Mapping Exposure-Induced Immune Effects: Connecting the Exposome and the Immunome


What is the exposome?

The term exposome refers to all life-course, environmental exposures one can encounter, from the prenatal period onwards. It therefore captures all the non-genetic factors that influence human health and disease.

The concept of the exposome was recently (2005) introduced to complement the concept of the genome. Until then, research was mostly focused on the impact of the genome on disease. However, disease is known to be a result of both genetic factors and environmental factors (i.e. nature – nurture).
Since then, the importance of research on the exposome has grown.

Learn more about the exposome and the immunome on our Background page.

What are typical examples of exposures?

Exposure refers to all kinds of agents individuals can come in contact to, and it can happen via various ways, like inhalation, skin contact and ingestion. These agents can be biological, chemical or physical agents and people can be exposed both in the general environment or in the working environment, when working intensively with specific agents. Typical examples of exposure from the general environment are fine particles in polluted air, pesticide residues in food, solvents in household product, viruses and bacteria, and UV from the sun or sunbeds. Typical examples of exposure from the working environment, on the other hand, can be metals and silica from engineering activities, hairdresser products and virus infections through needle-stick in hospitals or medical laboratories. Individuals are exposed to environmental agents throughout their entire lifetime.

In our research project, we will look at possible effects of variable exposure agents and effects of combined exposure of several of these agents.


What is the immunome?

The term immunome refers to the immune system of an individual. It includes all the genes, cells, tissues and proteins associated with the immune system. The immune system protects our body against disease (pathogens) and/or other potentially damaging foreign substances. An important feature of the immune system is that it can differentiate between foreign and body’s own cells or agents.


What are immune fingerprints?

In our research, we aim to;

1) Identify ‘immune fingerprints’ resulting from environmental exposures.

These immune fingerprints therefore reflect a person’s (lifetime) exposure. In other words, it refers to a unique signature, just like a normal fingerprint, but this time it is shown as changes and markers in the immune system due to a persons exposure. This immune fingerprint is a biomarker (What is a biomarker?) showing which exposures an individual was exposed throughout life..

2) Identify ‘immune fingerprints’ as an early marker of disease.

These immune fingerprints therefore reflect the disease state of an individual. It refers to a unique signature showing changes in the immune system due to the development of an immune-mediated disease. This immune fingerprint is a biomarker of disease / poor health and can be used as a diagnostic tool.

3) Identify ‘immune fingerprints’ which pick up both exposure and disease.


Why are immune fingerprints important?

The immune fingerprints can be used as early markers of poor health and they can reflect an individuals’ risk of disease development. By assessing these immune fingerprints, we can identify the individuals and groups at risk of disease. Therefore, the ultimate goal will be to prevent disease development by taking preventive measures.


What is a biomarker?

The term biomarker is short for a biological marker. Biomarkers are used as an indication that a biological process in the body has happened (or is ongoing) due to exposure of an individual. They can be measured as chemicals, metabolites, characteristics or changes in the body. For example, the analysis of alcohol in exhaled breath is a biomarker of alcohol consumption.

By measuring biomarkers, we receive information on the exposure of an individual. Moreover, some biomarkers can indicate health effects as a consequence of exposure.

In the EXIMIOUS project, we will assess changes in the immune system (immune fingerprints) as biological markers of exposure and in some cases also as indicator of disease.


How can the exposome impact our health?

Earlier research has confirmed the association between exposure and immune-related diseases, such as autoimmune diseases. Immune-mediated diseases are conditions which result from abnormal activity of the body’s immune system. The immune system may over-react or start attacking the body. Examples of groups of immune-mediated diseases are the autoimmune diseases, like type 1 diabetes, multiple sclerosis, and rheumatoid arthritis, and allergic diseases like asthma. Recently, the World Health Organisation (WHO) has highlighted the seriousness of autoimmunity and its association with exposure to the environment

But even without having full features of a clinical disorder, exposure is linked to changes in the immune system. For example, certain exposures are associated with changes in our antibody levels, while other exposures are linked to changes in immune cell maturation. The immune system might thus carry an ‘immune fingerprint’ that reflects lifetime exposure to (combinations of) exposure agents.

