The prevalence of latex allergy in children seen in a university hospital allergy clinic

Natural rubber latex allergy is responsible for a wide spectrum of clinical symptoms, ranging from rhinoconjunctivitis to severe anaphylaxis, in both adults and children. An association between allergy to latex and allergy to various fruits has been reported. This study investigated the prevalence and clinical significance of latex sensitization in children seen in a university hospital allergy clinic. A total of 453 consecutive children were screened in a 7-month period. A detailed clinical history with particular attention to the past surgical history and the eventual presence of latex- or food-induced allergic symptoms was obtained. Skin prick tests (SPT) for the more important inhalant allergens and foods were performed on all children. In patients with positive latex SPT, latex challenge and additional SPT for some fresh foods (avocado, pineapple, apricot, grape, banana, pear, apple, orange, almond, and chestnut) were also performed. RAST for the same food antigens, as well as patch test with latex and a standard battery of contact allergens, was also done. Of 326 atopic children, 10 (3%) presented positive skin test to latex, but only five (1.5%) also had a positive clinical history to latex exposure. Latex challenge was positive in 3/9 positive-latex-SPT children. None of the nonatopic children had positive skin test to latex or symptoms to latex exposure. A history of previous surgery was found in 5/10 positive-latex-SPT children, in 63/316 negative-latex-SPT atopic children (P<0.05), and in 23/127 nonatopic children. RAST to latex was positive in 5/10 positive-latex-SPT children. Associated fruit-specific IgE (SPT and/or RAST) were found in all latex-symptomatic children and in 2/5 latex-asymptomatic children. Apple, kiwi, and chestnut were the most common SPT-positive foods. Only one patient with clinical allergy to latex and positive skin tests to fruits had a history of clinical symptoms after ingestion of kiwi and orange. The natural history of the positive-latex-SPT children without clinical reactions to latex exposure and the clinical significance of the association of latex and fruit sensitivity require further studies.     

Evaluation of the value of 2 methods for measuring levels of allergen specific IgE antibodies in serum--Phadebas RAST I immuno CAP System

Two diagnostics sets Pharmacia--Phadebas RAST and Immuno CAP System determining the concentration of specific IgE antibodies in blood serum were compared with each other and with skin prick tests (SPT). Two common alergens--Dermatophagoides pteronyssinus and Dermatophagoides farinae were evaluated. Analysis of ROC curves shows that maximum specificity and sensitivity was obtained when the cut off value of RAST and CAP reached to 4.9 PRU/ml and 7.3 kU/l respectively. Our date shows the good correlation between RAST,CAP and SPT.     

Diagnostic work-up for food-dependent,exercise-induced anaphylaxis

Fourteen patients with suspected food-dependent, exercise-induced anaphylaxis (EIAn) were subjected to prick tests with commercial food extracts and common airborne allergens, prick + prick tests with fresh foods, determination of total IgE levels, and specific IgE for 31 foods (CAP System FEIA RAST). All were positive for two or more foods; 10 presented hypersensitivity to 11 or more foods. On the basis of these findings, history data, and responses to food-exercise challenges (treadmill stress tests 90 min after meals containing none of the suspected foods and none associated with skin-test and/or RAST positivity) and suspected food-exercise challenges (SFECs — administered after meals containing the suspected food), three patients were diagnosed as having specific food-dependent EIAn (for wheat in two cases, tomato in one). In nine others, the presence of specific IgE for numerous foods (including those suspected on the basis of histories and utilized in the SFECs) suggests involvement of specific food hypersensitivity, although SFEC confirmation could not be obtained. Avoidance of all foods associated with test positivity 4 h before exercise has prevented all further EIAn episodes in these 12 patients. In two others, the reactions did not appear to be related to IgE directed against specific food allergens, and these subjects have eliminated further reactions by avoiding all meals for the 4 h preceding exercise. These findings emphasize the importance of allergologic testing with a wide panel of food allergens (including foods used for seasoning, such as garlic or parsley) in all patients with suspected food-dependent EIAn. Prick + prick tests with fresh foods and the CAP System RAST disclosed numerous hypersensitivities.     

