RAST atopy screen

A single in vitro screening test for atopic allergy is described. It uses the radioallergosorbent test (RAST) principle, and has been applied to screening sera from U.K. patients with possible atopic symptoms. When compared with the Phadebas RAST, the test sensitivity was 97% and the specificity 100%, and these results suggest that it is useful in any preliminary allergy investigation.     

Allergy screening in asthma and allergic rhinitis

To detect atopy by a screening method employing skin prick testing with a limited number of allergens, the test results of 939 patients with allergic airways diseases were analysed. It was found that an allergen panel consisting of cat, timothy and house dust mite could detect 85% of atopic patients with asthma and/or rhinitis. For subgroups of patients the results were even more favourable. Thus 98% of atopic patients with seasonal allergic rhinitis were detected by an allergen panel consisting of timothy, birch and mugwort. It is concluded that screening methods using only three of four allergens could be used for detecting atopy in patients with airways diseases. The method should be most valuable for in vitro tests used in combination with standardized questionnaires.     

Lipopolysaccharides in Micropolyspora faeni

The radioallergosorbent test (RAST) was adapted for use in the dog employing purified anti-canine IgE. The agreement between positive RAST and positive skin test ranged from 82% for ragweed to only 12.5% for dandelion. Agreement between negative tests in the case of all allergens was 100%. Further developmental studies of canine RAST are warranted in view of the value of the dog as an experimental model of atopic disease.     

Determination of IgE antibodies to Candida albicans mannan with nitrocellulose-RAST in patients with atopic diseases

A nitrocellulose-based radioallergosorbent test (RAST) was developed and used for the determination of IgE antibodies to Candida albicans mannan in patients with atopic dermatitis, asthma and allergic rhinitis. The results were expressed as mannan-RAST index values (an inter- and intra-assay coefficient for variation of 8.0-10.2%). The normal range for mannan-RAST index values was determined in 102 non-atopic adults. Fifty-three of 78 (67.9%) patients with atopic dermatitis showed elevated mannan-RAST index values with a significant correlation to the severity of the dermatitis (r= 0.33, P < 0.01). Sixteen of 30(53 3%) patients with asthma had a positive mannan-RAST index value: however, 12 of the 16 asthmatics (75%) who were positive also suffered from atopic dermatitis. Those who had allergic rhinitis but not atopic dermatitis showed a positive mannan-RAST index value in 12 of 32 (37.5%) cases. Nitrocellulose-RAST offered a sensitive method for the determination of polysaccharide-specific IgE antibodies in alopic diseases. The results show that high values are observed mainly in atopic dermatitis and less sensitization to C. albicans occurs in respiratory allergy.     

Differences in skin-prick and patch-test reactivity are related to the heterogeneity of atopic eczema in infants

Current data indicate an obvious relation between food allergy and atopic eczema in infants. However, diagnostic methods for food allergy need to be supplemented. The objective was to study the relevance of food patch testing in the detection of food allergy in correlation with oral food challenge and skin prick tests in atopic infants. Infants with atopic eczema (n = 113) aged 2–24 months were studied. Each patient was subjected to double-blind, placebo-controlled, or open cow's milk challenge, and skin prick and patch tests. Polysensitization, as judged from skin test results, was common in patients with atopic eczema (79/113). Cow's milk challenge was positive in 54/113 infants; reactions were immediate in 36/54 and delayed in 18/54. Immediate-type reactions were associated with skin prick test positivity and delayed reactions with patch test positivity. Altogether 26% of the cow's milk-allergic infants were detected by patch testing only. Patch testing improved the accuracy of skin testing in the diagnosis of food allergy in infants with atopic eczema, but it needs to be standardized. Polysensitization appears to be more common than generally believed among infants with atopic eczema.     

