White blood cells Flashcards
Normal leukocyte count
4.5-11x10^9
Normal neutrophil %
40-70%
Normal lymphocytes %
20-40%
Normal monocytes %
2-8%
Normal eosinophils %
1-4%
Normal basophils %
0.5-1%
Total WBC count: 7 x 10^9 cells/L Neutrophils: 65% Lymphocytes 25% Monocytes: 7% Eosinophils 2% Basophils: 1%
Normal
Total WBC count: 7 x 10^9 cells/L Neutrophils: 60% Lymphocytes 25% Monocytes: 7% Eosinophils 7% Basophils: 1%
High eosinophils, allergies, asthma, parasitic infection
Total WBC count: 25 x 10^9 cells/L (v high) Neutrophils: 20% (low) Lymphocytes 76% (very high) Monocytes: 3% (low) Eosinophils 1% (low) Basophils: 0%
Acute viral infection
Total WBC count: 11 x 10^9 cells/L (higher than normal) Neutrophils: 85% (High) Lymphocytes 11% (Low) Monocytes: 3% (low) Eosinophils 1% (low) Basophils: 0%
Acute bacterial infection
Total WBC count: 3 x 10^9 cells/L (low) Neutrophils: 9% (very low) Lymphocytes 83% (very high) Monocytes: 7% Eosinophils 2% Basophils: 1%
Chronic viral infection
What are granulocytes?
Polymorphonuclear leukocytes (PMNs or polymorphs), eosinophils and basophils
What are mononuclear leukocytes?
Monocytes, B and T lymphocytes and NK cells
How can T lymphocytes be differentiated/ told apart?
Expression of molecules on their cell surfaces.
What antibodies are used to recognise B cells?
CD19
What antibodies are used to recognise both T cells?
CD3
What is flow cytometry?
Flow cytometry uses a machine termed a flow cytometer to detect fluorescently labelled antibodies bound to cell surfaces.
What does CD4 give rise to?
T cell co-receptor – defines T helper/Treg subsets, also monocytes
What does CD5 give rise to?
T cells and a subset of B cells
What does CD8 give rise to?
T cell co-receptor – defines cytotoxic T subset CD3+, also NK cells -CD3-
What are NK cell surface markers?
CD3- CD8+
What does CD14 show?
Co receptor for LPS expressed on human monocytes
What surface marker is CD20
B cell surface marker
What does CD25 show?
Lymphocyte activation marker - shows T cell is active
What is CD28?
Important T cell co-stimulatory molecule
What is CD45?
Leucocyte common antigen, expressed on all hematopoietic cells
How does the flow cytometer show relative size?
Forward light scatter (FSC channel)
How does the flow cytometer show relative granularity?
Side light scatter (SSC channel)
How is flow cytometry done?
- A sample containing cells or particles is suspended in a fluid and injected into the flow cytometer instrument.
- The sample is focused to ideally flow one cell at a time through a laser beam, where the light scattered is characteristic to the cells and their components.
- Cells are often labelled with fluorescent markers so light is absorbed and then emitted in a band of wavelengths.
What does forward scatter depend on?
Proportional to the diameter of the cell, and is primarily due to light diffraction around the cell
What does side scatter depend on?
Light refracted or reflected at the interface between the laser and intracellular structures, such as granules and nucleus
How are RBCs removed from being confounders?
Treated with an agent to lyse them
Where do neutrophils lie on a flow cytometry graph?
Top right (large forward scatter and large side scatter)
Where do lymphocytes lie on a flow cytometry graph?
Middle bottom (low side scatter, medium forward scatter)
Where do monocytes lie on a flow cytometry graph?
Medium to low side scatter and medium to large forward scatter
When blood is fractionated what are the layers?
Red blood cells (RBCs) pelleted to the bottom of the centrifuge tube.
Polymorphonuclear cells (PMNs) are found above the RBCs whereas peripheral blood mononuclear cells (PBMCs) are found at the plasma/histopaque interphase.
Name two of the white blood cell types found in the upper right of this graph i.e. high forward scatter and high side scatter
Granulocytes Neutrophils, Eosinophils, Basophils, Mast cells
Name two of the white blood cell types found in the lower left of this graph i.e. low forward scatter and low side scatter
Lymphocytes T cells, B cells + NK cells
CD31
Mediates interactions between leukocyte and endothelial cell diapedesis
