlation between IgE antibody titers measured by the Oriton IgE kit and the RAST. The correlation coefficient was 0.76 (p less than 0.01) and the total correspondence rate was 85.9%. We also found strong correlation between the Oriton IgE kit and RAST in IgE antibody titer against 5 different allergens, Dermatophagoides farinae, Japanese cedar, ragweed pollen, egg white and Candida. The correlation coefficient was over 0.70. The correspondence rate, sensitivity and specificity of the Oriton IgE kit to intradermal tests was 71.8%, 45.3% and 87.8% respectively. The sensitivity of the Oriton IgE kit was slightly higher, while the specificity was slightly higher in RAST, although the differences were not statistically significant between these methods. Correspondence rate of the Oriton IgE kit was similar to that of RAST. These results suggested that the Oriton IgE kit is useful in screening allergen specific IgE antibodies.     

Change in skin reactivity to common allergens in allergic patients over a 30-year period. Association with aeroallergen load]

Five-year changes in the percentage of positive intradermal test to allergens in patients with bronchial asthma (BA) and allergic rhinitis (AR) over a period of 30 years from 1969 to 1998 were analyzed, with consideration of their association with the yearly changes in the levels of airborne pollens and molds over 30 years. Allergens used throughout the period were house dust, pollens from various plants (Japanese cedar, pine, oak, Japanese alder, Zelkova, orchard grass, ragweed, mugwort and Japanese hop) and molds (Alternaria, Cladosporium, Aspergillus, Penicillium and Candida). Overall percentages to house dust were higher in BA patients than in AR patients, but those to pollens were distinctly higher in the latter. Those to molds were higher in BA patients, except that those to Alternaria were about the same in both BA and AR patients. Therefore, the clinical expression of allergy may differ according to the type of allergen to which subjects are sensitized. Over the course of 30 years, the increase in the percentage of positive intradermal test to all of the allergens used was noted in both BA and AR patients, although this did not always reflect the aeroallergen load. This includes the two extremes to pollens from Japanese cedar and pine, either of which is the most common source of allergen in Japan. Significant increases in the percentages to Japanese cedar pollen (from 12.5% to 54.4% in BA patients, and from 35.1% to 81.5% in AR patients) appeared to be roughly correlated to marked increases in pollen count. In contrast, that to pine pollen was kept low at about 2%, because of their weak allergenicity, but abruptly increased to 5-6% in the last decade, despite the almost invariable pollen count over the last 30 years. Therefore, the increased sensitivity to aeroallergens may also be associated with other factors besides their load in the air.     

Discrepancies between the skin test and IgE antibody assays: study of histamine release, complement activation in vitro, and occurrence of allergen-specific IgG

Intracutaneous skin tests (STs) and RAST with the common allergens, grass pollen, house dust mite, and cat dander, were performed on 660 adult patients. In 117 patients (18%), we found 140 discordances (7%) in a total number of 1980 ST and RAST combinations. In agreement with studies in the literature, greater than 80% of the discordances consisted of positive skin reactions without detectable allergen-specific IgE antibodies in serum. The percentages of discordant results were similar for the three allergens. Reproducibility of both the RAST and the ST was evaluated in the discordant group. Repetition of the routine RAST procedure elicited results similar to those in the first test in 81% (105/130). A second ST elicited identical results in 89% (47/53). In addition to the routine IgE antibody assay, sera of patients with a positive ST but without detectable IgE antibodies were tested in two other RAST systems: (1) a RAST with allergen extracts from the same production batch as the ST reagents, and (2) the Pharmacia RAST. In spite of having a clearly positive ST, sera from 68 (80%) of 85 patients remained completely negative in all three RAST systems. Histamine release (HR) in vitro from washed leukocytes was studied in 35 patients with a reproducible positive ST and negative RAST results with serum. Interpretation of this test was possible in 28 patients. In 82% (23/28) of these patients, clearly detectable HR was found with the relevant allergen extract. A role of IgE in the skin reactions and HR tests was confirmed by positive RAST results with IgE that was affinity purified from serum of seven of these patients. Allergen-specific IgG4 antibodies are unlikely to be implicated, since no antibodies against grass pollen and house dust mite were detectable in sera of these patients. Only 18% of the patients with an unexplained skin reaction with cat dander have detectable IgG4 antibodies, but these antibodies were found in a similar frequency in a nonallergic, ST negative control group. Low total IgG responses precluded false negative RAST results caused by competition of IgG antibodies with IgE antibodies. There were no significant differences in the degree of complement activation in vitro by house-dust extracts between healthy control subjects, nonallergic patients, and patients with unexplained skin reactivity. It is concluded that a high proportion of the positive skin reactions with common inhalant allergens, which are not accompanied by a positive RAST, are probably caused by IgE antibodies that are not detectable in serum with any of the RAST procedures.(ABSTRACT TRUNCATED AT 400 WORDS)     

