The Leukon

Question 1

Define the term “toxic change” with regards to neutrophils

Answer 1

Toxic changes in neutrophils can occur due to maturation defects. It is seen with inflammation that is severe enough to intensely accelerate neutrophil production (not necessarily from a toxin) - may see:

• increased cytoplasmic vacuolation
• increased cytoplasmic basophila
• Doehle bodies

Question 2

Outline the differences in neutrophils between dogs, cats, horses, and ruminants

Answer 2

Dog- white cytoplasm with pink granules
Cat - white cytoplasm with no visible granules
Horse - White to pink cytoplasm; no visible granules; one thin and knobby nuclei
Cow - White cytoplasm with small pink granules causing a pink tint

Question 3

What is the main component of neutrophil primary granules?

Answer 3

Myeloperoxidase **

Also contains 25% lysozyme, neutral proteases, acid hydrolases

Question 4

What is the primary component of secondary granules of neutrophils?

Answer 4

75% lysozyme

Also contains proteases and lactoferrin

Question 5

At what stage of development are secondary granules made in neutrophils?

Answer 5

They are made at the myelocyte stage onward (no secondary granules present before that)

Question 6

What effect does lactoferrin present in neutrophil secondary granules have?

Answer 6

• chemotactic for neutrophils
• stimulates oxidative burst
• binds strongly to acid macromolecules
• sequesters iron within phage during chronic disease and acute inflammation

Question 7

Name the 5 factors that contribute to degree of neutrophilia seen in a patient.

Answer 7

1. production rate of neutrophils
2. Rate of release from the bone marrow
3. Demargination
4. Half-life of the neutrophil
5. Rate of diapedesis into tissues

Question 8

What is the circulation time of a neutrophil?

Answer 8

6-8 hours

Question 9

What is the production time of a neutrophil?

Answer 9

6 days ( 2.5 days for myeloblast to form metamyelocytes which divide 3X)

Question 10

What effect does epinephrine have on neutrophils?

Answer 10

Epinephrine causes neutrophil demargination — mobilizing the neutrophils from the central neutrophil pool (CNP) to the marginal neutrophil pool (MNP)

Question 11

What effect does endotoxins from gram negative bacteria have on neutrophils?

Answer 11

Endotoxins ncrease the rate of release of neutrophils from the bone marrow

Question 12

What effect does cortisol have on neutrophils?

Answer 12

• cortisol increases the release from the bone marrow

- cortisol also reduces diapedesis

Question 13

How does the marginal neutrophil pool (MNP) in a cat compare to that of a dog with respect to the central neutrophil pool (CNP)

Answer 13

The MNP in a cat is 3X the CNP whereas in dogs the MNP =CNP normally

Question 14

What is abnormal in terms of bands in small animals compared to large animals

Answer 14

Bands >1000 is abnormal in small animals
Whereas
Bands >300 is abnormal in large animals

Question 15

How does an eosinophil differ from a neutrophil in terms of its appearance (cytoplasm, nucleus etc)

Answer 15

• the nucleus of an eosinophil is less segmented compared to the neutrophil
• the cytoplasm of an eosinophil has orange granules compared to a neutrophil that may or may not have light pink granules present depending on the species
• in some dogs, eosinophils have cytoplasmic vacuolation

Question 16

What are the differences in granule shape seen in eosinophils between horses, dogs, and cats?

Answer 16

Dogs - round
Cats - rice shaped
Horse - large and plumped shaped