Inhibition of CD23‐dependent facilitated allergen binding to B cells following vaccination with genetically modified hypoallergenic Bet v 1 molecules

Background Vaccination with hypoallergenic recombinant Bet v 1 derivatives (Bet v 1 fragments and Bet v 1 trimer) is associated with the induction of IgG antibodies specific to natural Bet v 1. Objective To investigate whether IgG antibodies induced following vaccination with genetically modified hypoallergenic Bet v 1 derivatives are able to inhibit IgE‐facilitated binding of allergen‐IgE complexes to B cells. Methods Sera from 46 patients obtained before and after subcutaneous vaccination with Bet v 1 trimer (n=14), Bet v 1 fragments (n=11) or placebo (n=21) were incubated with recombinant (r) Bet v 1 and an indicator serum (IS) from a birch pollen‐allergic patient with high CD23 binding capacity. Bet v 1 immune complexes were added to a CD23‐expressing B cell line and co‐operative binding of Bet v1‐IgE complexes to CD23 was measured with a polyclonal anti‐IgE FITC antibody using a bio‐functional cellular flow cytometric assay. Results When sera from patients vaccinated with rBet v 1 derivatives were incubated with Bet v 1 and the IS, a reduction of IgE binding to CD23 was observed. This effect was not seen when sera from placebo‐treated patients were used. The decrease in CD23/IgE binding was statistically significant in the trimer group [pre‐ vs. post‐specific immunotherapy (SIT): P=0.02; trimer vs. placebo: P<0.04] but not in the Bet v 1 fragments‐treated group. Trimer‐treated patients had higher levels of Bet v 1‐specific IgG than fragment‐treated patients. The degree of inhibitory activity of IgE‐facilitated allergen binding correlated with Bet v 1‐specific IgG levels following SIT (R=0.492; P=0.012). Conclusion Vaccination with both recombinant Bet v 1 derivatives induces Bet v 1‐specific IgG antibodies, which are able to inhibit the co‐operative binding of allergen‐IgE complexes to CD23, and may thereby reduce allergen‐specific T cell responses. Cite this as: I. Pree, M. H. Shamji, I. Kimber, R. Valenta, S. R. Durham and V. Niederberger, Clinical & Experimental Allergy, 2010 (40) 1346–1352.     

Sensitivity to two major allergens (Cry j I and Cry j II) in patients with Japanese cedar (Cryptomeria japonica) pollinosis

Background: Japanese cedar (Cryptmeria japonica: CJ) pollinosis is one of the most important allergic diseases in Japan. Recently, the second major allergen (Cry j II) was isolated from CJ pollen. There have been no prevalence studies of sensitivity to Cry j I and Cry j II among a large number of patients with pollinosis. Objective: This study was conducted to evaluate the prevalence of sensitivity to Cry j I and Cry j II. We measured specific IgE antibodies to these allergens in the sera of 145 patients. Furthermore, comparison of the sensitivity to Cry j I and Cry j II was examined by the hisiamine release assay. Methods: Specific IgE antibodies to Cry j I and Cry j II were assayed by a fluorometric ELISA. Allergen-specific histamine release was measured by a radioimmunoassay kit, Results: More than 90% of 145 patients had specific IgE antibodies to both allergens. the remainder had specific IgE to either one or the other. There were seasonal changes in the level of specific IgE. The changes in the levels of anti-Cry j II IgE antibodies were parallel to those of anti-Cry j I IgE. The histamine release assay with leucocytes from the patients demonstrated that the allergenic potency of the two allergens is almost the same. Conclusion: Cry j II is an as important a major allergen as Cry j I.     

A cross‐sectional study on the prevalence of food allergy to eggplant (Solanum melongena L.) reveals female predominance

