Effect of the added plasma rinseback on residual cell types in plateletpheresis leukoreduction systems.

Background: Platelets collected by the Trima Accel apheresis device (Terumo BCT) are automatically leukoreduced through a leukoreduction system (LRS) where WBCs are trapped in a conical-shaped LRS chamber. The content has been used as a valuable source of mononuclear cells for research purposes. In frequent, long-term platelet apheresis donors, lymphopenia has been associated with the use of LRS chambers, and implementation of plasma rinseback at the end of the procedure has been shown to mitigate the depletion of lymphocytes. In this report, the cellular content of the LRS chamber and remaining disposable was characterized with and without plasma rinseback.

Study design and methods: Trima disposable sets were obtained from apheresis platelet collections in 100% plasma or 35% plasma/65% PAS with or without plasma rinseback at the end of the collections. Cellular content was drained from the LRS chamber and the disposable and was characterized using a hematology analyzer and flow cytometer to establish total cell counts and proportions of RBC, platelet, and WBC subpopulations.

Results: LRS chambers contained approximately 10⁹ WBCs, with the majority being lymphocytes and monocytes. The addition of plasma rinseback significantly decreased the number of WBCs remaining in the disposable, thereby increasing the number of WBCs returned to the donor. However, rinseback did not impact the WBC content of the LRS chamber itself.

Conclusions: Blood Centers using the Trima Accel instrument may reduce lymphopenia in regular platelet donors by implementing plasma rinseback, while ensuring the cellular content of the LRS chamber intended for research purposes remains unaffected.