The results of skin prick testing in patients with allergic rhinitis: a comparison between a multiple lancet device and a single lancet

Skin prick testing (SPT) is widely used in the assessment of allergic disorders. Different SPT techniques are widely used. The aim of this study was to compare the response to SPT using a multiple lancet device (MLD) with the results of a single lancet (SL). Fifty patients with allergic rhinitis were included in this study. Initially, SPT was performed by a SL technique. After one week SPT was repeated using the MLD on all patients. The patients were tested with a panel containing 19 specific allergens including grass pollen, tree pollen, house dust mites, weed pollen allergen extracts, histamine and a negative control. The skin responses were recorded after 15 minutes for each device by measuring the diameter of the wheal and the erythema. The skin wheal responses for grass pollen, tree pollen, weed pollen and house dust mite allergen extracts obtained using the SL were generally significantly larger than those using the MLD. The comparison between the MLD and the SL methods revealed that SPT was positive with SL and negative with MLD in 176 tests (15.3%), and on the contrary SPT was positive with MLD and negative with SL in only 13 tests (1%). In conclusion, we claim that SPT using SL shows a higher degree of sensitivity and reproducibility.     

Animal dander allergy

In a group of twenty-three atopic patients skin tests were performed with the dander allergens of horse, cat and guinea-pig, and with house dust and Timothy pollen allergens. A good agreement was observed between positive skin reactions and the results of RAST with these various allergens. In a number of cases, positive skin reactions were not related to the clinical histories. Likewise, positive RAST scores in several instances proved clinically meaningless. In patients with history-related skin reactions better correlation with RAST was observed. In such patients, skin reactions with photo-inactivated allergens remained strongly positive.     

Relationship of Allergen-Specific IgE Antibodies, Skin Prick Tests and Allergic Disorders in Unselected Adolescents

The relationship between serum levels of allergen-specific IgE (RAST) and skin prick test reactivity and allergic disorders was evaluated in 137 subjects randomly selected from an adolescent population. All subjects were prick tested with six common allergens, interviewed and physically examined. In addition, serum was collected for RAST analysis with three to six allergens. At least one positive RAST result (score 1-4) was observed in 40% and at least two positive RASTs in 22% of the subjects. Boys experienced more RAST reactions and generally with higher scores than girls. For instance, 26% of boys but only 11% of girls were RAST positive to timothy grass pollen. The correlation between prick test and RAST results was better with pollens than with house dust and animal epithelia. When the test results were discordant, the skin test was usually positive and RAST negative. Many of the small skin reaction (weal diameter 3-4 mm) were accompanied by a negative RAST. Respiratory allergy was closely connected with both positive skin test and RAST reactivity, while atopic dermatitis was less related. In 17% of the adolescents positive skin tests and in 14% positive RASTs occurred in the absence of any allergic symptoms. We conclude that a positive RAST score 3-4 to inhaled allergens is a strong indicator of clinical allergy but low scores 1-2 are frequently found in healthy young people.     

