The defence mechanisms of our immune system – what happens during an allergic rhinitis?

What is allergic rhinitis?

It is an allergic response of our body to specific allergens, such as pollen produced from various plant species. Two different phases of an allergic reaction can be distinguished: an early and a late phase response. In the early phase (sensitization), a particular allergen enters our body for instance via the nose. Here, T- and B-cells, part of the immune system, recognize the allergen and produce a protein, a so-called antibody that memorizes the invading molecule. These antibodies connect to mast cells in the mucous membrane to build up an immune defence mechanism. At this point, our body is sensitized to the particular allergen. No allergic reaction occurs; we do not have any symptoms.

If the same allergen enters the body again, the late immune response kicks in. The allergen is detected and bound by the antibody on the mast cell. This causes the release of the inflammatory response molecule histamine, followed by several allergy symptoms including runny eyes, runny nose, sneezing and itching. Additionally, part of the white blood cells; the granulocytes, produce leukotrienes that mediate a delayed immune response, which we experience as a blocked nose.

What to do if you have hay fever?

To reduce the symptoms of allergic rhinitis to a minimum, you should keep the following things in mind:

• consult the pollen forecast to find out how much pollen is expected
• adapt your outdoor activities accordingly, if there is a peak pollen time stay inside as much as possible
• have windows open as little as possible
• wash your hair before going to bed
• do not dry your laundry outside

With these little tips and tricks, you will reduce sneezing and itching. Enjoy the spring awakening!

[1] UCB Institute of Allergy, Brussels