Besides alterations in our immune system, the exposome can have other, even life-threatening effects. Certain exposure agents are related to several kinds of cancer, like asbestos-exposure, while other agents can have effects.


What are common exposure-associated immune-mediated diseases?

Autoimmune diseases are conditions in which the immune system mistakenly attacks a person’s own body cells. This can be focused on one specific organ or one type of cells, like the pancreatic cells in type 1 diabetes, or it can affect your entire body, which is the case in for example rheumatoid arthritis. Allergic diseases, on the other hand, are mediated by a hypersensitivity reaction of the immune system after contact with harmless agents like pollen, certain foods or insect stings.


How common are exposure-related immune diseases?

Several immune-mediated diseases or syndromes have been described. some of which are organ-specific (e.g., autoimmune thyroid disease and type-1 diabetes), while others are systemic (e.g., systemic sclerosis, rheumatoid arthritis, systemic lupus erythematosus). These diseases are already affecting a very worrying 7.6–9.4% of the EU population and women are 2–10 times more likely to suffer from autoimmune diseases than men.

The WHO has also drawn attention to the fact that autoimmune diseases are multi-factorial, meaning that both intrinsic factors, like genetics, hormones, and age, and the environment contribute to the induction, development, and progression of autoimmune diseases. Furthermore, research has shown that the environmental contribution exceeds 50%—and is as high as 95% for some autoimmune diseases.


What is the aim of the EXIMIOUS project?

The EXIMIOUS project aims to improve people’s lives by gaining insight in exposure-induced immune effects.

Our study will identify immune fingerprints. These immune fingerprints can be used in future risk assessment and prevention of disease. 

We will construct different tools for different stakeholders. For example, a tool for policy makers aims to advise policy makers in their decision-making about environmental exposures. A tool for clinicians aims to improve disease assessment (in early stages) as well as disease prevention and treatment. A toolbox for the general public and patients aims to inform people.


Why is the EXIMIOUS project important?

The EXIMIOUS project aims to improve people’s lives by gaining insight in exposure-induced immune effects.

We believe that the potential for disease prevention is huge. (Auto)-immune disorders are very invalidating and require lifelong medical care. By gaining knowledge on the impact of the exposome on the immunome, we will be able to identify at risk individuals, groups and populations. Based on this knowledge we can then advise preventative measures that target these individuals or groups. 


How will EXIMIOUS benefit society?

The project will also have great benefits on societal level. Autoimmune diseases require expensive, lifelong medical care. The financial costs of these diseases should be considered. Furthermore, these diseases often lead to an inability to work and impacts the individual’s overall contribution to society.

For example, autoimmune diseases are already affecting a worrying 7.6% – 9.4% of the EU population. The severity of these diseases is also highlighted by the fact that it is one of the leading causes of death in women under the age of 65. Immune-mediated diseases are often of unknown aetiology, resulting in a lost opportunity for prevention, while exposure diseases are potentially preventable. Besides that, the burden for patients when diagnosed with an untreatable disorder should be considered and is often underestimated. Unravelling the aetiology and causes of autoimmune diseases can be a first step to the implementation of preventative measures in the working place, but also in the living environment. Apart from that, assigning a cause to a physical disorder is likely to enhance patient coping strategies.

The EXIMIOUS project aims to develop a toolbox for researchers and policy makers to support diagnoses and risk assessment.


How is the EXIMIOUS project organised?

The EXIMIOUS project is a European project that is funded by Horizon 2020 (European Commission). The project gathers 15 research groups that have expertise in different areas. These research groups are located in seven countries within Europe and the United Kingdom. Peter Hoet, professor and researcher at the Katholieke Universiteit Leuven (KULeuven), leads the project.


When does the project start and end?

The EXIMIOUS project started in January 2020. The duration of the entire project is five years (60 months) and ends in December 2024.


Where can I find important information about the results of the project?

You will find all the important information on this website.. There will be various toolboxes for different groups:

  • The general public
  • Clinicians
  • Researchers
  • Policy makers


What if I still have questions?