Phenotypic characterization of white cells in white cell‐reduced red cell concentrate using flow cytometry

The residual white cell (WBC) content of donated units of red cell concentrate rendered WBC‐reduced by filtration through commercially available polyester filters was quantified and phenotypically analyzed. All studies were performed by flow cytometery. Quantification studies were performed with a DNA/RNA fluorophore, propidium iodide. WBC subset analyses were performed with fluorescence‐labeled monoclonal antibodies directed against various cluster differentiation (CD) loci. The results indicate that the filter removes in excess of 3 log10 total WBCs from the red cell components and depletes granulocytes to or beyond the specific assay's sensitivity of 3 log10. Total T and B cells, T4 and T8 lymphocytes, and monocytes are reduced by approximately 4 log10. These analyses provide plausible explanations for the clinical success of the filter and suggest other potential applications. 1991 AABB