It’s well-known that the immune dysregulation contributes to an increase in immune-mediated diseases such as asthma, in general allergic diseases, autoimmune diseases, and cancer.
This dysregulation is often caused by environmental stressors, that are responsible of this complex immune response. Pollutants, allergens, and other environmental factors increase the risks of skin and mucosal barrier disruption and microbial dysbiosis, while a loss of biodiversity and reduced exposure to microbial diversity impairs tolerogenic immune development, in other words the way of producing immunological tolerance.
So, if you live in the hemisphere where now it should be springtime and you are asking what is happening to your immune system, the answer is soon given. Your immune system reacts to the climate change. Nonsense? Recent scientific reports speak clearly: atmospheric conditions affect the release of anemophilous pollen, and the timing and magnitude will be altered by climate change.
Global warming and climate change have increased the pollen burden and the frequency and intensity of wildfires, sand and dust storms, thunderstorms, and heatwaves, with concomitant increases in air pollution, heat stress, and flooding.
So, you are yourself a proof of how huge this climate change is.
An interesting study published in Frontiers in Science, result of an important collaboration between various research group, underlines that probably we get ill more and more frequently because climate change-associated exposures can trigger a complex array of inflammatory or tolerogenic responses.
In healthy individuals, the immune system mediates a tolerogenic response upon encountering common innocuous environmental factors. During immune dysregulation, the immune system mounts an inflammatory response, even to innocuous environmental factors or healthy cells in the body. These mechanisms are involved in allergic reactions to pollen, food, or insect allergens.
But where it comes from this considerable immune response? From the climate.
Changes in land use and climate, such as rising temperatures and nitrogen oxides (NOx), ozone (O3), and carbon dioxide (CO2) levels, have led to increased pollen quantity, quality, allergenicity, and duration of the pollen season. Greenhouse and field studies indicate that pollen concentrations are correlated with temperature and some estimates suggest that pollen concentrations may increase by 200% by the end of the century.
Most pollen types have shifted toward earlier times of the year for pollen outputs (e.g., ragweed), possibly aggravating the burden on pollen-allergic patients.
Furthermore, extreme phenomena affect human response to pollen. In fact, pollen is affected by thunderstorms, leading sometimes to a phenomenon called thunderstorm asthma characterized by severe asthma attacks and asthma-related deaths in patients with allergic rhinitis.
Goin further into details it’s known that exposure to numerous ambient air pollutants (e.g., PM, O3, NOx) is related to the incidence and exacerbation of asthma in both children and adults, but also with cancer and autoimmune diseases.
Wildfires, another increasing phenomenon caused by global warming, affect not only our respiratory system but also our skin. There was a significant increase in the use of dermatology clinics in San Francisco (~290 km downwind) for the treatment of atopic dermatitis and itch for a 2-week period during and after the Camp Fire in northern California in 2018.
Sand and dust storms carry pollen, fungal spores, bacteria, and viruses, leading to respiratory infections, asthma, and allergies. Many microorganisms and pathogens can survive long-range transport by sun and dust storms.
Heat stress has various direct and indirect effects on health and well-being. For example, a study in Australia found a significant increase in childhood asthma emergency department admissions during heatwaves.
Biodiversity loss involves microbial species loss. Since the human body is an ecosystem or “holobiont” (a concept describing the host – animal or plant – as a community of species linked to other ecosystems and subject to continuous evolutionary pressure), biodiversity (including genes, species, and ecosystems) is a key factor in maintaining a healthy and functioning ecosystem and for human health. Exposure to a greater diversity of microbes is thought to be a key factor driving the early immune system away from the development of asthma and allergies.
Solutions? They are yet available: mitigate the effects of climate change.
Key actions include reducing emissions and improving air quality (through reduced fossil fuel use), providing safe housing (e.g., improving weatherization), improving diets (i.e., quality and diversity) and agricultural practices, and increasing environmental biodiversity and green spaces.
There is also a pressing need for collaborative, multidisciplinary research to better understand the pathophysiology of immune diseases in the context of climate change.
References:
Frontiers in Science: DOI 10.3389/fsci.2024.1279192
