Pollens are making their comeback with the beautiful days. What is desensitization and why is it effective in case of allergies?
"The birch pollen will continue to hinder the allergic during these next sunny days with a risk of high to very high level in Ile de France, in the Center region, in the Bourgogne-Franche-Comté region and in the Greater East region. Reims and Nancy, "says the National Aerobiological Monitoring Network (RNSA) in its April 19th newsletter. The Marne, Meurthe-et-Moselle, Val-de-Marne and Hauts-de-Seine are on red alert. In the rest of France, the risk will be very low to medium. "People allergic to birch pollen should be on their guard and follow the treatments prescribed by doctors." That is to say, to be desensitized.
What is desensitization?
Mainly to gradually expose the body to the allergen so that the immune system can tolerate it. To begin, the allergist performs skin tests on patients with different allergens to determine the origin of the allergy (pollen birch, grass, cat hair, dog ...). These tests may be accompanied by a possible blood test and consultation with a pulmonologist. After receiving the results of the examinations, the doctor decides if a patient is "eligible" for desensitization. If this is the case, the patient can then gradually inject the allergen into his body by swallowing tablets or drops. The efficiency is the same for both processes. If it is a severe allergy, treatment is by injection at the doctor or hospital.
It is recommended to be desensitized 3 to 4 months before the beginning of the pollen season and to take this treatment for at least 4 months, since the doses of allergen introduced into the body will be more and more important during the months . It is also essential to specify that desensitization is possible from the age of 5, but that it does not work if the allergens are food, multiple or in case of autoimmune diseases or cancers. Overall, desensitization can significantly reduce the symptoms of allergy such as fatigue, colds, headaches or asthma attacks.
A real public health issue
Allergies are today a real public health issue, directly related to changes in the environment and changing lifestyles. The National Institute of Health and Medical Research (Inserm) estimates that "25 to 30% of the population is allergic". A figure that should reach 50% by 2050 according to the World Health Organization (WHO). In France, 15 to 20% of people aged 15 to 70 are affected.
"Reducing the reimbursement of desensitization treatments is reducing the number of patients who can be treated and take the risk of worsening the pathology," warn allergists. According to them, this would amount to denying the weight that allergies represent on everyday life: fatigue, absenteeism at school, lower productivity at work, etc.
What are the allergies to pollens?
But what is causing pollen allergies? Austrian researchers explained this phenomenon in the Journal of Biological Chemistry in 2014. They had recreated the allergen present in birch pollen in the laboratory: the Bet v 1 protein (Betula verrucosa). It makes the immune system hypersensitive and causes the formation of pathogenic antibodies in 95% of allergy sufferers. The researchers discovered that it is the molecular "pockets" of the Bet v 1 protein that determine whether or not the pollen will be allergenic.
Specifically, Bet v 1 can bind strongly to iron through molecular pockets. If these pockets remain empty, the pollen turns into an allergen because it manipulates the Th3 immune cells to make them react. Scientists note in people with allergies, an imbalance between Th3 cells - which defend the body from allergies and parasites - and Th1 cells - that respond to bacterial infections.