Description of a novel panallergen of cross-reactivity between moulds and foods

The present investigation is undertaken to demonstrate a novel cross-reactivity between aeroallergens (moulds fungi imperfecti) and allergens from foods (spinach and mushroom Agaricus bisporus). We have performed a dual study in vivo and in vitro, in a population of atopic patients. Data from in vivo tests performed with spinach and mushroom have been statistically analysed. To the in vitro assays, mushroom and spinach extracts have been obtained, and sera from moulds allergic patients analysed by means of IgE-immunoblott assays. Inhibition experiments have been also performed to study a possible relation between proteins. Statistical analysis of data showed a relation between allergenicity to moulds (Alternaria alternata, Cladosporium herbarum and/or Aspergillus fumigatus), and positive skin prick tests with mushroom and/or spinach. The immunoblotts performed showed that seven moulds allergic patients had a strong recognition of a protein with a molecular weight of about 30 kD present both in spinach and mushroom extracts, and by means of inhibition assays we could determine that these two proteins were related. This study demonstrates the existence of a new allergen responsible for cross reactivity between moulds and two frequently consumed foods, mushroom and spinach. We conclude that a novel cross-reactive allergen between aeroallergens and foods has been identified.     

The performance of a component-based allergen-microarray in clinical practice

BACKGROUND: Currently, the diagnosis of IgE-mediated allergy is based on allergen-specific history and diagnostic procedures using natural allergen extracts for in vivo and in vitro tests. OBJECTIVE: The aim of the study was to comparatively analyse a new component-based allergen-microarray and the 'quasi-standard' ImmunoCAP for their clinical relevance in patients with allergic rhinoconjunctivitis to five aeroallergens [house dust mite (HDM), cat dander, birch, grass and mugwort pollen] in a prospective, double-centre study. METHODS: We enrolled 120 subjects at the two study centres. Allergic patients were defined as having an allergen-specific history plus a concomitant positive skin-prick test (SPT) to natural allergen extracts and specific serum IgE was measured by both methods. Each allergen was analysed separately. RESULTS: The microarray performed equally well in receiver-operating characteristic curve (ROC) analyses when compared with the CAP in cat (23 allergic vs 97 non-allergic, ROC area under the curve microarray 0.950 vs CAP 0.894, P = 0.211), birch (31/89, 0.908 vs 0.878, P = 0.483) and grass pollen (47/73, 0.923 vs 0.915, P = 0.770). It was slightly less sensitive in HDM-allergic subjects (26 allergic vs 94 non-allergic, ROC area microarray 0.808 vs CAP 0.911, P = 0.053) and displayed a reduced sensitivity in the mugwort pollen-allergic patients (17/103, 0.723 vs 0.879, P = 0.032). CONCLUSIONS: Component-based testing and the whole-allergen CAP are equally relevant in the diagnosis of grass-, birch- and cat-allergic patients. Although slightly less sensitive, the microarray is sufficient for the diagnosis of HDM-allergic patients, but needs alternative and/or additional components for detecting mugwort allergy.     

Isolation and characterization of the 18-kDa major apple allergen and comparison with the major birch pollen allergen (Bet v I)

The major allergen from birch pollen, Bet v I, and the cross-reacting 18-kDa major allergen from Golden Delicious and Granny Smith apples were isolated by micropreparative SDS-PAGE followed by electroelution. In the case of apples, highly active, low-temperature extracts were used. The purity of the allergens was checked by analytic SDS-PAGE and immunoblotting with allergic patients’ sera, as well as by N-terminal amino acid microsequencing, and the allergens were found to be very pure. The strong immunologic activity of the isolates was determined by the enzyme allergosorbent test (EAST) and EAST inhibition assays; this activity was, in the case of Bet v I, similar to that of a preparation obtained by monoclonal antibody affinity chromatography. The allergenic potency of Bet v I and of the cross-reactive apple allergen was determined by EAST inhibition and dose-related histamine release. With both assay systems, the allergenic reactivity of Bet v I was considerably higher than that of the major apple allergen. Fürthermore, skin prick tests with the purified allergens and with whole allergenic extracts were performed on a group of 33 patients suffering from birch-pollen and apple hypersensitivity, and on a control group of 10 patients. The frequency of positive prick test results in the allergic patient group ranged from 73% for the major allergen from Golden Delicious apples to 97% with Bet v I and whole birch pollen extract, respectively. In contrast to our low-temperature extracts, commercial prick test solutions of four different manufacturers were found to be unreliable for the diagnosis of apple allergy. The skin test results again indicated the strong immunologic activity of the allergen isolates and the predominance of the major allergens in context with birch-pollen and apple hypersensitivity. Taken together, the results support the view that the 18-kDa major allergen represents most of the allergenicity of the the apple fruit, and that all allergenic epitopes of the apple proteins are present on Bet v I.     

