‘Entopy’: local allergy paradigm

Abstract

Allergy is defined as an immediate hypersensitivity type I immunological disease, which can be IgE or non-IgE driven, and in the latter case may be antibody or cell mediated. Atopy is a term used to describe individuals with a genetic predisposition for developing IgE-mediated allergic disease. But more recently, it has become evident that IgE-mediated disease can occur in non-atopic subjects. While it is now generally accepted that mucosal local IgE has a role in the expression of atopic allergic disease, the concept of 'local allergy' in non-atopic subjects has been proposed, with the term 'entopy' given to this condition. Although there is increasing evidence supporting this paradigm, entopy is only applicable to a proportion of non-atopic patients, suggesting that other disease mechanisms exist to explain non-atopic disease. This review considers the evidence for local mucosal allergy in atopic and non-atopic individuals with an emphasis on diseases affecting the upper airways and eye. Furthermore, the diagnosis, treatment and relationship between local allergy and conventional (systemic) allergy are discussed, and alternative disease mechanisms predominantly involving antibodies or their sub-components (free light chain Igs) are postulated to explain the 'entopy' paradigm. This review is intended to provide an improved understanding of the mechanisms and causes of local mucosal hypersensitivity.

Natural course and comorbidities of allergic and nonallergic rhinitis in children

“…Some children with nonallergic rhinitis who had symptoms of rhinoconjunctivitis or nasal symptoms upon exposure to inhaled allergens could have local allergic rhinitis, without circulating, specific, IgEs. [25][26][27] We did not examine the noses of children in our study, and therefore cannot exclude this possibility. However, among these children, only 1 of 36 had allergic rhinitis at age 8 years.…”

Nasal Sensitization with Ragweed Pollen Induces Local-Allergic-Rhinitis-Like Symptoms in Mice

“…Patients who manifest symptoms similar to AR during the allergen season but do not show elevated serum IgE levels are classified as non-allergic rhinitis (NAR) [2], [5], [6]. However, studies have shown that within NAR patients, some are indeed “allergic” and have locally increased IgE levels in their nose or nasal lavage [7]–[9]. This type of rhinitis with local IgE production is defined as local allergic rhinitis (LAR) [7] or entopy [8], [9].…”

“…However, studies have shown that within NAR patients, some are indeed “allergic” and have locally increased IgE levels in their nose or nasal lavage [7]–[9]. This type of rhinitis with local IgE production is defined as local allergic rhinitis (LAR) [7] or entopy [8], [9]. LAR is characterized by the local production of IgE in the nose, a Th2 pattern of mucosal cell infiltration, and positive nasal provocation test (NAPT), although serum antigen-specific IgE is negative [7].…”

Local Allergic Nasal Reactions Convert to Classic Systemic Allergic Reactions: A Long-Term Follow-Up

“…Specific IgE identified using the enzyme allergosorbent test (EAST) can be detected in nasal secretions but not in the serum of these patients [1]. This type of allergy is limited to the nasal mucosa and therefore referred to as local allergic rhinitis [2,3], entopy [4] or allergic rhinitis with a negative skin test [5]. Clinical symptoms, nasal secretions and the profile of cytokine production of local allergic rhinitis are similar to classic allergic rhinitis [6,7].…”