Defining pollen exposure times for clinical trials of allergen immunotherapy for pollen-induced rhinoconjunctivitis - an EAACI position paper.

BACKGROUND: Clinical efficacy of pollen allergen immunotherapy (AIT) has been broadly documented in randomized controlled trials. The underlying clinical endpoints are analysed in seasonal time periods predefined based on the background pollen concentration. However, any validated or generally accepted definition from academia or regulatory authorities for this relevant pollen exposure intensity or period of time (season) is currently not available. Therefore, this Task Force initiative of the European Academy of Allergy and Clinical Immunology (EAACI) aimed to propose definitions based on expert consensus. METHODS: A Task Force of the Immunotherapy and Aerobiology and Pollution Interest Groups of the EAACI reviewed the literature on pollen exposure in the context of defining relevant time intervals for evaluation of efficacy in AIT trials. Underlying principles in measuring pollen exposure and associated methodological problems and limitations were considered to achieve a consensus. RESULTS: The Task Force achieved a comprehensive position in defining pollen exposure times for different pollen types. Definitions are presented for 'pollen season', 'high pollen season' (or 'peak pollen period') and 'high pollen days'. CONCLUSION: This EAACI position paper provides definitions of pollen exposures for different pollen types for use in AIT trials. Their validity as standards remains to be tested in future studies.

Spatial and temporal variations in airborne Ambrosia pollen in Europe.

The European Commission Cooperation in Science and Technology (COST) Action FA1203 "SMARTER" aims to make recommendations for the sustainable management of Ambrosia across Europe and for monitoring its efficiency and cost-effectiveness. The goal of the present study is to provide a baseline for spatial and temporal variations in airborne Ambrosia pollen in Europe that can be used for the management and evaluation of this noxious plant. The study covers the full range of Ambrosia artemisiifolia L. distribution over Europe (39°N-60°N; 2°W-45°E). Airborne Ambrosia pollen data for the principal flowering period of Ambrosia (August-September) recorded during a 10-year period (2004-2013) were obtained from 242 monitoring sites. The mean sum of daily average airborne Ambrosia pollen and the number of days that Ambrosia pollen was recorded in the air were analysed. The mean and standard deviation (SD) were calculated regardless of the number of years included in the study period, while trends are based on those time series with 8 or more years of data. Trends were considered significant at p < 0.05. There were few significant trends in the magnitude and frequency of atmospheric Ambrosia pollen (only 8% for the mean sum of daily average Ambrosia pollen concentrations and 14% for the mean number of days Ambrosia pollen were recorded in the air). The direction of any trends varied locally and reflected changes in sources of the pollen, either in size or in distance from the monitoring station. Pollen monitoring is important for providing an early warning of the expansion of this invasive and noxious plant.

Geographic and temporal variations in pollen exposure across Europe.

BACKGROUND: The EC-funded EuroPrevall project examined the prevalence of food allergy across Europe. A well-established factor in the occurrence of food allergy is primary sensitization to pollen. OBJECTIVE: To analyse geographic and temporal variations in pollen exposure, allowing the investigation of how these variations influence the prevalence and incidence of food allergies across Europe. METHODS: Airborne pollen data for two decades (1990-2009) were obtained from 13 monitoring sites located as close as possible to the EuroPrevall survey centres. Start dates, intensity and duration of Betulaceae, Oleaceae, Poaceae and Asteraceae pollen seasons were examined. Mean, slope of the regression, probability level (P) and dominant taxa (%) were calculated. Trends were considered significant at P < 0.05. RESULTS: On a European scale, Betulaceae, in particular Betula, is the most dominant pollen exposure, two folds higher than to Poaceae, and greater than five folds higher than to Oleaceae and Asteraceae. Only in Reykjavik, Madrid and Derby was Poaceae the dominant pollen, as was Oleaceae in Thessaloniki. Weed pollen (Asteraceae) was never dominant, exposure accounted for >10% of total pollen exposure only in Siauliai (Artemisia) and Legnano (Ambrosia). Consistent trends towards changing intensity or duration of exposure were not observed, possibly with the exception of (not significant) decreased exposure to Artemisia and increased exposure to Ambrosia. CONCLUSIONS: This is the first comprehensive study quantifying exposure to the major allergenic pollen families Betulaceae, Oleaceae, Poaceae and Asteraceae across Europe. These data can now be used for studies into patterns of sensitization and allergy to pollen and foods.

A method to derive vegetation distribution maps for pollen dispersion models using birch as an example.

