Abnormalities of the Leukon

Question 1

Where are Leukocytes produced and where do they differentiate? (3/2)

Answer 1

Bone marrow (all cell lines!), spleen and liver
Thymus, lymph node- differentiation

Question 2

How do we typically measure leukocytes in a lab using machinery?

Answer 2

Take blood sample- lyse the red blood cells and allow nucleated cells to stream through a channel where electrical impedance (flow) is noted- this is the total nucleated cell count (TNC)

Question 3

What is a QBC Test?

Answer 3

Quantitative Buffy Coat Test- centrifugal test where machine scans a spun PCV tube and relates fractions to where each cell type settles

Question 4

How do we measure leukocytes in exotic/ avian species and why?

Answer 4

Manual methods e.g. chamber counts because their RBC’s are nucleated and cannot be separated based on that notion

Question 5

How do we make blood smear estimates?

Answer 5

From monolayer- assuming there’s no clots- count the number of leukocytes in this monolayer using x10 eyepiece & x10 lens
Then divide it by 4
Do this for 10 different fields of view

Question 6

Which leukocyte is most dominant in dog/cat blood?

Answer 6

Neutrophils

Question 7

Which leukocyte is most dominant in cow blood?

Answer 7

Lymphocytes

Question 8

What is a Neutrophils half life?

Answer 8

6 hours

Question 9

What cells are the CFU-G?

Answer 9

Colony forming unit granulocyte so basically self renewal cells

Question 10

What happens in the ProNP proliferation pool?

Answer 10

Progranulocytes > Myelocyte
Stimulated by Interleukins & Colony stimulating factors

Question 11

How long do neutrophils spend in the MatNP?

Answer 11

2-3 days maturing

Question 12

What is the difference between the CNP:MNP (circulating vs marginated neutrophil pools) ratio in dogs vs cats?

Answer 12

CNP: MNP in dogs is 1:1
CNP: MNP is 3:1

Question 13

When neutrophil demand is high…

Answer 13

more immature neutrophils are released (causing left shift)

Question 14

What are immature neutrophils also known as and what do they look like?

Answer 14

Toxic neutrophils- foamy cytoplasms, no lobuled/ segmented nucleus, could be larger than normal

Question 15

What is the difference between toxic and degenerative neutrophils? (3)

Answer 15

Toxic neutrophils are found in peripheral blood whereas degenerate neutrophils are found in tissues
Toxic neutrophils are that way due to accelerated production whereas degenerate are formed that way due to fighting with bacteria
Toxic neutrophils are regenerative & due to neutrophilia and degenerative are due to neutropenia

Question 16

Degenerative neutrophils are ordinarily found in tissues fighting bacteria- what if we see them in the circulation?

Answer 16

Septicaemia!

Question 17

What can cause ‘Right Shift’ aka Hypersegmented neutrophils?

Answer 17

Didn’t leave the MatNP fast enough due to downregulation of adhesion molecules
- Steroids

Question 18

What are the 5 mechanisms of Neutropenia?

Answer 18

Inflammatory
Endotoxin
Peripheral destruction
Granulocytic hypoplasia
Ineffective production

Question 19

What would cause Neutropenia due to increased demand?

Answer 19

Peracute bacterial infections
Endotoxaemia
Immune mediated

Question 20

What would be some causes of Neutropenia due to decreased production?

Answer 20

Bone marrow disorders
Certain infectious causes such as Parvovirus, FeLV, FIV
Toxicities and drug reactions

Question 21

What is different about Greyhounds when considering if an animal is Neutropenic?

Answer 21

Greyhounds naturally have lower neutrophil concentrations so need to remember to use greyhound specific reference intervels

Question 22

What are the 5 mechanisms that cause Neutrophilia?

Answer 22

Acute inflammatory
Chronic inflammatory
Steroid neutrophilia
Physiologic neutrophilia
Chronic myeloid leukaemia

Question 23

What pathologies may cause Neutrophilia due to increased demand? (3)

Answer 23

Infections- bacterial, viral etc.
Immune mediated diseases
Haemolysis, haemorrhage etc.

Question 24

What may cause neutrophilia due to increased production independent of demand? (2)

Answer 24

Chronic Granulocytic leukaemia & Acute myeloid leukaemia- bone marrow overproduction

Question 25

What may cause the leukocytes to persist in the circulation (and therefore cause Neutrophilia)?

Answer 25

Stress/ steroid response

Question 26

Give an example of Physiologic Neutrophilia. {think redistribution}

Answer 26

Stress/ excitement increases blood pressure- neutrophils are swept off vessel walls and into the circulation, increasing WBC numbers

Question 27

What are Russel Bodies and where are they commonly found?

Answer 27

Eosinophilic inclusions that have failed to release its immunoglobulins- found usually in Lymph nodes but are commonly seen in Neoplasm

Question 28

How do steroids cause Lymphopenia?

Answer 28

Via redistribution- Steroids disturb lymphocyte recirculation by inhibiting lymphocyte migration into the lymph nodes- steroids also in some cases cause lysis of lymphocytes too

Question 29

What may cause a decreased production of Lymphocytes? (3)

Answer 29

Infection with parvovirus, FeLV etc. Lympholytic drugs- chemotherapeutics e.g. Azathioprine Immunodeficiencies where T & B cells are affected

Question 30

How can Hypoadrenocorticism cause Lymphocytosis?

Answer 30

Lack of corticosteroid production which normally suppress lymphocyte production

Question 31

Do monocytes have a storage, marginated or circulating pool?

Answer 31

Storage Pool- NO Marginated & Circulating- Yes

Question 32

Once monocytes leave circulation to go into the tissues...

Answer 32

they differentiate into macrophages

Question 33

Monocytosis can occur secondary to immune neutropenia- how?

Answer 33

Monocytes come from the same precursors as Neutrophils- an increased demand of Neutrophils also increases monocytes- whilst the neutrophils get used up the monocytes remain

Question 34

What may increase demand for Eosinophils? (4)

Answer 34

IL-5 release Parasite antigens Allergic disease such as drug allergy, asthma Inflammation of mast cell rich tissue

Question 35

How would a Paraneoplasm cause Eosinophilia?

Answer 35

By producing IL-5 which causes Eosinophil release

Question 36

What pathologies do Basophils play a role in?

Answer 36

Type 1 hypersensitivities Anaphylaxis Rhinitis Asthma GI Sensitivities

Question 37

What is a stress leukogram/ what changes does it induce?

Answer 37

Neutrophilia (high), lymphopenia (low), monocytosis (high), and eosinopenia (low)

Question 38

Give an exogenous cause that would induce a stress leukogram?

Answer 38

Prednisolone/ any corticosteroid

Question 39

What endogenous cause will induce a stress leukogram?

Answer 39

Cortisol

Question 40

Would a stress leukogram help diagnose Addison's?

Answer 40

Yes and No- the onset of clinical signs with a reverse/ lack of response matching a stress leukogram would be the indicator for addison's

Question 41

How can we use a stress leukogram to differentiate acute from chronic inflammation?

Answer 41

Acute- neutrophilia (^) with lymphopenia (↓) Chronic- neutrophilia (^) with lymphocytosis (^)

Question 42

Adrenaline causes....

Answer 42

Increased neutrophils (neutrophilia) and increased lymphocytes (lymphocytosis)