Theme 2: Environment, Diet, Microbes and Parasites and their Role in the Development of Food Allergy
Leader: Ronald van Ree
Overall aim
Theme 2 looked at the complex interplay between genetic predisposition, early life (including prenatal) exposure to microbes, inhalant and food allergens as well as such exposures later in life; and how this results in the development of (food) allergy. More specifically through the three work packages associated with it, Theme 2 looked at:
1.Sensitisation to food, environmental agents and genetic factors in food allergy (Work Leader: Ronald van Ree)
Sensitization to food occurs either directly by food consumption or indirectly by exposure to inhalant allergens (cross-reactivity), coupled with the genetic predisposition of the individuals. This theme studied both ways of exposure, and investigated genetic factors. This was studied by:
- DNA samples from selected Theme 1 cohorts were analysed for polymorphisms.
- Analysis of all serum samples from Theme 1, Theme 2 (Ghanaian) and past (ECRHS II) cohorts for sensitization to foods (and some inhalant allergens). This also provided Theme 3 with well-defined serum samples that are indispensable for evaluation of novel diagnostic tools.
- IgE responses at the epitope level in serum samples of infants from the birth cohort were characterised using synthetic peptide chips to evaluate prognostic markers for outgrowth or persistence and disease severity;
- Analysis of present and historic data of pollen exposure throughout Europe was used to identify correlations between pollen exposure and food sensitisation.
- Current knowledge regarding consumption patterns across Europe for Priority 1 foods was summarised and an in-depth study on how one food (peanut) has changed over time and may have influenced subsequent development of food allergy.
2. Exposure to microbes during early life (Work Leader: Maria Yazdanbakhsh)
The Hygiene Hypothesis proposes that exposure to non-pathogenic and pathogenic microbes (and derivatives thereof) pre-natally and during early childhood affect the development of allergy (including food allergy) later in life. This was studied by:
- Placental and cord-blood samples were obtained from the Birth Cohort to facilitate future studies on how pre-natal sxposure to microbes may affect allergy outcomes later in life.
- Frequent and chronic (parasite) infections have been shown to have a protective effect against the development of inhalant allergies. The role chronic parasitic infections may play in the development of food (specifically peanut allergy) in Ghana (a major producer and consumer of peanuts) has been investigated.
- Studies which exploit geographical and lifestyle differences in Asia (India, China) and Western Siberia have been undertaken. The emphasis is on food allergies, although respiratory allergies are also included since these are frequently directly linked with food allergies and can be a risk factor for development of food allergy. The generation of a EuroPrevall INCO sample bank will form a platform for future funding for studies that will deliver knowledge of the immunological and physiological mechanisms underlying the cause of allergy and its rise in prevalence.
3. Sensitisation to food, dietary factors in food allergy (Work Leader: Gene Rowe)
Exposure (consumption) to foods is thought to be related to prevalence of allergies. To study this, a social anthropological study of the past 30 years in the four climatic regions represented in Theme 1 has been undertaken. The study has been used to investigate how peanut allergy, which has only emerged as a significant allergenic food in the past 25 years, has been affected by the following factors:
- Source (e.g. cultivars, country of origin)
- Food processing practices
- Types of food containing peanut or peanut derived ingredients
- How consumption rates vary demographically (especially pre-school children and pregnant mothers)
- Consumer segmentation data (socio-economic group, regions, age, gender), typical amounts per person.