by Jennifer Chain, Ph.D.
At the Oklahoma Blood Institute, we collect more than 20,000 platelet donations each year. During routine collection, platelets are separated from other blood components by centrifugation. Leukoreduction system (LRS) chambers play a direct role in the cell reduction process used to collect the platelets. When the donation process is completed, red blood cells, white blood cells, and plasma are returned to the donor. However, a small volume of concentrated white blood cells remains inside the LRS chamber. These chambers are typically discarded, but if they are sterilely separated from the collection kit, the white blood cells contained within can be used in a whole host of research applications. Collecting these chambers and providing them to scientists for research purposes is one way Oklahoma Blood Institute is being good stewards of our donors’ gift of life-saving platelets.
We have analyzed a group of LRS chambers for the number of cells and the different cell types contained within. An average of 1.8x109 total nucleated cells (Table 1) are obtained from a single LRS chamber, with an average of 96.3% of those cells being lymphocytes and monocytes (Mononuclear Cells). CD3+ T cells make up between 30% and 65% of the total LRS chamber contents, depending in the individual. Other common subpopulations in these chambers are B cells, monocytes, and NK cells. CD3+ T cells are currently being used in cutting-edge cancer treatments called CAR T cell therapies, and both NK cells and gamma/delta T cells are emerging as potential cell types for future CAR therapies. The CD14+ monocyte population has the potential to develop into dendritic cells, which can be used to develop cancer vaccines. Laboratories and companies in the research phases of their therapy development can benefit from using cells from LRS chambers as a source of their lymphocyte and monocyte cell populations. OBI is currently developing technology to harvest the cells out of the LRS chamber in an FDA compliant way so these cells can be used directly in allogeneic clinical applications.