Leucocyte response in disease Flashcards
Production and release of leucocytes from bone marrow is stimulated by?
Inflammatory cytokines from injured/infected areas
Name the 5 major leucocytes in circulation
Neutrophil Monocyte Lymphocyte Basophil Eosinophil
Which leucocytes are involved in:
- innate immunity
- adaptive immunity
Innate = neutrophils and monocytes Adaptive = lymphocytes
Which leucocytes have granules and polylobed nuclei?
- Neutrophil
- Eosinophil
- Basophil
How should a blood smear be analysed?
Begin count by moving back and forth across the smear in a pattern that avoids covering the same territory (and that keeps you in the optimal viewing area as much as possible).
- identify each leukocyte that is encountered until 100 white blood cells have been counted and sorted by type, giving you a percentage of each cell type or a relative differential leukocyte count
If < 15 WBC in a single LPF10x field = ?
If > 45 WBC in a single LPF10x field = ?
Leukopenia
Leukocytosis
Describe the appearance of:
- Mature neutrophils
- Banded neutrophils
1 = Nucleus divided into 3-5 lobes, cytoplasm clear or pale pink, granulated 2 = U shaped nucleus, parallel sides
What are the roles of neutrophils?
Vital role in defence against pathogens:
- Kill or inactivate bacteria, yeasts, fungi or parasites
- Eliminate infected or transformed cells
- Modulate the immune response
What are the 3 kinds of neutrophil pools in the bone marrow?
Proliferative pool
Maturation pool
Storage pool
What is the production of neutrophils regulated by?
Cytokines and growth factors
How long is the maturation time of neutrophils in the bone marrow, how is this time affected during inflammation?
Normally takes 7 days
- can be 2-3 days less in inflammation
If haemopoiesis stops, what will be the first manifestation in the blood?
Neutropenia
Describe the left shift
- A strong inflammatory stimulus leads to release of more immature forms of neutrophils
- Increased banded neutrophils
Compare a regenerative and degenerative left shift
Regenerative = neutrophilia with bands Degenerative = normal or low mature neutrophil count, increased immature cells, marrow cant meet the needs of inflammatory processes
Give examples of causes of neutrophilia (higher neutrophil count in the blood than the normal reference range)
- Physiological response e.g. stress, fear
- Acute inflammatory response
- Corticosteroid induced (stress)
- Adrenaline
Describe how adrenaline causes physiological neutrophilia
Redistribution of mature neutrophils from the marginating pool (rolling along the edges of blood vessels) to the circulating pool
- Largely mediated by increased blood flow
Describe steroid/stress induced neutrophilia
Mature neutrophilia
- Release of cells from the storage pool
- Shift of cells from marginating to circulating pool
- Reduced endothelial adherence
When would hypersegmented neutrophils be seen, what do they indicate?
Steroid/stress induced neutrophilia
- usually reflect the fact they have been in circulation for longer
What is myelopoiesis?
Production of the bone marrow
How would cells appear if a toxic change had occured?
- increased cytoplasmic basophilia in neutrophils (blue colour)
- Blue granules
- Less condensed chromatin
When does a toxic change occur?
When there is reduced maturation time in the bone marrow because of intense myelopoiesis stimulation
Which conditions/disease can cause neutrophil dysfunction?
- immunodeficiency syndromes
- diabetes mellitus
- neoplasia
What are the causes of neutropenia?
Overwhelming demand or decreased survival of neutrophils
- severe bacterial infection
- pyometra, pyothorax
- reduced haematopoiesis
What are some causes of reduced haematopoiesis?
- bone marrow hypoplasia
- after chemotherapy
- parvovirus infection
- oestrogens
- chronic ehrlichiosis
What are the functions of eosinophils?
- kill parasites
- control hypersensitivity reactions
- effector cells in allergic disease and inflammation
What are some causes of eosinophilia?
- Parasites
- Allergies e.g. asthma, fleas, foods
- Inflammation
- Neoplasia
- Hypoadrenocorticism (dogs)
Basophils are potent in which kind of reactions?
Inflammatory
Hypersensitivity
Monocytes are the circulating precursor of which cell?
Macrophage
In normal blood what are the levels of monocytes like?
Very low
What is the function of monocytes?
- Circulate for short time before migrating into tissues as macrophages
- Phagocytose
- Secrete various inflammatory and immunomodulatory factors
Monocytosis reflects which condition in the body?
Chronic inflammation
Where does most lymphopoiesis occur?
In the peripheral lymphoid tissue in response to antigenic stimulation
What is the function of B-lymphcytes?
Undergo antigenic stimulation where they differentiate into plasma cells which produce immunoglobulins
T-lymphocytes can differentiate into which 3 immune cells?
T-helper cells
Cytotoxic T cells
T-regulatory cells
What are some causes of lymphocytosis?
- Adrenaline induced
- Prolonged immune stimulation
- Post vaccination
- Hypoadrenocorticism
What are some causes of lymphopenia
- Corticosteroids
- Viral disease
- Loss of lymphocyte rich lymph e.g. chylothorax
- Sepsis
- Lymphoma
What are the three most likely clinicopathological abnormalities in a frightened 6m old kitten?
Neutrophilia
Lymphocytosis
Hyperglycaemia
How does the pattern of neutrophils differ in:
- stress response
- acute inflammation
- overwhelming inflammation
- High numbers with no left shift
- High numbers with a left shift
- Decreased numbers of neutrophils but a left shift present
