Leukocytes Part 1 Flashcards
What is a leukogram?
- White blood cell count
data (wbc circulating in peripheral blood) - Morphology of WBCs
- Abnormali:es: leads to
identify of pathological
processes - No specific dx given
Identify the cells below
The Leukon contains?
- Contains all white blood cell (WBC)/leukocytes types in an animal
- Precursors
- Blood and lymphatics
- Tissue - Neutrophils, eosinophils, basophils, monocyte, lymphocytes and mast
cells
- ^ Precursors in bone marrow
The leukon is divided into 2 cell types…
- 2 cell types:
1. Polymorphonuclear cells (AKA granulocytes) - Neutrophils
- Eosinophils
- Basophils
2. Mononuclear cells - Monocytes
- Lymphocytes
Monocyte
Lymphocyte
Basophil
Neutrophil
Define Leukopoiesis. How does this process differ from Myelopoiesis and Lymphopoiesis?
- To generate Leukocytes from pluripotent hematopoietic Stem cells of
the Bone Marrow - Myelopoiesis (granulopoiesis)
-Derived from myeloid stem cells - Lymphopoiesis
- Lymphocytes are generated from lymphoid stem cells
The mother of all is ?
Pluripotent stem cell
- What cell type is pictured below?
- What do they contain?
- What color are they when they stain?
- Describe the nucleus.
- Neutrophils: contain granules (stain neutral)
- Pale pink cytoplasm
- constricted, multilobulated nucleus
Type of granulocate
- What cell type is pictured below?
- What species is this seen in?
- What do they contain?
- How do they stain?
- These cells are equivalent to?
- Heterophils: in birds, rabbits, reptiles
- Granules –rod shaped- orange-pink
- Equivalent functionality to neutrophils
Type of granulocyte
Describe the way Normal neutrophils look in different species, specifically bovine and felids.
Species morphology differences
* Similar across species
* Bovine: Brighter pink cytoplasma
* Cats: can have Dohle bodies
* Angular, light blue cytoplasmic
inclusions
Canine neutrophil
Feline neutrophil
Equine neutrophil
bovine neuttrophil
Describe neutrophil development
- Various Cytokines s/mulate the stem cells in bone marrow to become
Myeloblast -TNF-alpha, TNF-gamma- - Promyelocyte
- Myelocyte
- Metamyelocyte = bean shaped nucleus. tells us the age of the cell. should not be present in normal blood.
- Band Neutrophil = The band description m eans that the neutrophil is not fully mature. May see band neutr in small numbers in a normal blood cell. The numbers compare with the real mature neutrophils to compare data leukogram?
- Segmented neutrophil = mature neutrophil in circulation.
What are the 4 neutrophil pools?
Pool = reserve
Release of neutrophils from the marginating pool occurs in
response to ?
corticosteroids (endogenous or exogenous), which downregulate adhesion molecules responsible for margination (or patrolling of the endothelium via selectin-mediated rolling) and has the potential to double the mature neutrophil count (so-called
“stress leukogram”).
What is a neutrophils half-life?
How long do they survive?
- Half life: 5-10h in circulation, then egress into tissues
- Survive ~ 24-48h in tissues
- Apoptosis by Macrophages in: spleen, liver, bone marrow
Neutrophils In many species it is the predominant leukocyte in health. Except in cattle; predominant one is lymphocytes
When are band neutrophils released?
Band neutrophils:
* Released in circulation in cases of overwhelming inflammation once storage
pool of segmented N0 is depleted
Label this image.
Describe the band neutrophils morphology?
Morphology:
* Similar cytoplasm to mature segmented N0
* U- or S- shaped nucleus with a few constrictions
Increase in band neutrophils is called?
Left shift
What function do neutrophils serve? Heterophils?
- Phagocytosis and defense against microorganisms
- Bacteria
- Granules:contain bactericidal agents
Heterophils: Equivalent functionality to neutrophils
Describe eosinophil morphology.
Morphology:
* Red to pink cytoplasm granules
* Round in most species
* Rod shape in cats
* Large round granules in horses
* Mul8lobulated nucleus with constric8ons
* Similar to neutrophils
What can be seen below?
Canine eosinophil
Label this image accordingly. What are the species differences?
Species morphology differences
* Very different among species
* Equine: large round granules
* Cats: rod-shaped granules
* Sighhounds (whippet, grey hounds): gray eosinophils
Label this image accordingly. What differences do you see below?
Segmented nucleus, granules in hetero = elongated and dull red; eosino = round and distinguished
Describe eosinophil development.
- Stem cells in bone marrow are s0mulated by cytokines from mast
cells, macrophages and lymphocytes - Need IL-5, IL-3 to mature.
