Apoptosis and phagocytosis of allogenic blood elements in the spleen of rabbit after intravenous infusion

ABSTRACT

After the recent introduction of blood cell separators, separate blood cell components became available for therapy of the serious hematologic diseases. However, unmatched transfused leukocytes and platelets express a variety of antigens that can be recognized by immunoglobulins of the recipients. Since these transfusion trials were clinically disputed, an experiment was designed to study the ultra structural changes of these cells during apoptosis and phagocytosis processes in the spleen of adult rabbit over 24 hours period after intravenous infusion of allogenic formed blood elements. Blood formed elements were found to be trapped early inside the splenic parenchyma in samples taken two hours after infusion. Apoptosis occurred earlier in polymorph nuclear leukocytes probably due to their high content of hydrolytic enzymes. Splenic macrophages were easily identified among the heavy cellular population composing the splenic parenchyma by their general morphology and containment of lysosomes and digestive vacuoles. The phagocytic activity of these cells was found to be directed toward transfused allogenic dying and even apparently normal formed blood elements. Based on the previous data, it may be concluded that the transfused allogenic blood formed elements readily become trapped and phagocytosed early in the splenic filter. This in vivo model may provide us a simple method to the histopathological structural characteristics associated with the clinically described refractory responses to transfusion therapy and evokes inquiry about the value of unmatched leukocytes and platelets transfusions