Identification of Bet v 1‐related allergens in fig and other Moraceae fruits

Background Allergy to fig fruit (Ficus carica) has been described in patients allergic to Ficus benjamina or rubber latex but may occur also in pollen‐allergic patients. Objective To study the potential cross‐reactivity between fig and taxonomically related fruits with the major birch pollen allergen Bet v 1. Methods One hundred and eighty‐eight patients with or without birch pollen allergy were prick‐to‐prick tested with fig (F. carica), mulberry (Morus alba), jackfruit (Artocarpus heterophyllus; all family Moraceae) and other pollen‐associated foods. Moraceae fruit extracts were separated by SDS‐PAGE and tested with patient sera and polyclonal antisera against Mal d 1. Western blot inhibition was performed with Moraceae fruit extracts, birch pollen and recombinant Bet v 1. Putative Bet v 1 homologs in Moraceae fruits were analysed by liquid chromatography‐ion trap mass spectrometry. Results Among 85 patients with isolated birch pollen allergy, 78% had a positive skin test to fresh fig, 10% to dried fig, 91% to mulberry, 91% to jackfruit, 77% to Rosaceae fruits and 83% to hazelnut. Sixty‐six per cent of birch pollen‐allergic patients positive for fig, reported symptoms after consumption of fresh figs, whereas dried figs were mostly well tolerated. In 60 patients with isolated Ficus benjamina sensitization, the reactivity rates to the same foods were 83‐40‐0‐0‐0‐0%. None of 32 mugwort pollen‐allergic patients reacted to Moraceae fruits. Rabbit anti‐Mal d 1 and patient sera reacted to a 17 kDa band in all Moraceae extracts. IgE binding to these proteins was completely inhibited by birch pollen and rBet v 1. Mass spectrometry identified several peptides from the 17 kDa fig, mulberry and jackfruit allergen with respectively 60%, 56% and 76% homology to Bet v 1. Conclusion Fig and other Moraceae fruits contain allergens homologous to Bet v 1 and represent clinically relevant birch pollen‐associated foods. Cite this as: W. Hemmer, M. Focke, G. Marzban, I. Swoboda, R. Jarisch and M. Laimer, Clinical & Experimental Allergy, 2010 (40) 679–687.     

Effects of IL-4 and IL-13 on total and allergen specific IgE production by cultured PBMC from allergic patients determined with recombinant pollen allergens

Background: Interleukin (IL)-4 and IL-13 have been shown to be potent switch factors for IgE synthesis in human B cells. Objective: In this study we investigated the effects of recombinant human IL-4 and IL-13 on total and allergen specific IgE synthesis by peripheral blood inononuclear colls (PBMC) from pollen allergic patients and healthy control individuals. Methods: Peripheral blood mononuclear cells (PBMC) from allergic patients were investigated for their capacity to produce allergen specific IgE in vitro. Total protein extracts from birch pollen and timothy grass pollen as well as purified recombinant birch pollen allergens, Bet v I, birch profiling (Bet v II) and recombinant timothy grass pollen allergens. Phi p I, Phi p II, and Phi p V were used to measure specific IgE-antibody synthesis in cell culture supernatants by IgE-immunoblot and ELISA. Reults PBMC obtained from allergic patients spontaneously secreted allergen specific IgE in the culture supernatants. Addition of Interleukin 4, Interleukin 13 and anti-CD40 antibody to the cultures alone or in combinations significantly induced total IgE production whereas allergen specific IgE production was not affected. Conclusion: Our results indicate that the peripheral blood of allergic individuals contains long lived allergen specific B cells which have already switched to IgE production and which are not sensitive to IL-4 and IL-13 treatment. These results may have implications on attempts to use cytokines or cytokine antagonists in therapy of Type I allergy.     

