Leukocytes Flashcards

1
Q

What are the two bone marrow pools? How long do cells spend in each?

A

Proliferation pool - 3 days

Maturation pool - 2 days

  • Total time spent in health: 5 days*
  • Total time spent in disease: <5 days*
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2
Q

What are the two WBC blood pools

A

Circulating pool (veins and arteries)

Marginated pool (capillaries - stuck to endothelium)

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3
Q

How much time is spent in blood pools in health? In inflammation?

A

Health: 8hrs

Inflammation: <8hrs

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4
Q

3 lymphocyte migration paths

A
  1. Lymph node path (blood –> LN –> efferent lymphatics)
  2. Tissue path (blood –> tissues –> lymphatics
  3. Blood path (capillaries –> tissues –> LNs)
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5
Q

Different ways to count WBCs in lab (5)

A

1. Imependence cell counters

2. Electronic cell counters

3. WBC differential count (microscope)

4. Centrifugation (IDEXX)

5. Hemacytometer

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6
Q

How do impedence cell counters work? Downsides of them?

A
  1. Lyse RBCs and platelets
  2. Send electrons through. Nucleated cells impede electrons
  3. Counts cells with nuclei
    * Problem: count all nucleated cells (including immature RBCs)*
    * Technically a total nucleated cell count*
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7
Q

How do electronic cell counters work

A
  1. Optical/laser flow
  2. Stain nuclei/cytoplasm
  3. ID cells by light scatter and absoprtion
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8
Q

Downsides of electronic cell counters

A
  • Dont ID abnormal cells correctly
  • Dont detect organisms
  • Technically a total nucleated cell count
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9
Q

Whats a WBC differential count. Downsides?

A
  1. Count 100 WBCs with microscope
  2. Determine percentage of each
  3. Multiply percentage by [WBC] to get individual concentrations
    * Poor precision*
    * Poor reproducibility*
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10
Q

Centrifugation (IDEXX)

A
  1. Centrifugal forces separate blood into 5 layers
  2. Layers recognized by fluorescent markers of DNA, RNA, lipoprotein
  3. Thickness used to get concentration
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11
Q

Leukocytosis

A

Elevated WBC count

Due to:

  • Acute/chronic inflammation
  • Glucocorticoids
  • Physiologic (excitement)
  • Neoplasia
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12
Q

Neutrophilia

A

Increased neutrophils

Due to:

  • Increased release from marrow
  • Shift from marginating pool to circulating pool
  • Decreased migration to tissues
  • Or all of the above*
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13
Q

Whats left shift

A

Increased banded neutrophils

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14
Q

Regenerative left shift

A

[Segs] > [Bands]

Adequate response to inflammation

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15
Q

Degenerative left shift

A

[Bands] > [Segs]

  • Inadequate response: marrow is not keeping up with demand*
    • Poor prognosis :(*
    • Normal in cows!*
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16
Q

Your patient is a cow with elevated bands but normal segs, suggesting a degenerative left shift. Are you worried?

A

No, this is normal in cows due to smaller storage pools

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17
Q

How do quantify the severity of neutrophilia?

A
  • Mild: <1,000/ul [bands]
  • Moderate: 1,000 - 10,000/ul
  • Severe: >10,000/ul
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18
Q

Whats a right shift? What causes it?

A

Hypersegmented neutrophils

Cause

  • Glucocorticoids (decreased immigration of neutrophils to tissue, increased lifespan in blood –> larger)
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19
Q

Which species have highest [neutrophil] with inflammation

A

Dogs

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20
Q

Pathogenesis of acute inflammatory neutrophilia

A
  1. Acute inflammtory disorder (hours-days)
  2. Macrophages and lymphocytes release cytokines
  3. Cytokines stimulate release of neutrophils from storage pool

—> Neutrophilia

  1. Cytokines stimuate release of bands from maturation pool

—> Left shift

  1. Cytokines stimulate production of neutrophils (granulocytic hyperplasia – after several days)

—> Regenerative

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21
Q

Magnitude of glucocorticoid neutrophilia

A

< 3x URI

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22
Q

Magnitude of acute inflammatory neutrophilia

A

>10x URL

Extreme inflammation = leukemoid response (increased WBC)

60-80,000 neutrophils

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23
Q

Pathogenesis of chronic inflammatory neutrophilia

A

1) Chronic inflammation (*weeks to months*)
2) Macrophages and lymphocytes release cytokines

—-> increased neutrophil production (neutrophilia)

3) Granulocytic hyperplasia

—–> more segs produced

—> neutrophilia w/o left shift

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24
Q

Magnitude of chronic inflammatory neutrophilia

A

<3x URI (slight to moderate)

