Clinical Pathology- Haematology: Leucocytes and Polycythaemia Flashcards
How do leucocytes get transported?
Where are they produced?
What causes their stimulation?
Use blood as transport system
Produced/release from bone marrow and egress into peripheral tissues
Stimulated by cytokines
Which 2 leucocytes are involved in innate immunity and phagocytosis of pathogens?
Which leucocytes are part of adaptive immunity?
Which two leucocytes deffend against parasites?
Neutrophil and monocytes- innate immunity
Lymphocyte- adaptive
Eosinophil/basophil- defense against parasites
Which leucocytes are granulocytes (polylobed nuclei and granules)?
Neutrophil
Eosinophil
Basophil
Fill in the covered names of these leucocytes
What it a leukogram?
Analysis of leucocytes a differential count is absolutely required
No substitute for a smeal exmaination
How many WBC need to be in a single field for leukopenia and leukocytosis?
<15 WBC in a single LPFx10 field- leukopenia
>45 WBC in a single LPFx10 field- leuckocytosis
How can mature and band neutrophils be distinguished?
Mature- nucleus divided into 3-5 lobes- cytoplasm clea or pale pink
Band- u-shaped nucleus, parallel sides, minimal indentation which are not >50% of width of nucleus
What is the role of neutrophils?
Vital role in defence against pathogens-
kill or inactivate bacteria, yeats, fungi or parasites
eliminate infected or transformed cells
modulate the immune response
Involved in regulation of haemopoiesis
What are the different neutrophil pools and where are they found?
Bone marrow:
Proliferative pool
Maturation pool
Storage pool
Blood pools
Some in tissues
Describe neutrophil kinetics
Production regulated by cytokines and growth factors
Maturation time in bone marrow is 7 days
Many neutrophils are stored in BM
Average blood transit time 6-10 hours
On exit from circulation, neutrophils are lost across mucosal surfaces or are removed by macrophages in liver/spleen
If haemopoiesis stops what will be the first manifestation in the blood?
Neutropenia
What is a left shift of neutrophils?
What causes it?
A shift/increase in band immature neutrophils
Caused by a strong inflammatory stimulus- release of more immature forms
What is the difference in regeneratvie and degenerative left shift of neutrophils?
Regenerative- neutrophilia with bands
Degenerative- normal or low mature neutrophil count, increased immature cells, poor prognostic indicator
What can cause neutrophilia?
Physiolgical response- emotional stress/fear, adrenalin
Acute inflammatory response- infection, IMD, neoplasia, necrosis
Stress/corticosteroid induced
Others- uncommon
What is physiological neutrophilia?
Redistribution of mature neutrophils from the marginating pool to the circulating pool:
increased blood flow
stress/fear
May also produce lymphocytosis in cats- can be quite marked, mat also see hyperglycaemia
How can stress/steroid induced neutrophilia be identified?
Mature neutrophilia
release of cells from the storage pool
Shift of cells for marginating to circulating pool
reduced endothelial adherance
What shows up in a stress leukogram?
Neutrophilia
Lymphopenia
Eosinopenia
What changes about a leucogram with an acute inflammatory response?
Neutrophilia with or without a left shift
What happens to leucocytes with toxic change?
Why?
Increases cytoplasmic basophilia (blue colour)
Blue granules (Dohle bodies)
Vacuoles (foamy appearence)
Less condensed chromatin
Due to reduced maturation time in bone marrow because of intense stimulation of myelopoiesis