Development and Evaluation of a High-Speed, Continuous-Flow, Automated Plasmapheresis Procedure for the Collection of Equine Plasma According to Current Good Manufacturing Practices

Abstract

The purpose of this investigation was to develop and evaluate a high-speed, continuous-flow, automated plasmapheresis procedure for the collection of equine plasma according to current good manufacturing practices. Once a safe and reliable method was achieved, the plasmapheresis procedure was used to perform serial donations. The effect of serial plasmapheresis on total plasma protein and total IgG concentrations was evaluated throughout the investigation. Adaptations were made to human-model automated plasmapheresis instruments and sterile collection sets, which allowed for dual-instrument, continuous-flow operation. Equine donors were connected to the modified collection sets via jugular vein catheters. The instruments extracted whole blood, infused an anticoagulant, fractionated the anticoagulated whole blood, harvested the plasma and returned the concentrated blood cells to the donors. The procedures lasted between 3 to 6 hours in length and yielded approximately 20L of plasma per 900kg horse. During the investigation, 3,240 plasmapheresis donations were performed, 143 different horses were plasmapheresed and more than 50,000L of plasma were collected. The majority of donors tolerated the procedure and remained calm during plasmapheresis. Adverse events associated with the procedure were minor, occurred with an extremely low frequency or were eliminated after making adjustments to the technique. iii The described plasmapheresis procedure was used to harvest 22ml of plasma per kg donor body weight at 14-day intervals. Donors experienced a statistically significant (p < 0.05) decrease in both total plasma protein and total IgG concentrations during the investigation. However, the decreases in concentration were not physiologically significant. Neither total protein nor total IgG concentrations were below the reference interval at the time of donation. Additionally, the concentrations did not decrease further with serial donations, but stabilized at a reduced concentration or returned to baseline. Despite the decreases in IgG concentration, the donors did not demonstrate an increase in disease incidence. These results indicate that the described serial plasmapheresis protocol allowed time for donor horses to replace lost plasma proteins and IgG. A safe and reliable method for automated equine plasmapheresis was achieved. The collection of 22ml of plasma per kg donor body weight at 14-day intervals did not cause sustained total protein or IgG depletion in the donors.