Assessment of skin reactivity and specific antibody to egg and milk proteins in patients with atopic dermatitis: comparison with responses to the house dust mite antigen

Sixty patients with atopic dermatitis attending an allergy clinic were assessed for evidence of skin sensitivity and serum antibodies to egg and milk proteins. Prick skin test responses to egg were found in 23 patients and in 74% of these positive egg radioallergosorbent test (RAST) was demonstrable. Positive prick test for milk were present in 10 patients, but only 30% gave a positive milk RAST. Quantitative intradermal skin testing, RAST, and a double antibody antigen binding radioimmunoassay confirmed the presence of IgE antibody to egg proteins but indicated that the levels were very low when compared to those seen to the house dust mite antigen in sensitive patients. In contrast, IgG antibody to purified egg and milk proteins was present in large amount in most patients, the levels being significantly higher than in non-allergic controls.     

Clinical and immunological responses to enzymes of Bacillus subtilis in factory workers and consumers

Skin (prick) and serological tests were made with enzyme preparations of Bacillus subtilis in exposed factory workers and potential ‘consumers’. Prick tests with these materials at 10 mg/ml gave positive immediate reactions in twenty-six out of sixty-five factory workers. Eighteen of the factory workers were classified as atopic because of allergy to common allergens and fifteen gave positive reactions to the enzymes compared with eleven out of forty-seven non-atopic workers. A group of eleven of the factory workers had consistent ventilatory impairment on repeated examination; all were prick test positive and seven were atopic, and four non-atopic. Of 2500 patients attending for investigation of respiratory allergy, 40% were highly atopic, 40% moderately atopic and 20% non-atopic. 80% were consumers of biological detergents. Only two gave weak, not clinically relevant, prick test reactions to the enzyme preparations. In radioallergosorbent (RAST) tests for specific IgE antibody against the enzyme preparations, counts in the present investigation of 600/30 sec or more corresponded best with prick test positivity, such values being found in twelve of the fifteen prick test positive atopics and in eight of the eleven workers with ventilatory impairment. Comparison of the RAST counts on sera from cord blood and from the patients who included non, light and heavy consumers showed increasingly higher specific IgE counts in these groups, although these counts were almost all below the level of 600/30 sec, which corresponded with skin test reactions and clinical relevance. Radioimmunodiffusion (RID) and radioimmunoelectrophoretic (RIEP) tests with enzyme preparations gave positive reactions only in the factory workers, of whom forty-three had IgG and twenty-one IgA antibody, none having only IgE antibody.     

The prevalence of atopy and hypersensitivity to formaldehyde in pathologists

Sixty-three pathologists in active practice in the province of Alberta, Canada, provided a history regarding atopy and sensitivity to formaldehyde. Serum samples were assayed for total IgE level and the presence of IgE with specificity toward timothy grass, cat, house dust, and formaldehyde. Twenty-nine of the subjects (46.0%) gave a history of atopy that was confirmed in 12 by either IgE level or a positive radioallergosorbent test. Twenty-nine (46.0%) complained of formaldehyde sensitivity. In this study, no pathologist had allergen-specific IgE directed against formaldehyde, and there was no evidence of a tendency for atopic subjects to be more prone to sensitivity to formaldehyde. However, this may be related to a deliberate reduction in exposure by individuals experiencing adverse effects.     

Clinical and immunologic studies of patients with large local reactions following insect stings

During the summer of 1978, 22 patients who had large local reactions following insect stings were evaluated for the development of potential systemic sensitivity. Approximately half the patients had venom IgE antibodies, detected by either the immediate skin test or radioallergosorbent test (RAST). A control group of 26 patients experiencing normal sting reactions had only a 15% incidence of venom-specific IgE. No correlations could be found between the presence of venom-specific IgE and age, sex, sting location, atopic history, or prior stings. IgE antibodies were found in 13 of 17 patients who had experienced local reactions lasting more than 48 hr. Serum venom-specific IgG was detected in only three of 19 patients. These results suggest that following large local reactions from insect stings patients must be individually assessed for the presence of venom-specific IgE and consideration for specific immunotherapy.     

