RESUMO
BACKGROUND: We evaluated residual leukocytes characteristics of white cell(WBC) reduction filter in platelet concentrates. Differential count and lymphocyte subset changes were measured before and after leukocyte filtration in platelet concentrates. MATERIAL AND METHODS: Ten units of platelet concentrates were prepared and were filtered with WBC-reduction filter(Sepacell PLS 5A, Japan). After filtration of blood products, WBC and differential leukocyte count and lymphocyte subsets were counted by microscopic examination of Wright-Giemsa stained smear and Facscan(Becton-Dickinson, USA). Monoclonal antibodies used for lymphocyte subset test were CD3(FITC), CD4(FITC), CD8(PE), CDl4(PE), CDl6(PE), CDl9(PE), CD33(PE), CD56(PE), IgGl(FITC), IgG2(PE). RESULTS: The main population of residual leukocytes after filtration was mainly lymphocytes(96.7%), and CD3 positive T lymphocytes showed 23.8% positivity of residual leukocyctes and the next were NK cell(8.7%). B lymphocytes were rarely found(<0.01%) and CD4/ CD8 ratio was within normal limits. CONCLUSION: The leukocyte reduction filters(Sepacell PLS-5A) would be effective for prevention of platelet alloimmunization but not sure about the effect for prevention of TA GVHD.