Leukocyte
Objectives
• Name the different stages of WBC development and
describe the morphology of each stages
• Discuss the important functions of different WBCs
• Discuss the different terms on how the various
lymphocytes are produced
• Diss the function of monocytes, macrophages, T cells , B
cells and natural killer cells in the immune response
Leukocytes
• also known as white blood cells, or WBCs
• colorless compared to red blood cells
• mediating immunity, either innate (nonspecific) or
specific (adaptive)
• production of antibodies by lymphocytes and
plasma cells
• Granulocyte
• Mononuclear Cell (Agranulocyte)
Granulocytes
• leukocytes whose cytoplasm is filled with
granules with differing staining characteristics
• nuclei are segmented or lobulated
• Basophil
• Eosinophil
• Neutrophil (PMN’s)
Mononuclear Cell
• Agranulocyte
• cells have nuclei that are not segmented but
are round, oval, indented, or folded
• Lymphocyte
• Monocyte
Granulocyte
Neutrophils
• make up the vast majority of circulating
leukocytes
• Segmented (matured) Band shape (young)
• Progenitor: GMP (granulocyte-monocyte
progenitor) cell
• Major Cytokine: G-CSF (granulocyte colonystimulating factor) responsible for the
stimulation of neutrophil production
Neutrophil Development
Maturation Stages
• Myeloblast
• Promyelocytes
• Neutrophil Myelocyte
• Neutrophil Metamyelocyte
• Bands
• Segmented Neutrophil (PMN’s)
Myeloblast
• Size: 14 to 20 µm
• Nucleus: round to oval
• Nucleoli: 2-5
• Chromatin: Fine
• Cytoplasm: Moderate basophilia
• Granules Absent or up to 29
• N:C ratio: 4:1
• Reference Interval: 0% - 2%
• Peripheral blood: 0%
Type I Myeloblast
• N:C ratio 8:1 to 4:1
• nucleus occupies most of the cell, with very little
cytoplasm
• slightly basophilic cytoplasm, fine nuclear
chromatin, and two to four visible nucleoli
• no visible granules when observed under light
microscopy with Romanowsky stains
Type II Myeloblast
•presence of dispersed primary
(azurophilic) granules in the cytoplasm
•granules does not exceed 20 per cell
Type III Myeloblast
• darker chromatin and a more purple cytoplasm
• contain more than 20 granules that do not obscure
the nucleus
• Rare in normal bone marrows but can be seen in
certain types of leukemia
Promyelocyte
• Size: 16-25 µm (slightly larger than myeloblast
• Nucleus: round to oval
• Nucleoli: 1 – 3 or more
• Chromatin: fine, but slightly courser than myeloblast
• Cytoplasm: basophilic
• Primary: more than 20; may be numerous; red to purple or burgundy
• Secondary: None
• N:C ratio: 3:1
• Reference Interval:
• Bone Marrow: 2% to 5%
• Peripheral Blood: 0%
Neutrophil Myelocyte
•Size: 15-18
•Nucleus: round to oval; slightly eccentric;
may have flattened one side; may have a
clearing next to the nucleus (Golgi
apparatus)
•Nucleoli: usually not visible
Neutrophil Myelocyte
•Chromatin: course and more condensed
than promyelocyte
•Cytoplasm: slightly basophilic, to cream
colored
•Granules:
• Primary: few to moderate
• Secondary: variable number, becoming
predominant as cell matures
Neutrophil Myelocyte
•N:C ratio: 2:1
•Reference Interval:
• Bone Marrow: 5% - 19%
• Peripheral: 0%
Neutrophil Metamyelocyte
• Size: 14-16 µm
• Nucleus: Indented; kidney bean shape; indentation
is less than 50% of the width of a hypothetical
round nucleus
• Chromatin: Moderately clumped
• CYTOPLASM: Pale pink, to cream colored, to
colorless
Neutrophil Metamyelocyte
• Granules
• PRIMARY: Few
• SECONDARY: Many (full complement)
• N:C RATIO: 1.5:1
• REFERENCE INTERVAL:
• Bone Marrow: 13% to 22%
• Peripheral Blood: 0%
Band Neutrophil
• SIZE: 10 to 15 μm
• NUCLEUS: Constricted but no threadlike filament;
indentation is more than 50% of the width of a
hypothetical round nucleus
• Nucleoli: Not visible Chromatin: Coarse, clumped
CYTOPLASM: Pale pink, to colorless
Bands Neutrophil
• Granules:
• PRIMARY: Few
• SECONDARY: Abundant
• N:C RATIO: Cytoplasm predominates
• REFERENCE INTERVAL:
• Bone Marrow: 17% to 33%
• Peripheral Blood: 0% to 5%
Segmented Neutrophil
•SIZE: 10 to 15 μm
•NUCLEUS: 2 to 5lobes connected by thin
filaments, without visible chromatin
•Nucleoli: Not visible
•Chromatin: Coarse, clumped
Segmented Neutrophil
• CYTOPLASM: Pale pink, cream-colored, or colorless
• Granules:
• PRIMARY: Rare
• SECONDARY: Abundant