Risk factors for latex allergy in patients with spina bifida

Objective and methods In order to study risk factors for latex allergy in patients with spina bifida, we investigated 165 patients with spina bifida (mean age 9 years). Besides answering a questionnaire, patients underwent skin-prick testing and determination of specific serum IgE to latex as well as a screening test for specific IgE to environmental allergens. A total of 80 patients(49%) were sensitized to latex according to the presence of specific IgE to latex. Results Skin-prick tests (SPT) with high ammonia latex milk were performed in 81 of our patients with spina bifida and were positive in 36 patients (46%). Concordance of SPT with specific IgE in serum was good. Nineteen out of 165 patients suffered from a clinically relevant latex allergy: five patients had a history of systemic reactions to latex (e.g. severe bronchospasm, anaphylactic reactions), mostly during surgery. Fourteen patients reported clinical symptoms while inflating a balloon; all these 19 patients were sensitized to latex. Number of operations ranged from one to 26 (mean 5 operations). Concentration of specific IgE to latex in serum correlated well with increasing numbers of operations. Some 32/76 patients (41%) with spina bifida who were sensitized to latex showed an atopic disposition, while 21 out of 81 latex-negative patients (26%) were atopic. Of 300 consecutive sera (mean age of patients 9 years) sent to our laboratory for routine determination of specific IgE, 144 (48%) were positive in terms of specific IgE to environmental allergens, of which 247144 (17%) were sensitized to latex. Conclusions From our data we conclude that in order to minimize risk of severe systemic clinical reactions, all patients with spina bifida should be screened for their individual risk of latex allergy to plan preventive measures before operations. Main risk factors for latex allergy seem to be: more than five operations, atopic predisposition, history of clinical symptoms while inflating a balloon, and a sensitization with a CAP-class of ± 4.     

Evaluation of a capsulated hydrophilic carrier polymer (the ImmunoCAP) for measurement of specific IgE antibodies

The Pharmacia CAP System is a new assay for serum specific IgE, utilising a solid phase capable of binding more antigen than conventional systems. The CAP System has been evaluated in 69 consecutive patients referred to one allergy clinic in relation to skin prick test (SPT), radioallergosorbent test (Phadebas RAST) and specific allergy diagnosis for five inhalant allergens, D.pteronyssinus, timothy grass pollen, cat epithelium/dander, Cladosporium and Alternaria. Good correlation was obtained between RAST and CAP for all allergens, e.g. r = 0.974 for D.pteronyssinus and r = 0.964 for grass pollen. When sensitivity and specificity were examined for both CAP and RAST versus SPT, CAP was usually found to be of greater sensitivity than RAST, and of similar or slightly lower specificity. SPT gave more positive reactions than either in vitro test, but CAP gave more positives than RAST. Twenty-two of 336 (6.6%) tests were CAP positive/RAST negative, whereas a negative CAP with a positive RAST occurred in only 2/336 (0.6%) tests. Of patients with any test (SPT or RAST or CAP) for specific IgE positive, up to 20-30% did not have clinical allergy, confirming the importance of the history in interpreting these tests. Our results suggest that, for the allergens tested, the Pharmacia CAP System is more sensitive than the RAST, identifying more positive tests and approximating more closely to the SPT. It offers the additional advantages of speed and efficiency.     

Interpretation of tests for nut allergy in one thousand patients, in relation to allergy or tolerance

