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Clinical Pathology > Lymphocytes > Flashcards

Flashcards in Lymphocytes Deck (55):
1

Lymphocyte size

- small: 1-1.5 erythrocytes
- medium: 1.5-2 erythrocytes
- large: more than 2 erythrocytes

2

Lympocyte recirculation - blood

Most are T lymphocytes
- CLP and MLP

3

Lymphocyte recirculation - lymph nodes

Enter cortices via specialized postcapillary venules
- exit via efferent lymphatic vessels
- 25% enter lymph nodes each day

4

Lymphocyte recirculation - tissue

Blastogenesis, recirculate, or die
- migration from vessels to tissue similar to neutrophils

5

Lymphocyte recirculation - blood concentration

Production (stem cell or blastogenesis)
- CLP and MLP
- life span: hours to years

6

Lymphocytosis

Chronic inflammatory
- chronic antigenic or cytokine stimulus
- reactive lymphocytes may be present
- enlarged lymph nodes or lymphoid organs (reactive lymphoid hyperplasia)
- mild to moderate: 2-3 URL
- neutrophilia, monocytosis

7

Physiologic lymphocytosis

- catecholamines
- MLP to CLP
- 2 x URL
- minutes to hours
- no morphologic change
- may cause large granular lymphocytes to increase
- would not see reactive lymphocytes!!

8

Lymphoproliferative disease

- neoplastic proliferation
- lymph nodes, BM
- BLV (neoplastic or not) and FeLV
- leukemia may be leukemic manifestation of lymphoma

9

Leukemia

Marked lymphocytosis, with cells displaying immature features

10

Hypoadrenocorticism

Due to lymphocytosis
- lack of glucocorticoids (limit lymphocyte production and alter distribution)
- dogs: neutropenia with lymphocytosis and azotemia
- may see high normal to mild eosinophilia

11

Young animal lymphocytosis

Puppies, kittens, calves, foals
- cattle: increases until 1 year old and then gradually decreases up to 2 x URL

12

Lymphopenia due to acute inflammatory

Change in lymphocyte kinetics decreasing CLP
- may be caused by stress, but not documented

13

Lymphopenia due to steroid

Change in lymphocyte kinetics, decreasing CLP
- endogenous and exogenous glucocorticoids
- immediate: shift from CLP to other pools (may be entrapped in lymph nodes or BM)
- later: lymphotoxic effects leading to lymphoid hypoplasia
- most common cause of lymphopenia

14

Lymphopenia due to depletion

Loss of lymphocytes due to incomplete circulation
- repeated chylothoracic fluid removal in cats

15

Lymphopenia due to lymphoid hypoplasia or aplasia

Congenital or acquired
- decrease lymphocyte production
- selective T lymphocyte hypoplasia/aplasia will cause more severe lymphopenia than selective B lymphocyte hypoplasia/aplasia

16

Lymphopenia due to lymphoma

Decrease production or altered kinetics

17

Monocytes

Stem cell (CFU-GM)
- CMP and MMP
- emigration

18

Mononuclear phagocyte system

- macrophages: Kupffer cells, alveolar macrophages, type A synoviocytes
- microglial cells
- dendritic cells: Langerhans cells (skin), interdigitating cells (lymph nodes)

19

Inflammatory monocytosis

Acute and chronic inflammation
- cytokine stimulation: production and release

20

Monocytosis due to steroid

Common in dogs and cats, minimal horses and cattle
- shift from MMP to CMP

21

Neoplastic monocytosis

- monocytic leukemia
- marked monocytosis
- normal or abnormal monocytes
- uncommon when compared to granulocytic and lymphoid leukemias

22

Monocytosis secondary to immune-mediated neutropenia

Monocytes and neutrophils share common progenitor
- may increase monocytopoiesis when stimulating neutropoiesis
- antibodies destroying neutrophils, not monocytes

23

Monocytosis due to cyclic hematopoiesis

Mild during neutropenic cycles
- herald increase neutrophil concentration

24

_____ treatment may increase production of neutrophils and monocytes

G-CSF

25

Is monocytopenia a diagnostic problem?

