Evaluation of leukapheresis and thrombocytapheresis in the horse.

This research assesses the impact and efficacy of leukapheresis, a procedure to remove white blood cells from the bloodstream of horses. It was found that the process collected significant volumes of leukocyte-rich plasma and the administration of hydrocortisone improved the harvesting of white blood cells. Additionally, the study examined any correlation between neutrophil yield and other variables, finding that preleukapheresis white blood cells and neutrophil counts showed a strong positive relationship.

Leukapheresis Procedure and Impact

• The researchers used continuous-flow centrifugation leukapheresis techniques on 10 horses – half of which were treated with corticosteroids, while the rest weren’t medicated. They collected up to 300-ml volumes of leukocyte-rich plasma from each horse.
• Different white blood cell counts were performed on the animals before (as a benchmark) and within 48 hours after the leukapheresis.
• The administration of hydrocortisone led to an increase in total WBC and neutrophils leading to better harvesting of these cells.
• For the nonmedicated horses, the average yield of leukocytes was 3.38 X 10(10) in the 300-ml volume, while the corticosteroid-stimulated horses averaged 6.88 X 10(10) leukocytes.
• Post-leukapheresis, the WBC counts had a median decrease of 38% in nonstimulated horses and about 30% in the stimulated ones. However, within 6 hours after the procedure, the circulating WBC counts of all horses had returned to preleukapheresis values.

Creation of Neutrophils

• The scientists also investigated the relationship between four variables (preleukapheresis WBC and neutrophil counts, preleukapheresis lymphocyte count, and the packed cell volume (PCV) of the leukocyte-rich plasma), using simple (pair-wise) correlation and multiple linear regression.
• A significant positive correlation was found between neutrophil yield and preleukapheresis WBC and neutrophil counts.

Effect of Sodium Citrate on Serum Calcium Concentrations

• Sodium citrate was used in the collection system to prevent the blood outside the body from clotting. Therefore, ionized and total serum calcium concentrations were monitored before and after the leukapheresis procedure.
• Whilst the total serum calcium concentrations remained the same, the ionized calcium concentrations saw a drop of about 33% during the 2-hour leukapheresis procedures from baseline values.
• Some horses exhibited mild muscle fasciculations, which are the only clinical signs of citrate toxicity observed.