Increased prevalence of sensitization against aeroallergens in adults in West compared with East Germany

Background An increased prevalence of allergic diseases and atopic sensitization as assessed by skin-prick testing in children in West compared with East Germany has been reported. Objectives This study was designed to evaluate whether such a difference is also present in adults, and if this can be shown when using a serological test for allergic sensitization. Methods Two large samples representative for all adults between 25 and 69 years of age were drawn in West (1991, n= 5313) and East Germany (1992, n= 2617). A serological test screening for IgE-antibodies to common aeroallergens (SXI) was performed. A questionnaire was used to assess the presence of clinical respiratory allergy, known possible risk factors for allergies and confounding variables. Results Allergic sensitization decreased with age. Significantly more subjects < 45 years of age had a positive allergy test in West as compared to East Germany. The prevalence of clinical allergy was also higher in West Germany. This difference was significant in younger adults and was independent of other risk factors identified. These additional risk factors encompassed younger age, higher educational level, male sex, and living in a community with more than 100000 inhabitants. Conclusion Sensitization to common aeroallergens as determined by a multiple allergen RAST test in adults below 45 years of age living in West Germany is increased compared to East Germany. This increase cannot be explained by genetic differences and is similar to the West to East decreasing gradient in allergies reported from studies in children employing skin-prick tests.     

Multiple grass mixes as opposed to single grasses for allergen immunotherapy in allergic rhinitis

Grass pollen allergy affects approximately 40% of allergic patients. Subcutaneous allergen immunotherapy (SCIT) is the only allergen‐specific and disease‐modifying treatment available. Currently available therapeutic vaccines for the treatment of grass pollen allergy are based on natural grass pollen extracts which are either made from pollen of one cross‐reactive grass species or from several related grass species. Clinical studies have shown that SCIT performed with timothy grass pollen extract is effective for the treatment of grass pollen allergy. Moreover, it has been demonstrated that recombinant timothy grass pollen allergens contain the majority of relevant epitopes and can be used for SCIT in clinical trials. However, recent in vitro studies have suggested that mixes consisting of allergen extracts from several related grass species may have advantages for SCIT over single allergen extracts. Here, we review current knowledge regarding the disease‐relevant allergens in grass pollen allergy, available clinical studies comparing SCIT with allergen extracts from timothy grass or from mixes of several related grass species of the Pooideae subfamily, in vitro cross‐reactivity studies performed with natural allergen extracts and recombinant allergens and SCIT studies performed with recombinant timothy grass pollen allergens. In vitro and clinical studies performed with natural allergen extracts reveal no relevant advantages of using multiple grass mixes as opposed to single grass pollen extracts. Several studies analysing the molecular composition of natural allergen extracts and the molecular profile of patients' immune responses after SCIT with allergen extracts indicate that the major limitation for the production of a high quality grass pollen vaccine resides in intrinsic features of natural allergen extracts which can only be overcome with recombinant allergen‐based technologies.     

Array-based profiling of ragweed and mugwort pollen allergens

Background: Ragweed (Ambrosia artemisiifolia) and mugwort (Artemisia vulgaris) pollen is the main cause of allergic reactions in late summer and autumn. The differential diagnosis between ragweed and mugwort pollen allergy is a frequent problem encountered by allergologists in areas where both plants are present due to shared antigenic structures and overlapping flowering seasons. Objective: To evaluate the sensitization pattern of weed allergic patients towards a large panel of purified allergens in the microarray format and by enzyme‐linked immunosorbent assay (ELISA). Methods: Eight ragweed and six mugwort pollen allergens were purified from natural source or expressed as recombinant proteins in Escherichia coli. Allergens were spotted on protein microarray slides or coated onto ELISA plates. Sera from 19 ragweed and/or mugwort allergic individuals were used to determine the reactivity towards single molecules in both assays. Results: All ragweed allergic individuals were sensitized to Amb a 1, among them 30% were monosensitized to the major ragweed allergen. Art v 1 and Art v 3 were recognized by 89% of mugwort pollen‐allergic patients. Extensive cross‐reactivity was observed for both patient groups mainly involving the pan‐allergens profilin and nonspecific lipid transfer proteins. Comparable IgE profiles were obtained with both allergen microarray and ELISA methods. Conclusions: Molecule‐based diagnosis provides essential information for the differential diagnosis between ragweed and mugwort pollen allergy and for the selection of the appropriate allergen source for specific immunotherapy.     