Sensitivity to house dust mite and grass pollen in adults

A comparison was made between the birth month of a control population and a sample of 240 adult patients with bronchial asthma or rhinitis and positive skin test towards house dust mite (Dermatophagoides pteronyssinus). The patients were born more frequently (P < 0.005) in the summer and autumn months than in the other seasons. A similar comparison of 336 allergic patients with a positive skin test towards grass pollen (Phlemt pratense) but no consistent seasonal preference in the birth months was revealed. This was possibly explained by the age of the patient group studied. The increased incidence of house-dust mite allergy in patients born in the months of May to September inclusive when house dust mites are supposed to be most abundant corresponds to a relative risk of 1.44. It is important lo diminish the exposure to house dust mites in early childhood because exposure to allergens may influence the development of allergic disease in later life.     

Total serum IgE, allergy skin testing, and the radioallergosorbent test for the diagnosis of allergy in asthmatic children

Correlations of total serum IgE, skin test reactivity, and specific IgE antibodies to selected antigens were evaluated in asthmatic children. There was a significant difference in mean IgE level of each positive RAST score group compared with that of the RAST-negative score for dog epithelium, Candida, ragweed, and Bermuda grass allergen. The correlation coefficient between the total IgE and the RAST to D. farinae was 0.39 (P less than .05). There was no significant correlation between the total IgE and the RAST to D. pteronyssinus, Candida, dog epithelium, ragweed, Eucalyptus pollen, and Bermuda grass (P greater than .05). This indicates a low total serum IgE concentration does not exclude the possibility of significant elevation of specific IgE to a common allergen. Concordance for results of intradermal skin testing and RAST was high for most allergens. Lower efficiency for dog allergen and Candida suggests greater sensitivity of allergy skin testing for these allergens.     

The prevalence of allergy in Danish farmers

Sensitization to work-related and other common inhalation allergens was studied in 187 farmers by means of SPT and RAST. A positive RAST to house dust mites occurred in 6.4% and to storage mites in 5.3% of farmers. Sensitization to grain, pollen and animal dander was less frequent and a positive RAST to moulds was not found. There was a very strong association between a positive RAST to house dust mites and storage mites (odds ratio 173.6). Smoking seemed to be a risk factor for sensitization to mites, pollen, grain, and animal dander. Smokers who had lived in damp dwellings had a significantly increased risk of sensitization to mites (odds ratio 6.2-12.6), whereas this was not so with non-smokers (odds ratio 0.9-2.0).     

Specific IgE estimations by RAST in Japanese asthmatics compared with skin, passive transfer and bronchial provocation tests

198 asthmatics and twenty healthy persons were studied by RAST and in vivo tests with four common inhalant allergens, (a) Higher RAST classes were elicited with mite (Dermatophagoides farinae) extract and lower classes with other allergens. The agreement between positive RAST and skin or P-K tests was highest with the mite extract. RAST sensitivity was dependent on the kinds of allergens and was most sensitive to mite extract. Positive RAST was most closely related to the prick test reactions, (b) RASTs to house dust and mite extract were examined in terms of the threshold dosage of house dust and also the types of bronchial response (early, dual and late) induced by a certain amount of house dust; higher RAST classes were found in subjects with bronchial response of the dual or early type, elicited by a threshold dosage of diluted extract, while lower RAST classes were found in cases of the late-type response elicited by the threshold dosage of concentrated extract, (c) Changes in IgE antibodies to house dust and mite extract were estimated in patients with positive house dust provocation. A greater increase occurred in cases of dual or early response, a smaller increase in those with a late response. Despite discordances in skin tests and RAST between house dust and mite extracts, the increases in IgE antibodies to mite extracts as well as house dust were observed in all cases, presumably caused by an allergenic identity between the allergens.     

