Objectives: Contaminating white blood cells (WBC) in apheresis platelet concentrates (PC) can cause a variety of adverse effects after platelet transfusion. To obtain PCs with low WBC contamination, a new leukoreduction system (LRS) utilizing 'fluidized particle bed' technology has recently been introduced.
Methods: We prospectively examined the effect of LRS apheresis on the donor, the quality of the resulting PCs (n = 120), and the platelet increment in the corresponding recipients. Conventionally prepared apheresis PCs served as control group (n = 27). Platelet glycoproteins were examined by flow cytometry.
Results: In LRS apheresis, we observed no serious adverse effects on the donors, but the postdonation absolute lymphocyte counts were reduced from 1,787 +/- 505/microliter to 1,405 +/- 383/microliter (p < 0.001). Comparable results were seen in non-LRS donors. The collection efficiency of the LRS procedures was 50.0 +/- 7.6%, resulting in a yield of 4.3 +/- 1.0 x 10(11) platelets/PC. In flow cytometry, platelet glycoproteins in LRS PCs were not elevated: mean fluorescence of CD62 (6 +/- 4) or CD63 (9 +/- 3) in comparison with non-LRS PCs (mean fluorescence of CD62: 7 +/- 4, CD63: 8 +/- 3). Median leukocyte contamination of the LRS PCs was 0.41 x 10(5) (range 0.07-8.5) WBCs/unit. In 43 recipients, the 24-hour corrected count increments after transfusion of LRS PCs (12,530 +/- 8,761) were essentially the same as those of 20 recipients of non-LRS PCs (13,133 +/- 9,812; p = 0.75).
Conclusions: LRS apheresis appears to be a safe procedure, which produced effective PCs with few contaminating leukocytes. With new apheresis technology, filtration of PCs may become superfluous.