Analysis of the allergenic composition of rat dust

Background Allergy to rats is an important occupational health problem. The allergens of rat urine have been well defined but those in rat room dust, a potentially important source of inhalant exposure, have not. Objective To describe the allergens present in rat room dust and to identify a suitable marker protein which may be used to quantify airborne rat allergen. Methods Dust collected from the air-conditioning system (bulk dust, ‘bd’) and with an air sampler (airborne dust, ‘ad’) were analysed by radioallergosorbent test (RAST) inhibition, immunoblotting and immunoblot inhibition techniques and comparisons made with hair and urine extracts prepared from adult male Wistar rats. Results Extensive crossreactivity was found between the extracts by RAST inhibition under different experimental conditions. Dust was more potent as an inhibitor than other extracts. The immunoblotting patterns of both dusts were similar although ‘ad’ contained an allergen at 29kDa not found in ‘bd’. Forty-two sera from rat allergic subjects were used to identify 18 allergens in ‘bd’. Three ‘major’ allergens were found; 100% of subjects had immunoglobulin (Ig)E to a 44 kDa allergen and 74% and 88% of subjects had IgE with bound to the 20.5 and 17 kDa allergens respectively. Immunoblot inhibition experiments identified the 17 kDa dust allergen as α_2u-globulin (Rat nI). Conclusions Rat dust is a complex allergenic source. The 17 kDa dust allergen has immunological identity with Rat nl and is a suitable marker protein for the quantitation of airborne rat allergen.     

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.     

Characterization of Der p 21, a new important allergen derived from the gut of house dust mites

Background: The house dust mite (HDM) Dermatophagoides pteronyssinus is a major allergen source eliciting allergic asthma. The aim of the study was to identify new important HDM allergens associated with allergic asthma. Methods: A cDNA coding for a new mite allergen, designated Der p 21, was isolated using immunoglobulin E (IgE) antibodies from patients with allergic asthma out of a D. pteronyssinus expression cDNA library and expressed in Escherichia coli. Results: Circular dichroism analysis of the purified allergen showed that rDer p 21 (14 726 Da) is one of the few mite allergens with an α‐helical secondary structure. The protein exhibited high thermal stability and refolding capacity, and, as determined by small angle X‐ray scattering, formed a dimer consisting of two flat triangles. rDer p 21 bound high levels of patients’ IgE antibodies and showed high allergenic activity in basophil activation experiments. Rabbit anti‐Der p 21 IgG antibodies inhibited mite‐allergic patients’ IgE binding and allowed the ultrastructural localization of the allergen in the midgut (epithelium, lumen and faeces) of D. pteronyssinus by immunogold electron microscopy. Der p 21 revealed sequence homology with group 5 mite allergens, but IgE and IgG reactivity data and cross‐inhibition studies identified it as a new mite allergen. Conclusions: Der p 21 is a new important mite allergen which is liberated into the environment via faecal particles and hence may be associated with allergic asthma.     

In situ hybridization analysis of ICAM-1 (CD54) mRNA on conjunctival epithelium during allergic inflammation

Background The intercellular adhesion molecule ICAM-1 has been detected by immunohistochemical methods on epithelial cells of the conjunctiva and nose during allergic inflammation. Objective The aim of the present study was to evaluate whether ICAM-1 expression on conjunctival epithelium derives from endogenous synthesis or is merely due to passive uptake of soluble ICAM-1 released from inflammatory cells. Methods In situ hybridization was performed using a 3’end dygoxygenin-labelled specific DNA oligonucleotide probe on fixed conjunctival smears from allergic subjects challenged with, or naturally exposed to the allergen, and from healthy subjects. Immunocytochemistry for ICAM-1 was performed by alkaline phosphatase antialkaline phosphatase. Results Results In allergic patients, both naturally exposed to the allergen and after specific challenge, a clear hybridization pattern on epithelial cells was apparent. Out of allergen exposure, some symptomfree pollinosic subjects, as well as a few healthy volunteers showed mild ICAM-1 mRNA cytoplasmic staining in the absence of immunohistochemically detectable ICAM-1. This finding may explain the very early appearance of ICAM-1 on conjunctival epithelium following specific challenge in allergic individuals. Conclusions These results indicate that the presence of ICAM-1 on conjunctival epithelium during allergic inflammation derives from endogenous synthesis and not from uptake of soluble ICAM-l.     

