THE DEFICIENCY of the enzyme pyruvate kinase (PK) in the human erythrocyte is associated with the group of congenital nonspherocytic hemolytic anemias formerly classified as type II by the autohemolysis test of Dacie.1 Erythrocytes from such patients exhibit marked autohemolysis when incubated in saline which is not corrected by the addition of glucose but is usually corrected in the presence of adenosine triphosphate (ATP). More than 60 patients with this enzyme deficiency have been described in the three years since its discovery by Tanaka et al.2 No therapy has been reported to be of general benefit. The purpose of this paper is to describe two further cases, emphasizing the beneficial effects of splenectomy and the marked variability of the clinical course in this genetic deficiency.
Hematologic studies were carried out using standard techniques. Autohemolysis studies on erythrocytes were performed as published by Dacie.1 Pyruvate kinase activity of the erythrocytes