Background Only a few case reports of allergy to eggplant (Solanum melongena) have been reported. A relatively large number of individuals appear to experience food‐related symptoms to eggplant in India. Objective The major aims of this study are to assess the prevalence of food allergy to eggplant and analyse the age and gender distribution. Methods Seven hundred and forty‐one subjects (age range: 5–60 years) randomly selected from rural and urban areas of Mysore city were analysed for the prevalence of eggplant allergy based on case history, skin prick test (SPT) with eggplant extracts and allergen‐specific IgE. The age and gender distribution for the prevalence of eggplant allergy and its association with other atopic conditions were assessed. Results Sixty‐eight (9.2%) subjects reported adverse reactions to ingestion of eggplant, of which 32 (4.3%) subjects had positive history/positive SPT and 36 (4.9%) had positive history/negative SPT. Sixteen (2.2%) subjects had negative history/positive SPT. Ten subjects (1.4%) experienced allergic symptoms in <2 h. Sensitization to eggplant by SPT was more in atopic (16.7%) compared with non‐atopic subjects (3.8%). All the SPT‐positive subjects (n=48) underwent evaluation for eggplant allergen‐specific IgE, which was detected in 6 subjects (0.8%). Majority of the subjects sensitized to eggplant were in the age groups 16–45 years, and females were twice as likely to be sensitized as males. Female predominance (4 : 1) is more in the 16–30 year group. Conclusions Many subjects experience adverse reactions to the ingestion of eggplant, possibly due to the pharmacologic action of histamine and other non‐protein components, rather than to specific protein allergen(s). The prevalence of IgE‐mediated eggplant allergy is estimated at ～0.8%, with higher rates of sensitization in females.     

The performance of a component‐based allergen microarray for the diagnosis of kiwifruit allergy

Background Allergy to kiwifruit is increasingly reported across Europe. Currently, the reliability of its diagnosis by the measurement of allergen‐specific IgE with extracts or by skin testing with fresh fruits is unsatisfying. Objective To evaluate the usefulness of a component‐based allergen microarray for the diagnosis of kiwifruit allergy in a large group of patients. Methods With an allergen microarray, we measured specific IgE and IgG4 levels to a panel of nine kiwifruit allergens in sera of 237 individuals with kiwifruit allergy. Sera from 198 allergic patients without kiwifruit allergy served as controls. Furthermore, we determined the extent of sensitization to latex. Results The panel of kiwifruit allergens showed a diagnostic sensitivity of 66%, a specificity of 56% and a positive predictive value of 73%. Sera from kiwifruit‐allergic patients contained significantly more frequently Act d 1‐specific IgE than sera from control patients. Furthermore, 51% of the positive sera contained IgE directed to a single allergen, namely Act d 1 (45%), Act d 9 (27%) or Act d 7 (13%). Within the control group, 36% sera recognized a single allergen. Out of those, 48% were positive to the cross‐reactive glycoallergen Act d 7, 43% to the profilin Act d 9 and only 5% to Act d 1. Allergen‐specific IgG4 levels did not differ between kiwifruit‐allergic and ‐tolerant patients. Kiwifruit‐ and latex‐allergic patients contained Hev b 11‐specific IgE significantly more frequently than latex‐allergic patients without kiwifruit allergy. Conclusions Act d 1 can be considered a marker allergen for genuine sensitization to kiwifruit. We demonstrated that a component‐based kiwifruit allergen microarray would improve the prognostic value of in vitro diagnostic tests. Cite this as: M. Bublin, S. Dennstedt, M. Buchegger, M. Antonietta Ciardiello, M. L. Bernardi, L. Tuppo, C. Harwanegg, C. Hafner, C. Ebner, B. K. Ballmer‐Weber, A. Knulst, K. Hoffmann‐Sommergruber, C. Radauer, A. Mari and H. Breiteneder, Clinical & Experimental Allergy, 2011 (41) 129–136.     

IgE sensitization to the fish parasite Anisakis simplex in a Norwegian population: a pilot study

The reports on fish parasite Anisakis simplex allergy have increased in countries with high fish consumption in the last decade. In Norway, a high consumption country, the prevalence of immunoglobulin E (IgE) sensitization to A. simplex was still unknown. Thus, our objective was to investigate the sensitization prevalence in this country. At the Haukeland University Hospital, Bergen, Norway, two main groups of surplus serum samples were collected: one from newly recruited blood donors (BDO) and the other from the Allergy laboratory (ALL) after analysing IgE and IgE antibodies. The latter was divided into three series: one containing unsorted sera and two sorted by either Phadiatop^®≥0.35 kU_A/l or total IgE ≥1000 kU/l. The sera were analysed for total IgE and IgE antibodies against A. simplex, shrimp, house dust mite (HDM), cod and cross‐reactive carbohydrates (CCDs). The prevalence of IgE sensitization to A. simplex was 2.0%, 2.2% and 6.6% in BDO, the unsorted and Phadiatop^® positive serum groups, respectively. A considerable degree of cross‐sensitization to shrimp and HDM is further suggested. Unspecific binding because of high total IgE or by binding to CCDs seemed to play a minor role. The prevalence of IgE sensitization to A. simplex appears to be lower in a Norwegian population than in other high fish‐consuming countries, but might still be overestimated owing to cross‐sensitization.     