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25
Pathogenesis Glucocorticoid Neutrophilia
1. Glucocorticoids in blood (stress, iatrogenic) 2. Reduced adhesion proteins in vessels 3. Shift from marginated pool to circulation pool **------\> NEUTROPHILIA** 4. Reduced neutrophil migration to tissue **-------\> Immuno-compromised** 5. Increased lifespan blood neutrophils **------\> Hypersegmented** **------\> sometimes RIGHT SHIFT**
26
Why are patients on glucocorticoids immunocompromised
Glucocorticoids reduce migration of neutrophils to tissues --\> fewer cells in tissue to fight pathogens
27
Pathogenesis Physiologic Neutrophilia
1. Flight/flight stimulus 2. Catecholamines 3. Down regulation of adhesion proteins in vessels 4. Neutrophils shift MP ---\> CP ------\> **Neutrophilia** 5. Increased blood flow rate through capillaries (vasodilation) ------\> Shift from MP to CP ------\> **Neutrophilia (NO SHIFT!)**
28
Magnitude physiologic neutrophilia
\< 3 % URI *Except cats: \>3% URI! Large marginated pool*
29
What are reactive lymphocytes
Large lymphocytes as a result of antigen stimulation
30
Which species has a higher magnitude of physiologic neutrophilia? Why?
Cats (\>3% URI) Because they have a larger marginated pool
31
Which diseases cause lymphocytosis
1. Chronic inflammation (\*uncommon\*) 2. Physiologic 3. Lymphoproliferative disorders 4. Hypoadrenocorticism
32
Magnitude of chronic lymphocytosis
\<2x URL
33
Pathogenesis of chronic lymphocytosis
1. Persistent infection (weeks-months, ie *Ehrlichia*, *Babesia*) 2. Macrophages and lymphocytes release **cytokines** 3. Cytokines stimulate production of lymphocytes in LNs **----\> Lymphoid hyperplasia** 4. Increased production and release of lymphocytes ----\> May be **reactive** (big lymphocytes)
34
Which is more common: lymphocytosis due to chronic inflammation or due to lymphoproliferative disorders
Lymhoproliferative disorders (ie neoplasia)
35
Pathogenesis of physiologic lymphocytosis
1. Fight/flight stimulus 2. Catecholamine release 3. Down regulation of adhesion proteins in vessels ---\> MP to CP ----\> Lymphocytosis 4. Increased blood flow through smaller vessels ----\> MP to CP ----\> **Lymphocytosis**
36
T/F - physiologic lymphocytosis is a common cause of lymphocytosis in relaxed, older dogs
False - its uncommon unless the animal is stressed/excited
37
You have a cat with physiologic lymphocytosis. Which other parameter will likely be elevated?
Neutrophilia Maybe monocytosis
38
Pathogenesis of lymphoproliferative lymphocytosis
1. Neoplastic transformation of a lymphocyte 2. **Clonal proliferation** of neoplastic lymphocytes 3. Production and release of neoplastic lymphocytes ----\> Lymphocytosis
39
What is the most common lymphocytosis in a sick animal?
Lymphoproliferative lymphocytosis (BVD, leukemia, neoplasia...)
40
How do you diagnose lymphoproliferative lymphocytosis
Mild-extreme lymphocytosis Atypical, large, immature lymphocytes
41
You see a lot of these on your cat's smear. What do you suspect?
These are large, atypical, immature lymphocytes Suspect **lymphoproliferative lymphocytosis**
42
Cause of monocytosis
* Inflammation (acute/chronic) * Steroids (stress)
43
What does monocytosis usually occur with?
Neutrophilia
44
What are causes of eosinophilia (4)
* Hypersensitivities, allergies * Parasitism * Mast cell degranulation (inflammation, neoplasm) * Idiopathic (eosinophilic myostitis)
45
Causes of basophilia (2)
1) Hypersensitivity/Allergies 2) Parasitism
46
Causes of neutropenia (5)
1) Inflammation 2) Peripheral destruction - *Immune mediated* * - Hemophagocytic syndromes* 3) Granulocytic hypoplasia - *Parvo, FeLV, Toxoplasma, Ehrlichia* * - Neoplasia* * - Toxic (estrogens, bracken ferns)* * - Marrow necrosis* * - Myeolofibrosis* 4) Ineffective production (ijf 5) Cyclic hematopoiesis
47
Causes of granulocytic hypoplasia
- Parvo, FeLV, Toxoplasma, Ehrlichia - Neoplasia - Toxic (estrogens, bracken ferns) - Marrow necrosis - Myeolofibrosis
48