BACKGROUND: Peanut and tree nut allergy are common, increasing in prevalence and the commonest food cause of anaphylaxis. In the USA, 7.8% are sensitized (have nut-specific IgE), but not all those sensitized are allergic. Lack of data makes interpretation of tests for nut-specific IgE difficult. OBJECTIVES: This is the first study to investigate the clinical significance of test results for peanut and tree nut allergy in allergic or tolerant patients. Findings are related to the severity of the allergy. METHOD: An observational study of 1000 children and adults allergic to at least one nut. History of reactions (severity graded) or tolerance to up to five nuts was obtained and skin prick test (SPT)/serum-specific IgE (CAP) performed. RESULTS: There was no correlation between SPT size and graded severity of worst reaction for all nuts combined or for peanut, hazelnut, almond and walnut. For CAP, there was no correlation for all nuts. Where patients tolerated a nut, 43% had positive SPT of 3-7 mm and 3% > or = 8 mm. For CAP, 35% were positive (0.35-14.99 kU/L) and 5% > or = 15 kU/L. In SPT range 3-7 mm, 54% were allergic and 46% were tolerant. There was poor concordance between SPT and CAP (66%). Of patients with a clear nut-allergic history, only 0.5% had negative SPT, but 22% negative CAP. CONCLUSIONS: Magnitude of SPT or CAP does not predict clinical severity, with no difference between minor urticaria and anaphylaxis. SPT is more reliable than CAP in confirming allergy. Forty-six per cent of those tolerant to a nut have positive tests > or = 3 mm (sensitized but not allergic). One cannot predict clinical reactivity from results in a wide 'grey area' of SPT 3-7 mm; 22% of negative CAPs are falsely reassuring and 40% of positive CAPs are misleading. This emphasizes the importance of the history. Understanding this is essential for accurate diagnosis. Patients with SPT > or = 8 mm and CAP > or = 15 kU/L were rarely tolerant so these levels are almost always (in > or = 95%) diagnostic.     

Value of a new screening test for respiratory allergy

Phadiatop (Pharmacia) is a new in vitro screening test for respiratory allergy which detects in serum the presence of specific IgE to a mixture of common inhalant allergens; results are either positive or negative. Among 100 patients suffering from rhinitis and/or asthma, investigated with 15 skin prick tests (SPT) and RAST for frequent allergens, the Phadiatop was positive in 63: all 63 had at least one positive SPT and RAST (specificity: 100%). Conversely, ther were 67 patients who had a positive RAST for at least one allergen: among these 67 the total IgE concentration in serum was high (greater than 100 kU/l) in 43 (64%) and the Phadiatop was positive in 63 (94%). Phadiatop was negative in serum obtained from 10 cord bloods and 10 non-allergic subjects (disease-free, 15 negative SPT and RAST). Results of the radio-immunoassay originally proposed by the manufacturer were similar to those obtained with a modified enzymo assay using a fluorometric substrate. In the prediction of respiratory allergy, Phadiatop was found to be specific and more accurate than the determination of total IgE in serum.     

IgE to Bet v 1 and profilin: cross-reactivity patterns and clinical relevance

BACKGROUND: Individuals with pollen allergy often have IgE against plant-derived foods. This can be due to cross-reactive IgE against Bet v 1 and homologues, profilins, and/or cross-reactive carbohydrate determinants. OBJECTIVE: The aim of this study was to correlate sensitization to Bet v 1 and profilin with individual recognition patterns to plant foods and clinical relevance. METHODS: Fifty-two patients with pollen allergy and IgE against at least one plant-derived food were included in the study. Adverse reactions to plant-derived foods were documented by using standardized interviews. Skin prick tests were performed for pollen (grass, birch, and mugwort) and 14 plant-derived foods. In addition, recombinant (r) Bet v 1 and rBet v 2 (profilin) were tested intracutaneously. Specific IgE against the abovementioned allergens were determined by means of RAST. Cross-reactivity was studied by means of RAST inhibition. RESULTS: Eighty-five percent of patients were sensitized to Bet v 1, and 71% were sensitized to profilin. Profilin was associated with a higher number of positive RAST results to plant-derived foods than Bet v 1. In contrast, Bet v 1 was associated with more positive skin prick test responses and more food-related symptoms. Sensitization to Bet v 1 was associated with IgE against apple, hazelnut, and peach, whereas sensitization to profilin was associated with positive RAST results to all investigated plant-derived foods except apple, peach, and melon. CONCLUSIONS: IgE antibodies against Bet v 1 have a more limited spectrum of cross-reactivity than those against profilin, but they frequently give rise to clinically relevant cross-reactivities to food. In analogy to anticarbohydrate IgE, cross-reactive IgE against food profilins have no or very limited clinical relevance.     

