Allergy: what it is and the role of the immune system

pollen and allergy

“My life is all roses and flowers but I’m allergic”

Matteo Molinari

Spring is here! But, with it, we also have really unwelcome guests: allergies! Yes, those darn allergies to pollens that make the season a nightmare.

Continuous sneezing, watery and swollen eyes, stuffy nose, headache. You really feel a wreck and to avoid this we turn to antihistamines.

But what is an allergy? It is the expression of an overreaction of our immune system against normally harmless substances such as pollen or food. These substances, or rather these molecules, are called “Allergens”.

How allergies work.

In the presence of an allergen, how does our immune system react? We divide the reaction into two stages: the sensitization phase and the reaction phase. The first stage occurs when the body enters in contact with the allergen. In the case of pollen, it occurs via inhalation. The macrophages (immune system cells) recognize the allergen and communicate the information to the B lymphocytes which, when transformed into plasma cells, make specific immunoglobulin E (IgE) against that specific allergen. They will then fix on mast cells.

The reaction phase occurs at the second contact of the allergen with the nasal mucosa . It is picked up by the IgE on mast cells and binding results in degranulation, the release of small vesicles containing active chemicals molecules. Among these we have histamine, which plays a key role in allergy and which is the origin of the allergic symptoms (rhinitis, asthma, urticaria.)

Fortunately for those who suffer from allergies, several antihistamines are available, a very valuable help to better enjoy this wonderful season. For some allergies, immunotherapy is available: Allergy Shots (learn more)

Enjoy the spring!