Annual Congress 2022 of the European Academy of Allergy and Clinical Immunology

(Prague, Czech Republic, 1-3 July 2022) The human immune system responds to environmental changes, which can affect health outcomes. A fundamental and critical role of the immune system is to distinguish pathogenic from benign antigens that are present in our environment and test whether they are allergic or tolerogenic, respectively. Humans have dramatically altered the environment since the industrial age. There are currently about 350,000 different types of artificial chemicals sold, which ultimately pollute the air, water, and soil. Some anthropogenic pollutants, such as microplastics, have recently been detected in human tissues,
such as lung, placenta, and blood. We have increased the concentrations of greenhouse gases (carbon-dioxide, methane, nitrous oxides, and fluorinated gases), leading to global warming. Global temperatures have increased by approximately 1.1°C since 1850-1900 and are expected to increase over the next few decades. Climate change and associated drought and water insecurity may lead to increases in pollutants combined with decreases in natural biodiversity which could further worsen immune dysfunction and increases in immunological diseases, like atopic diseases, autoimmune diseases, cancer, and gastroenterological diseases.

Climate change directly or indirectly affects immune health, and this is most evident with allergic diseases such as food allergy, allergic rhinitis, and allergic asthma, which have increased in the last few decades. With climate change, pollen seasons have lengthened, pollen concentrations have increased, and pollen is more widely distributed leading to increased duration and severity of allergic rhinitis and allergic asthma. Climate change is associated with increases in extreme weather events. Rare severe thunderstorms have been linked with asthma exacerbations and increased hospitalizations, a phenomenon termed thunderstorm asthma. In November 2016, a thunderstorm asthma epidemic struck Melbourne, Australia, and overwhelmed health services, leading to loss of lives.

Other extreme events associated with climate change are wildfires, dust storms, and flooding.
Wildfires and dust storms are both associated with increases in fine particulate matter, which can traverse tissues. Wildfires also contains gases, complex hydrocarbons, trace minerals, and several other toxic and carcinogenic compounds. During the Oregon (USA) wildfire, a 10 µg/m 3 increase in wildfire smoke was associated with increased risk of asthma diagnosis. A dust storm in Kuwait was linked with increases in respiratory disease in children. Increased exposure to particulate matter with wildfires and dust storms has been shown to increase expression of inflammatory cytokines possibly via epigenetic changes. Dampness in the aftermath of flooding increases fungal growth and mold spores and allergic exacerbations.

Research into the mechanism of immune modulation is an active area of research. Pollutants increase mucosal permeability within the airways and gut ultimately allowing increased barrier penetrance by allergens leading to inflammation and immune dysfunction. The microbiome associated with the skin and gut also plays an important role in immune health. The loss of biodiversity, increased consumption of processed foods, exposure to detergents, and use of toxic chemicals are altering skin and gut microbiota and immune health. Advancements in tools for testing of immune cells and associated cytokines, chemokines, antigens, DNA, RNA, and protein have made great advances. These tools such as single cell omics, proteomics,
metabolomics, ATAC-seq, EpiTOF, 3D tissue imaging, 3D printing, organoids, and other high throughput technologies are accelerating research in this area. A better understanding of immune function can enable better mitigation and prevention strategies to combat the effects of pollution and climate change.

“In the short and long run, we have to alter the trajectory of climate change. This is our window of opportunity. Global action is needed to reduce greenhouse gases and increase biodiversity.
We can take action now to try to protect the health of our planet and future generations,” says Kari Nadeau, Stanford University, at the Opening Plenary of the EAACI Annual Congress 2022.

About EAACI

The European Academy of Allergy and Clinical Immunology (EAACI) is an association of clinicians,
researchers and allied health professionals founded in 1956. EAACI is dedicated to improving the
health of people affected by allergic diseases. With more than 13 000 members from 125
countries and over 75 National Allergy Societies, EAACI is the primary source of expertise in
Europe and worldwide for all aspects of allergy.

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