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Results for “Radioallergosorbent Test”

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PubMed1988

New allergens from hen's egg white and egg yolk. In vitro study of ovomucin, apovitellenin I and VI, and phosvitin.

Three hen egg yolk proteins, apovitellenins I and VI and phosvitin, and one egg white protein, ovomucin, were purified and tested for their ability to bind IgE in the sera of patients hypersensitive to egg. All of the proteins bound IgE from the sera of egg-allergic individuals in the radioallergosorbent test, and they also inhibited binding of IgE to the parent fractions-either egg yolk (apovitellenins I and VI and phosvitin) or egg white (ovomucin). It appears that apovitellenins I and VI are major allergens for some of the individuals tested. This is the first report of the in vitro allergenicity of these proteins.

Allergens↗

PubMed1989

In vitro determination of IgE antibodies in the diagnosis of atopic allergy.

The reaction of IgE antibodies is important in asthma and hay fever. Their role in skin diseases is more obscure and needs to be studied further. IgE antibodies play a role in contact urticaria and a more doubtful role in the triggering of atopic dermatitis. A well-standardized radioallergosorbent test is a valuable tool in the diagnosis of these diseases. A new test for the detection of atopy is discussed.

Humans↗

PubMed2001

Positive skin and oral challenge responses to potato and occurrence of immunoglobulin E antibodies to patatin (Sol t 1) in infants with atopic dermatitis.

The clinical significance and molecular specificity of hypersensitivity reactions to raw and cooked potatoes remain ambiguous. We therefore investigated the clinical hypersensitivity to raw and cooked potato in infants suspected to have potato allergy and compared the findings with the occurrence of immunoglobulin E (IgE) antibodies to patatin (Sol t 1), characterized as the primary allergen of potato. Twelve infants (10 to 24 months of age) suffering from atopic dermatitis (AD) and suspected to have adverse reactions to potato, were examined. As a skin exposure test we used rubbing with both raw and cooked potato, and used open oral challenge with cooked potato for 7 days. A special eczema scoring system (SCORAD) was used to assess the severity of symptoms and signs of AD. Skin-prick tests (SPTs) were performed with raw potato and natural Sol t 1, and serological studies included measurement of total serum IgE and IgE antibodies to Sol t 1, and potato radioallergosorbent testing (RAST). The skin-rubbing test with raw potato was positive in seven (58%) and the oral challenge positive in eight (67%) infants. One infant presented with an immediate reaction and seven with a delayed reaction, i.e. exacerbation of AD, after oral challenge responses to cooked potato. Nine (75%) infants had IgE antibodies to Sol t 1 in enzyme-linked immunosorbent assay (ELISA), and SPT to natural Sol t 1 was positive in six (50%) potato-allergic infants. In conclusion, we observed positive challenge responses to both raw and cooked potato in food-allergic atopic infants. The presence of IgE antibodies and concomitant positive SPTs to the heat-stable potato allergen, Sol t 1, suggest that cooked potato can be an allergenic food for infants suffering from AD.

Administration, Oral↗

PubMed1976

In vitro diagnosis of atopic allergy. V. The value of repeated testing using several batches of the allergen extract.

The radioallergosorbent test (RAST) has been used for in vitro diagnosis of allergy in a selected group of children with asthma and allergic rhinoconjunctivitis. The results were compared with those of provocation tests and also with the results of skin tests. Where the results of RAST and the provocation tests differed, repeated tests were performed, initially in vitro and secondly in vivo. Selected commercial allergens of good quality were used and, for the most part, the same allergen batches were used in RAST, in the provocation tests and in the skin tests. A 76% correlation between RAST and provocation tests was found on preliminary investigation before divergent results were repeated. This degree of correlation is similar to that obtained previously in unselected patients using RAST as a part of the routine diagnostic. On repeated examination, agreement was obtained in an additional 16% of the cases. The major part of the improvement (13%) was due to conversion of preliminary RAST results from negative to positive in children with positive provocation tests. To a minor extent, the improvement was due to the fact that in, some children with positive RAST, negative provocation tests became positive when repeated. Finally, in one case an originally positive RAST in a child with a negative provocation test was found to be negative on re-examination. Comparing the final revised results of RAST and provocation tests there were no cases where a negative provocation test was combined with a positive RAST. Nearly all the children with positive provocation tests in spite of a negative RAST were shown to have low degree allergy. Although circulating reaginic antibodies are not always present, it seems that, on repeated investigations, the great majority of children with asthma and hay fever can be shown to have such antibodies even though the serum concentration may be low or very low. In doubtful cases repeated RAST examinations may be of value.

Allergens↗

PubMed1980

The heat stability of short ragweed pollen extract and the importance of individual allergens in skin reactivity.

