Horse allergy: Curly Horses can mediate immune tolerance

Abstract

American Bashkir Curly Horses are claimed to be hypoallergenic, but this has not been clinically proven. In the present study, the effect of exposure to Curly Horses was investigated in 141 patients allergic to horses by measuring their lung function and nasal patency during Curly Horse contact. Continuous contact with Curly Horses, including riding and brushing, decreased the allergic ridersʼ reactivity as measured by FEV₁, PEF, and PNIF. Subsequent visits (up to 40 or more hours of riding) further reduced reactivity to the Curly Horses. Allergic events to horses occurred only in 72 out of 1312 riding hours, mainly in the first ten riding hours.

In 41 out of the 141 patients, it was further investigated whether repeated exposure to Curly Horses could induce tolerance to other horses. Patients in the tolerance induction study were tested annually for horse allergy using a nasal provocation test. The tolerance induction study showed that exposure to Curly Horses induced immune tolerance to other horses in 88% of patients who completed the study.

To understand the mechanism causing hypoallergenicity, we performed IgE immunoblots to determine whether Curly Horse hairs contain IgE binding proteins. However, no differences in IgE reactivity were found between Curly and non-Curly Horses. Moreover, the immune tolerance induction study patients did not show decreased IgE reactivity to hairs from Curly or non-Curly Horses even though patients had developed tolerance. However, we did find increasing levels of anti-horse IgG antibodies in the study patients.

Overall, our data strongly suggests that continuous exposure to Curly Horses can induce immune tolerance, rendering these patients non-reactive to horses. The reason for the reduced clinical allergenicity of Curly Horses remains unclear, but the data suggest that blocking IgG antibodies may be of importance for immune tolerance development.

Zusammenfassung

American Bashkir Curly Horses gelten als hypoallergen, was jedoch nicht klinisch bewiesen ist. In der vorliegenden Studie wurde die Wirkung der Exposition zu Curly Horses bei 141 Pferdeallergikern untersucht, indem die Lungenfunktion und der nasale Fluss während des Kontakts mit Curly Horses gemessen wurden. Der kontinuierliche Kontakt mit Curly Horses, einschließlich Reiten und Bürsten, verringerte die Reaktivität der allergischen Reiter, gemessen an FEV₁, PEF und PNIF. Nachfolgende Besuche (bis zu 40 oder mehr Reitstunden) verringerten die Reaktivität gegenüber den Curly Horses weiter. Sehr starke allergische Reaktionen auf Curly Horses traten nur in 72 von 1312 Reitstunden auf, hauptsächlich in den ersten zehn Reitstunden.

Bei 41 der 141 Patienten wurde weiter untersucht, ob eine wiederholte Exposition zu Curly Horses eine Toleranz gegenüber anderen Pferden induzieren könnte. Die Patienten der Toleranzinduktionsstudie wurden jährlich mit einem nasalen Provokationstest auf eine Pferdeallergie getestet. Die Toleranzinduktionsstudie zeigte, dass die Exposition gegenüber Curly Horses bei 88% der Patienten, die die Studie abschlossen, eine Immuntoleranz gegenüber anderen Pferden auslöste.

Um den Mechanismus zu verstehen, der die Hypoallergenität verursacht, führten wir IgE-Immunoblots durch, um festzustellen, ob Curly Horse-Haare IgE-bindende Proteine enthalten. Es wurden jedoch keine Unterschiede in der IgE-Reaktivität zwischen Curly Horses und Nicht-Curly Horses festgestellt. Darüber hinaus zeigten die Patienten der Immuntoleranzstudie keine verringerte IgE-Reaktivität gegenüber Haaren von Curly Horses oder Nicht-Curly Horses, obwohl die Patienten eine Toleranz entwickelt hatten. Allerdings fanden wir bei den Studienpatienten steigende Werte von IgG-Antikörpern gegen Pferde.

Insgesamt deuten unsere Daten stark darauf hin, dass eine kontinuierliche Exposition zu Curly Horses eine Immuntoleranz induzieren kann, sodass diese Patienten nicht mehr auf Pferde reagieren. Der Grund für die geringere klinische Allergenität von Curly Horses bleibt unklar, aber die Daten legen nahe, dass blockierende IgG-Antikörper bei der Entwicklung der Immuntoleranz von Bedeutung sein könnten.

Keywords

horse allergy - immune tolerance induction study - curly horse study - horse-induced rhinoconjunctivitis - horse-induced asthma bronchiale

Schlüsselwörter

Pferdeallergie - Immuntoleranzinduktionsstudie - Curly Horse-Studie - Pferde-induzierte Rhinokonjunktivitis - Pferde-induziertes Asthma bronchiale

Publication History

Received: 27 March 2023

Accepted after revision: 23 May 2023

Article published online:
12 October 2023

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