Abstract
Based on the electron microscopic observations of the red pulp of the spleens from the patients with hemolytic anemias, such as hereditary spherocytosis, pyruvate kinase deficiency, pyrimidine 51-nucleotidase deficiency, unstable hemoglobin hemolytic anemia and autoimmune hemolytic anemia, the mechanism of hemolysis was tudied. Morphologically, stagnation of red cells in the cord, erythrophagocytosis by the cordal macrophages and occasinally by the sinus endothelial cells, intravascular hemolysis as evidenced by the red cell ghosts, and removal of rigid inclusions at the sinus wall were noted. All these findings were related directly or indirectly to the mechanism of hemolysis. Both congenital and acquired abnormalities of red cellls (abnormalities of membrane, metabolic process and hemoglobin molecule) are exaggerated during the passage through the spleen, finally leading to the reduced deformability and/or increased osmotic fragility of defective red cells. This function of the spleen is accomplished by the combination of anatomical structure, metabolic conditions and immunologic ability of of the red pulp. Thus, the spleen is not a simple filter, but works as the apparatus to scrutinize the circulating red cells and destroys only the defective ones.