The oral Prausnitz-Küstner reaction in food allergies

The oral Prausnitz-Küstner (P-K) reaction was examined in 41 children suspected of IgE-mediated food allergy. The recipients were served by their mothers in this study. A positive reaction was observed in 9 children when used hen's egg, cow's milk, chicken, buckwheat, red-bean, salmon or common-dolphin. Among them, seven have had an anaphylactic skin reaction (systemic urticaria and/or angioedema) to the foods. The other two were babies who were fed only by the breast milk. Therefore, the oral P-K test may be useful for the diagnosis and the prediction of food-anaphylaxis. The sera that had the radioallergosorbent test (RAST) scores of 3 or greater were negative in the oral P-K reaction in 26 out of 36 tests, and the sera that showed the positive oral P-K reaction to buckwheat or chicken were zero in the RAST scores. These results suggest that a soluble substance (e.g., histamine-releasing factor) in addition to the IgE antibody might be involved in the oral P-K reaction, and that the RAST technique does not always detect the IgE antibody that recognizes the food antigens degenerated during the absorption in vivo.     

Comparison of the atopic background between allergic and non-allergic beekeepers.

A study was carried out on beekeepers and their families. 34 subjects with a history of bee sting allergy and also a positive radioallergosorbent test (RAST) to honey bee venom were compared with 47 subjects with neither. 16 subjects in the bee allergy group (47%) had a history of atopic diseases as compared to 6 (13%) in the control group (p less than 0.01). 15 in the bee allergy group (44%) had at least one positive RAST to three common inhalant allergens as compared to 5 (11%) in the control group (p less than 0.01). These results suggest that, although bee sting allergy frequently affects non-atopic subjects, sensitization among beekeepers and their families occurs more readily in atopics. It is notable that a large proportion of patients injected with foreign proteins (the control group) either never develop venom-specific IgE antibodies or have suppressed their production.     

A case of the latex-induced anaphylaxis by contact with barium enema catheter]

The subject was a 34-year-old female with asthma and atopic dermatitis who had previously undergone a Cesarean section. In December 1995, the patient had an acute abdominal pain, so she underwent a barium enema examination. During the procedure, severe anaphylactic shock developed, and the examination was stopped. The patient responded well to appropriate emergency therapy, and her symptoms were resolved. However, the woman visited our outpatient clinic because the symptoms of her atopic dermatitis got worse. She indicated that she felt itchy when using rubber gloves. Also, at the age of thirty, she had urticaria and dyspnea after drinking a glass of fruit juice. Subsequently radioallergosorbent testing demonstrated the presence of specific IgEs against latex, banana, kiwi, grapefruit, and avocado. Skin prick tests were positive for banana, grapefruit, avocado, and latex extract at a dilution of 1:1000. A scratch test was positive to an extract of a balloon catheter which included 0.3 microg/g latex proteins by the LEAP method. In conclusion, the patient was diagnosed with an anaphylaxis to the latex contained in a balloon catheter used for the barium enema.     

Studies on the osmophilic fungus Wallemia sebi as an allergen evaluated by skin prick test and radioallergosorbent test

Recently, Wallemia sebi, a species of osmophilic fungi, has been abundantly detected in house dust using low water activity media. In this study, allergenic activity of W. sebi was assessed by skin prick test and radioallergosorbent test (RAST) in 74 asthmatic patients ranging from 6 to 32 years of age. Aspergillus fumigatus and house dust were used for comparison. In skin prick test, W. sebi extract, A. fumigatus extract and house dust extract elicited positive reactions in 4 (5.4%), 4 (5.4%) and 51 (68.9%) patients, respectively. RAST showed positive results in 14 subjects (18.9%) for W. sebi extract, in 8 (10.8%) for A. fumigatus extract and in 59 (79.7%) for house dust extract. These results indicated that some asthmatic individuals showed immediate-type hypersensitivity to W. sebi, and which means this fungal species may be of importance to atopic diseases as a causative agent.     

Association between CD62 ligand on na?ve and memory T cells and history of cow's milk hypersensitivity in atopic patients.