Evaluation of antigen specific IgE responses in Japanese asthmatics and non-asthmatics]

BACKGROUND: An increase in the prevalence of asthma does not seem to be comparable to the dramatic increase of atopy for the last two decades in Japan. Atopy is considered an important risk factor for asthma. It is, however, suggested that asthma itself may be responsible for the increased overall IgE responsiveness. We examined the significance of IgE responsiveness in asthma. METHODS: We studied 265 healthy controls and 275 patients with asthma. Total serum IgE levels and levels of antigen-specific IgE antibody to mite (D. farinae), cat, dog, timothy, and Candida spp. were determined. We defined atopy by positive RAST (>0.35UA/ml) or MAST scores (>1.0 lumicount) to at least one inhaled allergen. Frequencies of atopic subjects and frequencies of subjects sensitized to each allergen in atopic subjects were compared between the asthmatics and controls. All comparisons were made in younger (<41 yrs) and older (> = 41 yrs) groups, separately. RESULTS: In younger non-asthmatics, 76.5% (104/136) were atopic. The frequency of atopy was significantly higher in asthmatic subjects compared to non-asthmatics in both younger and older groups. In atopic subjects, older asthmatics were sensitized to animals more frequently than older controls. Although the frequency of subjects sensitized to mite did not differ between asthmatics and controls both in younger and older atopic subjects, asthmatics sensitized to mite had higher titers of specific IgE antibody to mite compared to those of controls sensitized to mite. Even non-atopic asthmatics had higher levels of total IgE compared to non-atopic controls. CONCLUSION: Our data may indicate that sensitization to animals and severer sensitizations to mite are risk factors for asthma. However, given the high prevalence of atopy in younger healthy controls, and increased levels of total serum IgE even in non-atopic asthmatics, our findings may reflect the increased overall IgE responsiveness that is inherent in asthma.     

Clonorchis sinensis infection is positively associated with atopy in endemic area

Background Epidemiologic studies have suggested that helminth infections play a protective role against allergy; this inverse association, however, has not been consistent. Clonorchis sinensis, the liver fluke of human, is prevalent in the Far East. The association between C. sinensis infection and allergy has not yet been reported. Objective We evaluated the association between clonorchiasis and atopy or allergic diseases in adults in endemic areas of clonorchiasis. Methods A total of 1116 subjects (males 419, females 697; age range, 30–86; mean age=61 years) were recruited from two endemic areas of C. sinensis in Korea. Clonorchiasis was confirmed by stool examination. Allergic symptoms were evaluated with a modified ISAAC questionnaire, and atopy was defined by skin prick test for common inhalant allergens. Total serum IgE and C. sinensis‐specific IgE level was measured by ELISA and methacholine bronchial provocation test was performed to evaluate airway hyperresponsiveness (AHR). Results Clonorchiasis was positively associated with atopy [odds ratio (OR), 1.856; 95% confidence interval (CI), 1.199–2.873] and high levels of total serum IgE (OR, 1.455; 95% CI, 1.050–2.016). Higher association with clonorchiasis was shown in subjects who showed both atopy and high total serum IgE levels (OR, 2.540; 95% CI, 1.448–4.455). Clonorchiasis had no association with wheezing, AHR, asthma or allergic rhinitis. Conclusion and Clinical Relevance Clonorchiasis was positively associated with atopy in adults in endemic area. Cite this as: M‐H Choi, Y‐S Chang, M. K. Lim, Y. M. Bae, S‐T Hong, J‐K Oh, E. H. Yun, M‐J Bae, H‐S Kwon, S‐M Lee, H‐W Park, K‐U Min, Y‐Y Kim and S‐H Cho, Clinical & Experimental Allergy, 2011 (41) 697–705.     

