Beschreibung:
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<jats:title>Background</jats:title>
<jats:p>Insect bite hypersensitivity (IBH) is an IgE-mediated allergic dermatitis in horses incited by salivary allergens from <jats:italic>Culicoides spp</jats:italic>. IBH does not occur in Iceland, as the causative agents are absent, however a high prevalence is seen in horses exported to <jats:italic>Culicoides</jats:italic>-rich environments.</jats:p>
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<jats:title>Aims</jats:title>
<jats:p>To study the natural course of sensitization to <jats:italic>Culicoides</jats:italic> allergens and identify the primary sensitizing allergen(s) in horses exported from Iceland utilizing a comprehensive panel of <jats:italic>Culicoides</jats:italic> recombinant (r-) allergens.</jats:p>
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<jats:title>Method</jats:title>
<jats:p>IgE microarray profiling to 27 <jats:italic>Culicoides</jats:italic> r-allergens was conducted on 110 serological samples from horses imported to Switzerland from Iceland that subsequently developed IBH or remained healthy. Furthermore, a longitudinal study of 31 IBH horses determined IgE profiles the summer preceding first clinical signs of IBH (T<jats:sub>IBH</jats:sub>-1), the summer of first clinical signs (T<jats:sub>IBH</jats:sub>) and the following summer (T<jats:sub>IBH</jats:sub>+1). In a group of Icelandic horses residing in Sweden, effects of origin (born in Iceland or Sweden) and duration of IBH (<4 years, 4–7 years, >7 years) on <jats:italic>Culicoides</jats:italic>-specific IgE was evaluated. Sero-positivity rates and IgE levels were compared.</jats:p>
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<jats:title>Results</jats:title>
<jats:p>At T<jats:sub>IBH</jats:sub>, horses were sensitized to a median of 11 r-allergens (range = 0–21), of which nine were major allergens. This was significantly higher than T<jats:sub>IBH</jats:sub>-1 (3, 0–16), as well as the healthy (1, 0–14) group. There was no significant increase between T<jats:sub>IBH</jats:sub> and T<jats:sub>IBH</jats:sub>+1(12, 0–23). IBH-affected horses exported from Iceland had a significantly higher degree of sensitization than those born in Europe, while duration of IBH did not significantly affect degree of sensitization.</jats:p>
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<jats:title>Conclusion</jats:title>
<jats:p>Significant sensitization is only detected in serum the year of first clinical signs of IBH. Horses become sensitized simultaneously to multiple <jats:italic>Culicoides</jats:italic> r-allergens, indicating that IgE-reactivity is due to co-sensitization rather than cross-reactivity between <jats:italic>Culicoides</jats:italic> allergens. Nine major first sensitizing r-allergens have been identified, which could be used for preventive allergen immunotherapy.</jats:p>
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