Leukopoor platelet concentrates: a direct comparison of three blood filters

Repeated exposure to foreign human leukocyte antigens (HLA) present on both platelets and leukocytes often results in refractoriness to transfusions of platelet concentrates. Evidence now exists which suggests that the leukocytes are more immunogenic and that their removal from blood products may delay or prevent the development of refractoriness. In this study, the ability of three blood filters to remove leukocytes from platelet concentrates was directly compared. Pooled platelet concentrates were filtered through the Fenwal 4C 2131 depth microaggregate blood filter (MABF), the Pall Ultipor SQ 40S screen MABF, and the Terumo Imugaard IG-500 blood filter. The results were then compared to a previous study (done in the same laboratory) which used differential centrifugation to render platelet concentrates leukocyte-poor. The Fenwal and Pall MABFs did not remove leukocytes or platelets from platelet concentrates. In contrast, the Terumo filter removed 90.2 percent of the leukocytes while sacrificing 7.5 percent of the platelets; results superior to differential centrifugation which removed 84.9 percent of the leukocytes but sacrificed many more platelets, 32.3 percent. The Terumo Imugaard IG-500 blood filter produces leukocyte-poor platelet concentrates as efficiently as differential centrifugation with much less platelet loss. Use of the Terumo filter may aid further studies required to evaluate the use of leukocyte-poor platelet concentrates for the prevention of platelet refractoriness.