- Stages of development identical to neutrophils
Label the image below
Eosinophil kinetics
- Marginated and circulating pools remain in blood from minutes to
hour and die in tissues - Duration in tissues: weeks or more
- Rarest leukocyte in circulation of most avian species
BM production 2-6 days for transit time, aqbout 30 min, and have maginal pool.
What are the functions of eosinophils?
- Tissue residents in _____ mucosa
- Defense against ________
- Releasing _______ _____ protein –> generate toxic ______ ______ –> killing parasite
- Type ___ hypersensitivity allergic reactions
Eo binds to _____ –> activate them to release ________ –> tissue ______, _______ reactions –> mast cells, release of histamine, etc.
- Tissue residents in GI mucosa
- Defense against Helminths
- Releasing Major basic protein –> generate toxic oxygen radicals –> killing parasite
- Type I hypersensitivity allergic reactions
Eo binds to IgE –> activate them to release granules –> tissue damage, allergic reactions –> mast cells, release of histamine, etc.
Label this image accordingly.
Describe basophil morphology.
- Granules are dark purple and often round
and vary in density - Range from sparse to numerous
- Exception: cat basophils can be light
gray-lavender and indistinct - Equine and bovine granules often more numerous
- Multilobulated nucleus, thin and ribbon-shaped
Canine basophil
Feline basophil
Equine basophil
Bovine basophil
Describe the species basophil morphology differences.
Equine
Bovine
Cats
Dogs
Species morphology differences
* Equine & bovine: numerous dark
purple granules
* Cats: gray to lavender granules
* Dogs & Cats: granules are often
more sparse compared to large
animals
Basophil kinetics
- Normally very low numbers in circula-on; may not see them on leuklogram
- Half-life about 6 hours in circula-on
- Migration to -ssues promoted by inflammatory cytokines
- Can survive as long as 2 weeks in -ssues
What are the functions of basophils?
- Granules contain most histamine measured in blood
- Similar function to mast cells
- Protective immunity against helminths
- IL-3, IL-5
Mononuclear cells
Describe differences in lymphocyte morphology
Specifically describe equine and bovine lymphocytes
- Small round cells with round nucleus
- High nuclear-to-cytoplasmic ratio
- Equine and bovine lymphocytes may be larger, with more cytoplasm
- May have pink cytoplasmic granules
The most predominant leukocyte in health in ruminants
Describe lymphocyte development and production
- Common lymphoid progenitor cells in bone marrow gives rise to:
- ____-lymphocytes (L0)
- ____-lymphocytes
- ____-lymphocytes
- Secondary lymphoid tissues: (?) are
the source of most lymphocytes in adult mammals.
- Common lymphoid progenitor cells in bone marrow gives rise to:
- B-lymphocytes (L0)
- T-lymphocytes
- NK-lymphocytes
- Secondary lymphoid tissues: tonsils, LN, spleen, Bronchial-associated
lymphoid tissue (BALT) and Gut associated lymphoid tissue (GALT) are
the source of most lymphocytes in adult mammals.
Lymphocyte kinetics
- In tissues, L0 may undergo blastogenesis, return to blood via
lymphatics, or die - Recirculate: L0 leave lymph nodes via efferent ducts and enter blood
via thoracic duct - Half life ~30 minutes in circulation
Can last for years in memory T cells
Lymphocyte pools
- Circula(ng pool
- Margina(ng pool
- Only 2-5% of L0 circulate in blood
- 50-75% T-lymphocytes
- 10-40% B-lymphocytes
- 5-10% NK
Lymphocyte function
- Defense against viruses and tumor cells, and important in
immunosuppression
1. T-lymphocytes
◦ for Cellular immunity- mediated for Th1; Th2
- B-lymphocytes
◦ Humoral immunity- Produce antibodies
K9 monocyte
Fel monocyte
Equine monocyte
Bovine monocyte
Monocyte morphology
* _______ WBC: __-__x a mature RBC in diameter
* Light _____ to _____ cytoplasm; often has _____
* Nucleus is ______, or _____-____ shaped
- Largest WBC: 2-4x a mature RBC in diameter
- Light blue to gray cytoplasm; often has vacuoles
- Nucleus is butterfly, or kidney-bean shaped
Monocyte production
- Stem cells stimulated to then have monoblast –> monocyte
- monoblast promonocyte Monocyte
- Faster production than granulocytes
- Production, Maturation mediated by….
