Das Alpha-Gal-Syndrom umfasst eine um 3–12 Stunden verzögert
einsetzende z.T. schwere Nahrungsmittelanaphylaxie. Diese Latenz kompliziert die
Diagnosestellung ebenso wie die Tatsache, dass das auslösende Allergen
ein Zucker ist, da proteinbasierte Testverfahren negativ bleiben können.
Diese Arbeit beschreibt die Entdeckung dieser neuen Entität, ihre
Ursachen, ihre Risiken und die relevante Diagnostik.
Abstract
The alpha-Gal syndrome is characterized by a 3–12 hour delay in
onset of sometimes severe food anaphylaxis to mammalian meat and products.
Alpha-Gal (galactose-alpha 1,3-galactose) is a disaccharide not existent in
humans, which makes it immunogenic. It induces IgE antibody-mediated allergy
with a significantly delayed onset of response to red meat and innards
(3–6 [up to 12] hours). This latency complicates diagnosis, as does the
fact that the triggering allergen is not a protein as known for other food
allergies, but a sugar, so that protein-based testing methods often remain
negative. Since alpha-Gal can also be found in drugs depending on how they are
manufactured or extracted, it can also induce immediate-type allergies to drugs.
One example is the chimeric treatment antibody Cetuximab. The intravenous
injection will induce an immediate type reaction after several minutes in
individuals with pre-existing IgE-antibodies to alpha-Gal.
The main route of sensitization is bites from certain tick species, so alpha-Gal
syndrome is actually considered a tick-borne disease.
Most patients with alpha-Gal syndrome develop skin symptoms such as pruritus,
erythema, local and or generalized urticaria and/or angioedema, and
approximately 70% develop gastrointestinal symptoms. Half of the
patients suffer from anaphylaxis (reactions that involve two or more organ
systems). Approximately one-fifth describe isolated gastrointestinal symptoms,
representing an endoluminal food allergy.
It is likely that gastrointestinal symptoms are an underdiagnosed symptom of the
alpha-Gal syndrome. Therefore, if new onset gastrointestinal symptoms such as
periodic cramping, nausea, and diarrhoea occur, alpha-Gal syndrome should be
considered, and the appropriate diagnostics be performed by an allergist.
Schlüsselwörter
Fleischallergie - verzögerte Anaphylaxie - Medikamentenallergie - Milchallergie - Einzelallergene - kreuzreaktive Kohlenhydratepitope (CCD) - zeckenübertragbare Erkrankung
Key words
meat allergy - delayed anaphylaxis - single allergens - cross-reactive carbohydrate determinants (CCD) - tick-borne disease - milk allergy, drug allergy
