The North-Western area of the Milan Province is the zone most infested by ragweed in Italy and one of the zones most infested in Europe. In 1999 the Lombardy Region promulgated the first measures to prevent the spread of the plant and the production of its pollen, to protect the citizen’s health. These measures included the functions of the Local Health Authority (LHA) in the management of the problem.

Since 2000, as LHA we have developed and improved our management strategy, a set of primary prevention actions: epidemiological study, assessment of direct health costs due to ragweed, studies on methods to limit the ragweed spreading, information, awareness and education of the Public Authority and the population, control of the territory (including aerobiological monitoring, surveillance of infested areas and town planning).

Several epidemiological studies were carried–out, demonstrating the increased prevalence of ragweed allergy and ragweed as main cause of pollinosis in the area. These studies are tools to quantify the impact on health, to point out the necessity to adopt a management strategy, to monitor its efficiency and the necessity to improve it.

During 2013, the beetle Ophraella communa was observed feeding on ragweed plants, with an impressive “herbicide-like” effect and a parallel decrease in the ragweed airborne pollen levels and a reduction of the new allergic patients. Studies are in progress to assess the long term effects of this beetle on concentrations of airborne ragweed pollen and the possibility to use it as management of ragweed. It would be important to implement a mandatory system of the allergy diseases data in all of Europe, including information on the kind of allergy and the prescribed drugs, in order to know in “real time” the epidemiological situation of the allergies, avoiding ad-hoc expensive studies.

Our management strategy reached a good outcome, because it is based on the collaboration at local and international levels.

This paper presents the main outcomes of the Atopica WP1, whose main goals are to:

1) Review available climate variability and change information over Europe relevant to the generation of pollen and produce targeted simulations, as needed by the project.

2) Identify climate conditions that are particularly conducive to high pollen concentrations

3) Provide climate information for assessment of uncertainties in pollen estimates

At the interannual variability level, one of the main outcomes of WP1 was the identification of seasonal climate variables which are tied to high pollen concentrations over the Southeastern Europe "hot-spot" (specifically, Croatia and Hungary). This was achieved through cross correlation analysis between climate (temperature, precipitation) and pollen data at Croatian and Hungarian stations. A climate/pollen index was identified involving temperature and precipitation conditions in the pre and peak pollen seasons (June-July, and August-September, respectively). This index shows that high pollen amounts are tied to wet/cool conditions in the pre-pollen season and hot-dry conditions during the peak season. It is envisioned that this index can be used for seasonal prediction of pollen amounts over the region based on seasonal climate forecasts.

Concerning future climate projections, in line with previous generations of models, also the CMIP5 ensemble shows that the central and southern European regions are expected to become substantially warmer and drier, with this signal being more pronounced with increasing greenhouse gas concentrations. The Atopica pollen simulations show that these conditions generally lead to increased pollen amounts. In fact, in the ICTP model we find a near-linear relationship between temperature and pollen changes when averaged over the central and southern European regions, at least for the scenarios (RCP4.5 and RCP8.5) and time slices (2021-2040, 2041-2060) analyzed in Atopica. This relationship is important because it has the potential to provide first order information on the uncertainties associated with varying future climate projections, and an example of this use is provided in the presentation.

In order to investigate the impact of climate and land use changes on airborne ragweed pollens, two modeling suites have been set up. They include an ecological model aiming at simulating and predicting the evolution of the ragweed plant establishment climate suitability. Together with land use changes and with a simplified model of seed diffusion, this allowed to provide several scenarios of the plant density in the future. Two production, emission and dispersion models then allow to estimate the expected changes in airborne pollens. The talk will describe methodologies and uncertainties of such a modeling, and preliminary results.

Populations across Europe are ageing, with already more than 18% of European citizens enjoying age 65 or beyond. While allergies are afflicting an increasing percentage of children and young adults, and pose a burden on quality of life and productivity as well as treatment cost, data on prevalence and morbidity of allergic diseases in the aged are scarce. Total serum level of the allergen-reactant IgE decrease with age, but prevalence of sensitisation to indoor or outdoor allergens in the aged are not well established. Neither have large studies been directed at assessing the benefit of therapies such as desensitisation or antihistamines in the aged. Hospital admission rates for severe respiratory diseases and asthma increase in the elderly, and the importance of certain allergens may shift, as has been demonstrated in food allergy, where factors such as usage of drugs decreasing stomach acidity may be linked to food allergy to celery in the aged.

Atopica scientists employed southern Germany as a model region, with one fifth of the population at age 65 or beyond, and with Ambrosia having just started to invade within the last decade, to study (I) whether allergies pose a burden on the aged, and (II) whether the aged immune system can react to newly encountered allergens, such as Ambrosia. Studying aged people from 60 to 89 years they found that while sensitisation decreases with age, rhinoconjunctivitis, eczema and asthma do affect more than a fifth of even the oldest age group (80 to 89years-old). While birch pollen allergy, and especially hay fever, is the most common allergy observed in the aged as in the young, weeds such as mugwort, and cat dander are also of high importance. Even though more than 95% of the aged studied do venture outdoors daily, the indoor allergen house dust mite is the second most important allergen.

