Influence of environmental and genetic factors on allergen-specific immunoglobulin-E levels in sera from Lipizzan horses.
Authors: Eder C, Curik I, Brem G, Crameri R, Bodo I, Habe F, Lazary S, Sölkner J, Marti E
Journal: Equine veterinary journal
Summary
# Editorial Summary Environmental management significantly influences allergic sensitisation in horses, yet genetic predisposition plays a substantial independent role in determining immunoglobulin-E responses to fungal allergens. Researchers measured allergen-specific IgE antibodies against whole mould extracts (Alternaria alternata and Aspergillus fumigatus) and five individual recombinant allergen proteins in 448 Lipizzan horses across six studfarms, using ELISA to quantify serum levels and statistical modelling to partition environmental and heritable variation. Whilst studfarm-specific factors—such as bedding type, ventilation and hay storage—created significant differences in IgE production, genetic factors accounted for approximately 33% of the variation in responses to whole mould extracts and 21% for one specific Aspergillus protein component, with equine leucocyte antigen (ELA) class I markers showing consistent associations, particularly ELA A8 conferring protection against sensitisation to certain Aspergillus proteins. These findings suggest that breeding decisions could potentially influence allergic disease susceptibility, though optimising stabling conditions remains critical; clinicians should recognise that horses with particular genetic markers may require tailored environmental management strategies to prevent chronic respiratory disease, and that serum-specific IgE testing could become a more targeted tool for identifying at-risk individuals within breeding populations.
Read the full abstract on PubMed
Practical Takeaways
- •Environmental factors at individual studfarms play a significant role in horses' allergic responses to mould allergens, suggesting management and housing modifications may reduce clinical signs
- •Genetic predisposition influences IgE production against some allergens (moderate heritability for extracts and Asp f 8), which could inform breeding decisions for horses prone to respiratory allergies
- •MHC typing may help identify horses genetically predisposed or resistant to specific mould allergen sensitization, enabling targeted management strategies for susceptible individuals
Key Findings
- •Studfarm-specific environment significantly influenced IgE levels against mould allergens (Alternaria alternata and Aspergillus fumigatus)
- •Heritability of 0.33 was found for IgE levels against mould extracts and 0.21 for rAsp f 8-specific IgE, indicating genetic contribution to allergen-specific IgE production
- •ELA A8 (equine leucocyte antigen) was most consistently associated with undetectable IgE titres against rAsp f 7 and rAsp f 8
- •ELA A1 was associated with higher specific IgE levels while ELA A14 was associated with lower IgE levels against mould extracts