SEPARATION OF RBCs WITH IMPROVED SURVIVAL FROM NORMAL BLOOD

Abstract

This study investigated the use of density gradients to prepare RBCs with greater potential “in vivo” survival. Solutions of the desired density, osmolarity, salt composition and pH were easily prepared with Stractan II (S-11), an inexpensive water soluble arabino-galactan polymer of 30,000 daltons. RBCs were centrifuged on parallel discontinuous gradients of S-11 and crystalline albumin. Similar age dependent separation in both systems was indicated by the same rates of decline of reticulocytes, glucose-6-phosphate-dehydrogenase, pyruvate-kinase and hexokinase. Rabbit RBCs were divided on single layers of S-11 into light (young) and heavy (old) fractions of varying proportions. Either fraction or both or unfractionated RBCs were labelled with 51Cr alone or with 1251 also and reinjected into the donor. The rate of decline of radioactivity was followed until total disappearance. When compared to the unfractionated cells, the rate of decline of radioactivity was similar in the combined fractions; it was slowest and fastest in the light and heavy 10$ fraction respectively and it was significantly slower and faster in the light and heavy 50% fractions respectively. Corresponding differences were found for the interval to total disappearance thus ruling out differential label elution. These findings suggest that this technique may be used to obtain sizeable RBCs fractions of improved survival for transfusion to patients with chronic anemia.