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Quality and Safety of Platelet Apheresis Concentrates Produced with a New Leukocyte Reduction System

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/μl to 1,405±383/μl (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 × 1011 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 × 105 (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.