The search of latex sensitization in spina bifida: diagnostic approach

BACKGROUND: Sensitization to latex has become a major problem in children with spina bifida. Life-threatening reactions may occur in these patients, therefore the search of latex sensitization must be an active task in all of these children. OBJECTIVE: To design an approach for the diagnosis of latex sensitization in children with spina bifida. METHODS: We studied 100 consecutive unselected patients. Skin prick tests with a commercial latex extract were performed, latex-specific serum immunoglobulin (Ig) E was determined by CAP test, and risk factors were studied. Originally, patients with an area of latex skin test > 50% of the area of histamine and/or CAP class > or = 3 were considered sensitized to latex. Diagnostic tests were also performed in a control group of 51 atopic and nonatopic children. RESULTS: After performing a receiver-operating characteristics curve for both tests we recommend skin tests > 25% of the area of histamine (sensitivity - SEN = 79%, specificity - SPE = 100%, positive predictive value - PPV = 100%, negative predictive value - NPV = 90%), or CAP class > or = 2 (SEN = 88%, SPE = 100%, PPV = 100%, NPV = 94%) as diagnostic cut-off points. The anamnesis had a SEN of 44% for diagnosis, and a SPE of 100%. Latex sensitization was associated with more than 5 operations (OR = 8, 95% CI = 3-21.3), a personal history of atopy (OR = 11.5, 95% CI = 2.3-57.1), and serum total IgE > or = 2 z-units (OR = 4, 95% CI = 1. 6-10). CONCLUSION: For the routine evaluation of children with spina bifida, we propose a diagnostic algorithm with skin prick tests as a first step and CAP second.     

Type I latex allergy in health care workers with latex-induced contact urticaria syndrome: a follow-up study

BACKGROUND: Latex allergy is an important occupational health issue among health care workers (HCWs). Secondary prevention in sensitized/allergic individuals involves avoiding exposure to NRL products. AIMS OF THE STUDY: The aim of this follow-up study is to determine the long-term health consequences in HCWs with type I latex allergy with latex-related contact urticaria syndrome, of providing appropriate information and practical avoidance education. METHODS: Seventeen HCWs with latex-induced contact urticaria syndrome, as ascertained by the glove use test, were investigated. Initial and follow-up visits included: a detailed questionnaire, skin prick test (SPT) with glove eluates and with commercial latex extract, SPT with common inhalant and food extracts, serum specific immunoglobulin (Ig)E to latex and some foods and the glove use test. RESULTS: On re-examination, 11 (64.7%) subjects showed positive SPTs to extemporaneous extract and 10 (58.8%) patients showed a positive SPT to commercial extract. Of the nine patients with detectable levels of serum latex specific IgE at first evaluation, four (44.4%) became negative and four were assigned to at least one class lower. Only one (11.1%) employee had higher radioallergosorbent test values than those at the latex allergy diagnosis. At follow-up, the 17 individuals had positive latex challenge results, although the duration of exposure causing a reaction increased. CONCLUSION: Our study shows that preventive measures are sufficient to induce a reduction of sensitization. Continued avoidance is needed to prevent re-sensitization or adverse reactions on re-exposure.     

Cross-reactivity between Ficus benjamina (weeping fig) and natural rubber latex

The importance of hypersensitivity to Ficiis allergens is reported, Cross-sensitization between fig (Ficus carica), weeping fig (F. benjamina [Fb]), and natural rubber latex (NRL) was confirmed by RAST inhibition. We performed skin prick tests with fresh Fb tree sap and NRL extracts in 346 consecutive patients and in 151 patients with immediate-type hypersensitivity to NRL, Total serum IgE and IgE antibodies to NRL and Ficus spp. were analyzed in sera. By the RAST-inhibition method, we studied cross-reactivity among latex, fig. and weeping fig, Sensitization to Fb was diagnosed in 23 of the 346 consecutive patients, and the simultaneous presence of latex-specific IgE was highly significant. Of 151 NRL-allergic patients, 35 were also sensitized to Fb. Cross-reacting IgE antibodies recognizing latex and Ficus allergens were demonstrated by RAST inhibition. The present study reinforces the importance of Fb as an indoor allergen. Cross-reacting IgE antibodies to NRL and Ficus spp, allergens frequently found in the sera of atopic patients. Development of commercially available standardized extracts for skin tests is urgently necessary.     