Increasing trend in atopy markers prevalence in a Croatian adult population between 1985 and 1999

Background Reports about the increasing prevalence of atopy and atopic diseases are common, but recently they have been critically reviewed and the need for relevant research methods has been established. Objectives This study evaluated a 15‐year trend in the prevalence of atopy markers [elevated total IgE, positive skin prick test (SPT) to common aeroallergens and positive atopic symptoms] in Croatian adults, separately for women and men. Methods The study included 721 subjects (445 men and 276 women), 18–45 years old, examined for allergies within a pre‐employment preventive examination. All subjects underwent medical history, SPT with common inhalatory allergens and total serum IgE measurement. The trend analysis of atopy prevalence was performed after stratification of subjects into three consecutive 5‐year periods from 1985 to1999. Results The prevalence of concurrently elevated total IgE and positive atopic symptoms significantly increased during the studied period in men [odds ratio (OR) 2.44, 95% confidence interval (CI) 1.39–4.29, P=0.002]. Women showed an increased prevalence of positive SPT only, with borderline significance (OR 1.65, 95% CI 1.00–2.71, P=0.050). In women, rural residence was found to be a predictor of elevated total IgE (OR 5.36, 95% CI 2.41–11.93, P=0.000) and smoking to be a predictor of concurrently elevated total IgE and positive SPT (OR 6.20, 95% CI 1.67–23.07, P=0.006). Conclusions An increasing trend in the prevalence of concurrently elevated total IgE and positive atopic symptoms was found in the Croatian adult male population between 1985 and 1999, but not in the female population. Sex differences responsible for the production and regulation of IgE were suggested.     

Differences in both prevalence and titre of specific immunoglobulin E among children with asthma in affluent and poor communities within a large town in Ghana

Background Reports from several African countries have noted an increasing prevalence of asthma in areas of extensive urbanization. Objective To investigate the relevance of allergen‐specific sensitization and body mass index (BMI) to asthma/wheezing and exercise‐induced bronchospasm (EIB) among children from affluent and poorer communities within a large town in Ghana. Methods Children with physician‐diagnosed asthma and/or current wheezing aged 9–16 years (n=99; cases) from three schools with differing socio‐economic backgrounds [urban affluent (UA), urban poor (UP) or suburban/rural (SR)] were recruited from a cross‐sectional study (n=1848) in Kumasi, Ghana, and matched according to age, sex and area of residence with non‐asthmatic/non‐wheezy controls. We assayed sera for IgE antibodies to mite, cat, dog, cockroach, Ascaris and galactose‐α‐1,3‐galactose. Results Children from the UA school had the lowest total serum IgE. However, cases from the UA school had a higher prevalence and mean titre of sIgE to mite (71.4%, 21.2 IU/mL) when compared with controls (14.3%, 0.8 IU/mL) or cases from UP (30%, 0.8 IU/mL) and SR community (47.8%, 1.6 IU/mL). While similar findings were observed with EIB in the whole population, among cases there was no difference in IgE antibody prevalence or titre between children with or without EIB. BMI was higher among UA children with and without asthma; in UP and SR communities, children with EIB (n=14) had a significantly higher BMI compared with children with asthma/wheezing without EIB (n=38) (18.2 vs. 16.4, respectively, P<0.01). Conclusions and Clinical Relevance In the relatively affluent school, asthma/wheezing and EIB were associated with high titre IgE antibodies to mite, decreased total IgE, and increased BMI. This contrasted with children in the urban poor school and suggests that changes relevant to a Western model of childhood asthma can occur within a short geographical distance within a large city in Africa. Cite this as: W. Stevens, E. Addo‐Yobo, J. Roper, A. Woodcock, H. James, T. Platts‐Mills and A. Custovic, Clinical & Experimental Allergy, 2011 (41) 1587–1594.     

Cat allergen‐induced blood basophil reactivity in vitro predicts acute human nasal allergen challenge responses in vivo

