Leukotrap, a device for white cell poor platelets quality control studies In vitro and In vivo

Most febrile transfusion reactions are due to leucoagglutinins. Cutter's Leukotrap platelet pooling bag has a distal conic pouch for depleting the platelets of white blood cells by centrifugation. We tested 33 Leukotraps each containing six platelet units in vitro and 32 in vivo. The mean in vitro platelet count was 3.7 ± 0.5 × 10¹¹ platelets before, and 3.0 ± 0.5 × 10¹¹ after spinning, representing a platelet recovery of 80.2 ± 9.6% Mean white blood cells were 3.8 ± 0.6 × 10⁸ before, and 0.6 ± 0.1 × 10⁸ after centrifugation, this constituting a white cell removal of 83.5 ± 7.7%. pH ranged from 7.37 for 24-h platelets to 7.19 for 96-h platelets. 24-h after platelet pooling, all Leukotraps were sterile. Platelet aggregation with physiologic agents showed little change compared to individual platelet units. Glucose ranged between 418 and 336 mg/dL, pCO₂ between 27.8 and 19.1 mmHg, but pO₂ dropped drastically from 74.8 mmHg to 11.6 mmHg. Hypotonic osmotic recovery was satisfactory. In vivo studies were carried out with pooled, leucocyte-poor platelets which were transfused to six bone marrow transplant patients with no splenomegaly or septicemia at the outset. These patients had all demonstrated febrile transfusion reactions to standard donor units. The mean platelet increment was 16.8 × 10⁹/L. A single febrile transfusion reaction witnessed in one patient, was accompanied by an adequate platelet response. Hence Leukotrap is a useful clinical tool for reducing febrile transfusion reactions related to white blood cells.