Leukocyte responses in disease

Question 1

What are the 5 leukocytes?

Answer 1

– Neutrophil
– Monocyte
– Lymphocyte
– Eosinophil
– Basophil

Question 2

What is classified as leukopenia?

Answer 2

• < 15 WBC in a single LPF10x field

Question 3

What is classified as leukocytosis?

Answer 3

• > 45 WBC in a single LPF10x field

Question 4

What do mature neutrophils look like?

Answer 4

• nucleus divided into 3 - 5 lobes
• cytoplasm clear or pale pink

Question 5

What do band neutrophils look like?

Answer 5

• U shaped nucleus
• Parallel sides

Question 6

What are the roles of neutrophils?

Answer 6

• Vital role in defence against pathogens
  – Kill or inactivate bacteria, yeasts, fungi or
  parasites
  – Eliminate infected or transformed cells
  – Modulate the immune response
• Also involved in regulation of haemopoiesis

Question 7

How long does maturation of neutrophils take?
What is the blood transit time?

Answer 7

*7days
*6-10hrs

Question 8

What is left shift?

Answer 8

Increased band neutrophils - regenerative

Question 9

What are the causes of neutrophilia?

Answer 9

• Physiological response
  – Emotional stress/fear
  – Adrenalin (esp cats)
• Acute inflammatory response
  – infection, IMD, neoplasia, necrosis
• Stress/corticosteroid induced

Question 10

What causes neutrophil dysfunction?

Answer 10

• Immunodeficiency syndromes
• Diabetes mellitus
• Neoplasia
• FeLV

Question 11

What causes neutropenia?

Answer 11

• Overwhelming demand/decreased survival
• Reduced or ineffective granulopoiesis
• Rare diseases

Question 12

What causes overwhelming demand?

Answer 12

• Severe bacterial infection
• Esp Gram -ve
• Pyometra
• Peritonitis
• Pyothorax

Question 13

What are the roles of eosinophils?

Answer 13

• Kill parasites
• Control hypersensitivity reactions
• Effector cells in allergic disease and
  inflammation

Question 14

What causes eosionophilia

Answer 14

• Parasitic
• Allergic – Feline asthma, canine atopy, fleas, EGC,
  atopy, food, hypersensitivity
• Inflammatory
• Neoplastic
• Hypoadrenocorticism (dogs, inconsistent)
• Hypereosinophilic syndrome(cats)

Question 15

What are the roles of basophils?

Answer 15

• Potentiate inflammatory/hypersensitivity
  reactions
• IgE + antigen -> basophil degranulation
• Histamine release -> hypersensitivity
  reaction
• Response in line with eosinophils

Question 16

What is monocytosis a sign of?

Answer 16

• Often reflects chronic inflammation
  – may or may not have concurrent neutrophilia (esp
  cats)
• Acute inflammatory response
• Tissue necrosis
• Immune mediated disease
  – esp IMHA
• Compensatory in neutropenia

Question 17

What do B + T lymphocytes distinguish into?

Answer 17

B cells = plasma cell = immunoglobulins
T cells = 1. T helper cells
2. Cytotoxic T cells
3. T-regulatory cells

Question 18

What causes lymphocytosis?

Answer 18

• Physiological
  – Adrenalin induced splenic contraction
• Prolonged immune stimulation
• Youth
• Lymphoproliferative disease
• Transient post vaccination
• Hypoadrenocorticism

Question 19

What causes lymphopenia?

Answer 19

• Corticosteroids
• Viral disease (esp feline retroviruses)
• Loss of lymphocyte rich lymph
  – chylothorax
• Sepsis/endotoxaemia
• Lymphoma
• (Immunosuppressive drug therapy)