Leukocyte responses in disease

Question 1

Where are WBCs produced and released from?

Answer 1

Bone marrow

Question 2

What stimulates the production/release of WBCs?

Answer 2

Inflammatory cytokines

From injured/infected areas

Question 3

What are the 5 major WBCs in circulation?

Answer 3

Neutrophil 
Basophil 
Eosinophil 
Lymphocyte
Monocyte

Question 4

Which 2 WBCs are mostly involved with innate immunity (therefore phagocytosis of organisms)?

Answer 4

Monocyte (become macrophages in tissues)

Neutrophils

Question 5

What type of immunity is associated with lymphocytes?

Answer 5

Adaptive immunity - able to recognise learned pathogens

Question 6

Which 2 WBCs are associated with allergies and defence against parasites?

Answer 6

Basophil

Eosinophil

Question 7

What are granulocytes (AKA polynuclearmorphs)?

Answer 7

WBCs with granules and polylobed nuclei

Neutrophils, eosinophils, basophils

Question 8

What regulates leukocyte production?

Answer 8

Cytokines

Growth factors

Question 9

How long does it take for WBCs to mature in the bone marrow?

Answer 9

7 days

Question 10

Where are many neutrophils stored?

Answer 10

Bone marrow

Question 11

What is the average blood transit time for neutrophils?

Answer 11

6-10 hrs

replaced 2.5X day

Question 12

How do neutrophils exit circulation?

Answer 12

Lost across mucosal surfaces
OR
Removed by macrophages in liver/spleen

Question 13

Most leukocyte patterns are not interpreted into specific diagnoses, but are used to identify processes e.g. inflammation/stress. Give an example of a diagnosis that can be made on leukocyte response alone

Answer 13

Leukaemia

Question 14

Which words describe an increase or decrease in neutrophils? What does the number of neutrophils depend on?

Answer 14

Neutrophilia
Neutropenia
Balance between production and consumption

Question 15

What is left shift?

Answer 15

Presence of band neutrophils in circulation

Question 16

What are band neutrophils?

Answer 16

Neutrophils step before fully matured

Question 17

What is left shift a hallmark of (although not always present)?

Answer 17

Acute inflammation

Question 18

Left shift can be regenerative (good) or degenerative (bad). What do these terms mean?

Answer 18

Regenerative = with neutrophilia
Degnerative = with normal neutrophils or neutropenia

Question 19

Left shift can be with toxic change. What is toxic change?

Answer 19

Increased basophilia (blue colour) of cytoplasm
Blue granules
Vacuoles
Less condense chromatin

Question 20

What causes toxic change?

Answer 20

Reduced maturation time in bone marrow

Due to intense stimulus of myelopoiesis

Question 21

What is the name of WBC production?

Answer 21

Myelopoiesis

Question 22

What is the most common cause of lymphopenia?

Answer 22

Acute viral infections

Question 23

What is the most common cause of lymphocytosis (RARE)?

Answer 23

Chronic inflammation causing lymphoid hyperplasia (increased lymphocytes in LNs, not usually peripheral tissues)

Question 24

What are the haematological responses to adrenalin (excitement/fear)?

Answer 24

Lymphocytosis - splenic contraction, more frequent in cats

Neutrophilia - less common

Question 25

What are the haematological responses to chronic stress or XS endogenous/exogenous steroids?

Answer 25

Lymphopenia - due to lymphocyte apoptosis with steroids

Neutrophilia - less common

Question 26

What is the expected haematological change seen with bone marrow injury (bone marrow hypoplasia)?

Answer 26

Neutropenia

Causes pancytopenia but neutropenia appears first

Question 27

Give examples of what may cause bone marrow hypoplasia (due to injury)

Answer 27

Chemotherapy
Parvovirus
Idiosyncratic drug reactions
Neoplasia 
Chronic ehrlichiosis

Question 28

What haematological changes are expected to be seen with haematopoietic neoplasia?

Answer 28

Leukocytosis

Due to neoplastic leukocytes

Question 29

Give 2 examples of haematopoietic neoplasia

Answer 29

Lymphoid leukaemia

Myeloid leukaemia

Question 30

What cells cause lymphoid leukaemia?

Answer 30

Neoplastic lymphocytes

Question 31

What cells cause myeloid leukaemia?

Answer 31

Neoplastic leukocytes (any except lymphocytes and their precursors)

Question 32

What haematological abnormality does Severe Combined Immunodeficiency (SCID - Arabian horses) cause?

Answer 32

Lymphopenia

Question 33

What is myelodysplasia? What may it show on microscopy?

Answer 33

Abnormal maturation of bone marrow

Abnormalities e.g. giant neutrophils, hypersegmentation

Question 34

What are the differentials for monocytosis?

Answer 34

Chronic inflammation

Stress leukogram

Question 35

What is a stress leukogram?

Answer 35

Neutrophilia
Eosinopenia
Lymphopenia
Monocytosis (dogs, cats)

Question 36

In which species is a stress leukogram most commonly seen?

Answer 36

Dog

Question 37

What are the differentials for a lymphocytosis?

Answer 37

Adrenalin release in cats

If atypical morphology - lymphoid leukaemia

Question 38

What are the differentials for neutrophilia?

Answer 38

Inflammation - due to infection/tissue damage/necrosis

Can be due to chronic stress or steroids

Question 39

What are some potential causes of neutropenia?

Answer 39

Overwhelming tissue demand
Reduced bone marrow production
Increased destruction - immune mediated

Question 40

What are the differentials for eosinophilia or basophilia (similar causes)?

Answer 40

Worm parasitism

Allergy - type I hypersensitivity

Question 41

How many WBCs are needed in a single 10X field to confirm leukopenia or leukocytosis?

Answer 41

<15 = Leukopenia

> 45 = Leukocytosis

Question 42

Is a manual or automated leukocyte count more accurate? What are the exceptions?

Answer 42

Automated more accurate
UNLESS leukocytes are clumped or many nucleated RBCs (machine detects as WBC)
Do manual for atypical cells and band cells

Question 43

Which is more important - the total WBC count or % of each WBC?

Answer 43

% of each WBC