Background Basophil histamine release (BHR) to allergen has been used as a confirmatory test to support the clinical diagnosis of allergic disease. Objective Among subjects reporting respiratory cat allergy, we hypothesized that cat‐induced BHR in vitro would predict nasal allergen challenge (NAC) response in that same individual. We therefore compared the magnitude of cat allergen‐induced BHR to NAC outcome and serological measures of cat‐specific IgE and the ratio of cat‐specific IgE to total IgE. Methods Forty‐two subjects with a history of cat allergy, positive cat puncture skin test (PST) and detectable cat‐specific IgE (>0.1 kAU/L, ImmunoCap) participated with consent. Subjects were grouped as positive or negative cat allergen‐induced BHR, with a positive result defined as the release of 20% of the total cellular histamine content. The majority of subjects also underwent a NAC with a positive result defined as 5 total sneezes. Results Subjects with a positive compared with a negative cat allergen BHR had higher cat‐specific IgE levels at 5.40±1.24 kAU/L (n=25) vs. 1.55±0.73 kAU/L (n=17, P=0.01) as well as a higher cat‐specific IgE/total IgE ratio [6.1±1.4% (n=25) vs. 1.6±0.9% (n=17, P=0.01)]. Of the 31 subjects who underwent a NAC, a positive NAC was observed in 78% (18/23) with a positive cat allergen BHR compared with 37% (3/8) with a negative cat allergen BHR, giving a positive predictive value of 78% and a negative predictive value of 63%. The diagnostic sensitivity and specificity of a positive BHR to predict a positive NAC was 86% and 50%, respectively. Conclusions and Clinical Relevance A positive cat allergen‐induced BHR is associated with higher cat‐specific IgE levels, a higher cat‐specific to total IgE ratio and is predictive of a positive cat‐induced NAC [ClinicalTrials.gov NCT00604786]. Cite this as: M. Paterniti, D. C. Kelly, J. A. Eckman, P. M. Sterba, R. G. Hamilton, B. S. Bochner, D. W. MacGlashan Jr. and S. S. Saini, Clinical & Experimental Allergy, 2011 (41) 963–969.     

Transaldolases are novel and immunoglobulin E cross‐reacting fungal allergens

Background Mould‐induced atopic respiratory diseases are a worldwide problem. Characterization of fungal allergens is of major clinical importance. Objective We identified a novel transaldolase family allergen of Cladosporium and Penicillium species. Methods Fungal allergens were identified by immunoblotting, peptide mass mapping and partial sequencing, cDNA cloning and IgE epitope mapping. Results A 36.5 kDa IgE‐binding component in a partially purified C. cladosporioides preparation was identified. Mass spectrometric analyses suggest that this novel IgE‐reacting allergen is a transaldolase. A corresponding full‐length 1246 bp cDNA encoding a polypeptide of 325 residues was isolated. The newly identified transaldolase allergen has been designated as Cla c 14.0101. The cDNA encoding the Pencillium chrysogenum transaldolase was isolated by RT‐PCR according to the cDNA sequence encoding a P. chrysogenum Wisconsin 54‐1255 hypothetical protein. The purified rCla c 14.0101 protein reacted with IgE antibodies in 10 (38%) of 26 Cladosporium cladosporioides‐sensitized asthmatic patients. Nine of the 10 rCla c 14.0101‐positive sera have IgE binding against the recombinant Penicillium transaldolase (rPen ch 35.0101). Among the eight fungal transaldolase‐positive sera tested, three showed IgE binding against the recombinant human transaldolase. To determine cross‐reactivity between the Cladosporium and Penicillium fungi, IgE cross‐reactivity was detected between these two fungal transaldolase allergens by inhibition assays. Both the N‐ and the C‐terminal fragments of Cla c 14.0101 were recognized by IgE antibodies. The C‐terminal IgE‐reacting determinant was narrowed down to a region encompassing Thr257 to Ser278 of Cla c 14.0101. It was mapped onto a loop‐like structure of a 3D model constructed for Cla c 14.0101. Conclusion and Clinical Relevance We identified transaldolase as a novel and IgE cross‐reactive allergen family of C. cladosporioides and P. chrysogenum. In addition, an IgE‐reacting fragment (Thr257 to Ser278) was pinpointed to a loop‐like structure on Cla c 14.0101. Results obtained provide important information in clinical mould allergy. Cite this as: H. Chou, M. F. Tam, C.‐H. Chiang, C.‐T. Chou, H.‐Y. Tai and H.‐D. Shen, Clinical & Experimental Allergy, 2011 (41) 739–749.     

