Clinical survey of antibodies against red blood cells in horses after homologous blood transfusion.

This study examines the presence of antibodies against red blood cells (RBCs) in horses following homologous blood transfusion. The report found that half of the tested horses developed transfusion-related antibodies, with different reactions observed depending on the specific horse blood group antigen involved.

Research Objective and Methods

• The purpose of the study was to investigate the presence and effects of antibodies against red blood cells (RBCs) in horses after they had undergone homologous blood transfusion. Homologous transfusion refers to a procedure where blood is transferred from one horse (the donor) to another (the recipient).
• The researchers collected serum samples from 20 horses for analysis. Particular attention was paid to antibodies against specific horse blood group antigens: Aa, Ae, Db, and Dc.

Findings and Observations

• In their tests, researchers found transfusion-related antibodies against RBCs in ten out of the twenty horses sampled. The creation of these antibodies is a standard immunological response when the body detects foreign elements – in this case, the antigens in the transfused blood.
• Among the tested antigens, reactions occurred most frequently against Aa and Ae. Every Aa-negative horse that received Aa-positive RBCs developed antibodies against Aa, and these antibodies were detectable for at least one year post-transfusion. Ae-related antibodies were found in seven out of the eight horses given Ae-positive RBCs. Ae-antibodies appeared between one week and 154 weeks after transfusion and seemed to disappear as early as four weeks after transfusion in some horses.
• Antibodies against Db or Dc were detected in up to 33% of horses lacking these antigens but receiving blood transfusions with Db or Dc-positive RBCs. These antibodies appeared later than those associated with the A-system.
• Interestingly, the presence of transfusion-related antibodies did not appear to have deleterious effects on the horses’ offspring. Three mares with transfusion-related antibodies gave birth to healthy foals. Two of these foals had blood antigens that matched the alloantibodies of their dams (mothers). One of these foals, which was Aa-positive, was prevented from consuming colostrum containing Aa-antibodies from its dam. The other foal, which was Db-positive, remained healthy despite nursing from a mare with serum antibodies against Db.

Implications of the Study

• This research provides insight into the immunological responses of horses following homologous blood transfusion. It indicates that a significant proportion of horses may develop antibodies against transfused RBCs, particularly if the blood contains Aa or Ae antigens.
• The findings also suggest the antibodies created due to blood transfusion do not negatively affect the health of the horse’s offspring, which is an important finding for breeding considerations.
• The delayed response to some antigens indicates that the body’s reaction to foreign RBCs can vary, likely due to differences in the immunological properties of the individual blood antigens.