Fifty to seven-five percent of RBC components from donors with sickle cell trait obstruct leukocyte reduction filters. People with sickle cell trait are healthy, but very low oxygen levels, low pH, and high hemoglobin concentrations can induce intracellular hemoglobin S polymerization. We have found that hemoglobin S polymerization due to low oxygen tension in venous blood and low ph and high osmolarity of the citrate anticoagulant is responsible for the failure of RBC components from donors with sickle cell trait to filter. The purpose of ongoing studies is to determine if the failure of sickle cell trait donor blood to filter can be avoided by improving the oxygenation of blood prior to filtration, reducing the exposure of RBCs to citrate or by the use of a combination of both. The oxygenation of blood will be improved by storing blood in gas permeable bags prior to filtration and using gas permeable flow paths to oxygenate blood as it is collected. The effects of citrate anticoagulant on filterability will be assessed by comparing blood collected by phlebotomy with blood collected by apheresis, which reduces citrate exposure by approximately 50%. RBC components collected from donors with sickle cell trait by both phlebotomy an apheresis will be collected with gas permeable flow paths and in gas permeable bags and there filterability will be tested. The goal of these studies is to develop a practical method to allow the successful leukocyte reduction by filtration of all RBC components collect from donor with sickle cell trait. The method should be easy to use in conjunction with existing blood collection technologies
