Present Status of Spiculed Red Cells and Their Relationship to the Discocyte-Echinocyte Transformation: A Critical Review

The literature on spiculed red cells, contains a redundant nomenclature and contradictory claims on the pathogenesis of the abnormal red cells. A resolution of these difficulties requires knowledge of the many conditions that induce crenation in normal and abnormal red cells because these artifacts have frequently been confused with spiculed cells in the patient’s circulation.

The biconcave red cells (disocytes) can be transformed into crenated red cells (echinocytes) (1) by extrinsic factors (plasma incubated at 37°C for 24 hr, lysolecithin, high levels of fatty acid or physiologic levels of fatty acid in the presence of lysolecithin and many others); (2) by intrinsic factors, such as aging of red cells, which are probably related to depressed ATP; and (3) by washing in saline and the "glass effect" of observing cells between slide and cover slip. The extrinsically induced discocyte-echinocyte transformation is generally reversible by washing in fresh plasma, the intrinsically induced transformation is not. The discocyte-echinocyte transformation due to glass contact is prevented by observation between plastic cover slips. Echinocytes probably occur in various diseases, but such claims must be reevaluated because examination of fresh cells between plastic cover slips is necessary to exclude artifactual crenation during preparation of smears.

Sphero-echinocytes and spherocytes may develop with higher concentration of echinocytogenic agents. The relationship of these cells to echinocytes, on one hand, and prelytic spheres, on the other, needs further clarification.

The spiculed cells in the circulation of certain patients with liver disease are indistinguishable from the acanthocytes of abetalipoproteinemia. Acanthocytes can develop crenation superimposed on their own spicules and become acanthoechinocytes. It is suggested that the term burr cell for echinocyte and spur cells for the acanthocytes of liver disease be abandoned because they are redundant and do not allow for designation of the mixed forms of acantho-echinocytes which are of diagnostic importance.

Speculations are presented on the pathogenesis of echinocyte formation and their importance for an understanding of the structure of the red cell membrane.