Siegfried Jäger

Identification of common allergenic structures in mugwort and ragweed pollen

UNLABELLED Identification of common allergenic structures in mugwort and ragweed pollen. BACKGROUND Despite the rare occurrence of ragweed in Middle Europe, a surprisingly high number of patients allergic to mugwort, a frequently encountered weed, display IgE reactivity against ragweed pollen allergens. OBJECTIVE The aim of this study was to investigate whether the high prevalence of IgE reactivity against ragweed in patients allergic to mugwort is caused by the presence of common allergenic determinants. We also sought to characterize any cross-reactive allergens. METHODS Common allergenic structures in mugwort and ragweed pollen were characterized by qualitative IgE immunoblot inhibition experiments performed with natural allergen extracts and recombinant allergens. The degree of cross-reactivity was estimated by quantitative CAP-FEIA competitions. The clinical significance of cross-reactive IgE antibodies was studied with histamine release experiments and nasal provocation tests. RESULTS Mugwort and ragweed RAST values were significantly correlated in a population of 82 Austrian patients allergic to mugwort. IgE antibodies cross-reacted with allergens of comparable molecular weight that were present in both extracts. By using recombinant birch profilin and specific antisera for IgE inhibition experiments, profilin was identified as one of the cross-reactive components in mugwort and ragweed pollen. Preincubation of sera from patients allergic to mugwort with mugwort extract inhibited IgE binding to ragweed pollen extract greater than 80%. Mugwort and ragweed pollen extract induced comparable histamine release and reduction of nasal air flow in a patient with IgE reactivity against the major mugwort allergen Art v 1. CONCLUSION In addition to profilin, mugwort and ragweed pollen contain a number of cross-reactive allergens, among them the major mugwort allergen Art v 1. Cross-reactive IgE antibodies can lead to clinically significant allergic reactions.

Ragweed (Ambrosia) sensitisation rates correlate withthe amount of inhaled airborne pollen. A 14-year studyin Vienna, Austria

Ragweed pollen have been monitored since 1976 inVienna. Since 1984, the outdoor patients of theallergy department of the ear-nose-and-throatUniversity Clinic underwent both Skin Prick Test andRAST/CAP test with a standard series of commoninhalant allergens, ragweed (Ambrosia elatiorL.) included. Both the ragweed counts and the number of positiveRAST results showed a significant increase by time.Furthermore, a clear correlation between the number ofairborne pollen and the percentage of positiveRAST/CAP results is evident.The immune-response in the Viennese population ofatopic subjects is dependent on the amount of inhaledpollen.

Trends of some airborne tree pollen in the Nordic countries and Austria, 1980—1993

Abstract Long term trends in the occurrence of airborne pollen might help in elucidating the probability or unlikelihood of developments which have been predicted in theory such as global warming or forest decline. We have investigated and compared the trends over a 14 year period (1980–1993) of five selected common tree pollen types (Alnus, Corylus, Betula, Pinus, and Ulmus) from three sites in North Europe (Stockholm, Trondheim, Turku) and one in Central Europe (Vienna) in terms of the start, peak, end, and duration of the season, peak values and annual totals, using data from the European pollen data bank. The existence of trends has been investigated by calculating correlation against years and the statistical significance of the regression lines has been examined at the 5% probability level (p<0.05). A consistent trend in the earlier commencement of the flowering season is observed in all cases, as well as an earlier incidence of peak days. A marked trend to an earlier end of the season was also foun...

Antigens drive memory IgE responses in human allergy via the nasal mucosa.

Background: Natural allergen contact induces an increase of IgE levels and sensitivity but the mechanisms underlying the allergen-specific memory responses are poorly understood. Furthermore, it has not been studied whether allergen exposure affects the molecular reactivity profiles in patients. The aim of this study was to analyze the influence of nasal allergen encounter on the molecular profile and magnitude of memory IgE responses and on systemic sensitivity. Methods: We investigated allergen-specific IgE, IgG subclass and IgM responses to defined allergen molecules (grass pollen: Phl p 1, Phl p 2 and Phl p 5; birch pollen: Bet v 1 and Bet v 2) in allergic patients in response to natural as well as to controlled nasal and dermal allergen exposure. Changes in systemic sensitivity were monitored by skin prick testing and by basophil histamine release experiments. Results: Respiratory antigen exposure boosted IgE levels to a pre-established profile of allergen molecules without inducing significant IgM responses or new IgE specificities in allergic individuals. The importance of the route of allergen contact is demonstrated by an increase of systemic IgE levels and sensitivity after nasal exposure. In vitro sensitisation of basophils with pre- and post-seasonal serum samples suggests an allergen-induced elevation of specific IgE as a cause for the increased allergen-specific sensitivity. Conclusion: The characteristics of the allergen-driven antibody responses indicate a direct activation of an established pool of IgE memory cells with defined specificities as an underlying mechanism. Our finding that nasal allergen contact is a major factor for the boosting of memory IgE and systemic sensitivity may open new therapeutic possibilities.

Ash (Fraxinus excelsior)‐pollen allergy in central Europe:specific role of pollen panallergens and the major allergen of ash pollen, Fra e 1

Background: The role of ash (Fraxinus excelsior) pollen as a cause of spring pollinosis in central Europe has received little attention. It is not clear whether ash pollen is a primary cause of sensitization or whether it is implicated through cross‐sensitization to other pollens.