No, hard to document due to already low LRL for monocyte concentration

26

Eosinophils

Differentiation: IL-5, GM-CSF
- CEP and MEP (minutes to hrs in blood)
- tissue: bactericidal properties, inactivate mast cell mediators, attack parasite larvae and adult stages

27

Eosinophilia

Due to anti-inflammatory function
- attraction after mast cell or basophil degranulation

28

Causes of eosinophilia

- hypersensitivity
- internal/external parasites
- inflammation in mast cell rich tissues
- occasionally in hypoadrenocorticism (lack of cortisol)

29

Idiopathic hypereosinophilic syndrome

Cats, dogs, horses
- persistent marked eosinophilia without apparent cause
- no features suggestive of leukemia
- hypereosinophilic = 20,000

30

Paraneoplastic eosinophilia

Mast cell neoplasms
- other neoplasms that can release IL-5
- dogs: T cells, thymoma, mammary carcinomas, oral fibrosarcoma, rectal adenomatous polyps
- cat: transitional cell carcinoma, T cells, alimentary lymphoma
- horses: intestinal lymphomas

31

Basophilia

Only persistent above (200-300 should be considered due to imprecision of differential counts
- allergic, parasitic, neoplastic stress

32

Basopenia

Hard to document due to already low LRL for basophiil concentration
- not clinically relevant

33

Toxic neutrophils

- foamy cytoplasm: cytoplasmic clearing due to dispersed organelles
- diffuse cytoplasmic basophilia: retention of RNA during maturation
- Dohle's bodies: aggregates of rough ER
- giant neutrophils: larger neutrophils due to asynchronous maturation

34

Toxic neutrophils represent maturation defects caused by _______

Rapid neutropoiesis
- due to inflammation

35

Hypersegmented neutrophils

- more than 5 lobes
- typically old neutrophils (glucocorticoids)
- myelodysplastic syndromes involving neutrophilic cell line
- found in poodle marrow dyscrasia

36

Reactive lymphocytes

Acute and chronic inflammation
- difficult to differentiate from atypical (neoplastic) lymphocytes

37

Monocytes with features of macrophages

- abundant gray cytoplasm
- with/out vacuolation
- seen in systemic infections (histo, ehrlichiosis, babesiosis, leishmaniasis)

38

Sideroleukocytes

Neutrophil or monocyte containing hemosiderin
- rare, but seen with hemolytic anemia, or after transfusions

39

Erythorphage

Neutrophil or macrophages with phagocytized erythrocyte
- occasionally seen in IMHA
- idiopathic immune mediated anemia in dogs
- equine infectious anemia
- neonatal isoerythrolysis

40

Lupus erythematosus cells

Neutrophil that phagocytized nuclear antigen-antibody complexes
- pink to pale basophilic inclusion of variable sizes

41

Bacteria in leukocytes other than from the family Anaplasmacetae

Rare in patients with bacteremia
- bacteria in blood: true bacteremia, or contamination of the sample

42

Bacteria from the family Anaplasmacetae

Invade and multiply in blood leukocytes
- monocytic tend to be more species specific
- leukocytic ones are less specific

43

Canine distemper inclusions

- monomorphic or pleomorphic
- red to purple
- neutrophils, monocytes, lymphocytes, erythrocytes

44

H. americanum

Gametocytes infect neutrophils and monocytes

45

H. canis

Gametocytes infect neutrohpils and monocytes
- Europe, Asia, Africa, SA
- lack clinical signs

46

Histoplasma capsulatum

Single or multiple in the cytoplasm of neutrophils, monocytes, or eosinophils
- yeast phase
- 2-4
- eccentric basophilic region with nuclear material

47

Leishmania

Kinetoplastid protozoan found primarily in the Mediterranean, central, and SA countries
- Ohio, Oklahoma, Texas, Maryland, Southeastern states
- amastigotes found in macrophages

48

Mycobacterium

Rarely systemic, can be seen in neutrophils or monocytes
- wont stain with Wright
- cytoplasm has cracks in it

49

Toxoplasma gondii

Tachyzoites rarely found in blood neutrophils and monocytes
- more common in macrophages of infected organs

50

Leukocyte adhesion deficiency

- irish red and white setters, Holstein cattle
- canine LAD, bovine LAD
- defects in the integrin CD18
- no functional CD11/CD18
- necessary for adherence, migration, aggregation

51

LAD in dogs

Persistent leukocytosis and granulocytic hyperplasia in BM
- susceptible to infections
- PCR diagnosis

52

LAD in cattle

Marked neutrophilia and recurrent infection
- PCR diagnosis

53

Pelger-Huet anomaly

Hyposegmentation of neutrophils, eosinophils, and basophils
- nuclear chromatin: hyperchromatic or normochromatic
- dogs, domestic shorthair cats and arabian horses
- is NOT a band because chromatin is condensed!

54

Pseudo Pelger-Huet neutrophils and eosinophils

- neutrophils: cow, dogs with severe inflammation, and cats with FeLV myeloid leukemia
- transient due to asynchronous maturation
- eosinophils: cattle and horse (w/ neutrophils)

55

Nonstaining eosinophil granules (grey) of dogs

Poor staining eosinophil granules or just the vacuoles, and grey cytoplasm
- greyhounds, golden retrievers, sheepdog
- modified chemical composition
- no pathological significance
- maybe misclassified by counters