Measurement of IgG antibodies to house dust mite and grass pollen by a solid-phase radioimmunoassay

Polystyrene microtubes, coated with extracts of either Dermatophagoides pteronyssinus (DPT) or grass pollens, were used as the solid-phase in a radioimmunoassay for the measurement of specific IgG antibodies to the corresponding allergen. Radiolabelled protein A from Staphylococcus aureus (SpA) was used to determine the IgG antibodies attached to the tubes. The binding of IgG from either normal or allergic sera to DPT-coated tubes was antigen specific and mediated by the Fab fragment of the immunoglobulin. IgG antibodies purified by affinity chromatography from non-allergic serum competed with IgE antibodies to DPT. IgE antibodies do not significantly interfere with the assay. Indeed, heating a reaginic serum resulted in a striking reduction of the (¹²⁵I) anti-IgE binding to allergen-coated tubes without modifying the (¹²⁵I)-SpA binding. Furthermore, filtration of a reaginic serum through Sephacryl S-200 separated a peak of IgE antibodies, characterized by a high binding of labelled a-IgE and a low binding of (¹²⁵I)-SpA from the peak of IgG antibodies defined by low a-IgE and high SpA binding. The solid phase method is more sensitive than a double-antibody technique employing the same DPT extract as labelled antigen. Non-allergic subjects had less IgG antibodies to DPT or grass pollens than allergic patients. In untreated patients, there was a good correlation between levels of IgG and IgE antibodies to grass pollens but not to DPT. Patients hyposensitized to house dust mite had on the average three times more specific IgG antibodies than untreated cases.     

Citrus red mite (Panonychus citri) is the most common sensitizing allergen of asthma and rhinitis in citrus farmers.

OBJECTIVE: To evaluate type I hypersensitivity to citrus red mite (Panonychus citri), its prevalence, and relationship to respiratory dysfunction, a cross-sectional survey was performed among citrus farmers on Cheju Island, Korea. MATERIALS AND METHODS: Questionnaires, and skin prick test responses to 11 common inhalant allergens and citrus red mite were performed in 181 citrus farmers, and serum-specific IgE antibodies to citrus red mite were measured by ELISA in sera of 123 subjects. To determine airway hyperresponsiveness, methacholine bronchial provocation tests were performed in 55 subjects who complained of recurrent lower respiratory symptoms. RESULTS: The prevalence of asthma-based on presence of asthmatic symptoms on the questionnaire and airway hyperresponsiveness to methacholine, and allergic rhinitis based on presence of nasal symptoms on the questionnaire and positive skin-test response were 12.1% and 19.3%, respectively. The positive rate of skin responses to one or more of 11 common inhalant allergens excluding citrus red mite was 17.1%, and if citrus red mite was included, 25.9% of farmers had positive responses. On skin prick tests, citrus red mite (16.5%) was the most common sensitizing allergen, followed by cockroach (11.0%), Dermatophagoides pteronyssinus (9.9%), and D. farinae (9.3%). Among farmers with asthma and allergic rhinitis, the positive skin responses to citrus red mite were noted in 54.5 and 68.5%, respectively. Serum-specific IgE antibodies to citrus red mite were detected in 45 farmers (36. 5%) of the 123 tested, and there was significant correlation between specific IgE level and weal (A/H ratio) to citrus red mite (r = 0.57, P < 0.001). The prevalence of asthma was higher in subjects with positive skin responses or high serum-specific IgE antibodies to citrus red mite than in those without skin response or serum specific IgE (P < 0.05, respectively). CONCLUSION: Citrus red mite is the most important allergen in citrus farmers with asthma and rhinitis in which causative allergen has not been identified. It should be included in the skin test battery for screening the causative allergen in farmers exposed to citrus red mite.     

Sulphidoleukotriene release of cord blood basophils in response to allergen stimulation correlates with neither a family history of atopy nor a subsequent development of atopic eczema

Objective We tested a possible relationship between sulphidoleukotriene (SLT) release of cord blood (CB) basophils, a family history of atopy (HA) and subsequent development of atopic eczema. Population and methods A cohort of 86 neonates were involved (48.8% males; 46.5% with a positive HA⁺). CB samples were analysed for in vitro SLT release quantified by ELISA, and in a subgroup for basophilic activation (CD 63 expression) by flow cytometry in response to a positive control (anti‐IgE‐receptor antibody), an allergen‐mix (TOP and PTOP), egg white (EW), egg yolk (EY), and the purified allergens β‐lactoglobulin (BLG) and α‐lactalbumin (ALA). Results Median concentrations of SLT were 124.2 (negative), 3871.5 (positive), 123.9 (TOP), 128.5 (PTOP), 113.1 (EW), 108.4 (EY), 125.2 (BLG) and 122.3 (ALA) pg/mL. Groups of HA⁺ and HA^– show no difference in all analysed allergens. An allergen‐specific SLT release (defined as SLT>125 pg/mL above individual baseline and a stimulation index >2) was detected in 98% (positive control), 5% (TOP), 7% (BLG), 3% (ALA) and 2% (EW and EY), respectively. After a median observation period of 18 months, n=7 out of 70 children developed an atopic eczema, but we observed no association between CB SLT release (positive response to at least one tested allergen). Conclusion Allergen‐specific SLT release is detectable in 15.5% of healthy neonates, irrespective of their family history of atopy. However, early allergen‐specific SLT release is not predictive for the development of atopy.     