Airborne olive pollen counts are not representative of exposure to the major olive allergen Ole e 1

Pollen is routinely monitored, but it is unknown whether pollen counts represent allergen exposure. We therefore simultaneously determined olive pollen and Ole e 1 in ambient air in Córdoba, Spain, and Évora, Portugal, using Hirst‐type traps for pollen and high‐volume cascade impactors for allergen.

A numerical model of birch pollen emission and dispersion in the atmosphere. Model evaluation and sensitivity analysis

An evaluation of performance of the System for Integrated modeLling of Atmospheric coMposition (SILAM) in application to birch pollen dispersion is presented. The system is described in a companion paper whereas the current study evaluates the model sensitivity to details of the pollen emission module parameterisation and to the meteorological input data. The most important parameters are highlighted. The reference year considered for the analysis is 2006. It is shown that the model is capable of predicting about two-thirds of allergenic alerts, with the odds ratio exceeding 12 for the best setup. Several other statistics corroborate with these estimations. Low-pollen concentration days are also predicted correctly in more than two-thirds of cases. The model experiences certain difficulties only with intermediate pollen concentrations. It is demonstrated that the most important input parameter is the near-surface temperature, the bias of which can easily jeopardise the results. The model sensitivity to random fluctuations of temperature is much lower. Other parameters important at various stages of pollen development, release, and dispersion are precipitation and ambient humidity, as well as wind direction.

Effect of continuous allergen challenge on clinical symptoms and mediator release in dust-mite-allergic patients.

This study investigated the early, prolonged immediate, and late‐phase reactions of dust‐mite‐sensitive subjects undergoing long‐term challenge in the Vienna challenge chamber (VCC) in terms of clinical symptoms and inflammatory mediator level patterns in nasal lavage fluids. A concentration of 70 ng Der p 1/m3 of air (feces of Dermatopliagoides) was maintained over 8 h in the VCC. To show the clinical impact of this challenge model, the effect of a histamine H1‐receptor antagonist that also has some antiallergic properties (loratadine) was also investigated. The study followed a doubleblind, placebo‐controlled, crossover design. Medication was given orally over 7 days before the provocation at a dose of 10 mg once daily. All 12 patients, whose dust‐mite sensitivity was confirmed by disease history, skin prick test, and RAST, completed the challenge session. The documentation of the chosen parameters was performed every 30 min. Subjective nasal and ocular symptoms were assessed via a visual analog scale of 100 mm. nasal flow was recorded by active anterior rhinomanometry, and mediator release was evaluated with nasal lavages. Clinical aspect: the whole sample population showed a rise of nasal and ocular symptom severity and a nasal flow reduction, which were perceptibly, but not significantly attenuated by active drug treatment. Mediator pattern: in each patient, prostaglandin (PG)D2 and leukotriene (LT)C4 levels peaked within the first 2 h of provocation, PGD2 then moving toward baseline levels, and LTC4 then again rising continuously. Eosinophil cationic protein (ECP) exhibited a constant level increase over the whole provocation period, and tryptase levels did not change significantly. Whereas the area under the curve values of tryptase and ECP were higher in drug‐treated patients than the placebo group, the early PGD, peak occurring during the first two challenge hours seemed to be mitigated by loratadine. These results reveal that there is no link between the clinical symptoms, the drug efficacy, and the released mediators (LTC4, PGD2, ECP and tryptase).

Monitoring, Modelling and Forecasting of the Pollen Season

The section about monitoring covers the development of phenological networks, remote sensing of the season cycle of the vegetation, the emergence of the science of aerobiology and, more specifically, aeropalynology, pollen sampling instruments, pollen counting techniques, applications of aeropalynology in agriculture and the European Pollen Information System. Three data sources are directly related with aeropalynology: phenological observations, pollen counts and remote sensing of the vegetation activity. The main future challenge is the assimilation of these data streams into numerical pollen forecast systems. Over the last decades consistent monitoring efforts of various national networks have created a wealth of pollen concentration time series. These constitute a nearly untouched treasure, which is still to be exploited to investigate questions concerning pollen emission, transport and deposition. New monitoring methods allow measuring the allergen content in pollen. Results from research on the allergen content in pollen are expected to increase the quality of the operational pollen forecasts.

Efficacy and safety relative to placebo of an oral formulation of cetirizine and sustained-release pseudoephedrine in the management of nasal congestion.

Background The aim of this study was to assess the clinical efficacy of an oral formulation of cetirizine 5 mg with sustained‐release pseudoephedrine (PSE) 120 mg relative to placebo in patients with nasal congestion. Methods Twenty‐four patients with perennial rhinitis due to house‐dust‐mite (HDM) allergy were recruited in this crossover study. A treatment period of 1 week, in which cetirizine/PSE was administered twice daily, was followed by a washout period of at least 2 weeks and a further period of 1 week in which the alternative treatment was given to each patient. Immediately after the first dose of each medication (day 1), nasal congestion and related symptoms were assessed during a 7‐h challenge with HDM feces, with the Vienna Challenge Chamber (VCC), to investigate onset of action of the preparation. A second challenge of 3‐h duration, carried out at least 12 h after the final dose, was undertaken after 1 week (mean) of twice‐daily treatment to assess residual effects of the formulation after achievement of steady state.