R. Valenta

Common epitopes of birch pollen and apples--studies by western and northern blot.

Eighty-three sera from patients with birch-pollen allergy were investigated for IgE antibodies against apple allergens by means of immunoblotting. In immunoblots, 81 patients (97.6%) exhibited IgE directed against the major allergen of birch, Bet v I (17 kd), and these patients also demonstrated IgE binding to apple allergens in the molecular weight range 17 to 18 kd. Inhibition studies by preincubation of sera with birch-pollen extract led to complete blocking of IgE binding to this 17 to 18 kd protein, whereas preincubation with apple extract could not diminish IgE binding to Bet V I. Furthermore, a 17 kd protein in apple extract could be detected by immunoblotting with a Bet v I-specific monoclonal antibody. Northern blotting with a Bet v I cDNA clone as a probe revealed cross-hybridization of birch and apple allergen coding nucleic acids under conditions of high stringency, suggesting significant homology of the nucleic acid level. Our results support the concept that antigens in birch pollen and apples share allergenic epitopes leading to IgE cross-reactivities that may cause clinical manifestations when a special threshold level of specific IgE antibodies is reached.

Practical guide to skin prick tests in allergy to aeroallergens

To cite this article: Bousquet J, Heinzerling L, Bachert C, Papadopoulos NG, Bousquet PJ, Burney PG, Canonica GW, Carlsen KH, Cox L, Haahtela T, Lodrup Carlsen KC, Price D, Samolinski B, Simons FER, Wickman M, Annesi‐Maesano I, Baena‐Cagnani CE, Bergmann KC, Bindslev‐Jensen C, Casale TB, Chiriac A, Cruz AA, Dubakiene R, Durham SR, Fokkens WJ, Gerth‐van‐Wijk R, Kalayci O, Kowalski ML, Mari A, Mullol J, Nazamova‐Baranova L, O’Hehir RE, Ohta K, Panzner P, Passalacqua G, Ring J, Rogala B, Romano A, Ryan D, Schmid‐Grendelmeier P, Todo‐Bom A, Valenta R, Woehrl S, Yusuf OM, Zuberbier T, Demoly P. Practical guide to skin prick tests in allergy to aeroallergens. Allergy 2012; 67: 18–24.

Efficacy of recombinant birch pollen vaccine for the treatment of birch-allergic rhinoconjunctivitis

BACKGROUND Recombinant DNA technology has the potential to produce allergen-specific immunotherapy vaccines with defined composition. OBJECTIVE To evaluate the effectiveness of a new recombinant birch pollen allergen vaccine in patients with birch pollen allergy. METHODS A multicenter, randomized, double-blind, placebo-controlled trial was undertaken to compare the following 3 vaccines in 134 adults with birch pollen allergy: recombinant birch pollen allergen vaccine (rBet v 1a), licensed birch pollen extract, natural purified birch pollen allergen (nBet v 1), and placebo. Patients received 12 weekly injections followed by monthly injections of the maintenance dose containing 15 microg Bet v 1 for 2 years. RESULTS Significant reductions (about 50%) in rhinoconjunctivitis symptoms (rBet v 1, P = .0002; nBet v 1, P = .0006; birch extract, P = .0024), rescue medication (rBet v 1, P = .0011; nBet v 1, P = .0025; birch extract, P = .0063), and skin sensitivities (P < .0001) were observed in the 3 actively treated groups compared with placebo during 2 consecutive pollen seasons. Clinical improvement was accompanied by marked increases in Bet v 1-specific IgG levels, which were higher in the rBet v 1-treated group than in the birch and nBet v 1-treated groups. New IgE specificities were induced in 3 of 29 patients treated with birch pollen extract, but in none of the 32 rBet v 1-treated or 29 nBet v 1-treated patients. No severe systemic adverse events were observed in the rBet v 1-treated group. CONCLUSION The rBet v 1-based vaccine was safe and effective in treating birch pollen allergy, and induced a highly specific immune response.

Clinical effects of immunotherapy with genetically modified recombinant birch pollen Bet v 1 derivatives

Background Birch pollen and pollen from related trees of the Fagales order are a major cause of allergic rhinitis, conjunctivitis, and asthma through the spring season in northern and central Europe.

Important research questions in allergy and related diseases: nonallergic rhinitis: a GA2LEN paper

 Nonallergic rhinitis (NAR) can be defined as a chronic nasal inflammation which is not caused by systemic IgE‐dependent mechanisms. It is common and probably affects far more than 200 million people worldwide. Both children and adults are affected. However, its exact prevalence is unknown and its phenotypes need to be evaluated using appropriate methods to better understand its pathophysiology, diagnosis and management. It is important to differentiate between infectious rhinitis, allergic/NAR and chronic rhinosinusitis, as management differs for each of these cases. Characterization of the phenotype, mechanisms and management of NAR represents one of the major unmet needs in allergic and nonallergic diseases. Studies on children and adults are required in order to appreciate the prevalence, phenotype, severity and co‐morbidities of NAR. These studies should compare allergic and NAR and consider different age group populations including elderly subjects. Mechanistic studies should be carried out to better understand the disease(s) and risk factors and to guide towards an improved diagnosis and therapy. These studies need to take the heterogeneity of NAR into account. It is likely that neuronal mechanisms, T cells, innate immunity and possibly auto‐immune responses all play a role in NAR and may also contribute to the symptoms of allergic rhinitis.

