Background: Neutrophils are important mediators of inflammation and may be activated by foreign surfaces in apheresis systems. Because most of the WBCs are returned to the donor, it was investigated whether artificial activation leads to altered donor neutrophil function.
Study design and methods: Three apheresis systems (Amicus, Autopheresis-C, and CS-3000; all: Baxter Fenwal) were investigated. Preapheresis and postapheresis blood samples were drawn from 10 volunteer donors, with all three apheresis systems used in random order for each donor. Changes in neutrophil phagocytic ability, oxidative burst, and expression of L-selectin and CD11b were measured by flow cytometry, and plasma concentrations of myeloperoxidase and lactoferrin were measured by EIA. Complement activation was evaluated by quantification of C3bc and the terminal complement complex by EIA.
Results: Neutrophil expression of L-selectin increased after apheresis (p = 0.02), and the production of oxygen radicals was reduced (p = 0.01). This effect was possibly a result of priming. Complement was not activated. There were no significant differences in neutrophil function after apheresis with any of the three apheresis systems.
Conclusions: Neutrophil function was altered after apheresis, although to a very small extent, and contact between neutrophils and the foreign surface in the apheresis systems is found to be a biotolerant procedure.