White Blood Cells (WBC) Flashcards
Questions and Definitions
A. How much Red Blood Cells are usually in a normal blood sample?
B. What are the rest?
A. 42%
B. Mostly Plasma, and a small percentage of White Cells and Platelets
Define Haematocrit
The ratio of the volume of Red Blood Cells to the total volume of blood
What is WBC differential?
WBC differential determines the percentage of each type of White Blood Cell present in a sample of blood. Additionally, it can also detect immature WBC and abnormalities.
Describe other additional tests used that are related to WBC
- Flow cytometry that is useful in showing Lymphoid and Myeloid populations, and degree of Cell maturity.
- Cytogenetics: involves analyzing chromosomes to identify structural abnormalities by using FISH in metaphase analysis
- Gene sequencing: looks for specific mutations
- Bone marrow examination: assessment of number/type of normal and abnormal cells
What is involved in Bone marrow examination?
Bone marrow examination includes same range of tests as FBC and can be either by Aspirate or Trephine
Describe stem cells and how they differentiate in the human body?
Stem cells are undifferentiated cells that are capable of giving rise to indefinitely more cells of the same types, and from which certain other kinds of cells arise by differentiation.
Typically, a stem cell forms blood islands in yolk sac. The cells then migrate into the liver, then spleen. After six months of development, they migrate into marrow in the foetus. At birth, marrow is widely distributed retreating to Axial Skeleton by adulthood.
What are some of the components of bone marrow?
Stroma and sinus capillary.
What is the commonest type of WBC in blood?
Neutrophils (50-70% of total blood cells)
Which type of WBC has the shortest life span (and how long is their life span? Where do they die?)
Neutrophils (8-10 hours) and they die in tissues or blood stream
What is the primary function of a Neutrophil?
Rapid response and defense against bacteria and fungi.
What type of defense do Neutrophils offer?
Non-specific
How are neutrophils attached to sites of infection?
Chemoattractant chemicals
Define Chemotaxis
The movement of a motile cell (neutrophil) in a direction corresponding to a gradient of increasing (chemoattractant chemicals) or decreasing concentration of a particular substance
How do Neutrophils kill bacteria?
Killing of ingested bacterial occurs by a variety of mechanisms (including oxygen-dependent pathway) but mainly neutrophil granules often contain several different proteins/ enzymes that kill those bacteria (such as peroxidase and lysozome)
What do neutrophils respond to?
They rise as acute response to bacterial infection, inflammation and malignancy.
Describe the appearance of Eosinophils
They have a striking orange appearance due to the cytoplasm that takes up eosin dye when blood films are stained
What gives Eosinophils the orange/pink colour?
Eosin stains granules orange of pink
What is the main function of Eosinophils?
Defense against helminth parasitic infestations/infection
What promotes the growth of helminth?
Interleukin-5
What attracts Eosinphils to the site of helminth infection?
Chemokines
Name some of the areas in which Eosinophils are commonly seen in
Atopy (e.g. eczema, asthma, hayfever)
In Hodgkin’s disease, Chronic myeloid leukaemia
List the mediators of inflammation that Basophils contain
Histamine
Protease
Heparin
Leukotrienes
What roles are Basophils involved in?
Inflammation, phagocytosis and hypersensitivity (allergic) reaction.
What types of cells are thought to be similar to Mast cells?
Basophils
What are the types of Agranulocytes and granulocytes?
Macrophages/monocytes and lymphocytes are agranulocytes.
Neutrophils, eosinophils, and basophils
What is the lifespan of a eosinophil?
4-5 hours
Which cell has a kidney-shaped nucleus?
Monocytes/macrophages
What do monocyte granules store?
Acid hydrolases and myeloperoidase
What is the main function of Monocytes?
- Kill mycobacteria, fungi and intracellular organisms
- They are Antigen-Presenting Cells, which means they can ingest pathogenic material and degrade it and present peptide or peptide fragments to T lymphocytes
Why are monocytes called Antigen-Presenting Cells?
Because they present peptide or peptide fragments to T lymphocytes
Which Blood Cell has the longest life span?
Lymphocytes, they live for years and act as memory cells
Which cell has very little cytoplasm and a round nucleus?
Lymphocyte
What are the main types of Lymphocytes (and where are they found?)
T (bone marrow or bursae) and B (thymus and chest). As well as NK (involved in cytotoxicity reactions)
Describe the two forms of Leukaemia and what are they different in?
Acute and Chronic.
Acute tends to present more dramatically, and must be treated early or death will occur shortly soon, and it is known to be more diverse.
Chronic is more slow growing (indolent).
They are different in their pace of disease, presentation, molecular mechanism, method of treatment and outcome.
Which type of Leukaemia is characterized with the presence of Ph?
Chronic Myeloid Leukaemia
What is Ph?
Philadelphia Chromosome, which is a specific genetic abnormality associated with the translocation of chromosome 22 (to Ch 9).
What does the new gene code of Ph inhibits?
Tyrosine kinase, and this allows the cell to keep dividing non-stop
What type of drugs are used for CML?
The drug used links to the Tyrosine kinase, and the activation of the cell cannot proceed because of the activation site that is blocked
What are some of the CML symptoms?
Anaemia, large spleen and bone pain
What are the symptoms of Acute Myeloid Leukaemia (and state why)?
Marrow failure.
Tiredness and shortness of breath, anaemia (due to reduced RBC)
Increased susceptibility of infection (due to reduced WBC)
Bruising or bleeding (due reduced platelets)
What are some of the treatments for AML?
Diverse cytogenetic changes
Chemotherapy to produce marrow aplasia
Transplant of peripheral blood or marrow (or derivation of marrow from stem cells)
What type of cells correlate blood level to clinical activity
Eosinophils
