Manual of basic techniques for a health laboratory - libdoc.who.int

9. Haematology 313Immature granulocytesImmature polymorphonuclear granulocytes of the bone marrow passinto the bloodstream in severe bacterial infections. They can be distinguishedby the following features:Size: 12–18mm.Nucleus: without lobes, with chromatin varying in colour from darkred to purple.Cytoplasm: pale blue or pink with many large mauve or dark red granules.Toxic granulation may be seen, in which the granules are verylarge and darkly stained.If immature polymorphonuclear neutrophils (“band form” or “stabcells”) (Fig. 9.99) are seen, report their number fraction as for othertypes of leukocyte.There are also immature cells without granules and with nucleoli(lymphoblasts) (see Fig. 9.102).Fig. 9.99 Immature polymorphonuclearneutrophilsHypersegmented polymorphonuclear neutrophils (Fig. 9.100)Hypersegmented polymorphonuclear neutrophils look like normalneutrophils, except that their nuclei have 5–10 lobes and are oftenlarger in size.Such neutrophils can be seen in patients with macrocytic anaemia,caused by folic acid or vitamin B 12deficiency.Atypical lymphocytes (Fig. 9.101)Atypical lymphocytes can be seen in viral infections, especially infectiousmononucleosis (glandular fever), whooping cough and measles.They are also found in tuberculosis, severe malaria and the acquiredimmunodeficiency syndrome (AIDS).Size: very variable, 12–18mm.Shape: usually irregular.Nucleus: round or irregular, often lying to one side of the cell; nucleolimay be seen.Cytoplasm: usually darker blue than that of large lymphocytes; formsa dark edge to the cell. Does not contain granules.Fig. 9.100 Hypersegmentedpolymorphonuclear neutrophilsLymphoblasts (Fig. 9.102)The earliest (most immature) of all the types of leukocyte.Lymphoblasts can be seen in the blood films of patients with leukaemia.Size: large, 15–25mm.Nucleus: large, round, pale mauve, containing 1–5 nucleoli.Cytoplasm: dark blue, with a clear unstained area round the nucleus.Does not contain granules.Fig. 9.101 Atypical lymphocyte