Analysis of the potency of individual allergens in relation to IgE recognition in patients with cow's milk, peanut or nut allergy.

The prevalence of food allergy is estimated around 2% in adults and 5-8% in
children. Symptoms of a food allergic reaction can vary from mild (itching in
the oral cavity) to severe (anaphylactic shock). Most foods contain several
allergens. IgE of patients is often directed against several allergens. It is
known that not all allergens are equally important for the clinical allergic
reaction. The severity of the symptoms can also differ, depending on the
allergen which is involved.
Little is known about the factors that determine the relevance of an allergen
for the allergic reaction. A possible explanation may be the stability of
allergens, the number of IgE epitopes recognized within an allergen, or
intrinsic features of the allergen, which influence the extent of mast cell and
T cell activation by allergens. For many food allergens, it is unclear what
these factors are and which allergens are most relevant. Insight into the in
vitro characteristics of the different allergens can provide important
information to determine whether IgE recognition of these specific allergens is
relevant for the diagnosis of food allergy.

To analyse which allergens within cow's milk, peanut or nuts are most potent in
activation of T cells and basophils.

Because our research in recent years has focussed on cow's milk, peanut and nut
allergy, we will include patients with these food allergies in this study. For
each allergen (cow's milk, peanut, nut) 30 patients will be included and asked
to donate blood. Because the tests for basophil activation and T cell
activation cost larger amounts of blood, we will ask to donate 2 x 100 ml
blood, with at least one month in between.

From the first blood sample, plasma will be collected and will be used to
measure IgE binding to the individual allergens by immunoblot. This will
provide information about the extent of recognition of the allergens by IgE.
The white blood cells (PBMCs) will be used to analyse the potency of allergens
to activate T cells. For this purpose, allergen-specific T cell lines will be
generated from PBMCs. Activation of T cells is measured by proliferation and
cytokine production upon allergen-specific stimulation.
The other blood sample will be used for analysis of basophil activation, to
measure how potent individual allergens are to activate basophils. Basophils
will be stimulated with an increasing allergen concentration of the available
allergens.

The burden for the patient in this study consists of 2 blood donations of 100
ml, for this study. The patient has no direct benefits from the study. The
risks of blood sampling are negligible.