Lecture 7 - Haem 4

Question 1

What is the half life of a blood neutrophil?

Answer 1

5 to 10 hours

Question 2

What is myelopoiesis and how long does the process take?

Answer 2

Process of the production of neutrophils and takes 6 to 9 days

Question 3

Briefly describe the kinetics of neutrophils and the three components of them:

Answer 3

Storage neutrophil pool (SNP): segmented neutrophils that are ready for release into the marrow sinusoids

Blood neutrophils: Circulating neutrophil = free flowing into the blood (the part that is collected in blood samples)
Marginated neutrophil pool (MNP) - temporarily adhere to the endothelial cells (capillaries and veins) in the peripheral blood and spleen - re-enter CNP or migrate into tissues.

Question 4

What is the MNP:CNP ratio?

Answer 4

1 in most mammals, 3 in cats

Question 5

What is the function of neutrophils?

Answer 5

They act as defence against invading micro-organisms, primarily bacteria. They recognise the inflammatory signal –> leave the blood –> migrate through the tissue to a site where bacteria are present

Question 6

What is the difference between left shift and right shift? What is the appearance of these?

Answer 6

Left shift = younger neutrophils (they typically appear much more banded in appearance)

Right shift = older (appears as hyper-segmented neutrophils)

Question 7

What is the Pelger-Huet anomaly? What species of dog is commonly affected

Answer 7

Inherited condition characterised by failure of mature granulocyte nuclei to lobulate = hypo-segmentation (common in Australian shepherd dogs)

Question 8

What is the half life on monocytes in blood and in tissue?

Answer 8

The half life of monocytes in tissues varies from 0.5 to 3 days. Once monocytes migrate to tissue they become macrophages (survive 3 months) and dendritic cells (antigen presenting cells)

Question 9

What are the three main functions of monocytes in the blood?

Answer 9

1. Phagocytosis (including erythrophagocytosis - macrophages generally move slowly and are not as good at killing bacteria - however they are much more active against viral, fungal, protozoal and helminthic infections than neutrophils)
2. Antigen presentation to T lymphocytes
3. Immunomodulation

Question 10

What are the main functions of eosinophils?

Answer 10

Important component of:
Type 2 cytokine induced inflammatory response that is critical in host defence against helminth infections = hypereosinophilia due to parasite infections

Type 1 hypersensitivity to allergic reactions - hypereosinophilia with allergic reactions

Question 11

What is the function of T-lymphocytes?

Answer 11

cellular immunity

Question 12

What is the function of B-lymphocytes?

Answer 12

humoral immunity

Question 13

What is a state of increased neutrophils called?

Answer 13

Neutrophilia

Question 14

What is a state of increased lymphocytes called?

Answer 14

Lymphocytosis

Question 15

What is a state of increased eosinophils called?

Answer 15

Eosinophilia

Question 16

What is a state of increased monocytes called?

Answer 16

Monocytosis

Question 17

What is a state of increased leukocytes called?

Answer 17

Leukocytosis

Question 18

What is a state of decreased leukocytes called?

Answer 18

leukopenia

Question 19

What is a state of decreased neutrophils called?

Answer 19

neutropenia

Question 20

What is a state of decreased lymphocytes called?

Answer 20

lymphopenia

Question 21

What is a state of decreased eosinophils called?

Answer 21

eosinopenia

Question 22

What is a state of decreased monocytes called?

Answer 22

monocytopenia

Question 23

Briefly describe the effect of catecholamine release (early exercise, fear or excitement) on the neutrophils in blood:

Answer 23

Shift from the marginal to the circulating pool without concurrent egress of neutrophils from blood into tissues - the leukogram returns to normal within 30 minutes of removal of the stimulus

Question 24

Briefly describe the effect of glucocorticoid release (early exercise, fear or excitement) on the neutrophils in blood: - many causes e.g pain, trauma, prolonged emotional stress, intense sustained exercise, hyperthermia, hyperadrenocorticism

Answer 24

Shift of neutrophils from storage and marginal pools and decreased egress of neutrophils from blood to tissues. Decreased neutrophil diapedesis and intravascular ageing hyper-segmentation can be seen. Neutrophilia associated with monocytosis, lymphopenia and eosinopenia

Question 25

Briefly describe what is occurring in mild or chronic inflammation or acute inflammation without left shift: (causes include haemorrhage, haemolysis, necrosis, chemical and drug toxicities, malignancy)

Answer 25

Mild or chronic inflammation - the increased peripheral demand for neutrophils is met by release of marginal pools Acute inflammation without left shift - the increased peripheral demand for neutrophils is met by release of marginal pools and storage pool

Question 26

Briefly describe what acute inflammation with regenerative left shift is: - the causes include infectious bacteria, tissue injury and immune mediated disorders

Answer 26

Occurs where the peripheral demand for neutrophils is greater than the storage and marginal pools and hence the bone marrow release young neutrophils as well. Regenerative left shift is where mature neutrophils are more numerous than band neutrophils

Question 27

Briefly describe the process that occurs in acute inflammation with degenerative left shift: - caused by a hyper-acute inflammatory process

Answer 27

Acute inflammation with degenerative left shift occurs where the peripheral demand for neutrophils is massive and fast. Both storage and marginal pools are exhausted and bone marrow release young neutrophils. Degenerative left shift occurs where band neutrophils are more numerous than mature neutrophils

Question 28

What occurs in hyper-acute inflammation with neutropenia? What causes it to occur

Answer 28

Hyper-acute inflammation with neutropenia - occurs where the peripheral demand for neutrophils exceed the compensatory ability of bone marrow - including increased myelopoiesis - the causes include acute necrosis and septicaemia

Question 29

Define the term leukaemia:

Answer 29

Defined as the presence of neoplastic cells of haematopoietic origin in blood and/or bone marrow - can be of any lineage

Question 30

What cells are of myeloid origin?

Answer 30

megakaryocytes, granulocytes, monocytes and erythrocytes

Question 31

Briefly explain the difference between acute and chronic leukemias:

Answer 31

Acute: Blast --> cell cannot be identified by morphological features Chronic: Differentiated cell --> cell type can be identified by morphologic features

Question 32

What cells are of lymphoid origin?

Answer 32

Lymphocytes

Question 33

Briefly explain the microscopic appearance of lymphoid leukaemia:

Answer 33

- medium-large size (20-25 micron) - cytoplasm is scant to moderately abundant - mildly to deeply basophillic - rarely granulation of vacuolisations - nuclei: usually round - chromatin is finely stippled - nucleoli are prominent

Question 34

Briefly describe the microscopic appearance of myeloid leukaemia:

Answer 34

- large size (25-35 micron) - cytoplasm: abundant and deeply basophilic - often vacuolisations and rarely granulations - nuclei are round or indented - chromatin: finely stippled - nucleoli - visible on or multiple