The identification of mature and immature cells in peripheral blood smears and preparations is fundamental to the laboratory diagnosis of haematological disorders. Here, you may review the mature and immature white cells to gain more practice and confidence in their identification. Immature cells are found in peripheral blood in leukaemia. Modified to printer-friendly form from Quensland University of Tehcnology, Our Medical Science pages & University of California Davis School of Medicine) Bone Marrow Peripheral Blood

(Neutrophile) Left - Nonsegmented (Neutrophile) Cell size: 12 -15 µm Cell size: 10-16 µm Cell size: 12 -23 µm N:C ratio: Ratio more reduced, 40% N:C ratio: Ratio more reduced 30 - 40% N:C ratio: 60%, decreasing Cytoplasm: Similar to mature cell Cytoplasm: Similar to mature cell Cytoplasm: Development of Nucleus: Indentation of nucleus Nucleus: Curved, without distinct lobes secondary (specific) granules, some begins; heavy chromatin clumping, Note: Also referred as "band forms" or primary granules may be visible nucleoli not visible "stab cells". Nucleus: Oval or round, with further Right - Segmented Neutrophil clumping, nucleoli no long visible Cell size: 10-16 µm Note: The term myelocyte infers it is a N:C ratio: Ratio more reduced 20 - 30 % neutrophil myelocyte, also found are Cytoplasm: Fine specific granules, pink- and tan cytoplasm. myelocytes. Nucleus: Segmented nucleus (normal up to 5 lobes)

Myeloblast Cell size: 15 -20 µm Cell size: 15 -25 µm N:C ratio: High N:C ratio: High (80%) (70%), decreasing Cytoplasm: Medium Cytoplasm: blue colour, medium Development of rim Eosinophil primary (non-specific) Eosinophil myelocyte Nucleus: Fine Eosinophil metamyelocyte Cell size: 10-16 µm granules which are Cell size: 12-23 µm chromation, one or Cell size: 12 -15 µm N:C ratio: Ratio 30 % coarse, red- purple N:C ratio: 60-50%, decreasing more nucleoi N:C ratio: Ratio more reduced, 40% Cytoplasm: Prominent specific granules and may overlie both Cytoplasm: Development of Note: Blast cells of Cytoplasm: Similar to mature cell, (orange-brown), blue cytoplasm (often not nucleus and secondary (specific) granules (orange- each series are prominent eosinophilic granulation seen) cytoplasm brown colour), some primary granules difficult to specifically Nucleus: Indentation of nucleus Nucleus: Segmented nucleus, usually two Nucleus: Slight may be visible identify beings; heavy chromatin clumping, lobes clumping nucleoli still Nucleus: Oval or round, with further morphologically, nucleoli not visible visible clumping, nucleoli no long visible immunological Note: markers and are morphologically cytochemistry are most variable. used to identify specific blasts.

Basophil myelocyte Cell size: 12 -23 µm Basophil N:C ratio: 60%, decreasing Basophil metamyelocyte Cell size: 10-14 µm Cytoplasm: Development of Cell size: 12 -15 µm N:C ratio: Ratio 30% secondary (specific) granules (overly N:C ratio: Ratio more reduced, 40% Cytoplasm: Large irregular dark purple- nucleus), some primary granules may Cytoplasm: Difficult to see due to the black granules. These granules may be visible specific (basophilic) granulation. dissolve during staining to give a "washed Nucleus: Oval or round, with further Granules overly nucleus out" appearance as seen in the basophil clumping, nucleoli no long visible Nucleus: When seen, indentation of on the right. Note: Very early basophil myelocyte nucleus begins, heavy chromatin Nucleus: Usually masked by granules, on the left, later basophil myelocyte on clumping, nucleoli not visible may be bilobed or non segmented. the right (with a myelocyte).

Monocytes Bone Marrow Peripheral Blood

Monoblast Cell size: 12 -20 µm Cell size: 12 -20 µm Cell size: 12-20 µm N:C ratio: High (80%) N:C ratio: 60-40% N:C ratio: 50 % or less. Cytoplasm: Medium blue colour, cytoplasm frequently Cytoplasm: Medium blue-grey colour, cytoplasm frequently Cytoplasm: Blue-grey cytoplasm, fine red- irregular with pseudopods irregular with pseudopods purple granules may be seen. Vacuoles Nucleus: Fine chromation, one or more nucleoli Nucleus: Lace like chromatin, 1 or 2 nucleoli, nucleus often present. Note: Blast cells of each series are difficult to specifically elongated, folded. Nucleus: Convoluted or kidney shaped, identify morphologically, immunological markers and rarely round oval or band. cytochemistry are used to identify specific blasts.