Ambrosia is an important allergen in a sizeable subgroup of allergic subjects in this age group, mostly in those sensitised to the native plant mugwort, whose allergens may induce antibodies cross-reacting with ambrosia pollen allergens. In the Atopica project, however, it was established that true de novo sensitisation to ambrosia may also occur in the aged. Depending on the age group (60-69yrs, 70-79yrs, 80-89yrs) to 3 percent of all aged subjects studied exhibited ambrosia sensitisation, some also already suffering from symptoms. This demonstrates that even the very aged are susceptible to acquire new sensitisations and allergies, if exposed to new allergens.

Ambrosia artemisiifolia (common ragweed) is a highly invasive plant with pollen that causes severe allergy and is spreading rapidly in Europe. To further study the allergen response to Ambrosia, we sought to establish an experimental animal model of Ambrosia-induced allergic disease. We administered commercially available pollen intranasally to laboratory mice over a period of up to 21 days. We then evaluated allergic responses. Groups of mice receiving intranasal ragweed pollen had severe allergic airway and lung inflammation, mucus hypersecretion and high levels of ragweed-specific antibodies. We observed that the administration of increasing doses of ragweed pollen induced a dose-dependent allergic response. This experimental mouse model provides novel opportunities to study allergic disease caused by pollens. For example, studies indicate that air pollutants like diesel particles have allergen amplifying effects and that allergenic pollens respond to climate changes such as extreme temperatures, changes in humidity, low pH and pollution. To determine whether environmental changes influence an allergen’s ability to cause more severe allergic disease, we investigated pollens from urban and rural regions in Austria and also studied pollens that were environmentally-modified in the laboratory. We found that there is a correlation between severity of allergic asthma and pollens from areas of high air pollution compared with those from rural areas. However, this was not replicated in the laboratory when the pollens were treated to diverse environmental conditions. To date, no changes in pH, temperature and exposure to diverse pollutants did not result in pollens becoming more allergenic. In conclusion, our pollen allergic asthma mouse model is useful and further studies are necessary to elucidate the mechanisms underlying how environmental changes influence ragweed allergy in animal models and in humans.

Atopy is an IgE-mediated clinical condition, characterized by hypersensitivity reaction to allergenes. The interplay between genetics and environmental factors in determining this condition is not fully elucidated. As partners of the ATOPICA project we are exploring how epigenetic landscape can be affected by environmental and pollen pressure leading to atopy development in European populations of different age groups. In particular, we present here the analysis of a well-characterized pediatric Croatian cohort recruited in the urban area of the Slavonia region, 4 to 9 years of age,and German cohort with elderly patients.Children underwent skin prick test (SPT) to a standard palette of inhaled agents (birch, hazel, grasses mix, ragweed, dog hair, cat dander, D. pteronyssinus, cladosporium) to determine their sensitization profile. Pollen concentration data in the recruitment area were also monitored. Blood samples were collected and processed for both DNA and RNA extraction; total IgE count was assessed. We performed whole-genome DNA methylation analysis on 59 unsensitized (control, negative SPT) and 57 sensitized children samples using methylated DNA immunoprecipitation technique (meDIP) coupled with next-generation sequencing. Data analyses revealed 591 differentially methylated regions (uncorrected p value<0.0005). Functional enrichment analysis of associated genes suggests regulation of pathways related to atopy and Th2 cell differentiation, immune system response-regulating signaling, such as MAP kinases, Toll-like receptors and NGF signaling pathways. In other analysis (German cohort),very similar but not identical results we obtained. The global pathway analisys show very similar results we found previously in Croatian cohort: immunological process,in particularly regulation of T or NK and again process regarding cell adhesion linked to DMR we found. The KIR2 are family of genes found in both male and female population. This genes are associated with function of natural killer lymphocyte,but until now not associated atopy syndrome. These candidate loci are currently being validated to confirm methylation status at single base-resolution and expression profile will be also assessed. Integration of those results with pollen and clinical data will provide an unprecedented assessment of the atopic and allergic phenotype in pediatric and elderly European population.

Atopica has aimed to better understand, and where possible to quantify, the key influences on the risk of allergic disease across Europe due to ragweed. In order to do this, we have had to consider physical environmental factors (climate, land cover, pollen and air quality) and human biology, together with socioeconomic factors and policy. The latter are important as they affect human behaviour, social conditions and medical interventions. Thus we have had to take a truly multi- and interdisciplinary approach involving climate scientists, plant and pollen experts, clinicians and statisticians. This has been both challenging and exciting.

It has been exciting in terms of the new insights coming from integrating the multiple sources of evidence. In particular, it has allowed us to consider how the risk of allergic disease may change across Europe over the next few decades (specifically the near-future 2021-2040, and the far future, 2041-2060).

The challenges have come from having to develop an understanding of the technical jargon used by different disciplines, but more importantly in trying to integrate the very different types of data and information produced by the various project teams. How for example, can we combine information from the daily diaries for Croatian children recorded in their homes in 2013 and 2014 with climate model projections which provide information averaged over 50 km grid squares for 1985-2060?

Each step of our analysis is based on a number of underlying assumptions and there are inevitably uncertainties which cascade through the integrated assessment. These include issues relating to the ability of dynamical climate models to simulate regional climate, lack of observed data for calibrating and validating our models (a particular issue for pollen data), gaps in our understanding of some processes (e.g., what influences the allergenicity of pollen?) and biases in our data (e.g., due to limited spatial sampling, or the ability of people to recall their medical history). By being transparent about our assumptions and uncertainties, we are better placed to draw robust messages from our work which will help to inform European decision makers and policy makers on how to respond to changing risks in ragweed-related allergic disease.