Study iron deficiency can trigger an allergy

Lack of iron loading of proteins makes them allergens

06/05/2014

Austrian researchers have decoded how proteins can trigger allergies. Apparently iron deficiency plays an essential role in this. On the basis of the example of birch pollen, the scientists of the Messerli Research Institute, a joint institution of the Vetmeduni Vienna, the MedUni Vienna and the University of Vienna, proved that too little "iron loading" of the protein components turns the pollen into allergens.

"In Austria alone, around 400,000 people are affected by birch pollen allergy and the associated food intolerances," reports the Medical University of Vienna. It still remains completely unclear why so many people are allergic to birch pollen. Although it is known that "a certain birch pollen protein provides for an overreaction of the immune system", but "what makes this protein to allergen, so the allergy trigger," the researchers could only now decipher. The results of her study have been published in the journal "Journal of Biological Chemistry".

Main allergens of birch pollen investigated
The scientists around Erika Jensen-Jarolim from the Messerli Research Institute discovered that the pollen protein can bind iron to itself. If the iron load is missing, the pollen becomes an allergen. The researchers conducted their investigations on the most well-known allergen, the so-called "Bet v 1" from birch pollen (Betula verrucosa). According to the MedUni "25 years ago, this protein was artificially produced in the laboratory in Vienna for the first time and has since been used worldwide as an allergen model for research." It is the main allergen among hundreds of other birch pollen proteins. The contact leads in 95 percent of birch pollen allergy sufferers to the formation of pathogenic antibodies, the IgE immunoglobulins, the MedUni Vienna continues.

Lack of iron loading to altered immune response
Similar to the human protein "Lipocalin 2", the birch pollen protein has so-called molecular pockets, with which iron can be bound. "If these pockets remain empty, the birch pollen protein becomes an allergen and can cause allergic reactions in humans and animals," the researchers write. In the absence of iron loading, the protein manipulates certain cells of the immune system (the T helper 2 cells, Th2 cells) in the direction of an allergy. The balance between the Th1 and Th2 cells shifts towards the Th2 cells. It has already been known from previous investigations that in the case of allergy sufferers the Th2 cells prevail over the Th1 cells. "Typical of allergies is a disturbed balance between Th1 and Th2 immune responses," explains Erika Jensen-Jarolim, Head of Comparative Medicine at the Messerli Research Institute.

Connection between environmental impact and increasing number of allergy sufferers
After identifying the lack of iron loading as the cause of allergen development, the researchers say they are "wondering which mechanisms contribute to a reduced iron loading of the Bet v 1"Perhaps the" aggravated environmental conditions to which the plants are exposed "are the reason for the reduced iron loading of the birch protein, explained Erika Jensen-Jarolim. For example, there could even be a direct link between environmental pollution and rising allergy numbers. The current results are quite transferable to other allergens. "Current work suggests that we can directly apply the birch pollen allergen principle to other allergens with a similar molecular structure," Jensen-Jarolim said, adding, "Thus, for the first time, we begin to understand why allergies to pollen, food, and fungal spores actually work originally arise. "

Improvements to the therapy possible?
On the basis of their study results, the scientists come to the conclusion that it would make sense in the future, "allergenic molecules of the type Bet v 1If they are used for immunotherapy in people with allergies, they can be loaded with iron. "In this way, the therapy," which lasts two to four years today, could be significantly shortened and increased in efficiency, "explains the head of the comparative department Medicine at the Messerli Research Institute, Erika Jensen-Jarolim. (Fp)