Studies in red blood cell preservation. 1. Effect of the other formed elements

The purpose of this study was to determine if the removal of most of the leukocytes and platelets would affect the in vitro characteristics of stored red blood cells (RBC). Fresh RBC concentrates prepared by removing platelet-rich plasma and filtration through Imugard IG 500 filters were compared with unmanipulated units after storage for up to 56 days. The filtered units were significantly better after 56 days storage for supernatant K+ (p = 0.001), hemolysis (p = 0.05), total vesicle membrane protein shed (p = 0.03), and RBC morphology score (p = 0.04). These differences occurred even though ATP levels were well maintained in both groups. The measurements that did not differ significantly were pH, hematocrit, ATP, 2,3-DPG, glucose and supernatant Na+. It is suggested that enzymes, leukotrienes, catecholamines and eicosanoids released by degenerating leukocytes and platelets may be inimical to RBC. Some may act as agonists on alpha-adrenergic and cholinergic muscarinic receptors present on RBC membranes.