Pathogenesis of inflammatory (overwhelming) neutropenia
1. Acute, severe infection (hours-days) 2. Macrophages and lymphocytes release **cytokines** 3. Cytokines stimulation **migration** of neutrophils to inflammed tissue ---\> CP to MP 4. Cytokines stimulate release of **bands** from maturation pool ---\> **NEUTROPENIA with _DEGENERATIVE_ left shift**
49
What condition causes a degenerative left shift
Acute, overwhelming inflammation
50
Pathogenesis of granulocytic hypoplasia
1. Damage of stem cells (infectious, neoplasia, toxic etc) 2. Reduced granulocytic precursors (hypoplasia) ---\> May also reduce RBC and platelet precursors 3. Reduced neutrophils --------\> **NEUTROPENIA with (possible) concurrent anemia and thrombocytopenia = APLASTIC ANEMIA**
51
What is aplastic anemia
Condition that causes **neutropenia, anemia, thrombocytopenia** Due to granulocytic hypoplasia
52
T/F Granulocytic hypoplasia often has a degenerative left shift
FALSE, no left shift
53
T/F - bacterial endotoxins can cause a degenerative left shift
True, as is seen in acute overwhelming neutropenia
54
Diseases and conditons of lymphopneia
1. **Acute inflammation** - Bacterial - Viral 2. **Glucocorticoids** - Stress - Cushings - Iatrogenic 3. **Lymphocyte depletion** - Lymphoid effusion: chylothorax, feline cardiomyopathy - Loss of lymph 4. **Lymphoid hypoplasia, aplasia**
55
Pathogenesis of acute inflammatory lymphopenia
1. Acute disorder (hours to days) 2. Macrophages and lymphocytes release **cytokines** 3. **Cyokines** promote homing of lymphocytes to LNs and reduce exit from LNs 4. Cytokines promote lymphocyte migration from CP to inflammed tissues **--------\> LYMPHOPENIA with _left shift neutrophilia_ or _inflammatory neutropenia_**
56
Pathogenesis of stress lymphopenia
1. Incrased glucocorticoids in blood 2. Shift of lymphocytes from CP to marrow/LNs 3. May also have lymphotoxic effects \*can occur in minutes!\* **---\> Lymphopenia with evidence of _steroid excess_ (mature neutrophilia, monocytosis, hyperglycemia, dilute urine)**
57
Pathogenesis of Depletion Lymphopenia
1. Damaged lymphatic vessel 2. Loss of lymph into pleural/peritoneal cavity --\> *Chylothorax, chyloabdomen* 3. Repeated drainage of lymph from LNs 4. Breaks lymphocyte recirculation pattern 5. Depletion of circulation lymphocytes **----\> Lymphopenia with history of lymphocyte rich fluid drainage**
58
Fill in the blanks
59
Describe toxic neutrophils (6)
1. Foamy cytoplasm - *displaced organelles* 2. Diffuse cytoplasmic basophilia - *RNA* 3. Dohle bodies - *rough ER with RNA \*cats\** 4. Asynchronous nuclear maturation 5. Giant neutrophils 6. Toxic granules *\*horses\**
60
Cause of toxic neutrophils
Severe inflammatory disease (often bacterial) ## Footnote *Sometimes caused by non-infectious inflammatory disorders*
61
What causes hypersegmented neutrophils (4)
1. Steroids (!) 2. Delayed sample analysis 3. Idiopathic 4. Chronic inflammation *(sometimes)*
62
Characteristics of **reactive lymphocytes**
1. Increased cytoplasmic basophilia 2. Prominent golgi zone 3. Hyperchromatic nuclei
63
What causes reactive lymphocytes
Acute and chronic inflammatory disease - *usually infectious*
64
Which pathogen causes morula in cells
Ehlrichia
65
Which pathogen causes buds in cells
Histoplasma capsulatum
66
Which pathogen causes rectangular **gamonts** in monocytes and neutrophils
Hepatozoon
67
What are Myeloproliferative diseases (4)
1. Leukemias 2. Myelodysplastic syndrome (MDS) 3. Granulocytic sarcoma (rare!) 4. Histiocytic proliferative diseases
68
What are lymphoproliferatives diseases (4)
1. Lymphoma 2. Myeloma 3. Extramedullary plasmacytoma 4. Lymphoid leukemia (rare)
69
Whihc CD molecule is used to distinguish acute from chronic leukemia
**CD34**
70
Purpose of the PARR test
PCR for Antigen Receptor Rearrangements *Take FNA of LN. Test for receptors on lymphocytes. They should be different (LNs have diverse colonoy of lymphocytes. If they are all the same, idicates **neoplasm****, Ehrlichiosis (hyperplastic) or bad samples)***