Four cases of pollen-food allergy syndrome suspected the cross reactivity including latex]

BACKGROUND: Generally it is recognized that the occurrence of fruit allergy is attributed not to the sensitization of itself but to the cross reactivity with pollens or latex. But the relationship as to the sensitization between pollen and latex is obscure. So we aimed to investigate the relation of sensitization among pollens, fruits and latex. METHODS: We tried to examine latex-specific IgE titer and practice skin prick test of latex for the patients of pollen-food allergy syndrome. RESULTS: It was confirmed that some patients of pollen-food allergy syndrome showed positive reactions against both specific IgE and skin prick test of latex, though they could tolerate latex products in their daily lives. We present here four patients of such clinical courses concretely. CONCLUSION: The patients of pollen-food allergy syndrome should be practiced examination about latex allergy, even if they can use latex products without any symptoms. And more if positive results are obtained, additional examination such as immunoblot and IgE RAST inhibition test are recommended to practice in order to clarify the unresolved problems, such as 1) which factor is the major allergen to cause cross-reactivity among these three factors? 2) what occurs if patients of same clinical courses with our cases continue to use latex products? Further investigation will be indispensable to resolve these problems in the future.     

Cross-reactivity between Ficus benjamina latex and fig fruit in patients with clinical fig allergy

BACKGROUND: Anaphylactic reactions to fig fruits (Ficus carica) have been reported from subjects sensitized to Ficus benjamina (FB) latex allergens. Figs may also be involved in the latex-fruit syndrome. OBJECTIVE: To study the immunologic relationship between fig fruit, Ficus benjamina, natural rubber latex (Hevea brasiliensis), and other tropical fruits. METHODS: RAST inhibition and Western blotting with FB and fruit extracts was performed in five patients with oral allergy syndrome (OAS) or anaphylaxis after the ingestion of figs and one patient with symptoms from exposure to FB trees. Co-sensitization to rubber latex and tropical fruits (kiwi, banana, avocado, papaya, pineapple, mulberry) was studied by skin testing. RESULTS: RAST to FB was inhibited >95% by FB extracts and 16-65% (mean 49%) by extracts from fresh fig. RAST to fig fruit was inhibited >95% by FB and fresh fig, 63-97% (mean 86%) by dried fig, and 0-84% (mean 35.5%) by kiwi fruit. FB and fig extracts lost most of their allergenicity when denatured by heat (95 degrees C) or reduced by dithiothreitol. Western blotting after non-reducing gel electrophoresis revealed IgE binding to proteins of 22 and 28-34 kDa in FB latex; however, no corresponding allergens could be detected in fig extracts. Positive skin tests were obtained most often with kiwi fruit, papaya, and avocado. Sensitization to rubber latex could not be demonstrated in any of the patients. RAST to papain was positive in three of five patients. CONCLUSIONS: Allergic reactions to fresh or dried figs can present as a consequence of primary sensitization to airborne FB allergens independent of sensitization to rubber latex allergens. Kiwi fruit, papaya, and avocado as well as pineapple and banana may be other fruits associated with sensitization to Ficus allergens.     

Heterogeneity of banana allergy: characterization of allergens in banana-allergic patients.

BACKGROUND: Banana is a frequent cause of food allergy, particularly in latex-sensitized patients. OBJECTIVE: The aim of the study was to get insights in immunoglobulin (Ig)E antibody responses of patients with a history of allergic reaction to banana but not to latex. METHODS: In four patients who complained about symptoms after banana consumption, skin prick tests (SPTs) with aeroallergens, latex, banana, avocado, and kiwi were performed. Total and specific serum IgE to birch pollen, rBet v 1 and rBet v 2, latex, banana, avocado, and kiwi were determined by the CAP method (Pharmacia Diagnostics, Uppsala, Sweden). Allergens were identified by immunoblotting with banana extract and recombinant banana profilin. Two patients underwent double-blind, placebo-controlled food challenges (DBPCFC) with banana. RESULTS: All patients showed a positive SPT to banana, and three were IgE-CAP positive (> or = class 2). Two patients were also sensitized (SPT and CAP) to latex, avocado, kiwi, and birch pollen. In the immunoblot these two patients' sera reacted to 32- to 34-kDa proteins, which had already been described as major banana allergens. In both patients banana allergy was confirmed by DBPCFC. The third patient also had a sensitization to avocado, but not to latex or pollen. Immunoblot analysis detected a single band at 70 kDa. The fourth patient was sensitized to birch pollen, rBet v 1 and rBet v 2, but not to latex. Immunoblot analysis in this patient's serum was positive with recombinant banana profilin. CONCLUSIONS: The relevance of banana as a source of food allergy was confirmed in two patients by DBPCFC. In 1 of 2 patients, in whom banana allergy was not a consequence of latex sensitization, a 70-kDa protein was identified as a banana allergen, and in the other patient profilin was detected as a putative cross-reactive allergen.     