Exposure-response relationships for work-related sensitization in workers exposed to rat urinary allergens: results from a pooled study

BACKGROUND: Recent studies in a few industries have shown that the likelihood of IgE-mediated sensitization increases with increasing exposure. The shape of the exposure-response relationships and modification by age, sex, and smoking habit has hardly been studied. OBJECTIVE: The purpose of this study was to determine exposure sensitization relationships for rat sensitization and to evaluate the influence of atopy, smoking habits, and sex. METHODS: Data from 3 cross-sectional studies in The Netherlands, the United Kingdom, and Sweden were used and involved 1062 animal laboratory workers. Selection criteria were harmonized, and this resulted in a study population of 650 animal laboratory workers (60.6% female) with less than 4 years of exposure. Air allergen levels were assessed previously and converted on the basis of an interlaboratory allergen analysis comparison. Available sera were analyzed for the presence of specific antibodies against common allergens (house dust mite, cat, dog, and grass and birch pollen) and work-related allergens (rat and mouse urinary proteins). Questionnaire items on work-related respiratory symptoms, hours worked with rats per week, job performed, smoking habits, and sex were used in this analysis RESULTS: The prevalence of work-related sensitization to rat urinary allergens (IgE >0.7 KU/L) was 9.7 % (n = 63). Thirty-six of the sensitized workers had work-related symptoms (asthma or rhinitis). Two hundred forty-eight workers (38.2%) were atopic (defined as specific IgE to 1 of the common allergens). The sensitization rate increased with increasing air allergen exposure. Atopic workers exposed to low levels of allergen had a more than 3-fold increased sensitization risk compared with nonexposed atopic workers. For atopic subjects, the risk increased little with increasing exposure, whereas for nonatopic subjects, a steadily increasing risk was observed. Smoking and sex did not modify the sensitization risk. CONCLUSION: Rat urinary allergen-sensitization risk increased with increasing exposure intensity. Workers who were atopic had a clearly elevated sensitization risk at low allergen exposure levels.     

The complexities of defining atopy in severe childhood asthma

Background Defining atopy in children with severe, therapy‐resistant asthma is complex. There is currently no gold standard test; both skin prick testing (SPT) and allergen‐specific IgE (sIgE) are used. Furthermore, atopy is increasingly considered to be a spectrum, not an all‐or‐none phenomenon. Hypothesis SPTs and sIgE cannot be used interchangeably, and if both tests are not performed, opportunities for intervention will be missed. Furthermore, the severity of atopy will be defined differently by the two tests. Methods Cross‐sectional study of 47 children with severe, therapy‐resistant asthma, mean age 11.8 years, range 5.3–16.6 years, who underwent SPT, and measurement of total and sIgE as part of their clinical work‐up. Results Overall, 42/47 (89%) were atopic (defined as either one positive SPT or sIgE). There was 98% concordance between the two tests in classifying atopy. When each allergen was considered individually, in 40/200 (20%), the SPT and sIgE results were discordant, most commonly in 25/200 (12.5%), the SPT was negative and the sIgE was positive. House dust mite and cat sensitization were more likely detected by sIgE, but dog sensitization by SPT. When atopy was quantified, the sum of sIgEs compared with the sum of SPT weal diameter showed a moderate correlation (r²=0.44, P<0.001). Total IgE increased with an increasing number of positive sIgEs (P=0.028), but not significantly with increasing numbers of positive SPTs. Conclusion and Clinical Relevance SPT and sIgE identify group prevalence of atopy equally well; however, for individual allergens, concordance is poor, and when used to quantify atopy, SPTs and sIgE were only moderately correlated. In a clinical setting, if allergen avoidance is contemplated in children with severe, therapy‐resistant asthma, both tests should be performed in order to detect sensitization. Cite this as: J. Frith, L. Fleming, C. Bossley, N. Ullmann and A. Bush, Clinical & Experimental Allergy, 2011 (41) 948–953.     