Aspergillus fumigatus regulates mite allergen‐pulsed dendritic cells in the development of asthma

Background The role in allergic asthma development of the immune response against fungi with concomitant exposure to other common aeroallergens has yet to be determined. In particular, there is little understanding of how inhaled fungi affect the host response to mite allergens. Objective To characterize the in vitro and in vivo effects of concurrent exposure of Aspergillus fumigatus (Af) and Dermatophagoides farinae (Derf) on dendritic cells (DCs) in the development of allergic asthma. Methods Murine bone marrow‐derived DCs were pulsed with Derf and/or live or heat‐inactivated Af. Cytokine production and the expression of pathogen recognition receptors (PRRs) were determined in vitro. Subsequently, these DCs were inoculated into the airway of naïve mice to assess the development of allergic airway inflammation in vivo. The effect of antibodies against PRRs was also evaluated. Results Live Af significantly enhanced IL‐10 production and the expression of Toll‐like receptor (TLR) 2 and Dectin‐1 in Derf‐pulsed DCs. Live Af infection significantly attenuated Derf‐pulsed DC‐induced allergic airway inflammation in vivo. Antibodies against either TLR2 or Dectin‐1 significantly reversed the inhibitory effects of live Af in the development of Derf‐pulsed DC‐induced allergic airway inflammation. Conclusion Concurrent exposure of DCs to fungal antigens has profound influences on the subsequent mite allergen‐induced allergic airway inflammation. Live Af could regulate the functions of airway DCs in the development of mite allergen‐induced allergic airway inflammation via regulation of their PRRs. Our results suggest that concurrent exposure to pathogens such as fungi and mite allergens has profound influences on the subsequent allergen‐induced allergic airway inflammation. Furthermore, modulating PRR signalling could provide a therapeutic regimen for the development of asthma. Cite this as: S. Fukahori, H. Matsuse, T. Tsuchida, T. Kawano, S. Tomari, C. Fukushima and S. Kohno, Clinical & Experimental Allergy, 2010 (40) 1507–1515.     

Adverse reactions to foods.

Allergic reactions to foods represent a prominent, actual and increasing problem in clinical medicine. Symptoms of food allergy comprise skin reactions (urticaria, angioedema, eczema) respiratory (bronchoconstriction, rhinitis), gastrointestinal (cramping, diarrhea) and cardiovascular symptoms with the maximal manifestation of anaphylactic shock. They can be elicited by minute amounts of allergens. The diagnosis of food allergy is done by history, skin test, in vitro allergy diagnosis and--if necessary--oral provocation tests, if possible placebo-controlled. Avoidance of respective allergens for the allergic patient, however, is often complicated or impossible due to deficits in declaration regulations in many countries. Increasing numbers of cases including fatalities, due to inadvertent intake of food allergens are reported. It is therefore necessary to improve declaration laws and develop methods for allergen detection in foods. Allergens can be detected by serological methods (enzyme immunoassays, in vitro basophil histamine release or in vivo skin test procedures in sensitized individuals). The problem of diagnosis of food allergy is further complicated by cross-reactivity between allergens in foods and aeroallergens (pollen, animal epithelia, latex etc.). Elicitors of pseudo-allergic reactions with similar clinical symptomatology comprise low-molecular-mass chemicals (preservatives, colorings, flavor substances etc.). For some of them (e.g. sulfites) detection assays are available. In some patients classic allergic contact eczema can be elicited systemically after oral intake of low-molecular-mass contact allergens such as nickel sulfate or flavorings such as vanillin in foods. The role of xenobiotic components in foods (e.g. pesticides) is not known at the moment. In order to improve the situation of the food allergic patient, research programs to elucidate the pathophysiology and improve allergen detection strategies have to be implemented together with reinforced declaration regulations on a quantitative basis.     