Microarrayed recombinant allergens for diagnosis of allergy

We suggest that the coapplication of recombinant allergens and microarray technology can lead to the development of new forms of multi‐allergen tests which allow the determining and monitoring of complex sensitization profiles of allergic patients in single assays. The allergen extracts which have so far been used for diagnosis only allowed the determining of whether an allergic patient is sensitized against a particular allergen source, but the disease‐eliciting allergens could not be identified. Through the application of recombinant DNA technology a rapidly growing panel of recombinant allergen molecules has become available which meanwhile comprises the epitope spectrum of most of the important allergen sources. We demonstrate that microarray technology can be used to establish multi‐allergen tests consisting of microarrayed recombinant allergen molecules. Microarrayed recombinant allergens can be used to determine and monitor the profile of disease‐eliciting allergens using single tests that require minute amounts of serum from allergic patients. The wealth of diagnostic information gained through microarray‐based allergy testing will likely improve diagnosis, prevention and treatment of allergy.

Factors responsible for differences between asymptomatic subjects and patients presenting an IgE sensitization to allergens. A GA2LEN project

The synthesis of allergen‐specific IgE is required for the development of allergic diseases including allergic rhinitis and allergic asthma (patients), but many individuals with allergen‐specific IgE do not develop symptoms (asymptomatic subjects). Differences may exist between asymptomatic subjects and patients. Whether the presence of allergen‐specific IgE translates into clinical allergy most likely depends on a complex interplay of multiple factors. These include a family history of atopy, the levels of total serum IgE and, allergen‐specific IgE or IgG, epitope‐specificity of IgE and their degree of polyclonality (mono‐ vs polysensitized), as yet unidentified serum factors, the balance of T regulatory cells (Treg) and Th1/Th2 cells, the polymorphisms of the high affinity receptor for IgE (FcɛRI) and other factors regulating the activation of FcɛRI‐bearing cells. Asymptomatic subjects may be more often monosensitized than patients who may be more often polysensitized. There are many unanswered important questions that need to be addressed in order to better understand how IgE sensitization translates into clinical allergy. The assessment of differences between the asymptomatic and symptomatic groups of subjects represent one of the scientific programs of Global Allergy and Asthma European Network funded by the European Union and the hypotheses underlying these differences are presented in this paper.

Variability of IgE reactivity profiles among European mite allergic patients

Background  House dust mites (HDM) Dermatophagoides pteronyssinus are a frequent indoor allergen source. Our aim was to determine the frequencies of IgE reactivity to purified HDM allergen molecules in mite allergic patients from different parts of Europe in order to establish an allergen panel for diagnosis of HDM allergy.

Natural latex, grass pollen, and weed pollen share IgE epitopes

BACKGROUND Because of the frequent use of natural latex products, IgE-mediated reactions to latex proteins represent an important health threat in industrialized countries. Although several latex allergens have been characterized and IgE cross-reactivities with allergens present in plant-derived food have been described, limited information is available regarding the presence of common IgE-binding components in latex and plant pollen. METHODS By using serum IgE from 56 individuals with latex allergy, the IgE-binding components in ammoniated latex milk and latex glove extracts were characterized by immunoblotting. The presence of cross-reactive IgE-binding components in the different latex extracts, extracts from mugwort, ragweed, timothy grass pollen, and recombinant birch pollen allergens (Bet v 1 and Bet v 2 [birch profilin]) was studied by immunoblot inhibitions and quantitative competition experiments. The involvement of carbohydrates in the constitution of cross-reactive IgE epitopes was studied by periodate treatment of extracts. RESULTS Although sera from certain individuals with latex allergy showed IgE reactivity with protein bands of different molecular weights in Western-blotted latex milk and glove extracts, both extracts contained common IgE epitopes. Although preincubation with recombinant Bet v 1 and Bet v 2 did not significantly inhibit IgE binding to latex proteins, weed and, in particular, timothy grass pollen extract strongly inhibited IgE binding to latex allergens. The cross-reactive IgE epitopes were sensitive to periodate treatment. CONCLUSIONS Mugwort, ragweed, and timothy grass pollen share IgE epitopes with glycoprotein latex allergens. The presence of common epitopes might in part explain clinical symptoms in patients allergic to pollen on contact with latex.

Recombinant allergens for allergen-specific immunotherapy: 10 years anniversary of immunotherapy with recombinant allergens

To cite this article: Valenta R, Linhart B, Swoboda I, Niederberger V. Recombinant allergens for allergen‐specific immunotherapy: 10 years anniversary of immunotherapy with recombinant allergens. Allergy 2011; 66: 775–783.