Diagnostic value of a glass fibre-based histamine analysis for allergy testing in children

The aim of this study was to compare the diagnostic value of common allergy tests with basophil histamine release in 124 children with symptoms of asthma. The patients were evaluated by case history, skin prick test, RAST-analysis, and basophil histamine release using a glass fibre-based histamine assay to 10 common inhalant allergens. The bronchial provocation test was used as a reference of "true" IgE-mediated asthma. To compare the various diagnostic parameters each absolute test value was classified into a scoring system. The concordance between the tests varied between 85-97%. In general, the best concordance was found between basophil histamine release and RAST. Sensitivity, specificity and predictive values were calculated on the basis of 104 bronchial provocation tests. It was found that histamine release was the best single analysis, followed by RAST and prick testing. The sensitivity of RAST and histamine release was very high (1.00) for pollen and house dust mites. Histamine release showed a predictive value between 0.91 and 1.00 for pollen and house dust mites, thus indicating the possibility of omitting the bronchial provocation test. In the dander group histamine release gave the best sensitivity (0.91), however at the expense of specificity (0.64), whereas RAST and skin prick test gave a specificity of 1.00. In the mould group histamine release also showed the best diagnostic value. The combination of skin testing with histamine release or RAST was of no additional diagnostic help. It is concluded that the glass fibre-based histamine analysis, which makes routine histamine release testing possible, is a reliable diagnostic test in children.     

Comparison of parallel line skin test assay (PLST) and ELISA inhibition (EI) methods for determination of relative potency of polymerized grass and ragweed antigenic extracts

Relative potency estimates were performed by parallel line skin test assay (PLST) and ELISA inhibition methods for three polymerized allergen extracts (Bermuda grass, orchard grass, and a copolymer of short and giant ragweed) versus four unmodified RAST standardized reference extracts (Bermuda grass, orchard grass, and giant and short ragweed) in nine subjects. One subject experienced a systemic reaction, requiring treatment at the end of the PLST assay. Another subject had a systemic reaction during limited skin testing performed approximately 72 hours after completion of PLST. Relative potency values for the polymerized extracts obtained by PLST were much lower than those obtained by ELISA inhibition, but results were significantly (r = 0.95; p less than 0.01) correlated. Because polymerized allergen extracts are designed to be hypoallergenic, a skin test assay may underestimate their potency relative to an unmodified reference extract.     

Classification of allergens by positive percentage agreement and cluster analysis based on specific IgE antibodies in asthmatic children]

Classification and characterization of allergens is important because allergic patients are sensitized by a variety of allergens. One hundred and sixty-one sera from asthmatic children were investigated for specific IgE antibodies against 35 allergens including 20 inhalants and 15 foods by means of the MAST method. We assessed the allergenic properties of the allergens based on positive percentage agreement and cluster analysis. There was a high positive percentage agreement of specific IgE antibodies between house dust and Dermatophagoides spp., a relatively high agreement between 5 molds, cat and dog epithelium, mugwort and wormwood and 5 grasses. Among the food allergens, the positive percentage agreements were relatively high, especially between cow's milk, casein, cheese, and between 3 cereal grains. In the cluster analysis, house dust and Dermatophagoides spp. made a big cluster; therefore 32 allergens except house dust and mites were analyzed. From the results of the cluster analysis, the major cluster consisted of (1) ragweed, (2) mugwort and wormwood, (3) timothy, sweet vernal, velvet and cultivated rye, (4) wheat, barley and rice, (5) molds, (6) cow's milk, casein, soybean and cheese, (7) shrimp and crab, (8) egg white, (9) Japanese cedar, (10) dog epithelium, (11) cat epithelium. The cluster of grass pollens and cereal grains made one cluster. These results tend to confirm the presence of species cross-reactivities within the major classes of allergens.     

Inhibition Experiments with Solid Phase Mite or Epithelia in House Dust Hypersensitivity

The present study was undertaken to verify that mites are not the only allergens in house dust extracts and that other allergens such as cat epithelia can also be responsible for house dust hypersensitivities detected both by house dust skin tests and house dust RAST studies. In order to determine whether mite or epithelia fixed on a solid phase could remove not only the IgE antibodies reactive with the homologous allergens, but also the IgE antibodies reactive with house dust allergens, the authors have absorbed 10 sera of house dust allergic patients with solid phase mite or epithelia. The absorption procedure removed a large part of the IgE antibodies reactive with specific immunosorbent (Dermatophagoides pteronyssinus or cat epithelia) and in the same way the IgE antibodies reactive with house dust immunosorbent. The percentage of RAST inhibition varied from 65% to 92% for Dermatophagoides pteronyssinus and from 65% to 94% for house dust in patients allergic to house dust and mite; the percentage of RAST inhibition varied from 67% to 92% for cat epithelia and from 73% to 90% for house dust in patients allergic to house dust and cat epithelia. This is in accordance with the hypothesis that house dust is not an allergen per se, but rather a complex mosaic of several allergens including mite, animal epithelia, etc.     

