Transcript Review, Leukocytes

King Saud University
Riyadh
Saudi Arabia
Dr. Gihan Gawish
Assistant Professor
Dr Gihan Gawish
Dr Gihan Gawish
• Definition: leukocytes are cells of the immune
system defending the body against both
infectious disease and foreign materials.
• Formation: Five different and diverse types of
leukocytes exist, but they are all produced and
derived from a multipotent cell in the bone
marrow known as a hematopoietic stem cell.
• Occurrence: Leukocytes are found throughout
the body, including the blood and lymphatic
system
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Hematopoietic stem cell
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Normal range
9
• There 9 are normally between 4×10 and
11×10 white blood cells in a liter of blood,
• making up approximately 1% of blood in
a healthy adult.
• The number of leukocytes in the blood is
often an indicator of disease.
Dr Gihan Gawish
White blood cells (LEUKOCYTES)
Classification
Granulocyte
Neutrophil
Eosinophil
Agranulocyte
(lymphoid cells)
Basophil
Lmphocytes
Monocytes
• The term granulocyte is due to the presence of granules in the
cytoplasm of these cells. These granules have a different affinity
towards neutral, acid or basic stains and give the cytoplasm different
colors.
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3
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1.Neutrophil
• They are also known as polymorphonuclear
leukocytes.
• They have a multilobed nucleus which may
appear like multiple nuclei, hence the name
polymorphonuclear leukocyte.
• The cytoplasm may look transparent because of
fine granules that are faintly pink in color.
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Function of Neutrophil
• Neutrophils defend against bacterial or fungal infection
and other very small inflammatory processes that are
usually first responders to microbial infection
•
Their activity and death in large numbers forms pus.
• Neutrophils are very active in phagocytosing bacteria
and are present in large amount in the pus of wounds.
• These cells are not able to renew their lysosomes used
in digesting microbes and die after having phagocytosed
a few pathogens
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Neutrophil
.Approx
%
in adults
Diameter
(μm)
%62-54
10-12
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Main
targets
Nucleus
Granules
bacteria multilobed fine,
faintly pink
fungi
Lifetime
6hours-few
days
2.Eosinophil
• Generally their nucleus is bi-lobed. The cytoplasm is full
of granules which assume a characteristic pink-orange
color with eosin stain.
Function:
• Eosinophils primarily deal with parasitic infections and an
increase in them may indicate such.
• Eosinophils are also the predominant inflammatory cells
in allergic reactions.
• The most important causes of eosinophilia include
allergies such as asthma, hay fever and also parasitic
infections.
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Eosinophil
.Approx Diameter
%
(μm)
in adults
Main targets
Nucleus
1-6%
parasites
in allergic
Bi-lobed
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10-12
Granules
Lifetime
full of pink- 8-12 days
orange
3. Basophils
• The nucleus is bi- or tri-lobed, but it is hard to
see because of the number of coarse granules
which hide it.
• They are characterised by their large blue
granules.
Function:
• Basophils are chiefly responsible for allergic and
antigen response by releasing the chemical
histamine causing inflammation.
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Basophils
.Approx Diameter
%
(μm)
in adults
<1%
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12-15
Main targets
Nucleus
in allergic Rx Bi-lobed or
Tri-lobed
Granules
large blue
4. Lymphocyte
• Lymphocytes are much more common in
the lymphatic system.
• Lymphocytes are distinguished by having
a deeply staining nucleus which may be
eccentric in location
• It has a relatively small amount of
cytoplasm.
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The blood has three types of
lymphocytes:
• 1-B cells:
• B cells make antibodies that bind to
pathogens to enable their destruction.
• Some B cells will retain the ability to
produce an antibody to serve as a
'memory' system.) after an attack with
pathogens
Dr Gihan Gawish
types of lymphocytes:
• 2-T cells:
– CD4+ (helper) T cells co-ordinate the immune
response and are important in the defense against
intracellular bacteria. In acute HIV infection, these T
cells are the main index to identify the individual's
immune system activity.
– CD8+ cytotoxic T cells are able to kill virus-infected
and tumor cells. CD8+ cells are also another index to
identify human's immune activity.
– γδ T cells possess an alternative T cell receptor as
opposed to CD4+ and CD8+ αβ T cells and share
characteristics of helper T cells, cytotoxic T cells and
natural killer cells.
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Lymphocyte
% .Approx
in adults
25-33%
Dr Gihan Gawish
Diameter
(μm)
7-8
Main targets
Granules
Lifetime
B cells: pathogens
CD4+
extracellular bacteria
broken
down
into
peptides
CD8+
virus-infected tumor
cells.
γδ T cells:
virus-infected
tumor
cells.
deeply
staining
weeks
to years
5. Monocyte
• They have the kidney shaped nucleus and are
typically agranulated. They also possess
abundant cytoplasm.
Function:
• Monocytes share the "vacuum
(phagocytosis) function of neutrophils
cleaner"
• Monocytes eventually leave the bloodstream to
become tissue macrophages which remove
dead cell debris as well as attacking
microorganisms.
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Monocyte
.Approx Diameter
%
(μm)
in adults
2-8%
14-17
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Main targets
Nucleus
Monocytes migrate from kidney
the bloodstream to other shaped
tissues and differentiate
into
tissue
resident
macrophages or dendritic
cells
Lifetime
hours-days
Macrophage
• Phagocytosis (engulfment and digestion)
of cellular debris and pathogens, and
stimulation of lymphocytes and other
immune cells that respond to the pathogen
• activated=days
• immature=months-years
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Dendritic cells
• Main function is as an antigen-presenting
cell (APC) that activates T lymphocytes.
• activated=days
• immature=months-years
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Leukemia
• Leukemia is a cancer of
the blood or bone
marrow
• It is characterized by an
abnormal
proliferation
(production
by
multiplication) of blood
cells, usually white blood
cells
Dr Gihan Gawish
Four major kinds of leukemia
Cell type
Acute
Chronic
Lymphocytic
leukemia
or lymphoblastic
Acute
lymphoblastic
leukemia
)ALL(
Acute
myelogenous
leukemia
)AML(
Chronic
lymphocytic
leukemia
)CLL(
Chronic
myelogenous
leukemia
)CML(
Myelogenous
leukemia
also myeloid or
nonlymphocytic
Acute leukemia is characterized by the rapid increase of immature blood cells
Chronic leukemia is distinguished by the excessive build up of relatively
mature, but still abnormal, blood cells
Dr Gihan Gawish