A short ragweed pollen extract that was heated in a boiling-water bath remained skin reactive for some allergic individuals and lost reactivity for others. Comparison of heated and unheated extract by immunodiffusion showed that AgE, AgK, and Ra3 could not be detected in the boiled extract but Ra5 was present. By inhibition of the radioallergosorbent test the concentration of Ra5 remained essentially unchanged, but the concentrations of AgE and Ra3 were greatly diminished. The sera of these ragweed-allergic individuals were analyzed for IgE antibodies to AgE, Ra3, and Ra5. Skin reactivity in 17 ragweed-allergic individuals to the heated extract correlated significantly with the levels of IgE antibodies to Ra5. However, the large number of individuals reacting to the boiled extract indicates that Ra5 is not likely to be the only heat-stable allergen. Skin reactivity of the unheated extract did not correlate with IgE antibody levels to any allergen. The results underscore the importance of individual allergens in the materials used for skin testing.

Allergens↗

PubMed1987

[Allergologic-immunochemical study of tree and bush pollen. II--Study of the sensitization spectrum of patients with seasonal rhinitis in the spring].

80 patients sera were investigated by means of radioallergosorbent test (RAST) and enzyme linked immunosorbent assay (ELISA). Specific IgE antibodies against ten various tree pollens were determined. There is a significant correlation between RAST and ELISA results. It was found that birch, beech, alder, hazel and oak pollens are most important as causes of springtime hay fever. 75% of patients had increased specific IgE-titres against these pollens whereas maple, poplar, elm, sallow and ash allergens more often gave negative or only weak positive test results.

Antibody Specificity↗

PubMed1981

Anaphylaxis after ingestion of millet seeds.

We report the case of a patient with anaphylaxis after ingestion of millet seeds, a previously unreported allergen. Skin testing with freshly prepared millet seed extract produced positive intradermal responses at a concentration of 100 pg/ml. The reaction was mediated by IgE antibodies to millet, as demonstrated by elevated specific IgE antibody levels by radioallergosorbent test (RAST) and by significant in vitro histamine release from leukocytes incubated with millet seed extract.

Adult↗

PubMed1992

Immune response to flour and dust mites in a United Kingdom bakery.

In a study of 279 United Kingdom bakery workers a high prevalence of immunological response to storage mites was found. To determine whether this was the consequence of exposure to storage mites in bakery work, a population of salt packing workers was examined as a comparison group not at occupational risk of exposure to storage mites. Forty two per cent of both groups were atopic (had a positive skin prick response greater than negative controls to D pteronyssinus, grass pollen, or cat fur by 2 mm or more) and 33% had an immediate skin prick test response to at least one of four storage mites (L destructor, G domesticus, T putrescentiae, A Siro). A higher percentage of the salt packing workers than the bakery workers had a positive radioallergosorbent test (RAST) (greater than or equal to 0.35 PRU) to D pteronyssinus and to the four storage mites. Logistic regression analysis identified atopy as the most significant variable for a positive skin test and RAST response to storage mites in both groups of workers. RAST inhibition was used to analyse extracted area and personal air samples. Analysis of static area samples for aeroallergen showed immunological identity with flour but L destructor was found in only one of seven exposed filters. The concentration of airborne flour was related to exposure rank of perceived dustiness and gravimetric measurement of total dust. Nineteen out of 32 filters from workers in jobs with higher dust exposure (rank >/=6) had a level of > 10 microgram/m(3) flour whereas this concentrations was exceeded in only one of 23 filters from workers in low dust exposure (< rank 6). It is concluded that storage mites are not of special significance in allergic responses in bakery workers. The development of immunological (and airway) responsiveness to inhaled flour dust is increased in those exposed to higher concentrations of airborne allergen, which appears to be predominantly flour and not storage mites.

Air Pollutants, Occupational↗

PubMed1996

Association of otitis media with effusion and allergy as demonstrated by intradermal skin testing and eosinophil cationic protein levels in both middle ear effusions and mucosal biopsies.

This study was performed to ascertain the role of allergy, as defined by skin testing and histochemical markers, in the pathogenesis of otitis media with effusion (OME). A historical perspective of allergy as it relates to OME is presented. The study included 89 patients: 48 with persistent effusion but no recent acute infection, 25 with purulent OME complicated by a superimposed infection, and 16 control subjects. All 89 patients had persistent effusion for more than 2 months and subsequently required the placement of tympanostomy tubes. Allergy was defined using the radioallergosorbent test (RAST), serum immunoglobulin E (IgE) levels, and skin tests. Allergies were present in 97% of the patients with nonacute OME. The relationship between allergy and OME was corroborated clinically in 89% of patients and was also substantiated by elevated levels of effusion eosinophil cationic protein (ECP) in 87.5% of OME patients. Histologically, polyclonal antibody staining for ECP demonstrated the presence of eosinophils in middle ear mucosal biopsy specimens. This study confirms that OME is a sign of allergic inflammation in the middle ear that is associated with an increase in eosinophils and a concomitant release of ECP into the effusion in individuals with allergy demonstrated by skin testing.

