Cabot Rings

Cabot Rings, discovered by Cabot in 1903, are delicate, thread-like structures located inside red blood cells, most often in the form of a small or large eccentrically situated circle, frequently in the shape of a figure eight, a rocket, or another figure [see separate table (pp. 223-224), Fig. 15]. According to Giemsa, Cabot rings are colored bright red, more rarely bluish. The red blood cells in which they occur may otherwise appear completely normal, but they may also be polychromatophilic, contain basophilic granules, Jolly bodies, etc. Most authors consider Cabot rings to be remnants of nuclear membranes that have undergone certain changes and therefore stain differently. Schilling finds Cabot rings alongside preserved nuclei and is inclined to consider them as protoplasmic formations. They occur in malignant anemia and rarely in other severe anemias and are considered, similar to nuclei and Jolly bodies, as a sign of increased regenerative activity of the erythropoietic system and a pathologically altered process of nuclear disappearance.