Nasal polyposis, eosinophil dominated inflammation, and allergy

Abstract

A polyp is an oedematous mucous membrane which forms a pedunculating process with a slim or broad stalk or base. Nasal polyps originate in the upper part of the nose around the openings to the ethmoidal sinuses. The polyps extend into the nasal cavity from the middle meatus, resulting in nasal blockage and restricted airflow to the olfactory region. The polyp stroma is highly oedematous with a varying density of inflammatory cells. Nasal polyposis, consisting of recurrent, multiple polyps, is part of an inflammatory reaction involving the mucous membrane of the nose, paranasal sinuses, and often the lower airways. The polyps are easily accessible for immunological and histological studies and an increasing number of publications have appeared in recent years, including two monographs. Nasal polyps have long been associated with rhinitis and asthma. However, the role of allergy in the aetiology and pathogenesis of nasal polyps is a controversial issue. It has been postulated that allergy is an aetiological factor for nasal polyposis. If this is so, then it can be expected that allergic patients will have polyps more often than a control population and that patients with polyps have an increased occurrence of positive allergy testing.In this paper we will describe the possible connection between nasal polyposis and allergy, based on an analysis of (1) the occurrence of polyps and of allergy, (2) the anatomy and histology of nasal polyps, (3) the inflammation in nasal polyps, (4) the occurrence of positive allergy tests in patients with polyps, (5) the eVect of allergen exposure on nasal symptoms in patients with polyps, and (6) the response to treatment.

Allergic rhinitis-induced nasal congestion: its impact on sleep quality

“…2,88,92 Both of these associations, however, require further investigation. 2,[91][92][93] Nasal polyps are growths that develop in the nasal and sinus membranes and extend into the nasal cavity, causing obstruction and interference with breathing. Nasal polyposis also impairs sense of smell 2,94 and has been found to impact negatively on QOL and sleep.…”

“…Intranasal corticosteroids may partially prevent recurrence of polyps, thus potentially reducing or delaying the need for treatment. 92,96 Intranasal surgery traditionally has been the most common approach to treatment of nasal polyps. However, evidencebased guidelines published in a recent European Academy of Allergology and Clinical Immunology (EAACI) position paper recommend the use of INS as first-line treatment for nasal polyposis.…”

“…95 Intranasal corticosteroids are effective in treating nasal polyposis, possibly by downregulating the expression and production of cytokines such as IL-5, which effectively reduces the number of eosinophils. 92 Intranasal corticosteroids attenuate rhinitis symptoms, improve nasal breathing, and reduce polyp size. Intranasal corticosteroids may partially prevent recurrence of polyps, thus potentially reducing or delaying the need for treatment.…”

The presence of B7-H4+ macrophages and CD25+CD4+ and FOXP3+ regulatory T cells in the microenvironment of nasal polyps - a preliminary report.

“…The histomorphologic analysis of nasal polyps in patients suffering from chronic rhinosinusitis reveals frequent epithelial damage, thickened basement membrane, and mostly edematous to fibrotic stroma [2]. The accumulation of a variety of inflammatory cells (plasma cells, eosinophils, neutrophils, mast cells, macrophages, dendritic cells, monocytes, and lymphocytes and their subgroups) was also found in the nasal polyps [3,4]. Eosinophils made up the predominant cellular infiltration in about 80% of the nasal polyps occurring in members of the Caucasian population.…”

Chronic Rhinosinusitis: More Than Just “Asthma of the Upper Airway”

“…In addition to the (relative) ease of being able to use NPs to define the CRS phenotype, the driving feature behind the decision to give polyp presence such prominence in phenotyping these disorders was that the presence of polyps typically (although far from universally) defines a condition whose central feature is infiltration with eosinophils (3,4). CRSwNP is also highly associated with asthma and has an appearance remarkably similar to asthma (5), a condition more often than not present in these patients.…”