sIgE Reactivity Research Articles

Cor a 14: Missing Link in the Molecular Diagnosis of Hazelnut Allergy?

Background: Hazelnut allergy shows distinct clinical patterns that can be predicted through component-resolved diagnosis. However, identification of sensitization profiles remains incomplete. Methods: Sera of 75 patients allergic to hazelnuts, 14 infants with atopic dermatitis (AD) sensitized to hazelnuts, 15 hazelnut-tolerant individuals with specific IgE (sIgE) to hazelnuts and 15 healthy control individuals were tested for sIgE reactivity to rCor a 1.04, rCor a 8, nCor a 9, nCor a 11, rCor a 14, rBet v 1, rBet v 2 and cross-reactive carbohydrate determinants (CCDs). Results: Sensitization to Cor a 14 was observed in 18 out of 20 preschool children, 8 out of 10 school-aged children and 2 out of 7 adults with generalized reactions and in 3 out of 14 infants with AD. Only 2 out of 38 patients with an oral allergy syndrome (OAS) were sensitized to Cor a 14. No sensitization to Cor a 14 was observed in the group of hazelnut-tolerant and healthy control individuals. Sensitization to Cor a 1.04 was seen in 36 out of 38 OAS patients and in 14 out of 37 patients with generalized reactions. However, only 3 patients with generalized reactions were monosensitized to Cor a 1.04. Sensitization to Cor a 9 was observed in 26 out of 37 patients with generalized reactions and in 4 out of 14 infants with AD. Sensitization to Cor a 11, Cor a 8, rBet v 2 and CCDs was rare. Conclusions: Sensitization to Cor a 14 can have early onset and shows age-related variations. Together with Cor a 9, Cor a 14 enables us to correctly identify almost 90% of children with generalized reactions to hazelnut.

Basophil activation tests: a diagnostic break-through in opiate allergy.

We have read the manuscript about codeine (3-methylmorphine) anaphylaxis by Hey-Soo Yoo et al.1 with great interest and would like to take the opportunity to raise some issues and communicate our experience. As recently reviewed, despite their frequent and ubiquitous use, genuine IgE-mediated allergy to opiates remains exceedingly rare. Also, correct diagnosis is not straightforward, mainly because of uncertainties associated with measurement of drug-specific IgE antibodies and skin testing.2 Actually, the key to correct diagnosis of opiate allergy lies in elucidating the clinical significance of positive specific IgE (sIgE) results and distinguishing skin test responsiveness resulting from direct histamine release from a true IgE-mediated activation of cutaneous mast cells. From investigations about morphine and pholcodine (3-[2-morpholinyl-ethyl] morphine)-reactive IgE antibodies it is clear that positive IgE results towards these compounds cannot be considered as a proof for opiate allergy. As a matter of fact, sIgE reactivity to opiates has been observed in up to 10% of the general population and over 80% of patients allergic to rocuronium.3,4,5 Mutatis mutandis, this observation applies to skin testing with these potent histamine releasers that, for years, have been used as a positive control in skin testing (for review2). In contrast, opiates seem not to trigger histamine release from human basophils,6,7,8 making these cells highly attractive as a complementary diagnostic instrument to discriminate non-immunologic hypersensitivity reactions from genuine allergy with an underlying IgE-mediated mechanism (for review2). In their manuscript the authors describe a patient who suffered from anaphylaxis due to oral intake of codeine and document their diagnosis with a drug provocation and histamine release tests. However, due to the unavailability of codeine-sIgE tests, they were unable to establish a potential IgE-mediated mechanism. However, several points might be addressed here. First, measurement of pholcodine and morphine sIgE antibodies, that are readily available from Phadia Thermo Fisher Scientific, might have proven to be useful. As a matter of fact, these three opiates are structurally almost identical, except the substituent in position 3. At this position codeine has a methoxy group, morphine a hydroxyl group, and pholcodine a 2-morpholinoethyl group. Second, mutatis mutandis, the recommendation also applies to histamine release and drug provocation tests. Recently, we have described three patients with immediate hypersensitivity reactions to pholcodine in who measurement of drug-specific IgE and basophil activation tests (Figure) lead to the diagnosis of an IgE-mediated pholcodine allergy.9 Because these patients demonstrated a positive sIgE to morphine but negative basophil activation and provocation tests with the closely related structures morphine and pholcodine, the conclusion seems inescapable that the currently available quantification of opiate-sIgE tests should not be used to diagnose or predict clinical outcomes. Moreover, these observations seem to indicate the likelihood of antibody combining site heterogeneity with recognition at the fine structural level of features additional, and adjacent to, the position 3 substituent. Figure Representative plot CD63 appearance and histamine release in response to buffer, anti-IgE as a positive control, pholcodine 10 µg/mL (top), and the structurally almost similar opiates codeine 100 mg/mL and morphine 100 µg/mL (both bottom) ...

