Comparison of four filters for leukocyte depletion of single donor plateletapheresis products.

Removal of leukocytes from platelet suspensions is important in preventing the development of alloimmunization to HLA antigens in repeatedly transfused patients. Several types of filters have recently become available to remove leukocytes from platelet suspensions. We have compared the results obtained with Pall PL100S, Pall PL50S, Sepacell PL-10N and Sepacell PL-5N filters. Platelets were obtained by plateletapheresis using the Haemonetics V-50 TSPP surge procedure. A total of 160 platelet suspensions were studied, 40 for each type of filter used. The median number of leukocytes pre-filtration was 321x10 6 (range: 16-4068). The median number of leukocytes post-filtration was 2x10 6 ( less than 1-521) and was dependent on the number of leukocytes present pre-filtration but not on the type of filter used. All filters tested showed approximately a 2 log 10 reduction of leukocytes. When the number of leukocytes was below 500x10 6 pre-filtration, the number of leukocytes post-filtration did not exceed 10x10 6. Overall platelet loss was 11+/-7% and was lowest with the Pall PL50S filters (7+/-7%). Mean platelet volumes post-filtration were decreased with all types of filters used.