BACKGROUND: Both IgE and non-IgE cell-mediated reactions can contribute to the immunopathogenesis of food hypersensitivity. OBJECTIVE: To study L-selectin expression in na?ve (CD45RA+) and memory (CD45RO+) T cells in atopic patients with a history of cow's milk allergy and CD69 expression. METHODS: We evaluated 12 children with a history of cow's milk allergy. All 12 children underwent clinical history, examination, in vivo skin prick testing to inhalants and milk allergen, and in vitro radioallergosorbent testing for milk and total serum IgE levels. L-selectin levels on naive and memory T cells from patients and controls were analyzed by flow cytometry with fluorochrome-conjugated monoclonal antibodies after 4 hours or 7 days of incubation with medium alone, 1 microg/mL of pokeweed mitogen, or 50 microg/mL of casein. RESULTS: The percentage of CD45RA+ 62L+ cells with casein was 56% +/- 11% vs 38% +/- 7.7% in healthy controls (P < .009). The percentage of CD45RO- 62L+ cells was 22% +/- 7.1% vs 39% +/- 7.6% in healthy controls (P < .001), whereas the expression of CD62L+ in CD45RA+ and CD45RO+ cells decreased 149% +/- 33% vs 540% +/- 36% for healthy controls (P < .001) and 89% -+/- 16% vs 402% +/- 103% for healthy controls (P < .001), respectively. CONCLUSIONS: The results of the present study demonstrate the presence of CD62 ligand on naive and memory T cells, which might serve as a predictive marker for atopic dermatitis withother overlapping atopic disorders, such as asthma and allergic rhinitis.     

Diagnostic tests in children with atopic dermatitis and food allergy

Background Skin testing is a common diagnostic procedure in food allergy. The skin prick test is the test of first choice for investigating the immediate IgE-mediated reaction, TTie skin application food test (SAFT) has been developed on the basis of the mechanism of the contact urticaria syndrome (CUS), Methods We studied the relevance of the SAFT in children younger than 4 years with atopic dermatitis and (suspected) food allergy as compared with the prick-prick test, the radioallergosorbent test (RAST), and the oral challenge. In the skin tests, we used fresh food, in the same state as it was consumed.
Results There was a good agreement between the SAFT and the prick-prick test. A moderate agreement was observed between the SAFT and the serologic test (RAST). Significantly more positive results in the RAST were observed than in the SAFT, There was very good agreement between the SAFT and the oral challenge (K = 0,86).
Conclusions The SAFT is a reliable and child-friendly skin test for evaluating (suspected) food allergy in children younger than 4 years with atopic dermatitis. The very good correlation with the oral challenge indicates that one may probably consider the SAFT a "skin provocation" in children younger than 4 years.     

IgE production in vitro by human blood mononuclear cells: a comparison between atopic and nonatopic subjects

In vitro IgE synthesis by blood mononuclear cells from atopic patients and nonatopic subjects was examined. A total of 1 X 10(6) mononuclear cells cultured in RPMI-1640 and 10% fetal calf serum with or without cycloheximide was found to be optimal to detect de novo synthesis. A modified Phadebas IgE paper radioimmunosorbent test was employed for the quantitation of supernatant IgE concentration. Kinetic studies indicated that about half the peak amount of IgE is secreted within the first 2 days and the maximum concentration is reached at day 7. Mononuclear cells obtained from six of six atopic patients with eczema and elevated serum IgE levels and 22/33 atopic patients without eczema spontaneously synthesized significant amounts of IgE in vitro. We failed to detect de novo IgE synthesis by the cells obtained from 40 nonatopic controls. Polyclonal activators such as pokeweed mitogen. Staphylococcus aureus Cowan I, concanavalin A, and phytohemagglutinin failed to induce or enhance in vitro IgE synthesis in normal and atopic subjects. These findings indicate that the study of immunoregulation of IgE synthesis in man will be difficult to accomplish until new methods are developed that allow induction of the IgE response in vitro in nonatopic subjects.     

