Leukoreduction System Chambers as a Source of Viable Human Peripheral Blood Mononuclear Cells.

Many blood banks are using apheresis machines to collect blood components such as platelets (PLTs), RBCs, or plasma. Especially, leukoreduced plateletpheresis using apheresis instrument (Trima Accel, Gambro BCT, Lakewood, CO) provided subsidiary cell products retained in leukoreduction system (LRS) chamber that was originally discarded. The LRS chamber is a conical-shaped chamber that uses saturated, fluidized, particle bed filtration technology to remove WBCs from PLTs. In the current study, a total of 24 LRS chambers from different donors were investigated to determine it would be a valuable source of viable human peripheral blood mononuclear cells (MNCs). The proportions of CD3+, CD19+, CD16+/CD56+, CD14+, CD45+ cells, and absolute CD34+ cell count within the LRS chambers were determined by flow cytometry. Dendritic cells (DCs) were generated from the immunomagnetically purified CD14+ cells from LRS chamber and characterized by phenotypic surface marker and stimulatory capacity in an allogeneic mixed lymphocyte reaction. In the LRS chamber, the total number of WBC count was 1.1 × 10⁹ ± 0.3 × 10⁹ and the mean percentage of MNCs was 80.6 ± 13.1%. The mean proportion of T cells, B cells, NK cells, CD14+ monocytes among CD45+ cells was 54.3 ± 11.5%, 6.4 ± 3.1%, 14.6 ± 3.9%, 12.9 ± 7.5%, respectively. Total absolute CD34+ cell count in LRS chamber was 0.95 × 10⁶ ± 0.65 × 10⁶. Also, we could demonstrate CD14+ cells isolated from LRS chamber was capable of differentiating into functionally mature DCs in vitro. LRS chambers are a valuable and convenient source of viable human peripheral blood mononuclear cell population and could replace standard buffy coat preparations for research applications.