Allergenic reactivity of the melon profilin Cuc m 2 and its identification as major allergen

BACKGROUND: Melon allergy is commonly associated with oral allergy syndrome (OAS) and with hypersensitivity to pollens and other plant foods. No melon allergen responsible for these clinical characteristics has yet been isolated, although profilin has been proposed as a potential target. OBJECTIVE: To isolate natural and recombinant melon profilin, to evaluate its in vivo and in vitro reactivity, and to analyse its behaviour in simulated gastric fluid (SGF) and heat treatments. METHODS: A pool or individual sera from 23 patients, and an additional group of 10 patients, all of them with melon allergy, were analysed by in vitro and in vivo tests, respectively. Natural melon profilin (nCuc m 2) and its recombinant counterpart (rCuc m 2) were isolated by poly-l-proline affinity chromatography, and characterized by N-terminal amino acid sequencing, matrix-assisted laser desorption/ionization analysis, DNA sequencing of cDNAs encoding rCuc m 2, and immunodetection with anti-profilin antibodies. In vitro analysis included IgE immunodetection, specific IgE determination, ELISA-inhibition assays, and histamine release (HR) tests. In vivo activity of nCuc m 2 was established by skin prick testing (SPT). The effect of SGF and heat treatment on rCuc m 2 was followed by immunodetection, ELISA inhibition, and HR assays. RESULTS: Both purified forms of melon profilin were recognized by rabbit anti-profilin antibodies and IgE of sera from allergic patients, and showed molecular sizes typical of the profilin family. nCuc m 2 had a blocked N-terminus, whereas rCuc m 2 rendered the expected N-terminal amino acid sequence, its full protein sequence being highly similar (98--71% identity) to those of profilins from plant foods and pollens. The natural allergen displayed a slightly higher IgE-binding capacity than its recombinant counterpart. Specific IgE to nCuc m 2 and rCuc m 2 was found in 100% and 78% of the 23 individual sera analysed, respectively. nCuc m 2 evoked positive SPT responses in all (10/10) patients tested, and rCuc m 2 induced HR in two out of three sera assayed. SGF treatment readily inactivated rCuc m 2, as shown by its loss of recognition by anti-profilin antibodies, lack of IgE binding, and inability to induce HR. In contrast, heat treatment did not affect the IgE-binding capacity of rCuc m 2. CONCLUSIONS: Profilin is highly prevalent in melon-allergic patients, and promptly inactivated by SGF, as expected for an allergen mainly linked to OAS.     

Discordance between aeroallergen specific serum IgE and skin testing in children younger than 4 years

BackgroundAtopic sensitization to aeroallergens in early life has been found to be a strong risk factor for the development of persisting asthma in young children with recurrent wheeze.ObjectiveTo assess the yield of skin prick test (SPT) compared with allergen specific serum IgE (sIgE) testing at identifying aeroallergen sensitization in atopic children younger than 4 years.MethodsConcordance between SPT and allergen-specific sIgE testing for 7 common aeroallergens was analyzed in 40 atopic inner-city children 18 to 48 months of age (mean [SD], 36 [9] months) with recurrent wheezing and family history of asthma and/or eczema.ResultsIn 80% of children one or more allergen sensitizations would have been missed if only SPT had been performed, and in 38% of children one or more sensitizations would have been missed if only sIgE testing had been performed. Agreement between the SPT and sIgE test was fair for most allergens (κ = ?0.04 to 0.50), as was correlation between sIgE levels and SPT grade (ρ = 0.21 to 0.55). Children with high total sIgE (≥300 kU/L) were more likely to have positive sIgE test results, with negative corresponding SPT results (P = .02).ConclusionOur study revealed a significant discordance between allergen-specific SPT and sIgE testing results for common aeroallergens, suggesting that both SPT and sIgE testing should be performed when diagnosing allergic sensitization in young children at high risk of asthma.Trial Registrationclinicaltrials.gov Identifier: NCT01028560     

