Effects of serial harvest of plasma on total plasma protein and total immunoglobulin G concentrations in donor horses involved in a plasmapheresis program.

OBJECTIVE: To determine the effects of intensive serial plasmapheresis on total plasma protein and total IgG concentrations in donor horses involved in a plasmapheresis program. ANIMALS: 18 horses (13 mares and 5 geldings; 13 Belgians, 3 Percherons, 1 Standardbred, and 1 warmblood) ranging from 7 to 14 years of age (mean ± SD, 10 ± 3 years) and weighing 822 ± 128 kg. PROCEDURES: Horses from which 22 mL of plasma/kg of donor body weight was harvested at 14-day intervals for a minimum of 8 consecutive plasmapheresis donations were retrospectively selected for use in the evaluation. Automated plasmapheresis procedures were performed by use of 2 modified plasmapheresis instruments/donor horse. Plasma samples were obtained at each donation and used for determination of total protein and total IgG concentrations. Total plasma protein concentrations were determined via refractometry. A commercially available ELISA was used to determine total equine IgG concentrations.
RESULTS: The 18 donor horses were used in 8 to 19 serial donations (mean ± SD, 13 ± 3 donations) during the study. Donor horses had significant decreases in both plasma protein and IgG concentrations over the study period. CONCLUSIONS AND CLINICAL RELEVANCE: Serial plasmapheresis procedures caused significant decreases in both plasma protein and IgG concentrations in donor horses; however, decreases were not physiologically relevant. Performing plasmapheresis in horses in accordance with the evaluated automated plasmapheresis procedures did not result in a critical decrease in total plasma protein or total IgG concentrations.