Leukocyte responses in disease Flashcards
Where are WBCs produced and released from?
Bone marrow
What stimulates the production/release of WBCs?
Inflammatory cytokines
From injured/infected areas
What are the 5 major WBCs in circulation?
Neutrophil Basophil Eosinophil Lymphocyte Monocyte
Which 2 WBCs are mostly involved with innate immunity (therefore phagocytosis of organisms)?
Monocyte (become macrophages in tissues)
Neutrophils
What type of immunity is associated with lymphocytes?
Adaptive immunity - able to recognise learned pathogens
Which 2 WBCs are associated with allergies and defence against parasites?
Basophil
Eosinophil
What are granulocytes (AKA polynuclearmorphs)?
WBCs with granules and polylobed nuclei
Neutrophils, eosinophils, basophils
What regulates leukocyte production?
Cytokines
Growth factors
How long does it take for WBCs to mature in the bone marrow?
7 days
Where are many neutrophils stored?
Bone marrow
What is the average blood transit time for neutrophils?
6-10 hrs
replaced 2.5X day
How do neutrophils exit circulation?
Lost across mucosal surfaces
OR
Removed by macrophages in liver/spleen
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
Leukaemia
Which words describe an increase or decrease in neutrophils? What does the number of neutrophils depend on?
Neutrophilia
Neutropenia
Balance between production and consumption
What is left shift?
Presence of band neutrophils in circulation
What are band neutrophils?
Neutrophils step before fully matured
What is left shift a hallmark of (although not always present)?
Acute inflammation
Left shift can be regenerative (good) or degenerative (bad). What do these terms mean?
Regenerative = with neutrophilia Degnerative = with normal neutrophils or neutropenia
Left shift can be with toxic change. What is toxic change?
Increased basophilia (blue colour) of cytoplasm
Blue granules
Vacuoles
Less condense chromatin
What causes toxic change?
Reduced maturation time in bone marrow
Due to intense stimulus of myelopoiesis
What is the name of WBC production?
Myelopoiesis
What is the most common cause of lymphopenia?
Acute viral infections
What is the most common cause of lymphocytosis (RARE)?
Chronic inflammation causing lymphoid hyperplasia (increased lymphocytes in LNs, not usually peripheral tissues)
What are the haematological responses to adrenalin (excitement/fear)?
Lymphocytosis - splenic contraction, more frequent in cats
Neutrophilia - less common
What are the haematological responses to chronic stress or XS endogenous/exogenous steroids?
Lymphopenia - due to lymphocyte apoptosis with steroids
Neutrophilia - less common
What is the expected haematological change seen with bone marrow injury (bone marrow hypoplasia)?
Neutropenia
Causes pancytopenia but neutropenia appears first
Give examples of what may cause bone marrow hypoplasia (due to injury)
Chemotherapy Parvovirus Idiosyncratic drug reactions Neoplasia Chronic ehrlichiosis
What haematological changes are expected to be seen with haematopoietic neoplasia?
Leukocytosis
Due to neoplastic leukocytes
Give 2 examples of haematopoietic neoplasia
Lymphoid leukaemia
Myeloid leukaemia
What cells cause lymphoid leukaemia?
Neoplastic lymphocytes
What cells cause myeloid leukaemia?
Neoplastic leukocytes (any except lymphocytes and their precursors)
What haematological abnormality does Severe Combined Immunodeficiency (SCID - Arabian horses) cause?
Lymphopenia
What is myelodysplasia? What may it show on microscopy?
Abnormal maturation of bone marrow
Abnormalities e.g. giant neutrophils, hypersegmentation
What are the differentials for monocytosis?
Chronic inflammation
Stress leukogram
What is a stress leukogram?
Neutrophilia
Eosinopenia
Lymphopenia
Monocytosis (dogs, cats)
In which species is a stress leukogram most commonly seen?
Dog
What are the differentials for a lymphocytosis?
Adrenalin release in cats
If atypical morphology - lymphoid leukaemia
What are the differentials for neutrophilia?
Inflammation - due to infection/tissue damage/necrosis
Can be due to chronic stress or steroids
What are some potential causes of neutropenia?
Overwhelming tissue demand
Reduced bone marrow production
Increased destruction - immune mediated
What are the differentials for eosinophilia or basophilia (similar causes)?
Worm parasitism
Allergy - type I hypersensitivity
How many WBCs are needed in a single 10X field to confirm leukopenia or leukocytosis?
<15 = Leukopenia
> 45 = Leukocytosis
Is a manual or automated leukocyte count more accurate? What are the exceptions?
Automated more accurate
UNLESS leukocytes are clumped or many nucleated RBCs (machine detects as WBC)
Do manual for atypical cells and band cells
Which is more important - the total WBC count or % of each WBC?
% of each WBC