Local and systemic immune responses in humans againstHelicobacter pyloriantigens from homologous and heterologous strains

The capacity ofHelicobacter pylorito induce strain specific immune responses was studied in adult Swedish volunteers. Sera and gastric aspirates from 11H. pylori-infected subjects were tested for specific antibody levels against, respectively, lipopolysaccharides (LPS) and total membrane preparations (MPs) prepared from the study subjects» own strains, as well as with corresponding antigens from two referenceH. pyloristrains or heterologous strains collected from other subjects within the study. It was found that sera from five of the 11 subjects had significantly higher IgA antibody titres against LPS from the homologous strain than against LPS from either of the reference strains and in five cases sera reacted with higher IgG titres against the homologous LPS than with LPS preparations from the reference or heterologous patient strains. Analyses of specific titres against MPs revealed that six sera had higher IgA titres and four sera had higher IgG titres against MPs prepared from the subjects» own strains than against MPs from either of the two reference strains. Determination of specific antibodies in gastric aspirates revealed significantly higher IgA titres against LPS from the homologousH. pyloriisolate than against LPS from the two reference strains in five cases, and six aspirates reacted in higher IgA titre with the homologousH. pyloriMPs. Results from immunoblotting analyses of sera support induction of strain specific immune responses againstH. pyloriLPS. By means of specific monoclonal antibodies againstH. pyloriLPS, antigenic heterogeneity between the different LPS preparations tested was confirmed.     

Immunologic analysis of monoclonal and immunoglobulin E antibody epitopes on natural and recombinant Amb a 1

Background Amb a 1 is the major allergen from ragweed pollen and more than 90% of ragweed‐allergic patients react with this protein. Although Amb a 1 was cloned and sequenced in 1991, little is known of the specificity of anti‐Amb a 1 antibodies or of the immunologic properties of the recombinant allergen. Objective To compare binding of monoclonal antibodies (mAb) and IgE antibodies to purified natural Amb a 1 (nAmb a 1) and recombinant Amb a 1 (rAmb a 1). Methods Binding of a panel of anti‐Amb a 1 mAb and IgE antibodies to nAmb a 1 or rAmb a 1 was compared by immunoblotting. Chimeric ELISA was used to measure specific IgE to these allergens using 89 ragweed‐allergic sera from Austria, Italy, Canada and the United States. Results The 8 mAb bound to a 38 kDa Amb a 1 band in ragweed pollen extract and a subset of 5 mAb also bound to the 26 kDa chain of nAmb a 1. A two‐site ELISA was developed using a mAb pair, which was ～10‐fold more sensitive to rAmb a 1. There was a significant correlation between IgE antibody binding to nAmb a 1 and rAmb a 1 (n=89, r=0.79, P<0.001). A subset of ～40% of patients showed greater reactivity to nAmb a 1 than to rAmb a 1. Conclusions The data suggest that there is less reactivity of human IgE to rAmb a 1 compared with nAmb a 1. The development of more sensitive, quantitative ELISA for Amb a 1 will require the production of new mAb especially directed against nAmb a 1.     

Evaluation of atopy by antigen specific IGE antibody]

BACKGROUND: Atopy is usually defined as the genetic propensity to produce IgE antibodies (Abs) specific to common environmental allergens. The aim of this study was to evaluate impacts of the number of allergens examined on prevalence of atopy. METHODS: Subjects comprised 116 healthy controls, 104 patients with asthma, 294 patients with COPD, 64 patients with sarcoidosis and 218 residents of Kamishihoro town. Total serum immunoglobulin E and antigen-specific IgE antibody levels for 26 common allergens were examined. Atopy was defined as positive IgE Abs specific to > or =1 allergen. We serially increased the number of allergens to define atopy from the most common allergens in order of frequency, and changes in prevalence of atopy were evaluated. In residents of Kamishihoro, betula pollen antigen was also examined, as this antigen is very common in the town. RESULTS: The increasing prevalence of atopy was dramatically reduced relative to the number of allergens examined. Among residents of Kamishihoro town, 5 cases displayed specific IgE Abs to this allergen alone and prevalence of atopy was increased 2.3 percents. CONCLUSION: When atopy was defined as the production of specific IgE Abs to common allergens, roughly 10 of the most common allergens may cover common environmental allergens.