• N:C RATIO: Cytoplasm predominates
• REFERENCE INTERVAL:
• Bone Marrow: 3% to 11%
• Peripheral Blood: 50% to 70%
Neutrophil
Granules
Neutrophil
Granules
Neutrophil
Granules
Neutrophil
Granules
Eosinophil
• make up 1% to 3% of nucleated cells in the bone
marrow
• more than a third are mature, a quarter are
eosinophilic metamyelocytes, and the remainder
are eosinophilic promyelocytes or eosinophilic
myelocytes
Maturation Stage
•Eosinophil Myelocyte
•Eosinophil Metamyelocyte
•Band
•Eosinophil
Eosinophil Myelocyte
• SIZE: 12 to 18 μm
• NUCLEUS: Round to oval; may have one
flattened side
• Nucleoli: Usually not visible
• Chromatin: Coarse and more condensed than
promyelocyte
Eosinophil Myelocyte
• CYTOPLASM: Colorless to pink
• Granules:
• PRIMARY: Few to moderate
• SECONDARY: Variable number; pale orange to dark orange;
round; appear refractile
• N:C RATIO: 2:1 to 1:1
• REFERENCE INTERVAL:
• Bone Marrow: 0% to 2%
• Peripheral Blood: 0%
Eosinophil Metamyelocyte
• SIZE: 10 to 15 μm
• NUCLEUS: Indented; kidney bean shape;
indentation is less than 50% of the width of
the hypothetical round nucleus
• Nucleoli: Not visible
• Chromatin: Coarse, clumped
Eosinophil Metamyelocyte
• CYTOPLASM: Colorless, cream-colored
• Granules:
• PRIMARY: Few
• SECONDARY: Many pale orange to dark orange; appear
refractile
• N:C RATIO: 1.5:1
• REFERENCE INTERVAL:
• Bone Marrow: 0% to 2%
• Peripheral Blood: 0%
Band (eosinophil)
• SIZE: 10 to 15 μm
• NUCLEUS: Constricted but no threadlike
filament; indentation is more than 50% of the
width of a hypothetical round nucleus
• Nucleoli: Not visible
• Chromatin: Coarse, clumped
Band (eosinophil)
• CYTOPLASM: Colorless, cream-colored
• Granules:
• PRIMARY: Few
• SECONDARY: Abundant pale to dark orange; appear
refractile
• N:C RATIO: Cytoplasm predominates
• REFERENCE INTERVAL:
• Bone Marrow: 0% to 2%
• Peripheral Blood: Rarely seen
Eosinophil
• SIZE: 12 to 17 μm
• NUCLEUS: Two to three lobes connected by
thin filaments without visible chromatin;
majority of mature cells have two lobes
• Nucleoli: Not visible
• Chromatin: Coarse, clumped
Eosinophil
• CYTOPLASM: Cream-colored; may have irregular
borders
• Granules:
• PRIMARY: Rare
• SECONDARY: Abundant pale orange to dark orange;
appear refractile
• N:C RATIO: Cytoplasm predominates
• REFERENCE INTERVAL:
• Bone Marrow: 0% to 3%
• Peripheral Blood: 0% to 5%
Eosinophil
Granules
Eosinophil
Granules
Eosinophil
Granules
Eosinophil
Granules
Basophil
• Basophils and mast cells are two cells with
morphologic and functional similarities
• true leukocytes because they mature in the bone
marrow and circulate in the blood as mature cells
with granules
• least numerous of the WBCs, making up between
0% and 2% of circulating leukocytes and less than
1% of nucleated cells in the bone marrow
Maturation Stage
•Immature Basophils
•Mature Basophils
Basophils
• SIZE: 10-14 μm
• NUCLEUS: Usually two lobes connected by
thin filaments without visible chromatin
• Nucleoli: Not visible
• Chromatin: Coarse, clumped
• CYTOPLASM: Lavender to colorless
Basophils
• Granules:
• PRIMARY: Rare
• SECONDARY: Large, variable in number with
uneven distribution, may obscure nucleus deep
purple to black; irregularly shaped. Granules are
water-soluble and may be washed out during
staining; thus they appear as empty areas in the
cytoplasm
Basophils
•N:C RATIO: Cytoplasm predominates
•REFERENCE INTERVAL:
• Bone Marrow: Less than 1%
• Peripheral Blood: 0% to 1%
Basophil
Granules
Mast Cell
• not considered to be leukocytes
• tissue effector cells of allergic responses and
inflammatory reactions
• mast cells have several phenotypic and
functional similarities with both basophils and
eosinophils
Mast Cells
• Mast cell progenitors (MCPs) originate from the
bone mar row and spleen.
• major cytokine responsible for mast cell
maturation and differentiation is KIT ligand (stem
cell factor)
• can also be activated independently of IgE, which
leads to inflammatory reactions
Mast Cells
•function as antigen-presenting cells to
induce the differentiation of T Helper 2
cells
•mast cells act in both innate and adaptive
immunity
Mononuclear
Cell/Agranulocyte
Monocyte
•Monocytes make up between 2% and
11% of circulating leukocytes, with an
absolute number of up to 1.3 3 109/L.