Heterogeneity of commercial timothy grass pollen extracts

Background The diagnosis and specific immunotherapy of allergy is currently performed with allergen extracts prepared from natural allergen sources.
Objective To analyse commercial timothy grass pollen allergen extracts used for in vivo diagnosis regarding their qualitative and quantitative allergen composition and in vivo biological activity.
Methods Antibodies specific for eight timothy grass pollen allergens (Phl p 1, Phl p 2, Phl p 4, Phl p 5, Phl p 6, Phl p 7, Phl p 12, Phl p 13) were used to detect these allergens in timothy grass pollen extracts from four manufacturers by immunoblotting. ELISA assays were developed and used to quantify the three major allergens (Phl p 1, Phl p 2, Phl p 5) in the extracts. The magnitude of skin responses to the four extracts was studied by skin prick testing in 10 grass pollen-allergic patients.
Results The allergen extracts showed broad variations in protein compositions and amounts (24.1–197.7 μg/mL extract). Several allergens could not be detected in certain extracts or appeared degraded. A considerable variability regarding the contents of major allergens was found (Phl p 1: 32–384 ng/mL; Phl p 2: 1128–6530 ng/mL, Phl p 5: 40–793 ng/mL). Heterogeneous skin test results were obtained with the extracts in grass pollen-allergic patients.
Conclusions Timothy grass pollen extracts from different manufacturers exhibit a considerable heterogeneity regarding the presence of individual allergens and hence yield varying in vivo test results. Problems related to the use of natural grass pollen allergen extracts may be circumvented by using defined recombinant grass pollen allergens.     

Clinico-immunologic Study on Immunotherapy with Mixed and Single Insect Allergens

Background  Immunotherapy (IT) is practiced mainly with mixed and single allergen vaccines. But studies are rare with mixed allergen preparations. Objective  The objective of this study is to study mix and single insect allergen IT in patients of allergic rhinitis and asthma. Methods  We performed a double-blind placebo-controlled trial of mix and single allergen IT for 1 year in 99 patients of asthma or rhinitis or both. There were two groups, (1) active allergen IT (n = 61) with three subgroups single insect extract (cockroach, housefly, or mosquito) and mix allergen IT (two or three insect extracts) and (2) placebo (n = 38). Clinical (skin reactivity, airway reactivity, and symptom score) and immunological (IgE/IgG4 and IgG1/IgG4 ratio) parameters were assessed at baseline and after 1 year of IT. Results  Eighty-five patients completed 1 year of IT. The active allergen IT group patients showed a significant improvement compared to baseline values (p < 0.05) and placebo group patients (p < 0.05) with regard to symptom scores, FEV1 values, and immunological parameters (IgG4). No significant difference was found between mixed and single IT group patients for changes in clinical and immunological parameters. Positive correlation was observed between increase in IgG4 and clinical improvement. The changes in above parameters in placebo group were nonsignificant after 1 year of treatment. Conclusion  IT with two to three mix extract from the same allergen group is effective for insect hypersensitivity.     

Environmental prevention in atopic eczema dermatitis syndrome (AEDS) and asthma: avoidance of indoor allergens

 Indoor allergens represent an important precipitating factor for both asthma and atopic eczema dermatitis syndromes (AEDS). There is also accumulating evidence that sensitization to those allergens is associated with the onset of atopic disorders. Patients with AEDS present aeroallergen-specific T-cell responses associated with worsening of symptoms when exposed to specific aeroallergens. Furthermore, application of indoor allergens to the skin of patient with AEDS induces a local eczematous response in one-third of these patients. Exposure to high concentrations of mite allergens in early infancy have been demonstrated to be a risk factor for developing atopic dermatitis during the first 3 years of life. Moreover, a clear dose–response relationship has been documented between mite exposure and disease activity. Primary prevention of AEDS by avoiding indoor allergen exposure has been proved to be effective only when allergenic foods have also been avoided. Mite allergen avoidance in infants with AEDS and food allergy may however, prevent mite sensitization and the onset of asthma. Indoor allergen avoidance has been demonstrated to be effective in the majority of studies performed in patients with established AEDS. Negative results may be explained either by individual susceptibility variation, by long duration of disease with the consequent irreversible pathological changes in the target tissue or by exposure to allergens outside the house. Education of the patients and public consciousness of the problems are crucial for the efficacy of indoor allergen avoidance in allergic diseases.