2.6, 2.7, 2.8 WBC Flashcards
what cell appears largest on a slide
monocyte
what is the neutrophil:lymphocyte ratio in ruminants
1:1
how long does it take neutrophils to develop in the bone marrow
5-7 days
what is the process of neutropoiesis from stem cells
stem cell -> myeloblast -> promyelocyte -> myelocyte -> metamyelocyte -> band neutrophil -> neutrophil
what are the two compartments of neutrophils in the blood
circulating neutrophil pool (CNP) and marginating neutrophil pool (MNP)
what is the clinical significance of CNP and MNP
when you take a blood sample you do NOT capture the MNP
what is the ratio of MNP:CNP in most species
1:1
what is the ratio of MNP:CNP in cats
3:1
what is the half-life of neutrophils in blood
12-24h
what is neutrophilia
increase in circulating mature, segmented neutrophils
what are the five mechanisms of neutrophilia
1) physiologic response
2) stress leukogram
3) acute inflammation
4) chronic inflammation
5) necrosis/neoplasia
the epinephrine (physiologic) response is characterized by
mild neutrophilia and mild lymphocytosis
what is the mechanism behind the physiologic response
marginating neutrophils move into CNP; lymphocytes stay in circulation longer
the physiologic response occurs more often in
younger animals
stress leukogram is characterized by
mild to moderate neutrophilia, monocytosis, lymphopenia, eosinopenia
what is the mechanism behind a stress leukogram
release of bone marrow storage pool of mature neutrophils; longer circulation time; decreased margination; lymphocytes retained in lymph nodes
acute inflammation is characterized by
neutrophilia with moderate to marked left shift
what is the mechanism behind acute inflammation
depletion of segmented neutrophils and release of younger neutrophils from the bone marrow
chronic inflammation is characterized by
marked neutrophilia with variable left shift
what is the mechanism behind chronic inflammation
bone marrow has more time to upregulate neutropoiesis
what is tissue necrosis/neoplasia characterized by
mild to marked neutrophilia often with a left shift
what is the mechanism behind tissue necrosis/neoplasia
release of cytokines that increase production of neutrophils
dogs and cats produce a __________ of neutrophilia in response to inflammation in comparison to horses and ruminants
increased magnitude
you can equate a neutrophil count of _____ in a horse or ruminant to a neutrophil count of ______ in a dog or cat
30; 100
the degree of neutrophilia correlates with; the degree of left shift correlates with
the intensity of the inflammatory stimulus; acuteness
what is a consideration r.e. draining/open vs closed lesions
in open lesions will not see as high of a count
what are leukemoid reactions
very intense neutrophilia that resembles a leukemia
a patient is treated by ovariohysterectomy for a closed pyometra; the next day, what do you expect to happen to the neutrophil count and why?
expect more severe neutrophilia; the bone marrow would have undergone hyperplasia, so lots of neutrophils will be released, but now they have nowhere to go to, so they stay in the CNP and increase the count
what are two broad causes of neutropenia
decreased production of neutrophils; tissue demand of neutrophils exceeds bone marrow storage
what causes neutropenia due to increased tissue demand
acute suppurative inflammation
what are common signs of neutropenia due to increased tissue demand
toxic changes and left shift
what is a regenerative left shift
mature neutrophils > band cells and other immature neutrophils
what is a non-regenerative (degenerative) left shift
mature neutrophils < band cells and other immature neutrophils
most insults on the bone marrow first manifest with _________, followed by ________ or _____________
neutropenia; anemia; thrombocytopenia
what can cause decreased neutrophil production
radiation; cytotoxic drugs; erlichia spp. infection; estrogen toxicity; viral infection; leukemia
what are aggregates of rough ER in neutrophils
a toxic change called Dohle bodies
what causes increased RNA in neutrophils
a toxic change called cytoplasmic basophilia
what causes autophagocytosis in neutrophils
a toxic change called cytoplasmic vacuolation
what is a consideration when assessing neutrophils for cytoplasmic vacuolation
EDTA can cause this feature (making it an artifact)
what WBC can have a long tissue phase in some disease conditions
eosinophils
eosinophil granules contain proteins that are particularly toxic to
complex parasites
what cytokine directs eosinophil growth and differentiation in the bone marrow
IL-5
how to tell mast cells from basophils
mast cells have a round nucleus
what is unique about mast cells
develop in the bone marrow but mature in tissue
what two WBCs have similar inflammatory mediators and similar functions
basophils and mast cells
what is a clinical scenario when you might expect to see circulating mast cells
mast cell tumor (ex. in boxers)
what is the largest WBC on a blood smear
monocytes
what is the sequence that monocytes go through to mature? what is an important consideration
monoblast -> promonocyte -> monocyte; way less steps than other WBCs, so they have a short maturation time (2-3 days compared to 5-7 in other WBCs)
what WBC has no bone marrow storage pool
monocytes
corticosteroids ____________ the amount of circulating monocytes
increase
lymphocytes with prominent granules are
T lymphocytes
what distinguishes a reactive lymphocyte
bluer cytoplasm and larger
what are 6 causes of monocytosis
1) corticosteroid excess
2) recovery from bone marrow suppression
3) fungal infections
4) granulomatous or pyogranulomatous inflammation (chronic inflammation)
5) bacterial infection
6) IMHA
name 4 causes of eosinophilia
1) allergies
2) parasitic infections
3) eosinophilic bronchopneumopathy
4) hypereosinophilic syndrome (leukemia and paraneoplastic syndrome from lymphoma and mast cell neoplasia)
name 2 causes of basophilia
1) parasitic infections
2) eosinophilic inflammation
heartworm, fleas, habronemiasis, strongyle and mast cell tumors cause
basophilia
name 5 causes of lymphocytosis
1) epinephrine
2) vaccines
3) chronic infection
4) BLV infection in cattle
5) lymphocytic leukemia
what are 4 causes of lymphopenia
1) corticosteroids
2) acute infections (especially viral)
3) loss of lymphocyte-rich fluid
4) immunodeficiency
what is the MAIN cause of lymphopenia
corticosteroids
what is the difference in cell types for acute vs chronic leukemia
acute: blast cells
chronic: usually mature cells
what does the BM look like in acute vs chronic leukemia
acute: hyper or hypo cellular
chronic: hypercellular
what is the maturation like in acute vs chronic leukemia
acute: minimal
chronic: maturation present
when do you see organomegaly in leukemia
chronic leukemia
when do you see dysplasia in leukemia
acute leukemia
when do you see cytopenias in leukemia
acute leukemia
do diagnose leukemia, what is typically needed
blood smear and bone marrow analysis
why do we see anemia, neutropenia and/or thrombocytopenia in patients with leukemia
myelophthisis (crowding out) normal cells in bone marrow
lymphoproliferative leukemias are that of which cell types
T or B cells
myeloproliferative leukemias are that of which cell types
granulocytes, monocytes, megakaryocytes/platelets, erythrocytes
why do we see cytopenias in patients with myelodysplastic syndrome
genetic mutations lead to accelerated proliferation -> improper maturation -> apoptosis -> cytopenias -> further accelerating proliferation (and the cycle continues)
up to half of dogs with lymphoma also have what
lymphoma-associated leukemia
what is characteristic of lymphoma-associated leukemia
patchy infiltration of bone marrow
why might a dog with lymphoma have a non-regenerative anemia
anemia of chronic disease