Quantitative changes of red blood cell shapes in relation to clinical features in beta-thalassemia/HbE disease

Quantitative analysis of red blood cell (RBC) shapes was performed in 79 patients with beta-thalassemia/HbE disease, using scanning electron microscopy (SEM). Most patients had many abnormal RBC shapes, namely: torocytes, codocytes, dacryocytes, keratocytes, and schizocytes with a reduction in the number of normally shaped red blood cells (discocytes). Splenectomy, larger splenic sizes, and increasing anemia all were associated with a further reduction in the number of discocytes, reflecting increasing numbers of abnormally shaped RBC. The number of torocytes was increased with anemia; a larger spleen was associated with a decrease and splenectomy with an increase in the number of torocytes, indicating that they are destroyed by the spleen. The numbers of codocytes and echinocytes were singularly associated with splenectomy. Most likely, almost all of the echinocytes are destroyed by the spleen. The red blood cell types that occur as a result of RBC fragmentation, namely, dacryocytes, keratocytes, and schizocytes, were remarkably associated with the splenic status; larger splenic size was associated with an increased number of these cells, while splenectomy was associated with a noticeable reduction in their numbers. This finding confirms the role of the spleen in the fragmentation of thalassemic RBC. An increasing degree of anemia did not affect the number of codocytes and echinocytes, but was associated with a mild increase in the number of fragmented RBC and a significant increase in the number of torocytes.