* IL-1, IL-3, IL-6 - Little marrow reserves of monocytes
Monocyte Kinetics
- Marginated and circulating pools; no BM storage
- Monocytes emigrate to tissues
- Once in tissues, differentiate into macrophages:
- Kupffer cells – liver
- Alveolar macrophages – lungs
- Type A synoviocytes – joints
- Microglial cells – CNS
- Dendritic cells – skin, lymphoid organs
- Circula(ng half-life 0.5-3 days
- Can survive 3 months in (ssues
◦ Langerhans cells in skin can survive > 1 year
Monocyte function
- Phagocytosis
- Microorganisms
- Greater defense against fungi, helminths, protozoa than neutrophils
- RBCs, Extracellular material
- Microorganisms
- Antigen presentation to T-L0
- Source of cytokines involved in inflammation and hematopoiesis
- Such as IL-1, IL-3, TNF
- Tissue repair and remodeling via facrors that stimulate4 differntiaon and activation of toher cells
Mast cell morphology
- Round, purple cytoplasmic granules
- Look similar to a basophil (common progenitor cell)
- Mast cell nucleus is circular; basophil nucleus is multilobulated
Mast cell
Mast cells are not…
- Not rou’nely reported on a CBC leukogram
- Presence on a blood film indicates pathology (inflamma’on or neoplasia)
- Can be seen in cases of … Enteri’s, pleuri’s, peritoni’s, hypersensi’vity reac’ons also cancer
Mast cell function
- Reside in sub-epithelial loca2ons
* Dermis, submucosa of GIT
* In any 2ssues
* Mature in 2ssues (liver, spleen, LN) - Promote inflammatory reac2ons
* Hypersensi2vity - Fibrosis
Neutrophil toxicity is,….
- Morphologic changes caused by increased neutrophil produc4on and
shortened matura4on 4me in the bone marrow - Indicates inflammation:
- Cytoplasmic basophilia
- Cytoplasmic vacuolation (foamy appearance)
- Döhle bodies
- Ring form nuclei
Neutrophil toxicity: Cytoplasmic basophilia
- Normally matured segmented and late band
neutrophils, shown in panels A and C, have
white cytoplasm with pink granules, long and
fairly narrow nuclei and tightly condensed
chromatin. - Segmented and band neutrophils with toxic
change (examples shown in panels B and D)
have less condensed chromatin than their
normal counterparts and bluer cytoplasm
due to retention of ribosomal RNA.
Neutrophil toxicity: Döhle Bodies
blue cytoplasmic inclusions
Can present in single or multiples
remnants of RER. Assoc with myelo left shif and seen in conjuunction of toxic granulation of neutrophils
Pelger-Huet Anomaly
Seen in: __________ ________ dogs, _____ horses
* Mutation in ________ __ receptor gene leads to ____________ of granulocytes
* All neutrophils look like ______ or ____ mature forms
Australian Shepherd, Arabian
* Mutation in lamin B receptor gene leads to hyposegmenta4on of
granulocytes
* All neutrophils look like bands or less mature forms
What phenomenon can be seen below?
In which species does this commonly occur?
Pelger-Huet Anomaly
A-C
Segmentation of neutrophils; look like bands
hyperpigmentation in E, F are eosinophils
9% in aus shep
Reactive lymphocytes
- Cells proliferate due to antigenic stimulation – usually inflammation
- Cytoplasmic changes:
- Deeply basophilic
- Increased amounts
- Perinuclear Golgi clearing
- May contain vacuoles
- Cytoplasmic changes:
- Increased cell size
- Nuclear changes
* Variation in shape
* Less condensed chromatin
* May contain nucleoli
What can be seen in the image below?
Reactive lymphocytes
nuclear density lost, can see nucleoli
RBC and monocyte containing erlichia
- Anaplasmataceae spp.
- Monocy*c
* Erlichia canis - Granulocy*c
- Erlichia ewingii= needs granulocyte to complete life cycle
- Anaplasma phagocytophilum
Erlichia canis
needs monocyte
morula of erlichia inside monocyte
Histoplasma capsulatum - Yeast
Yeast are spheircla -2-5 um in diameter. purple in color with clear halo.
Intracellular in MQ and histiocytes.
Cytauxzoon felis - protozoa
complete various stages in different cells.
This is the Schizonts stage which is completed in the macrophage.
Later, the schizonts will burst MQ and then freed into the blood.
Cytauxzoon felis - protozoa
Merozoites stage (final stage) occurs in RBCs
Hepatozoon spp
The gamont of this parasite lives within canine leukocyte. Look like a capsule within cell.
Toxoplasma spp.
Toxo ghondi is an oblicage intracellular protosoa.
Infects all warm blooded animals.
Domestic cats are definitive and itnermediate host
bradyzoites are fre, sporpo enter nucleated cells in lamina propria.
Tachyzoites within parasitoferous vacuum disseminate into blood and invade various cell types. Cells rupture –> necrosis of tissue and tachy will invade mononuclear cells of animal.