Adolescent↗

PubMed1983

Detection of IgE antibodies in onchocerciasis using a semi-purified fraction from Dipetalonema viteae total antigen.

A Dipetalonema viteae extract was separated by gel filtration on ACA 34 Ultrogel into four fractions (A, B, C and D). The allergenic activity of the D. viteae extract and its various fractions was assayed by the passive cutaneous anaphylaxis (PCA) test in rats using mouse sera obtained from Balb/c mice transplanted with D. viteae. The PCA reaction showed that fraction B was the most potent allergenic fraction of the D. viteae extract. By the radioallergosorbent test (RAST) the use of fraction B coupled to CNBr-activated paper discs showed elevated binding of IgE antibodies in onchocerciasis human sera. A comparative study demonstrated the efficiency of the above fraction in the RAST technique in distinguishing between Onchocerca volvulus-infected patients and those infected with other human filarial worms or other helminth parasites. The binding of IgE to fraction B was confirmed by the radioimmunoelectrophoresis and radio-double diffusion methods using an 125I anti-human IgE. Since D. viteae antigens are more readily obtainable than those of O. volvulus, a further purification of fraction B to improve its specificity for the detection of IgE antibodies in human onchocerciasis is warranted.

Allergens↗

PubMed1998

[Re-evaluation of multi-allergen skin prick test for infants with atopic dermatitis--clinical relevance and evaluation by mothers].

We performed skin-prick tests (SPT) for 8 food and inhalant allergens on 55 infants (between 3 months and 2 years of age) with atopic dermatitis (AD) at their initial visit to our allergy clinic. SPT results were compared with those of radioallergosorbent tests (RAST) and the severity of AD symptoms. We also administered a questionnaire-based survey of 46 patients mothers to see how they evaluated SPT compared to blood tests. SPT for egg white had the highest positive rate (91%) and far exceeded that for other allergens. More than two allergens showed positive in more than half of the patients, and about 30% of them showed positive reactions to more than three allergens. Concordance rate between SPT and RAST was 78.6%. Patients showing positive reactions to multi-allergens tended to have more severe AD symptoms. Mothers appreciated the SPT test and felt that quick results for multi-allergens was the greatest advantage of SPT. More than 90% of the mothers wanted the allergic status of their next children to be evaluated with SPT. Especially, more than 30% of the mothers preferred SPT than RAST as initial screening test. As SPT is harmless, easy to administer even in infancy, and has different advantages for those of RAST, this method deserves further re-evaluation as a means of identifying allergic status especially among infants.

Child, Preschool↗

PubMed1986

Isolation and characterization of two allergens from Dermatophagoides farinae.

Two purified allergens, designated as DF1 and DF2, were isolated from the extract of the whole culture of Dermatophagoides farinae by a combination of ammonium sulfate precipitation and ion exchange, hydrophobic, chelate and gel chromatography. DF1 was isolated as a heat-sensitive acidic protein with an apparent molecular weight of 25,000 and an isoelectric point of 4.6-7.2. DF2 was isolated as a heat-stable basic protein with an apparent molecular weight of 15,000 and an isoelectric point of 7.8-8.3. No allergenic cross-reactivity was seen between DF1 and DF2. Both DF1 and DF2 were shown to be the major allergens of D. farinae by the results of radioallergosorbent test and histamine release assay.

Allergens↗

PubMed1996

Reactivity to IgE-dependent histamine-releasing activity in asthma or rhinitis.

We investigated the relation between IgE reactive with histamine-releasing factor (HRF) and clinical status in patients with asthma or rhinitis. Sera were used to passively sensitize purified, lactic-acid treated basophils. IgE-independent HRF due to chemokines was removed from mononuclear cell supernatants with heparin-Sepharose. IgE-dependent HRF was determined by measuring the increase in histamine release between 1 min and 60 min, which was designated delta HRF. HRF-reactive IgE was demonstrable in nine of 18 patients with allergic asthma, three of 19 patients with nonallergic asthma, five of 17 patients with allergic rhinitis, and none of 19 control patients. The presence of HRF-reactive IgE was associated with: (1) IgE to inhalant allergens; 40% of radioallergosorbent test (RAST)-positive individuals versus 8% of RAST-negative individuals were positive (OR = 7.8, p < 0.005); (2) bronchial sensitivity to histamine in all asthmatic patients (geometric mean PC20: 1.50 versus 0.51 mg/ml; p < 0.005); and (3) bronchial sensitivity to histamine in allergic asthmatic patients (geometric mean PC20: 1.27 versus 0.37 mg/ml, p < 0.02). These findings support the hypothesis that IgE-dependent HRF might contribute to the chronic allergic reaction.