Isolated IgE reactivity to native walnut vicilin-like protein (nJug r 2) on ISAC™ microarray is due to cross-reactive carbohydrate epitopes

The last version of the microarray-based testing ImmunoCAP ISAC 112™ includes the native walnut (Junglans regia) molecules 2S albumin (nJug r 1), vicilin (nJug r 2) and lipid transfer protein (nJug r 3). In view of the many unexpected cases of isolated positivity to nJug r 2 occurring in daily practice, we evaluated the association of these reactivities with clinical symptoms, as well as the relationship between sIgE and nJug r 2 and cross-reactive carbohydrate determinants (CCDs). Sera from 320 consecutive allergic outpatients tested by ImmuoCAP ISAC™ 112 were considered. The medical records of all nJug r 2 positive patients were reviewed to assess clinical symptoms related to walnut allergy. A linear regression analysis was performed to evaluate the correlation between nJug r 2 and CCDs (nMUXF3) sIgE values, and a CAP inhibition assay was carried out to confirm the possible cross-reactivity between CCDs and nJug r 2. Thirty-seven out of 320 sera tested (11.6%) were positive to nJug r 2. Among them three (8.1%) and eight (21.6%) scored positive for nJug r 1 and nJug r 3 as well, respectively. Twenty-seven (73%) sera showed isolated nJug r 2 positivity. Only nJug r 1 reactors had symptoms referred to walnut allergy. Twenty-five/37 nJug r 2-positive sera (67.6%) showed a simultaneous positivity to nMUXF3 and a significant correlation (p<0.0001) between the IgE levels to nJug r 2 and nMUXF3 (r²=0.787). After incubation with nMUXF3 a complete inhibition of sIgE reactivity to both nMUXF3 and nJug r 2 was shown. The unexpected isolated sIgE reactivity to nJug r 2 found by ImmunoCAP ISAC™ 112 is frequently related to reactivity to cross-reactive carbohydrate epitopes and it is lacking clinical significance.

The major royal jelly proteins 8 and 9 (Api m 11) are glycosylated components of Apis mellifera venom with allergenic potential beyond carbohydrate‐based reactivity

As hymenoptera venoms are one of the allergen sources causing the highest incidence of anaphylaxis and sometimes fatal consequences, the detailed characterization of all venom allergens is imperative for design of component-resolved diagnostic approaches and improved intervention strategies. Our aim was the immunochemical characterization of major royal jelly proteins (MRJP) 8 and 9, both components identified in honeybee venom (HBV) and putative allergens. Both MRJPs were recombinantly produced as soluble differentially glycosylated proteins providing a defined degree of reactivity to cross-reactive carbohydrate determinants (CCD) in insect cells. Allergen-specific IgE(sIgE) reactivity of HBV-allergic patients was analysed by ELISA and immunoblotting. MRJP8 and MRJP9 were identified as venom components by MS-based proteomic analyses. In a population of 47 HBV-allergic patients, reactivities with CCD-carrying MRJPs were in the range of 56% (61%), underlining the contribution of CCDs to allergen-binding. Beyond CCD-reactivity, 15% of patients showed sIgE reactivity with MRJP8 and 34% with MRJP9 respectively. These reactivities roughly in the range of Api m 2 render the MRJPs minor, but important allergens. The glycosylated MRJP8 and MRJP9 of HBV have IgE-sensitizing potential in HBV-allergic patients beyond CCD reactivity and have to be considered as allergens, which might be potentially important for a fraction of venom allergic patients. They are valuable tools to elucidate individual component-resolved reactivity profiles of venom allergic patients and to provide insights into the role of particular venom components. Due to their allergenic properties, MRJP8 and MRJP9 were designated as isoallergens Api m 11.0101 and Api m 11.0201 respectively.

