Allergen-specific immunotherapy in horses with insect bite hypersensitivity: a double-blind, randomized, placebo-controlled study.

The research paper titled “Allergen-specific immunotherapy in horses with insect bite hypersensitivity: a double-blind, randomized, placebo-controlled study” investigates how effective allergen-specific immunotherapy (ASIT) is for horses suffering from insect bite hypersensitivity (IBH), a prevalent cause of itchiness in these animals.

Objective of the Study

The aim of the study was to evaluate whether ASIT can help horses with IBH. The researchers used off-the-shelf allergen extracts and testing tools for their experiment.

Methodology

In this study:

• Twenty horses demonstrating seasonal itchiness and positive bodily reactions to the Culicoides extract were selected.
• An enzyme-linked immunosorbent assay test (Allercept®) was used for detecting concurrent allergen-specific IgE for other insects and environmental allergens.
• The ASIT was created by integrating relevant serologically positive allergens into the Culicoides extract.
• After the horses were divided randomly, ten were treated with ASIT and the remaining ten with a placebo solution.
• The clinical response was evaluated every four months over a year using a scoring system rooted in the severity of four clinical signs across ten different body regions.
• A weekly application of insect repellent was maintained on the subjects, which were not stabled, in order to mitigate the potential for dropouts.

Results

The researchers found that the clinical scores between the ASIT and placebo groups didn’t differ significantly at any point during the re-evaluation period. Interestingly, both groups seemed to improve comparably, which the authors attribute likely due to the use of the insect repellant.

Conclusions

The study concluded that, based on the commercially available extracts and tests used, the research was unable to prove a beneficial effect of ASIT after one year of continuous treatment in non-stabled horses suffering from IBH. Hence, it sheds doubt on the utility of ASIT in managing IBH in horses, albeit further research is needed for a more conclusive elucidation.