Adolescent↗

PubMed1981

Use of IgE antibody determinations in cutaneous Coelenterate envenomations.

Elevated levels of serum anti-sea nettle venom IgE persisted for several years in two patients who had exaggerated reactions to jellyfish (sea nettle, Chrysaora quinquecirrha) stings. These antibodies also cross reacted with Portuguese man-of war venom. The determination of increased antigen specific IgE concentrations may be of value in identifying patients "at risk" or in diagnosing stings by "unseen" animals. Because of the increased frequency of IgE radioallergosorbent testing (RAST) in dermatologic practice, a brief review of the use of this test is included.

Adult↗

PubMedDate not supplied

Insoluble and soluble allergens from wheat grain and wheat dust: detection of IgE binding in inhalant and ingestion allergy.

The need for better in vitro testing for wheat allergy particularly involved correlating clinical evidence of Type I hypersensitivity with laboratory detection of specific IgE antibodies in serum. We report here an improvement in this relationship by the use of a modified method for RAST (Radioallergosorbent test), involving nitrocellulose as the solid phase and alkali (or ethanol) for extraction of allergens and treatment of discs. Serum IgE reactions with the full range of wheat grain and dust proteins were studied using this method and the results were related to wheat allergies due to flour ingestion and the inhalation of flour, pollen or grain dust.

Adult↗

PubMed1992

Specific IgE antibodies to nickel in workers with known reactivity to cobalt.

Twenty-one workers with hard metal asthma, including eight atopics, diagnosed on the basis of peak flow diaries and positive reaction to cobalt chloride (CoCl2) and/or nickel sulphate (NiSO4) in skin and provocation tests were studied for sensitization by detection of specific antibodies to nickel-conjugated human serum albumin (Ni-HSA), and nickel-conjugated exchange resin (Ni-resin). Their results were compared with those of sera obtained from control sera from 60 asthmatic patients and pair-matched asymptomatic control workers in the hard metal plant. In the RASTs (radioallergosorbent tests), sera from the same six subjects developed positive reactions both to Ni-HSA (RAST index greater than 2.0, P less than 0.01) and Ni-resin (RAST index greater than 2.0, P less than 0.01), while the counts measured for the others of the 15 subjects (RAST index less than 1.52) were about the same as those for control groups (RAST index less than 1.58). Subject HSA RAST and resin RAST results (378 +/- 52 c.p.m. in HSA RAST and 324 +/- 56 in the resin RAST) were about the same as those of the control sera (388 +/- 65 c.p.m. and 398 +/- 59 c.p.m., respectively). There was no difference in the prevalence of smoking habit and high IgE between Ni-RAST positive and negative subjects. However, subjects with simultaneous sensitivity to nickel and/or cobalt still developed asthmatic attacks following medications, while those without sensitivity to these metals were almost symptom free. The positive sera had simultaneous sensitivity to both cobalt and nickel, suggesting the presence in them of specific IgE antibodies to nickel playing some role in the aetiology of hard metal asthma.

Adult↗

PubMedDate not supplied

Laboratory tests for total and allergen-specific immunoglobulin E.

The principles of measurement of IgE by enzyme-immunoassay are given. A Bayesian approach is taken for the clinical interpretation of serum total IgE. Application of Bayes' Theorem to serum total IgE can significantly influence the probability of a clinical diagnosis of allergy. There is a correlation between allergen-specific IgE measured by enzyme-immunoassay, by radioallergosorbent test and by skin tests for immediate hypersensitivity. However, there is a need to standardize the reagents used for allergy skin testing, as well as the reagents and methods used for the laboratory measurement of allergen-specific IgE.

Allergens↗

PubMed1988

Fatal anaphylactic reaction to suxamethonium: new screening test suggests possible prevention.

A 40-year-old woman suffered cardiovascular collapse, cardiac ischaemia and arrest during induction of anaesthesia. Severe cerebral ischaemic damage was sustained during this episode and the patient died 4 days later. This fatal reaction was shown to be anaphylactic in origin; the causative agent was suxamethonium. High levels of IgE antibodies specific to the quaternary ammonium group (two of which are present in suxamethonium) were detected by the radioallergosorbent test. Results of the leucocyte histamine release test were less clear, partly as a result of steroid treatment. The two most relevant points were the absence of a history of previous anaesthesia, and involvement of the heart as the principal target of the reaction. This unfortunate and extreme case indicates the necessity for allergy testing (screening) before anaesthesia, and the need for organisation and funding of this procedure, if these fatal or near-fatal reactions are to be prevented. It is a timely reminder that action should be taken, since neuromuscular blockers have been confirmed as the most common culprits, and that specific tests for IgE antibodies are now available against haptenic groups generally common to all neuromuscular blockers.

Adult↗