Maturation Stage
•Monoblast
•Promonocyte
•Monocyte
•Macrophages
Monoblast
• SIZE: 12 to 18 μm
• NUCLEUS: Round to oval; may be irregularly shaped
• Nucleoli: 1 to 2; may not be visible
• Chromatin: Fine
• CYTOPLASM: Light blue to gray
• Granules: None
• N:C RATIO: 4:1
• REFERENCE INTERVAL:
• Bone Marrow: Not defined
• Peripheral Blood: 0%
Promonocyte
• SIZE: 12 to 18 μm
• NUCLEUS: Irregularly shaped; folded; may have brain like
convolutions
• Nucleoli: May or may not be visible
• Chromatin: Fine to lacy
• CYTOPLASM: Light blue to gray
• Granules: Fine azurophilic (burgundy colored)
• N:C RATIO: 2 to 3:1
• REFERENCE INTERVAL:
• Bone Marrow: Less than 1%
• Peripheral Blood: 0%
Monocyte
• SIZE: 15 to 20 μm
• NUCLEUS: Variable; may be round, horseshoe shaped,
or kidney shaped; often has folds producing brainlike
convolutions
• Nucleoli: Not visible
• Chromatin: Lacy
• CYTOPLASM: Blue-gray; may have pseudopods
• Granules: Many fine granules frequently giving the
appearance of ground glass
Monocyte
•Vacuoles: Absent to numerous
•N:C RATIO: Variable
•REFERENCE INTERVAL:
• Bone Marrow: 2%
• Peripheral Blood: 3% to 11%
Macrophages (Histiocyte)
• SIZE: 15 to 80 μm
• NUCLEUS: Eccentric, kidney or egg-shaped,
indented, or elongated
• Nucleoli: 1to2
• Chromatin: Fine, dispersed
• CYTOPLASM: Abundant with irregular borders;
may contain ingested material
Macrophages (Histiocyte)
•Granules: Many coarse azurophilic
(burgundy-colored)
•Vacuoles: May be present
•REFERENCEINTERVAL: Macrophages reside
in tissues such as bone marrow, spleen, liver,
lungs, and others. Rarely, seen in the
peripheral blood during severe sepsis
Monocyte
Destination
Lymphocyte
•Three Major Groups
•T cells, B cells, and NK cells
•Categories
•Humoral Immunity and Cellular
Immunity
Maturation Stage
Lymphoblast
• SIZE: 10 to 20 μm
• NUCLEUS: Round to oval
• Nucleoli: Greater than or equal to 1
• Chromatin: Fine, evenly stained
• CYTOPLASM: Scant; slightly to moderately basophilic
• Granules: None
• N:C RATIO: 5:1 to 2:1
• REFERENCE INTERVAL:
• Bone Marrow: Not defined
• Peripheral Blood: 0%
Prolymphocyte
• SIZE: 9to18μm
• NUCLEUS: Round or indented
• Nucleoli: 0 to 1; usually single, prominent, large nucleolus
• Chromatin: Slightly clumped; intermediate between
lymphoblast and mature lymphocyte
• CYTOPLASM: Light blue
• Granules: None
• N:C RATIO: 3 to 4:1
• REFERENCE INTERVAL:
• Bone Marrow: Not defined
• Peripheral Blood: None
Lymphocyte
• SIZE: 7to18μm
• NUCLEUS: Round to oval; may be slightly
indented
• Nucleoli: Occasional
• Chromatin: Condensed, clumped, blocky,
smudged
• CYTOPLASM: Scant to moderate; sky blue;
vacuoles may be present
Lymphocyte
• Granules: None in a small lymphocyte; may be a
few azurophilic in larger lymphocytes; if granules
are prominent, the cell is called a large granular
lymphocyte.
• N:C RATIO: 5:1 to 2:1
• REFERENCE INTERVAL (FOR COMBINED SMALL
AND LARGE LYMPHOCYTES):
• Bone Marrow: 5% to 15%
• Peripheral Blood: 20% to 40%
• Large lymphocyte
with irregular nucleus
and more abundant
cytoplasm than small
lymphocyte.
• Large granular
lymphocyte with
prominent azurophilic
granules in cytoplasm.
Plasma Cells
• SIZE: 8to20μm
• NUCLEUS: Round or oval; eccentric
• Nucleoli: None
• Chromatin: Coarse
• CYTOPLASM: Deeply basophilic, often with perinuclear clear
zone (hof)
• Granules: None
• Vacuoles: None to several
• N:C RATIO: 2:1 to 1:1
• REFERENCE INTERVAL:
• Bone Marrow: 0% to 1%
• Peripheral Blood: 0%
Assignment!
•Summarize the following:
•Development
•Kinetics
•Function
Of each cell that we discussed.
•HAND WRITTEN, YELLOW PAD
•Quiz next meeting, discussion and
assignment