THE ORIGIN OF 'BURR' ERYTHROCYTES.

Abstract

The term ‘burr’red cell was introduced by Schwartz and Motto (1949) to describe irregularly shaped erythrocytes ‘having one or more large spiny projections’along their periphery. These abnormal erythrocytes are found most frequently in uraemia and gastric carcinoma and less frequently in association with bleeding peptic ulcer (Aherne, 1957). They are also seen in haemolytic anaemia where they are associated with fragmented erythrocytes (schistocytes), triangular forms, or other unusual shapes (Brain, Dacie and Hourihane, 1962). Recently they have also been described in aplastic anaemia (Lewis, 1962). On rare occasions they may be seen in blood smears of normal subjects. Very little is known about how these abnormal erythrocytes are produced. Dacie (1960) suggested that burr cells were artefacts produced on the slide as the cell dries. There is evidence suggesting that mechanical injury to the cell may be a major factor (Brain et al., 1962; Sayed, Dacie, Handley, Lewis and Cleland, 1961) but they may also result from the action of unknown metabolic or ‘toxic’factors. It is the purpose of this paper to present some morphological evidence that suggests a mechanism for their development. The sequence of events ending in a burr cell appears to be the formation of a vacuole at the periphery of the cell that subsequently ruptures through the cell membrane leaving a crater and a deformed erythrocyte.