LOW RETENTION OF WHITE CELL FRAGMENTS BY POLYESTER FIBER WHITE CELL-REDUCTION PLATELET FILTERS

Background: There is intense interest in the potential of current whit e cell (WBC)reduction filters to prevent the alloimmunization of patie nts by the residual donor WBCs in filtered blood components transfused to them. Little attention has been paid to the capacity of current sy nthetic fiber filters to remove WBC membrane fragments bearing detecta ble leukocyte antigens. Study Design and Methods: Fluorescein isothioc yanate-conjugated monoclonal antibody to a universal WBC membrane anti gen (CD45) and high-speed centrifugation coupled with ficoll-hypapue d ifferential sedimentation were used to quantitate low-density WBC frag ments In single-donor platelet components before and after filtration to determine if a polyester fiber filter retained WBC fragments.Result s: Prefiltration measurements in 25 single-donor platelet components i ndicated that WBC fragments increased with length of storage up to 5 d ays at room temperature (p<0.0001). When fragments in eight components were measured before and after filtration, absolute values for differ ences were insignificant (p = 0.15). Conclusion: WBC fragments were po orly retained by these polyester fiber WBC-reduction filters. The anti genicity of WBC fragments could contribute to the WBC alloimmunization of some recipients of WBC-reduced blood components.