Detailed knowledge of the spatial distribution of sources is a crucial prerequisite for the application of pollen dispersion models such as, for example, COSMO-ART (COnsortium for Small-scale MOdeling-Aerosols and Reactive Trace gases). However, this input is not available for the allergy-relevant species such as hazel, alder, birch, grass or ragweed. Hence, plant distribution datasets need to be derived from suitable sources. We present an approach to produce such a dataset from existing sources using birch as an example. The basic idea is to construct a birch dataset using a region with good data coverage for calibration and then to extrapolate this relationship to a larger area by using land use classes. We use the Swiss forest inventory (1 km resolution) in combination with a 74-category land use dataset that covers the non-forested areas of Switzerland as well (resolution 100 m). Then we assign birch density categories of 0%, 0.1%, 0.5% and 2.5% to each of the 74 land use categories. The combination of this derived dataset with the birch distribution from the forest inventory yields a fairly accurate birch distribution encompassing entire Switzerland. The land use categories of the Global Land Cover 2000 (GLC2000; Global Land Cover 2000 database, 2003, European Commission, Joint Research Centre; resolution 1 km) are then calibrated with the Swiss dataset in order to derive a Europe-wide birch distribution dataset and aggregated onto the 7 km COSMO-ART grid. This procedure thus assumes that a certain GLC2000 land use category has the same birch density wherever it may occur in Europe. In order to reduce the strict application of this crucial assumption, the birch density distribution as obtained from the previous steps is weighted using the mean Seasonal Pollen Index (SPI; yearly sums of daily pollen concentrations). For future improvement, region-specific birch densities for the GLC2000 categories could be integrated into the mapping procedure.

[National Observation Network for Air Pollutants. Measurements up to now--planned extensions]. / Nationales Beobachtungsnetz für Luftfremdstoffe (NABEL). Bisherige Messungen--geplante Erweiterungen.

Since 6 years a Swiss national emission monitoring network measures several air pollutants (sulfur dioxide, nitrogen oxides, ozone, carbon monoxide, suspended particulates, particle deposition and precipitations) at 8 sites with different pollution levels (Dübendorf, Zürich, Basel, Sion, Payerne, Lugano, Tänikon, Jungfraujoch). The emission concentrations of sulfur dioxide, nitrogen dioxide and ozone exceed the limit values proposed by federal legislation at several sites, though the monitoring stations are not located at sites with extreme exposure. At present the network is extended for two or three new stations in forests as a part of a Swiss research programme concerning air pollution and forest damages. A further extension of the NABEL will comprise improvements of the measuring programme at the existing stations as well as new stations.

[Effect of climatic changes on the phenology of plants and the presence of pollen in the air in Switzerland]. / Influence du changement climatique sur la phénologie des plantes et la présence de pollens dans l'air en Suisse.

The phenologic observations carried out in Switzerland since 1951 show a clear tendency to the earlier appearance of the spring phases of development of the vegetation during last decades. As these phases are strongly influenced by the temperature, these results reinforce the hypothesis according to which the climatic reheating in progress strongly influences the development of the vegetation. The flowering and the release of the pollen of the plants allergens are significant phenologic phases for human health. Modifications in their dates of manifestation lead to a displacement of the periods of allergic risk. The analysis of the aerobiologic data of the Swiss stations over one duration of more than 20 years showed that the species which flower in winter and in spring were subject to the influence of the soft winters of the years 1990 to 2000. In certain areas the pollen of birch, for example, is nowadays waited on average 3 weeks earlier than 20 years ago, whereas the pollen of ash appears with one month in advance. The phenologic and aeropalynologic studies thus prove sensitive witnesses of the climatic change in progress. This last intervenes like an indirect but significant component of human health, in particular when the field of the allergies is considered.

[Ambrosia pollen in Switzerland--produced locally or transported?]. / Pollen d'ambroisie en Suisse: production locale ou transport?

The ambrosia (Ambrosia artemisiifolia L.) has been announced in Switzerland for more than 100 years. During the last decade, signs of an increased presence of the ambrosia and its pollen appear in the south-west of Switzerland, in particular in Geneva. Aerobiologic measurements make it possible to highlight the importance of the transport of pollen by the winds since the area of Lyon, where the ambrosia is abundant. It also bring elements making it possible to detect a local production of pollen in the Geneva area, where several invaded fields were discovered with the autumn 2001. A multidisciplinary group was created in Geneva and it attempts to prevent as far as possible probable invasion of the ambrosia.

On source identification and alteration of single diesel and wood smoke soot particles in the atmosphere; an X-ray microspectroscopy study.

Diesel and wood combustion are major sources of carbonaceous particles in the atmosphere. It is very hard to distinguish between the two sources by looking at soot particle morphology, but clear differences in the chemical structure of single particles are revealed by C(1s) NEXAFS (near edge X-ray absorption fine structure) microspectroscopy. Soot from diesel combustion has a dominant spectral signature at approximately 285 eV from aromatic pi-bonds, whereas soot from wood combustion has the strongest signature at approximately 287 eV from phenolic carbon bonds. To investigate if it is possible to use these signatures for source apportionment purposes, we collected atmospheric samples with either diesel or wood combustion as a dominant particle source. No spectra obtained from the atmospheric particles completely matched the emission spectra. Especially particles from the wood dominated location underwent large modifications; the phenolic spectral signature at approximately 287 eV is greatly suppressed and surpassed by the peak attributed to the aromatic carbon groups at approximately 285 eV. Comparison with spectra from diesel soot samples experimentally aged with ozone show that very fast modification of the carbon structure of soot particles occurs as soon as they enter the atmosphere. Source attribution of single soot particles with microspectroscopy is thus hardly possible, but NEXAFS remains a powerful tool to study aging effects.

