L9. Myeloblast line White Blood cells Flashcards
What are the 4 cell types that are the phagocytes (vs lymphocytes) and which of those are granulocytes.
Order them from highest to lowest concentration in blood
Neutrophils, Eosinophils, Basophils (are Granulocytes) + Monocytes/phagocytes
Highest in the blood= neutrophils (75%), then monocytes, then eosinophils and basophils.
What is the common progenitor of granulocyte
how long does granulocyte maturation take in the marrow, how long do they circulate and what is the immature form and what do higher numbers of this mean
=Marrow has more myeloid than erythroid cells
Granulocytes arise from myeloblast. They mature for 7-10 days in the marrow and circulate for 6-10 hrs then into tissues to site of infection.
Immature form is the band *neutrophil/eosinophil/basophil. higher numbers in the blood imply increased stress on bone marrow
What are the regulators of granulopoiesis vs monocyte production and which one is used clinically for what?
Growth factors/cytokines for granulopoeisis
eg. IL3, SCF, GM-CSF, G-CSF
G-CSF eg. filgastim is used for congenital neutropenia and post chemotherapy or as prophylaxis.
For monocyte GMCSF affects it as well as M-CSF
What is the appearance of Neutrophil : diameter, nucleus, cytoplasm, granules?
Quite large, 10-20um diameter.
- Dense nucleus with 2-5 lobes and a pale cytoplasm.
- Fine pink or violet granules containing lysosomal enzymes for phagocytosis
What is the appearance of Monocyte : diameter, nucleus, cytoplasm, granules?
- Large 15-20 um
- Central oval or indented nuclei
- Blue-gray cytoplasm with granules
What cell does monocyte arise from, how long is maturation, and circulation.
What does it do after circulating
Monocyte arise from the Monoblast ->promonocyte-> monocyte. Matures in bone marrow for 6 days
It circulates for 1-3 days, enters tissues to transform into macrophage.
eg. langerhans, kupffer cell, alveolar macrophage etc
What is the function of neutrophils and monocytes/tissue macrophages
Compare.
Both
- Chemotaxis: chemotactic substances from damaged tissues and bacteria attract it to site of infection.
- Neutrophils can exit blood to go to tissues - Phagocytosis:
- Both have receptors for Fc region of immunoglobulins
and C3 complement to improve recognition of opsonised things - Killing of bacteria
- Can undergo oxidative (H2O2)- or non oxidative pathways (lysosomal enzymes and lower pH) - monocyte way, neutrophil both
Tissue phagocytes only
4. Immune surveillance and Antigen presentation to T cells
- Synthetic function of
- complement, interferon, cytokines and prostaglandins
In what situations are is neutrophil numbers increased. What about when monocytes increased (cytosis)
- what type of infection do they do usually
Neutrophil leucocytosis:
- including more band neutrophils (shift to left) is
-reactive to inflammation, usually bacterial infection but can be trauma, acute blood loss
Monocytosis
- Reactive to chronic infections - eg. TB, osteomyelitis.
Generally does parasitic, protozoal, fungal infections and tumours.
-Malignant - myelodysplasia, monoblastic acute myeloid leukaemia etc.
What is the appearance of Eosinophils vs Basophils : nucleus, cytoplasm, granules?
Basophils are related to mast cells
E: Similar to neutrophils but
Bilobed nucleus, coarse red staining granules
B: Deep violet blue granules which overlie the nucleus
What is the function of Eosinophils. When are they increased in blood
Eosinophilia
- allergic/ hypersensitivity reactions eg. hayfever, drug reactions
-parasitic infections
They are able to phagocytose antigen-antibody complexes, particles and bacteria and bind parasites after chemotaxis
They also release histaminase and aryl sulphatase which inactivates histamine and slow reacting substance of anaphylaxis to dampen type 1 hypersensitivity reaction.
What is the function of Basophils/mast cells in tissues . When are they increased in blood
Doesn’t increase in allergic reaction, only in chronic neoplastic conditions
Function; have IgE attachment sites, which if crosslinked by allergen results in degranulation of histamine, slow reacting substance of anaphylaxis and eosinophil chemotactic factor which mediates the type 1 hypersensitivity reaction
What is the appearance of Lymphocyte: diameter, nucleus, cytoplasm, granules?
What are more populous T, B or NK cells (similar morphology)
10um diameter,
High nucleus to cytoplasm ratio, with condensed chromatin nuclei
Thin rim of blue-grey agranular cytoplasm
T cells = 65-80%, then B (10-15%) then NK
What is a primary and secondary lymphoid organ.
What is the spleen
Bone marrow
Spleen is a 2ndar lymphoid organ where there is antigen presentation.
What are the two reasons for lymph node enlargement and what is the difference in presentation
- Reactive enlargement to viral/local bacterial infection.
- Node is tender, transient enlargement. Accompanied by malaise, febrile illness - Malignancy: primary lymphoma or metastatic spread
- Isolated non tender node, with persistent enlargement >1-2cm for more than 2 weeks
In what cases is there lymphocytosis and lymphocytopenia
Lymphocytosis:
1. mild and transient increase in response to infections in children, infants
in adults there is reactive increase to viral infections - eg. EBV
- Malignancy
- eg chronic lymphocytic leukaemia
Lymphocytopenia: leading to opportunistic infections and malignancies
- HIV infection due to destruction of CD4 pos T cells
- Congenital immunodeficiency, steroid therapy, severe bone marrow failure
