Lecture 4: White blood cells Flashcards
What is thrombocytopaenia?
Low platelet count
What are the phagocytes?
Granulocytes (neutrophils, eosinophils, basophils) and Monocytes
Write some notes on neutrophils
- Dense nucleus with 2-5 lobes
- Granules in cytoplasm
- Beyond five lobes is an indicator of age
How are neutrophils measured?
In absolute values
What are neutrophil precursors?
Myeloblasts and these come from MSC and HSC
Describe the granulocyte growth kinetics?
- 7-10 days maturation in bone marrow
- Theres a range of precursors & the presence if banded nucleus indicates inflam and early release
- Circulate only for 6-10hrs
What is neutropenia?
Low granulocyte count and they cant be transfused
v at risk of infection
What regulates granulopoiesis?
Heamopoetic growth factors
-> IL3, stem cell factor, GM-CSF, G-CSF
RELEVANT GROWTH FACTORS AND MICROENVIRONMENT
NB: G-CSF in clinical use in NZ
What are the functions of neutrophils?
- Chemotaxis
- Phagocytosis
- Killing of bacteria: Oxidative and non-oxidative
What is neutrophil leucocytosis:
- Feature of infection and inflammation i.e bacterial infection (examined for in appendicitis)
- May be associated with left shift i.e more immature forms of blood cells i.e banded neutrophils
Describe histological appearance of monocytes:
- Central oval or indented nuclei
- Blue-grey cytoplasm with granules
Describe monocyte development:
Monoblast -> Promonocyte -> Monocyte
Share common precursor with neutrophil (Myeloblast)
Describe monocyte kinetics:
- Circulate for 1-3 days
- Enter tissues and transform into macrophages
- Related cells throughout body; Kupffer cells, alveolar macrophages, langerhan cells, microglial cells brain
What are the functions of monocytes/macropahges:
Phagocytosis
Synthetic function
Antigen presentation
What types of infections do monocytes/macrophages fight? and what are their methods?
Phagocytic cells:
- Chronic infections, intracellular parasites i.e TB
- > Chemotaxis
- > Opsonisation
- > Phagocytosis and ingestion
- > Killing of ingested bacteria by fusion with monocytic lysosomal granules
What is the synthetic function of macrophages/monocytes:
Synthetic function:
- Complement
- Interferon
- Cytokines i.e TNF, IL1, Growth factors
- Prostaglandins
What is monocytosis and its clinical picture:
Monocytosis: (increased count)
- Reactive in origin: Chronic infections i.e TB, Osteomyeltiis
- Malignant: Acute myeloid leukaemia (monoblastic sub type), Chronic myeloid leukemia (absent of underlying illness of course)
Describe the histological appearance of eosinophils:
- Bilobed nucleus (fortune cookie)
- Red staining granules
- Very rare in blood
What is eosinophilia?
Allergic or hypersenstivity reactions i.e hayfever, asthma, drug reactions
Parasetic infestations
Describe basophils appearance under microscope and primary function:
Infrequent cells in blood
- Deep blue granules over the nucelus
- IgE binding sites (degranulation->histamine)
- Releated to mast cells
What is the function of basophils?
- Close relationship to mast cells
- Granules-> Histamine
- Type 1 hypersenstivity reaction
When are basophils high?
Probably in neoplastic syndromes, not hypersensitivity reactions
Whats the histological appearance of lymphocytes?
- Condensed chromatin nuclei
- Thin rim of agranular cytoplasm
- Cant distinguish B from T
What are the proportions of circulating lymphocytes?
Circulating lymphocytes:
- 65-80% T cells
- 5-15% B cells
- NK cells (Larger cytplasmic granules)
What are the primary lymphoid organs?
B cells = bone marrow
T cells = Thymus
IF the spleen is palpable whats the implication?
It has doubled in size
Whats of note with lymph node enlargement?
Reactive: Viral infection, local bacterial infection (short lived, tender)
Malignant: Lymphoma or metastatic spread (often isolated nodes, no tender, not resolving)
What is lymphocytosis?
Reactive i.e viral infections i.e infectious mononucleosis
Malignant i.e CLL
What can cause lymphopenia?
HIV infection: CD4 pos T cells
-> Profound T cell deficit, opportunistic infections, malignancies
Others: Congenital immune defects, steroid therapy, severe bone marrow failure