Detection of house dust mite (HDM)-specific IgE antibodies on nasal mast cells from asthmatic patients whose skin prick test and RAST are negative for HDM.

Mast cells are found in nasal smears of pediatric patients with perennial bronchial asthma whose skin prick test and radioallergosorbent test (RAST) are negative for inhalant allergens. IgE antibodies were demonstrated on these mast cells by monoclonal anti-human IgE antibodies, whereas IgG antibodies were not detected by monoclonal anti-IgG antibodies. In order to pursue the causative allergen for asthma in these patients, binding potential between IgE antibodies on nasal mast cells and house dust mite (HDM), the most prevalent aeroallergen, was examined by an immunochemical technique. Out of 9 patients whose skin prick test and RAST were negative for HDM, 7 were found to have HDM-specific IgE antibodies on their nasal smear mast cells. None of these 7 patients had IgE antibodies to cedar pollen, a negative control aero-allergen, on their mast cells. Specific binding of HDM on the mast cells was further confirmed by the fact that nasal mast cells from patients with egg allergy bound egg white but not HDM on their surface. Preincubation of mast cells with anti-IgE antibodies inhibited binding of HDM on the mast cells, indicating that HDM was bound to surface IgE antibodies on the mast cells. These experiments enabled us to expeditiously identify sensitization to an inhalant allergen, such as HDM, in young asthmatic patients whose allergen cannot be found by conventional laboratory diagnostic procedures.     

Diagnosis of reaginic allergy with house dust, animal dander and pollen allergens in adult patients. I. A comparison between RAST, skin tests and provocation tests.

RAST analyses were performed with house dust, animal dander and eleven pollen allergens in 410 adult patients with asthma and/or rhinitis and the findings were compared with skin test and provocation test results. The overall correlation between 1,316 provocation tests and RAST was 78% and the correlation between 1,778 skin tests and RAST was 66%. The relationships between RAST and in vivo tests differed considerably from allergen to allergen. No significant differences were found between various age groups. According to the in vivo tests the RAST showed more often positive results in patients with pronounced allergy than in patients with low-grade allergy. Higher RAST classes were most often combined with positive in vivo tests. It is concluded that in cases with RAST classes 2-4, a reasonably well-established allergy diagnosis can be reached without the inclusion of additional in vivo tests. In other cases, however, application of further diagnostic methods is required.     

Sensitivity to tomato and peanut allergens in children monosensitized to grass pollen

Possible associations between allergy to grass pollen and positive skin tests to food allergens were studied in 102 children monosensitized (as to inhalant allergens) to grass pollen, and in 117 children monosensitized (as to inhalant allergens) to Dermatophagoides. Thirty-two foods were tested by an epicutaneous method. Positive skin tests to food allergens were more frequent in children with allergy to grass pollen (59.8%) than in children with allergy to Dermatophagoides (9.4%). A considerably high frequency of positive reactions to tomato (39.2%), peanut (22,5%), green pea (13.7%), and wheat (11.7%) was observed in children with allergy to grass pollen. Positive skin tests to peanut closely correlated with positive RAST results and nasal provocation tests, whereas in children with skin test positivity to tomato a close correlation with nasal provocation tests but a 45% correlation with a positive RAST result were observed. RAST inhibition experiments were carried out, and the results may suggest the presence of cross-reacting IgE to grass pollen, tomato, and peanut antigens. Clinical implications of these findings are discussed in the light of histories of food hypersensitivity, urticaria-angioedema, and atopic dermatitis in children with allergy to grass pollen.