Leukocytes Flashcards
Leukocytes are derived from ___________________
A common Hameopoietic Stem Cell
Haemopoeitic stem cells are _________ and are __________
Pluripotent
Self-renewing
When HSCs divide one cell becomes ___________________ and the other becomes ____________
Becomes dedicated to a particular lineage
Quiescent
Lineage commitment is dependent on _________, ________, _________ and ___________________.
Cytokines
Hormones
Epigenetics
Other signally molecules
Give 3 examples of lineage-commitment specific cytokines
EPO = Erythropoietin commits cells to the erythroid lineage G-CSF = Commits cells to the granulocyte lineage TPO = Thrombopoietin commits cells to the Megakaryocyte lineage
The process of lineage commitment and maturation can be __________ at any point
Disrupted
Early precursor cells are usually found ___________________ and maturing forms are found ___________________
Adjacent to Trabecular bone
Deeper in the marrow space
What is the composition of Bone marrow haematopoietic regions?
60% Granulopoiesis
25% Erythropoiesis
15% Lymphocyte
Neutrophils comprise ___ to ___ of WBC count. They develop from _________ in the _________
40-70%
Myeloblasts
Bone Marrow
Neutrophils are characterised by:
- 3-5 nuclear segments
- Cytoplasmic granules (Primary and Secondary)
- 9-15um in diameter
Primary granules are made during the ___________ stage, an important granule component is ___________________.
Promyelocyte stage
Myeloperoxidase MPO
Secondary granules are made during the _________ stage
Myelocyte stage
Neutrophils generally leave the circulation by following ____________ this is called ________. To do this they have to ___________________.
Chemical signals
Chemotaxis
Rearrange their cytoskeleton
For efficient phagocytosis targets need to be __________ with __________ or ____________. These are recognised by ________________.
Opsonised (Coated)
Immunglobulin (Ig) or Complement protein
Cell-surface receptors
During phagocytosis temporary __________ called _______ encircle the particle before ingestion
Cell projections
Pseudopods
What are the 2 pathways used to destroy pathogens?
Fusion with the primary or secondary granules
Generation of reactive oxygen species
Neutrophils can abnormalities in _________________ or ________________. This may increase the risk of ____________.
Granule development
Intracellular killing
Infection
Neutrophil Extracellular Traps (NETs) are composed of _________________ studded with __________________. They allow pathogens to be killed ___________, however this results in _________.
Smooth Filaments
Granule components
Extracellularly
NETosis
What is NETosis?
A unique form of cell death caused by the use of NETs b neutrophils. It is due to the progressive loss of intracellular membranes which causes the cell membrane to rupture.
How are NETs formed and what induces this?
Generated through ejection of intracellular components, it can be induced by:
- Infection
- Reactive Oxygen Species
- Antibodies and Antibody-Antigen Complexes
- Activated by platelets
What is Neutrophilia?
Increased Neutrophil count 10-50 x 10^9 per L
- There is increased granulation and Dohle bodies and cytoplasmic vacuoles are present
- Nucleus lobes maybe also appear as one, “left shift” neutrophils
What causes Neutrophilia?
- Infection
- Acute Inflammation
- Stress
- Pregnancy
- Trauma
- Steroid and cytokines
What is Neutropenia?
Decreased Neutrophil count can be classed as
Mild = 1-1.9 x 10^9 per L
Moderate = 0.5-0.9 x 10^9 per L
Severe =
What is the normal range for Neutrophil count?
2-8 x 10^9 per L
What causes Neutropenia?
- Infection
- Drugs/Chemo
- Autoimmune disease
- Presence of Anti-granulocyte antibodies aka Immune neutropenia
- Some Haematological disorders
Eosinophils are characterised by:
- 2-3 nuclear lobes
- Granule filled cytoplasm, usually more densely packed than neutrophils
- 12-17um in diameter
Eosinophils are _________ at killing bacteria than neutrophils. They bind to ____ and ____ coated _________. They are capable of developing _____ and are also involved in _______________.
Slower IgG and C-3 coated Parasites NETs Allergic Reaction
Eosinophilia is often caused by _________, __________ and _________________.
Allergies
Medication
Parasite Infection
Basophils are characterised by:
- 2 nuclear segments
- Large round cytoplasmic granules that overlie the nucleus
- 12um in diameter
Basophils play a role in ______________ and the response to _________. They have receptors for ___, ___, ___, _________ and __________.
Allergic Reactions
Parasites
IgG, IgE, C5a, Histamine and Chemokines
Basophils release _________ on activation.
Histamine
Basophilia is very ________. It occurs _________________________.
Rare
Only in malignancies like Chronic Myeloid Leukaemia (CML)
Monocytes are characterised by:
- Horseshoe shaped nucleus
- Faint blue-grey cytoplasm
- Cytoplasmic Vacuoles
- 15-30um in diameter
Monocytes are __________ but they cannot be seen clearly on the microscope. They contain _________, ________, ____ and _________
Granular Enzymes Lysozyme MPO Coagulation system proteins
Monocytes are able to respond to _________________ in order to move. When they enter the tissues they can form ___________. These cells are capable of _______________ and can release chemicals that can ________ or _________ immune response
Chemical Signals Macrophages Antigen Presentation Increase Decrease
What is Monocytosis?
An increase in the number of Monocytes
Monocytosis is associated with ________ and ________. Rarely we see persistent Monocytosis, this is usually due to _________________________.
Infection
Inflammation
Chronic Myelomonocytic Leukaemia
Lymphocytes are characterised by:
- Round and slightly indented nuclei
- Mature Chromatin
- Scant blue cytoplasm
- 7-12 um diameter
Give a brief summary of B-cells:
- Mature in the bone marrow and lymph nodes
- 5-25% of the lymphocytes in blood are B-cells
- Produce antibodies
- Undergo genetic changes to optimise receptor binding
Give a brief summary of T-cells:
- Mature in the thymus
- 70-85% of the lymphocytes in the blood are T-cells
- They are involved in cell-mediated immunity
- Can act as APCs or cytotoxic cells
Give a brief summary of NK cells:
-
Large Granular Lymphocytes are characterised by:
- Larger size
- More voluminous blue cytoplasm
- Contain Azurophilic granules
Large Granular Lymphocytes are commonly _____ and occasionally ______
NK cells and occasionally T-cells
Lymphocytosis is an increase in ______________. It is commonly seen in _____________, __________ and __________
Lymphocyte count
Viral Infection
Seizures
Hypoxia
Malignant Lymphocytosis is common in ____________. It can be from the _ or _ cell lineage but is commonly from the _ lineage. It ______ be identified based on morphology
Older people
B or T
B lineage
Cannot
Plasma cells are end stage _____ that can produce _____________. They are ______ found in the blood
B cells
Immunoglobulins
Rarely
Plasma cells are characterised by:
- Eccentric nucleus
- Perinuclear hofs
- Intensely basophilic cytoplasm
