At the heart of type 2 inflammation, to understand certain chronic inflammatory diseases such as nasal polyposis.

When pathogens or allergens enter the body, it defends itself. These external attacks induce a specific inflammatory response, called inflammation type 2. Although this reaction is quite normal, it can be too intense and too prolonged, and in some cases cause illness. THE’asthma or theeczema are diseases that may be associated with a type 2 inflammatory reaction, nasal polyposis too.

Uncontrollable inflammation

Doctors cannot always identify the trigger for inflammation in patients with polyposis nasal. Several avenues of research were mentioned, such as the involvement of allergies respiratory tract or a previous infection with a microorganism. The consequences are well known in the context of nasal polyposis: appearance of polyps, loss ofsmell and taste, or a nose crowded or runny, accompanied by pains facial.

At the cellular level, the mechanisms of type 2 inflammation in nasal polyposis are increasingly understood by scientists. The cells of the mucous nasal gland identify a threat, and communicate with the immune system to neutralize it. The lymphocytes T activate and differentiate into a Th2 lymphocyte. They then secrete three molecules keys in type 2 inflammation: IL-4, IL-5 and IL-13.

Those cytokines serve as a communication message between differentiated lymphocytes and other immune cells. They indicate the presence of a threat and its location. By chemotaxis (displacement of certain cells triggered in the presence of cytokines), eosinophils and the mast cells travel to the nasal mucosa. For their part, Th2 proliferate and amplify the warning signal.

The birth of polyps

Mast cells store in their cytoplasm granules containing pro-inflammatory molecules, such ashistamine or TNF-alpha. Eosinophils also release their content, it is said that they “degranulate.” “ All this activity damages the nasal mucosa, it is destabilized and irritated. Polyps result from the infiltration of immune cells into the epithelium and its destabilization; just like an abnormal production of mucus, or even itching and facial pain.

In the case of nasal polyposis, this local inflammation gradually becomes chronic and does not go away. The prescribed treatments are adapted according to the symptoms. Local corticosteroids, in addition to washing the nose with saline solution, are the first-line treatment for nasal polyposis. Their anti-inflammatory properties help calm this immune rush, but do not treat its origin.

The objective of this therapeutic management is to relieve the most disabling symptoms, but also to improve the quality of life of patients and to protect them as much as possible from the risks of complications and recurrences. In the most serious forms of nasal polyposis, the ENT doctor may use the surgery or to systemic corticosteroids, which then act on the whole organism and no longer in the nasal cavity only, to “turn off the fire Of inflammation. Finally, in the event of failure, other solutions must be considered.

When several inflammatory diseases coexist

Type 2 inflammation is involved in other diseases that can coexist. It is not uncommon for a patient to have several pathologies inflammatory type 2, to varying degrees. Nasal polyposis frequently coexists with asthma or even atopic dermatitis. Combined, these pathologies are more difficult to manage than when they appear on their own. Thus, patients with nasal polyposis combined with asthma are three times more likely to have a post-surgical relapse.

Understanding the links between type 2 inflammation and inflammatory diseases such as nasal polyposis could help improve overall patient management.

Article produced in partnership with Sanofi Genzyme.

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Reference 7000035242 – 11/2021