Erythrocyte Populations in Pyruvate Kinase Deficiency Anaemia Following Splenectomy

Abstract

The deformability of 3 previously described morphological populations of erythrocytes from splenectomized pyruvate kinase (PK) deficient patients was assessed using both Nucleopore filtration and micropipette techniques. Mean deformability was decreased in fresh cells from all patients studied. Selective measurements indicated that immature lobulated reticulocytes in each patient were the least deformable cells, followed by bizarre echinocytes characterized by a hyperviscous behavior, and by thin macrocytic discocytes whose values were closest to those of control erythrocytes. Poorly deformable reticulocytes in these patients, after initial trapping in the spleen, are unable to return to the circulation because of their inordinate dependence on mitochondrial oxidative phosphorylation for maintenance of a sufficient intracellular concentration of ATP; hence, their rapid and selective destruction. Splenectomy therefore may be beneficial by allowing such cells to mature more slowly in the circulation of these patients until they develop crenation and hyperviscosity, 2 manifestations of profound ATP depletion possibly leading to destruction by the liver.