[UV exposure in Switzerland: time- and topography-associated factors important for the skin]. / Die-UV-Belastung in der Schweiz: Abhängigkeit von Ort und Zeit und ihre Bedeutung für die Haut.

The intensity of UV-A and UV-B-radiation in Switzerland shows big differences that result from the various altitudes, the season and the time of the day. Additionally the intensity of UV-radiation is influenced by other factors like aerosols, cloudiness and ozone. In higher altitudes there is an additional enhancement by reflection of snow. The most important consequences of the UV-radiation for the population are, however, relevant in spring and summer time during the bathing season and during the late winter season for ski tourists. On a day with a clear sky in summer the UV-radiation can reach maximum values for UV-A of 45 W/m2 and for UV-B of 0.175 W/m2. The ratio of UV-A/UV-B shows an annual course with a maximum in winter of about 500 and a minimum of about 220 in summer. The possible effects on health by extensive UV-exposition are photoageing, skin cancer, inflammation processes and cataract. In Switzerland about 5000 new melanoma cases in men and about 4000 in women occur per year. In contrast to other environmental factors like pollen UV-radiation has the big advantage that the personal exposition can be controlled. Therefore, it is very essential that the general rules of a judicious behaviour such as avoiding the sun at noon, always wearing a hat, shirt and trousers as well as sunglasses with UV-filter are often reiterated.

Responses in the start of Betula (birch) pollen seasons to recent changes in spring temperatures across Europe.

A shift in the timing of birch pollen seasons is important because it is well known to be a significant aeroallergen, especially in NW Europe where it is a notable cause of hay fever and pollen-related asthma. The research reported in this paper aims to investigate temporal patterns in the start dates of Betula (birch) pollen seasons at selected sites across Europe. In particular it investigates relationships between the changes in start dates and changes in spring temperatures over approximately the last 20 years. Daily birch pollen counts were used from Kevo, Turku, London, Brussels, Zurich and Vienna, for the core period from 1982 to 1999 and, in some cases, from 1970 to 2000. The sites represent a range of biogeographical situations from just within the Arctic Circle through to North West Maritime and Continental Europe. Pollen samples were taken with Hirst-type volumetric spore traps. Weather data were obtained from the sites nearest to the pollen traps. The timing of birch pollen seasons is known to depend mostly on a non-linear balance between the winter chilling required to break dormancy, and spring temperatures. Pollen start dates and monthly mean temperatures for January through to May were compiled to 5-year running means to examine trends. The start dates for the next 10 years were calculated from regression equations for each site, on the speculative basis that the current trends would continue. The analyses show regional contrasts. Kevo shows a marked trend towards cooler springs and later starts. If this continues the mean start date will become about 6 days later over the next 10 years. Turku exhibits cyclic patterns in start dates. A current trend towards earlier starts is expected to continue until 2007, followed by another fluctuation. London, Brussels, Zurich and Vienna show very similar patterns in the trends towards earlier start dates. If the trend continues the mean start dates at these sites will advance by about 6 days over the next 10 years. Following this work, amendments will be needed to pollen calendars and local predictive models. It will also be important to assess the implications of earlier seasons for allergy sufferers.

Left-sided stellate ganglion ablation or "rate-controlled" vagal nerve stimulation decreases regional myocardial metabolic impairment during acute ischemia in dogs.

This study was designed to see whether during ischemia a metabolic advantage results with left-sided ablation of the stellate ganglion (SGA), an available clinical technique. Its effects on hemodynamics and regional metabolism during myocardial ischemia were compared with those of electrical stimulation of the left vagus nerve (VS), a nonclinical technique, and those of a control condition (ischemia without intervention). The left anterior descending coronary artery (LADa) of 30 dogs was constricted to reduce blood flow by 50% and then 75% from that before constriction and after autonomic intervention (baseline). Electrocardiogram, left-ventricular (LV) first-time derivative (dP/dt), and systemic, LADa, and LV end-diastolic pressures were continuously recorded. Before and during each constriction, cardiac output and regional myocardial blood flow (by microspheres), blood gas tensions, pH, hemoglobin O2 saturation, lactate, glucose, sodium, and potassium concentrations were measured. During ischemia, SGA and VS each decreased heart rate, myocardial contractility (dP/dt), and filling pressures, the decrease in each variable being greater with VS. Also during ischemia, myocardial O2 delivery and consumption decreased to the same extent in the ischemic zone with VS, but the O2 delivery/consumption ratio was higher only with SGA. In addition, ischemic lactate production was lower with SGA and VS than with no autonomic intervention. It is concluded that left-sided SGA or VS to a heart rate of 80 to 90 beats per minute similarly mitigated metabolic impairment during myocardial ischemia. Although the study was only designed to compare modification of ischemia by two different techniques, the results suggest that ischemic zone O2 delivery/consumption ratio and hemodynamic stability were better with SGA.