Detection of IgE‐binding activity in serum after intranasal treatment of normal rabbits with P. judaica extract

Abstract

Local intranasal immunotherapy relieves the allergic symptoms of rhinitic patients but little is known about the absorption and distribution of inhaled allergens in the body. The aim of this study was to establish whether allergenic proteins are able to reach the bloodstream by penetrating through the nasal mucosa when aqueous P. judaica extract was administered into the nostrils of normal rabbits. Optimal conditions for a sensitive modified RAST (immunocapture RAST) were set up and the method was used to detect clinically relevant allergenic activity in the systemic circulation. The kinetic profile after intranasal treatment was compared with the profile after intravenous injection of the allergenic extract. The findings are discussed in relation to the mechanism by which local immunotherapy acts.

Decrease of allergen‐specific T‐cell response induced by local nasal immunotherapy

“…A last possible explanation for the same effects of SIT and LNIT is that LNIT is not just a local immunotherapy leading to local immunological modifications, but is also a systemic therapy. Indeed the absorption into the bloodstream of Parietaria judaica pollen extract administered intranasally was clearly shown in rabbits [ 41]. Moreover, it has been shown that radiolabelled Par j 1 allergen intranasally administered in healthy volunteers, appeared into the plasma 15–20 min and peaks after 2–3 h after the local administration.…”

Monomeric chemically modified allergens: immunologic and Physicochemical characterigation

“…The allergen has been found in the systemic circulation after nasal or sublingual administration to experimental animals (21,22). Absorption of a radiolabeled allergen after sublingual administration follows a kinetic pattern, showing rapid appearance of the allergen in the systemic circulation which persists for several hours (22).…”

“…It is likely that the therapeutic action of these products is linked to the ability of allergenic components to pass through the mucosal barrier. The high molecular mass of polymerized allergens could hinder this passage, but native allergens involve a higher risk of side-effects because they reach the systemic circulation fast (21,22). Therefore, in any strategy aimed at obtaining allergens for administration by routes other than parenteral injection, an important goal would be to develop derivatives with lower allergenicity but fully preserved immunogenicity, and the same molecular size as the native form.…”

“…On the other hand, the rapid absorption of allergens after local administration (21,23) suggests it would be safer to use allergenic extracts with lower allergenic potency for IT, as this would lower the risk of side-effects.…”

Wirksamkeit und Sicherheit der sublingualen Immuntherapie (SLIT) - eine ausführliche Standortbestimmung

“…Nachdem sie zunächst beim Tier nachgewiesen wurde [32], konnte die systemische Resorption von Allergenen nach topi− scher Verabreichung auch beim Menschen bestätigt werden [33]. Das gereinigte Parietaria−judaica−Majorallergen Par j1 wur− de radioaktiv mit 123 [38,41].…”