Comparison of skin prick tests with specific serum immunoglobulin E in the diagnosis of fungal sensitization in patients with severe asthma

Background It has been shown that patients with allergic bronchopulmonary aspergillosis (ABPA) and patients with severe asthma with fungal sensitization (SAFS) can benefit from antifungal therapy. It is not known whether allergy skin prick tests (SPT) or specific IgE tests are more sensitive in the identification of patients who are sensitized to fungi and who are therefore candidates for antifungal therapy.
Objectives To compare SPT and specific serum IgE tests for fungal sensitization in patients with severe asthma.
Methods We have undertaken SPT and specific serum IgE tests to six fungi ( Aspergillus fumigatus, Candida albicans, Penicillium notatum, Cladosporium herbarum, Alternaria alternata and Botrytis cineria ) and specific serum IgE test for Trichophyton in 121 patients with severe asthma (British Thoracic Society/SIGN steps 4 and 5).
Results Sixty-six percent of patients were sensitized to one or more fungi based on SPT and/or specific serum IgE results. Positivity to SPT and/or specific serum IgE was as follows: A. fumigatus 45%, C. albicans 36%, P. notatum 29%, C. herbarum 24%, A. alternata 22%, B. cineria 18%, Trichophyton 17% (specific serum IgE only). Concordance between the tests was 77% overall but only 14–56% for individual fungi. Twenty-nine (24%) patients were sensitized to a single fungus and seven (6%) were sensitized to all seven fungal species. Fifty percent of patients were sensitized to fungal and non-fungal extracts, 21% were sensitized only to non-fungal extracts, 16% were sensitized only to fungal extracts and 13% had no positive tests.
Conclusion This study is consistent with previous reports that fungal sensitization is common in patients with severe asthma. At present, it remains necessary to undertake both SPT and specific serum IgE testing to identify all cases of fungal sensitization. This may be important in the identification of patients with ABPA and SAFS who may benefit from antifungal therapy.     

Anaphylactic reactions to ingested carmine (E120)

We report five cases of anaphylactic reaction to carmine (cochineal. E120) after patients drank an alcoholic beverage. By means of positive skin prick tests (SPT) and positive RAST to carmine, IgE-mediated sensitization could be established. One nonalopic patient showed also a great amount of serum IgE antibodies to the carmine acid-albumin conjugate. Due to its widespread use in the food and cosmetic industry, carmine should be tested in the allergy work-up in case of allergic reactions after a drink or a meal.     

Association of features of atopy and diagnostic parameters in hymenoptera venom allergy.

In a total of 525 patients with hypersensitivity reactions to hymenoptera stings diagnostic parameters of hymenoptera venom (HV) allergy (severity of reactions, skin test threshold and RAST for bee and vespid venoms) were investigated for their relationship to the following indicators of atopy: positive history of atopic diseases, elevated (less than or equal to 100 kU/l) total serum IgE and positive prick test reactions to common inhalant allergens (CIA) (grass pollen, cat epithelium, house dust mite). There was a conclusive history of atopic disease in 25%, a total serum IgE greater than or equal to 100 kU/l in 48%, and at least one positive reaction to CIA in 53%. Total IgE greater than or equal to 100 kU/l correlated with a higher frequency of RAST classes greater than or equal to 2 (P less than 0.01) and with less severe reactions to hymenoptera stings (P less than 0.05). In the presence of at least one positive reaction to CIA, there were more frequently skin test thresholds less than or equal to 10 micrograms/ml (P less than 0.05) and RAST classes greater than or equal to 2 (P less than 0.01) for HV than in CIA prick test negative individuals. There was no significant, relationship between the other pairs of parameters evaluated. Thus, reactivity to HV in diagnostic tests is increased in the presence of certain indicators of atopy. This has to be considered in the interpretation of skin test and RAST results obtained with HV.     

