Distribution of leucocyte antigens in Icelandic horses affected with summer eczema compared to non-affected horses.

The research studied the distribution of leucocyte antigens in horses from Iceland that were affected with summer eczema, compared with those that were not affected. The results showed a significant difference in the distribution of one antigen, Be 8, between horses with and without the disease.

Study Overview

• The scientists examined 303 horses that were exported from Iceland to Norway, Sweden, Denmark, Switzerland or Germany. They were tested for their distribution of leucocyte antigens, which are cell surface proteins that play a crucial role in the immune system’s response to foreign substances.
• Out of the total population, 136 horses were found to be affected by summer eczema, a chronic, recurrent skin disorder often occurring in horses that are hypersensitive to insect bites.

Methodology and Test Parameters

• The researchers used a panel of sera (the clear part of the blood left after coagulation) that recognized internationally accepted Equine Leucocyte Antigen (ELA) specificities from A1 to A10.
• The study also delved into nine workshop specificities (W11 to W15 and W18 to W21), some local specificities characterised in Switzerland (Be I, Be III, Be 8, Be 25, Be 26, Be 27), and two antigens that are non-major histocompatibility complex (MHC)-linked (Ely 1:1, Ely 2).

Results of the Study

• Out of all the antigens tested, the researchers found only Be 8 antigen showed a statistically significant difference in its distribution when comparing the affected versus the non-affected horse populations.
• This disparity points to Be 8 having a relative risk factor of 2.5, with a chi-squared (x2) value of 10.11, and a corrected P-value less than 0.01, indicating that fewer than 1 in 100 times would this result occur by chance, thus underlining the significance of this finding.