Ali Rebeihi
· Thierry, for this last visit of the year, you went to the CEA (Commissariat for Atomic Energy and Alternative Energies) in Saclay, near Paris, to visit the laboratory of Karine Adel-Patient.
· She is director of research at INRAE (the National Research Institute for Agriculture, Food and the Environment) and head of the Food Immuno-Allergy Laboratory, attached to this institute.
· She is coordinating a study supported by the FRM on the theme of health and the environment.
· She received you with her colleague Blandine de Lauzon-Guillain, who is director of research at INRAE, at the Center for Research in Epidemiology and Statistics, in Villejuif, and who works closely with her for this study.
Thierry Lhermitte
· Exactly. Karine Adel-Patient’s laboratory specializes in the assessment and prevention of the risk of food-induced allergies. This is currently a very strong societal and industrial demand, particularly with the revegetation of diets and the arrival on the market of new foods.
· As for Blandine de Lauzon-Guillain, she studies with her team how food before and after birth can influence the health and development of children and adolescents.
· The study they are working on together is called PeriContAll. It aims to study whether an association exists between exposure to food contaminants before and after birth, and the onset of allergies during childhood.
AR
· What are food contaminants?
TL
· This is what ends up on our plate due to environmental pollution and food production and processing methods: these are pesticides, antibiotics, flame retardants, toxins, etc.
· These are substances which generally accumulate in our body, especially in fats, and which can cross the placental barrier or pass into breast milk.
AR
· And can you remind us what an allergy is?
TL
· It is an abnormal and excessive immune response against a foreign substance that is normally harmless and should be tolerated.
· These foreign substances, called allergens, are proteins. These are natural constituents of our environment which are contained in pollens, mites, animal hair, moulds, insect bites, medicines or foods (peanuts for example).
· When these allergens reach the barriers that protect us from the outside world (the skin, the bronchi, the intestinal mucosa), they cause an unsuitable immune reaction.
There are therefore different forms of allergy depending on the route taken by the allergen: skin allergies (such as eczema), food allergies (which affect the mouth, intestine and all other organs), allergies respiratory (which in particular cause asthma and allergic rhinitis), etc.
· The most severe reactions can be fatal, we have all heard of anaphylactic shock, which causes asphyxia and cardiorespiratory arrest. It must be treated immediately with an injection of epinephrine.
· We must also remember that we should not hesitate to use it in case of doubt, this injection is not dangerous, it has no side effects.
AR
· It seems that many people are allergic?
TL
· Indeed, because allergy has become a real public health problem.
· The number of cases has been constantly increasing since the 1970s. It now concerns 30% of the population and it is estimated that in 2050 it will be half of the people who will be affected!
· Just for asthma, which is in 80% of cases of allergic origin, it is 4 million people and 1,000 deaths per year in France. 10% of children are affected, it is the leading cause of school absenteeism.
· So whether they are respiratory, food or other, allergies have a strong impact on the quality of life; and that for both children and adults.
AR
· Do we know the mechanisms?
TL
· Yes, it is due to the immune system, which reacts as if the allergen were an aggressor, representing a danger.
It happens in two phases:
o first awareness, at the first encounter with the allergen. The immune system “arms” itself in a way;
o The second phase is the triggering of the allergy, at the time of the second encounter with the allergen. There is then a cascade of reactions that lead to a runaway immune system.
· One can develop cross allergies, for example when one is allergic to birch pollen. As it contains a protein very close to a protein contained in the apple, you can also trigger an allergic reaction when you eat the apple, it’s quite common.
AR
· Why are some people allergic and others not?
TL
· As often, there is a part of genetic predisposition and a part of environment.
· If you are in a family of allergy sufferers, there is a good chance that you will become one too. We speak of “atopic terrain”.
AR
· In this context, what is the PeriContAll project coordinated by Karine Adel-Patient?
TL
· The idea is to determine whether the contaminants present in the mother’s diet during pregnancy, then in the baby’s diet, can promote the occurrence of allergies in the child.
· For this, two cohorts will be studied. A cohort is a group of individuals followed over the long term.
· The first cohort is called EDEN: it included 2,000 pregnant women in France between 2003 and 2006, who were subsequently followed up with their babies. So it’s been 18 years of follow-up with a lot of data: the diet of the mother and the child, the weight, the size of the child, his health, his development…
· The second cohort is called ELFE: it is more recent and included 18,000 children born in France in 2011 in 350 maternities. They have since been followed with a collection of different data about their diet, their health, their development, their socialization, etc.
AR
· What are the researchers going to do to carry out their allergy project?
TL
· The team first assessed the exposures to which the women and children were subjected via their diet. This epidemiological study (which is only theoretical) shows that pregnant women and babies are all potentially exposed to some 200 contaminants, in mixtures.
· The objective is now to detect contaminants present in meconium (the first stool of the newborn) and in breast milk, which were collected in the cohorts.
· Why ? Because meconium reflects prenatal exposure to these contaminants and breast milk reflects exposure during the first few weeks: very sensitive exposure windows that can impact the future health of the child.
· For this, the team analyzes all the small molecules present in the samples collected. It is a very complex technique, which required 3 years of development on state-of-the-art equipment. You also need skills in bioinformatics, because there is a whole part of modeling compounds and mining tens of thousands of data.
· The team will then make the link between the contaminants detected and the occurrence of allergies in children.
· And, finally, it will look for the mechanisms involved.
AR
· This study promises very interesting results!
TL
· Yes, there are many expectations, particularly in terms of public health recommendations.
The strength of this project is its scale, the support of partners such as the BNP Paribas Foundation and the FRM, but there are also the families who have been taking part in the EDEN and ELFE cohorts for years and without whom this work could not take place. The researchers would like to thank them here.