A comparison of the development of antibody responses to the polysaccharide antigen (Candida albicans mannan) in atopic and healthy infants and children

Background Defeetive antibody response againsl bacterial polysaccharide antigens is known to be associated with recurrent pyogenic infectiotis. The role of childhood allergy as a risk factor for repeated infections with capsulated micro-organisms has been controversial. Objective To compare the devetopment of polysaccharide specific antibody responses in atopic and healthy infants and children. Methods The antibody responses against a common polysaccharide antigen, Candida albicans mannan, were studied longitudinally in 18 atopic and 19 non-atopic children over the first 5 years of life. Determinations of IgA, IgG and IgM antibodies were carried out by enzyme-linked immunosorbent assay and IgE antibodies by nitrocellulose-based radioallergosorbent test. Results The polysaccharide specific antibody responses were similar in both groups, except that anti-mannan IgM levels were higher at 5 years in the atopic children (P<0.05. student's t-test). Conclusion Atopic children are not more susceptible to bacterial infections on the basis of poorer ability to produce antibodies against polysaccharide antigens.     

A new method of allergen standardization. Passive cutaneous anaphylaxis inhibition in a mouse-to-rat system in comparison with other methods.

Various methods have been employed for standardization of potency of allergen extracts. We used passive cutaneous anaphylaxis (PCA) inhibition in a mouse-to-rat system as a new means of standardization. Several allergen extracts, including mite, short ragweed, house dust, Aspergillus, Candida, and Japanese cedar, were examined. Mouse IgE antibodies were produced after two or three injections of antigen and alum. The potency measured by PCA inhibition in the mouse-to-rat system was compared with that of protein nitrogen (PN) content, end point of prick test in humans, and 50% radioallergosorbent test (RAST) inhibition. Our studies suggest that the mouse-to-rat system could be used to determine allergenic potency and to standardize allergen extracts.     

Occupational asthma and rhinoconjunctivitis caused by senna

Occupational sensitization to senna is seldom reported. We describe a 21-year-old male atopic factory worker who developed IgE-mediated asthma and rhinoconjunctivitis 5 months after exposure to senna while he was working for a company manufacturing hair dyes. In the bronchial challenge test with senna, he exhibited a strong reaction. The skin prick test gave a 12-mm wheal reaction. The radioallergosorbent test (RAST) with senna was highly positive (33.6 PRU/ml, class 4), and could not be inhibited with pollens or foods. In protein staining with SDS-PAGE, two heavy bands were detected in senna at about 14 and 25 kDa, and two faint bands were visible at 19 and 21 kDa. In IgE immunoblotting with the patient's serum, one heavy band was detected at about 16 and four faint bands at 23, 25, 28, and 38 kDa. The patient became symptom free after he had changed his job within the same company.     

Multicenter study on the prevalence of perennial allergic rhinitis and allergy-associated disorders.

Multicenter Study on the Prevalence of Perennial Allergic Rhinitis and Allergy-Associated Disorders This study was aimed to determine the prevalence of perennial allergic rhinitis (PAR) using the skin test, radioallergosorbent test (RAST), or multiple allergosorbent test (MAST) and to clarify the clinical aspects of the patients diagnosed as having PAR by the questionnaire survey and rhinologic examination. The 71,120 subjects who had visited the 23 otolaryngology clinics at the randomly selected tertiary referral hospitals in Korea between November 1, 1999 and April 30, 2000 were studied. PAR was diagnosed when subjects complained of two or more associated symptoms and the skin test, RAST, or MAST using perennial inhalant allergens was positive. The questionnaire survey and rhinologic examination were performed in subjects with PAR. The prevalence of PAR was 3.93%. We could find no significant difference in the prevalence of PAR between the two sexes. However, there was a significant difference in the prevalence of PAR between the child and adult groups. The chief complaints were, in order of decreasing frequency, nasal obstruction, watery rhinorrhea, and sneezing. There was a family history of PAR in 40.2% of the subjects. The 39.6% of the subjects had associated allergic diseases, being atopic dermatitis most common. In conclusion, the prevalence of PAR in tertiary referral hospitals in Korea is 3.93%. Many subjects with PAR have family history and appear to be associated with other allergic diseases.