Comparison of the Phadebas RAST with the Pharmacia CAP system for insect venom

Determination of specific IgE by RAST is a well-established method in the diagnosis of immediate allergic reactions. In this study, we have compared the RAST with the ImmunoCAP, a novel test system which is based on a new type of solid phase. A total of 123 sera from 111 insect venom-allergic patients (74% female) were investigated. All patients had their diagnosis confirmed on the basis of their history and skin tests with insect venom. The patients' age showed a mean +/- S of 44.2 +/- 14.6 years. The total serum IgE levels ranged from 4-1712 kU/l, with a median of 108 kU/l. The results of specific IgE, as determined by RAST and CAP, showed a significantly higher sensitivity, by almost one class, with the CAP compared with the RAST system. The quotient of specific IgE to total IgE, determined with the CAP system, could not be shown to be an expression of sensitization, compared with the severity of sting reactions (Müller classification (16)). A conversion factor for vespid venom RAST to CAP was calculated from the present data by subtracting the RAST from the CAP values. The mean delta value +/- SD was found to be 0.9 +/- 0.65, with a range from -0.8 to 2.7 and a median of 0.9. The data clearly show the differences between RAST and CAP-RAST classes, indicating that the CAP-system has a higher sensitivity and that patients with a low level sensitization are missed by the RAST method.     

Clinical evaluation of a new in-vitro assay for specific IgE, the immuno CAP system

The Pharmacia CAP system is a new assay for specific IgE characterized by a new solid phase (hydrophilic polymer encased in a capsule). The CAP results were compared to those of the Phadebas IgE RAST and skin-prick tests (SPT) performed in 145 subjects suffering from rhinitis and/or asthma with eight common inhalant allergens (total number of tests = 1160). Concording CAP/RAST results were found in 91% of the tests. The CAP was positive in 78% and the RAST in 65% of the positive SPT. Conversely, the CAP was negative in 90.6% and the RAST in 96.4% of the negative SPT. A pattern negative SPT, negative RAST and positive CAP' was found in 56 tests (40 subjects): in four such subjects, the CAP positivity was confirmed by a positive IgE crossed radioimmunoelectrophoresis. Three borderline positive results were found among 240 negative controls (serum from cord blood or non-atopics). These data indicate that compared with SPT the CAP system is (a) more sensitive than the Pharmacia RAST and (b) does not seem less specific.     

Clinical symptoms and immunologic reactivity to bee and wasp stings in beekeepers

We compared the history of sting reactions with venom skin prick test (SPT) and CAP RAST reactions in beekeepers in order to assess the value of structured questions and symptom backgrounds. The study population consisted of 102 beekeepers, who were 25–75 years of age. Bee and wasp venom SPT was performed with concentrations of 10, 100, and 300 μg/ml. The CAP Phadiatop® test was used in the screening of IgE antibodies against common inhalant allergens. Eorty-two beekeepers had never experienced large local or systemic reactions after a bee sting. Of the 31 subjects with a history of systemic reactions, 13 had experienced these during the previous year. A significant difference ( P <0.01) between systemic reactors and nonreactors was found in bee venom CAP and SPT (300 μg/ml). However, due to considerable overlap, these tests are unable to discriminate between allergic and nonallergic beekeepers. Both bee venom SPT (300 μg/ml) and CAP tests were positive in 65% of systemic reactors and in 34% of nonreactors ( P =0.008). Venom SPT (300 μg/ml) correlated significantly with CAP for both venoms. No correlation was observed between venom allergy and atopy. Clinically, the most practical concentration for evaluating bee and wasp venom sensitization by SPT proved to be 300 μg/ml.