Lymphocytes

Bone Marrow Peripheral Blood Tissues

Plasma cell (in): Prolymphocyte Cell size: 8-20 µm Cell size: 15-20 µm Cell size: 15-18 µm Cell size: 8-15 µm (small, intermediate and large) N:C ratio: Ratio 40-30% N:C ratio: 90-80 % N:C ratio: 80-60 % N:C ratio: Ratio 80 % small, 50 % large Cytoplasm: Cytoplasm Cytoplasm: Medium blue, Cytoplasm: Medium blue, Cytoplasm: Blue cytoplasm, paler in large . stains dark blue, with a sometimes with a darker sometimes with a rim of lighter area near the blue border Clusters of azurophilic granules may be seen (see note). darker blue Nucleus: Round, dense chromatin. Nucleus may be clefted. Nucleoli are nucleus (perinuclear halo) Nucleus: Round or oval, Nucleus: Oval, condensed Nucleus: Round, occasionally visible in mature lymphocytes. delicate chromatin. Nucleoli chromatin. Nucleoli 0-1 eccentric (off centre) 1-2 Note: In high magnification, the cytoplasmic cluster of dark granules in the Note: Blast cells of each lymphocyte in picture 3 actually seem to lie in a ’vacuole’, i.e. it might represent a series are difficult to morula of Human Monocytic Ehrlichia ! specifically identify Single Ehrlichia are often seen in the cytoplasm of leukaemia cells inoculated with morphologically, Ehrlichia, see CDC, Google. Tick bites are very common. New facts are that immunological markers and Ehrlichia species are found in ticks all over the world and that most Ehrlichia cytochemistry are used to infections probably go unnoticed, only causing other infections, because of immune identify specific blasts. inhibition - it is very likely, also in previous eras, that inclusions of Ehrlichia were found now and then in WBCs, but nobody new what it was and considered it to be a normal finding, just because it was so common ?

Thrombocytes

Bone Marrow Peripheral Blood

Megakaryoblast Cell size: 15-20 µm N:C ratio: High, ratio 90-80 % Cytoplasm: Relatively small amount, non granular, basophilic (intensely) Cell size: 20-80 µm Thrombocytes / Nucleus: Large oval, kidney shaped N:C ratio: Ratio 70 - 50% (located between red blood cells.) nucleus, fine chromatin structure, Cytoplasm: More abundant, Cell size: 2-5 µm several nucleoli. basophilic cytoplasm contains Platelets are highly variable, round-oval Note: Blast cells of each series are granules anuclear cytoplasmic fragments of a difficult to specifically identify Nucleus: Oval or irregular megakaryocyte, staining pale blue; smaller morphologically, immunological markers nucleus, slightly dense chromatin Cell size: 35-160 µm platelets tend to be older, while large and cytochemistry are used to identify pattern, nucleoli may be still N:C ratio: Ratio low platelets tend to be young. specific blasts. visible Cytoplasm: Abundant - light blue/purple colour, packed with fine azurophilic granules Nucleus: Irregularly lobed, ring or doughnut shaped nucelus, may have up to 16 (occas 32) lobes, dense chromatin pattern, nucleoli not visible.

Erythrocytes

Bone Marrow Percentages refer to average bone marrow distribution. Peripheral Blood Not shown are Monocyte: 4.0%, Lymphocyte: 12.5%, and : 2.5% Normoblast

Erythrocyte Cell size: ~7 µm (methylene-blue stain) N:C ratio: Erythroblast Cell size: Cytoplasm: 0,5% N:C ratio: Cytoplasm: moderate size: 15-20 µm Basophilic (8%) Polychromatic (17,5%) Orthrochromatic (2,5%) moderate t acidophilia acidophilia N:C ratio: 90-80 % Cell size: Cell size: Cell size: Nucleus: extruded at Nucleus: none Cytoplasm: Relatively small amount, N:C ratio: 75% N:C ratio: 60% N:C ratio: 40% the orthochromatic Note: biconcave non granular, basophilic (intensely) Cytoplasm: intense Cytoplasm: slight basophilia Cytoplasm: slight acidophilia stage. are cell shape Nucleus: Large round, Nucleus: Large oval, kidney shaped dark blue (basophile) Nucleus: small, very dark positively identified with nucleus, fine chromatin structure, Nucleus: Large chromatin darker, more blue-black (pyknotic) supravital dyes several nucleoli. round, chromatin condensed (precipitating E.R.) Note: Blast cells of each series are slight clumping, Note: ~polychromasia difficult to specifically identify nucleoli may not be morphologically, immunological markers visible and cytochemistry are used to identify specific blasts.

Normal distribution of white blood cells in peripheral blood: Neutrophile (granulocytes) 40-75%, Lymphocytes 20-45%, 2-8%, Eosinophile 1-4%, Basophile 0-1% IURPSDJH+DHPDWRORJ\DWD*ODQFHE\$WXO0HWKD 9LFWRU+RIIEUDQG%ODFNZHOO6FLHQFH,6%1   

Howell-Jolly bodies Also known as: Howell’s bodies, Jolly’s bodies. Associated persons: William Henry Howell Justin Marie Jolly Description: Spherical granules, 1-2 µ, seen in erythrocytes in slides of stained blood. They are thought to be nuclear particles. The bodies are seen in cases of congenital absence of the spleen; following splenectomy, in haemolytic anaemia, in percicious anaemia, in thalassaemia, and in leukaemia. Bibliography: W. H. Howell: The life-history of the formed elements of the blood, especially the red blood corpuscles. Journal of Morphology, New York, 1890- 91, 4: 57-116. J. M. J. Jolly: Sur la formation des globules rouges des mammifères. Comptes rendus de la Société de Biologie, Paris, 1905, 58: 528-531. Recherches sur la formation des globules rouges des mammiféres. Archives d’anatomie microscopique, 1907, 9: 133-314.