Color Atlas of Hematology - Practical Microscopic and Clinical ...

54Normal Cells of the Blood and Hematopoietic OrgansDistribution and Cell Quality in Erythropoiesis. In erythropoiesis polychromaticerythroblasts normally predominate. Proerythroblasts and basophilicerythroblasts only make up a small portion (Table 4). Here, too, aleft shift indicates an increase in immature cell types and a right shift anincrease in orthochromatic erythroblasts. Qualitatively, vitamin B 12 andfolic acid deficiency lead to a typical loosening-up of the nuclear structurein proerythroblasts and to nuclear segmentation and break-up in theerythroblasts (megaloblastic erythropoiesis).A left shift is seen in regenerative anemias except hemolysis. Atypicalproerythroblasts predominate in megaloblastic anemia and erythremia.A right shift is seen in hemolytic conditions (nests of normoblasts, erythrons).Distribution and Cell Quality in Granulopoiesis. The same principle is validas for erythropoiesis: the more mature the cells, the greater proportion ofthe series they make up. A left shift indicates a greater than normal proportionof immature cells and a right shift a greater than normal proportionof mature cells (Table 4). Strong reactive conditions may lead to dissociationsin the maturation process, e.g., the nucleus shows the structure ofa myelocyte while the cytoplasm is still strongly basophilic. In malignancies,the picture is dominated by blasts, which may often be difficult toidentify with any certainty.A left shift is observed in all reactive processes and at the start of neoplastictransformation (smoldering anemia, refractory anemia withexcess blasts [RAEB]). In acute leukemias, undifferentiated and partiallymatured blasts may predominate. In agranulocytosis, promyelocytes aremost abundant.A right shift is diagnostically irrelevant.Cytochemistry. To distinguish between reactive processes and chronicmyeloid leukemia, leukocyte alkaline phosphatase is determined in freshsmears of blood. To distinguish between different types of acute leukemia,the peroxidase and esterase reactions are carried out (pp. 97 and 99), andiron staining is performed (p. 109) if myelodysplasia is suspected.Cytogenetic Analysis. This procedure will take the diagnosis forward incases of leukemia and some lymphadenomas. The fresh material must beheparinized before shipment, preferably after discussion with a specialistlaboratory.