The effect of single and multiple infections on atopy and wheezing in children

The current epidemic of asthma and atopy has been explained by alterations in immune responses related to reduction in childhood infections. However, the findings of epidemiologic studies investigating the association between infection with atopy and asthma have been inconsistent. We sought to investigate the effect of single or multiple infections (pathogen burden) on atopy and wheeze in urban children from Latin America. Specific IgE against aeroallergens (sIgE) and skin prick test (SPT) reactivity for the most common local allergens were measured in 1128 children aged 4 to 11 years. Data on wheezing and potential confounders were collected by questionnaire. Infections by 8 pathogens were assessed by using serology and stool examination. Associations of wheeze and atopic outcomes with single and multiple infections were analyzed by means of logistic regression. Negative results for Toxoplasma gondii were associated with a higher prevalence of sIgE (≥0.70 kU/L), whereas negative results for Ascaris lumbricoides, T gondii, herpes simplex virus, and EBV were associated with a higher prevalence of SPT reactivity. Children with 3 or fewer infection markers had a higher prevalence of sIgE and SPT reactivity compared with those with 4 or more infection markers. However, isolated infections or pathogen burden were not associated with the prevalence of atopic or nonatopic wheeze. The findings provide support for the idea that the hygiene hypothesis is operating in an urban Latin American context, but its expression is thus far restricted to the atopic status of patients and not the perceived asthma symptoms.

Low sensitivity of commercially available rApi m 1 for diagnosis of honeybee venom allergy

Low sensitivity of commercially available rApi m 1 for diagnosis of honeybee venom allergy

Suitability of Different Glycoproteins and Test Systems for Detecting Cross-Reactive Carbohydrate Determinant-Specific IgE in Hymenoptera Venom-Allergic Patients

Background: In hymenoptera venom allergy, about 75% of detected in vitro double positivity to yellow jacket and honeybee venom is ascribed to specific IgE (sIgE) directed against cross-reactive carbohydrate determinants (CCDs). To date, for the detection of CCD-sIgE, different carbohydrate antigens and methods are used. The most suitable one still has to be identified. Methods: Eighty-seven patients with confirmed hymenoptera venom allergy and venom sIgE values of ≧0.7 kU/l were investigated. Sixty-five patients showed sIgE reactivity to both yellow jacket and honeybee venom, 22 were venom mono positive and served as controls. Occurrence of CCD-sIgE was determined using bromelain, horseradish peroxidase (HRP) and MUXF³ on system A, and ascorbic acid oxidase (AAO), bromelain and HRP on system B. Further, a reference standard for CCD-sIgE evaluation was created: CCD positivity was assumed when at least 4 of the 6 test results were positive. Results: According to the defined reference standard, 45/65 venom double positive patients exhibited CCD-sIgE. Using system A, comparison with the reference standard revealed sensitivity and specificity values of 96 and 97%, respectively, for MUXF³, 100 and 100%, respectively, for bromelain, and 96 and 97%, respectively, for HRP. Using system B, sensitivity and specificity was 98 and 97%, respectively, for AAO, 62 and 95%, respectively, for bromelain, and 96 and 69%, respectively, for HRP. Results of the 3 test allergens obtained with system A showed strong correlations (r = 0.932–0.976), whereas results with system B showed lower correlations (r = 0.714–0.898). Conclusions: All 3 test allergens used with system A are suitable for CCD-sIgE detection in hymenoptera venom allergy. With system B, only AAO seems to be a reliable tool.