WBCs Part 3

Question 1

in what species are lymphocytes the predominant WBC type?

Answer 1

ruminants!! also rats, pigs, mice, and many birds

Question 2

what is a reason for lymphopenia?

Answer 2

stress response: SSMILED

also see increased segmented neutrophils, decreased lymphocytes, increased monocytes, and decreased eosinophils

Question 3

what is the most common reason for lymphocytosis?

Answer 3

epinephrine (physiologic) leukocytosis: ELSI

increased segmented neutrophils and increased lymphocytes

this is the FIRST rule out for lymphocytosis in a cat!!

Question 4

what are 5 more reasons for lymphocytosis that aren’t physiologic/epinephrine leukocytosis?

Answer 4

1. antigenic stimulation: mild increase post vaccination, infectious disease, or autoimmune stimulation (INFLAM CAUSES)
2. endocrine diseases: hypoadrenocorticism/Addison’s, hyperthyroidism
3. lymphoid neoplasia: lymphoma or lymphocytic leukemia
4. persistent lymphocytosis of cattle
5. primary response to some infectious diseases in birds

Question 5

how to differentiate nRBCs from lymphocytes? (3)

Answer 5

nRBCs have
1. grayish blue cytoplasm
2. a greater amount of chromatin
3. darker, coarser chromatin

Question 6

what are 6 causes of lymphopenia?

Answer 6

1. stress leukogram
2. acute viral infections
3. destruction of lymphocytes or lymph node architecture
4. loss of lymphocyte-rich fluid
5. immunodeficiency viruses
6. severe combined immunodeficiency (SCID)

Question 7

describe monocytes (4)

Answer 7

1. rapid maturation in bone marrow and immediately released upon production (no storage pool)
2. increasing monocyte counts usually PRECEDES recovery from neutropenia!!
3. transit in blood for 12-24 hours
4. develop into macrophages and APCs

Question 8

what are the 2 causes of monocytosis?

Answer 8

1. stress response: ONLY IN DOGS!!!!!!
2. chronic inflammation!!

Question 9

is monocytopenia clinically relevant?

Answer 9

hell. no

Question 10

when is eosinopenia seen?

Answer 10

1. cortocosteroid (stress) response but
2. recognition depends on lab RI (could have RI set to 0 and then you’d never see it, sad)

Question 11

what are the 3 main causes of eosinophilia?

Answer 11

worms, wheezes, and weird diseases

1. worms: parasitic infections, esp with tissue stages
2. wheezes: hypersensitivity reactions (Type I)
3. weird diseases:
   -infections: fungal
   -associated with neoplasia: mast cell tumor, T cell lymphoma, carcinomas
   -hypereosinophilic syndrom
   -hypoadrenocorticism: opposite of stress response
   -hyperthyroidism in cats

Question 12

when is basophilia seen?

Answer 12

often parallels eosinophilia but to a smaller degree, is rate without eosinophilia; similar differentials

Question 13

describe mast cells (2)

Answer 13

1. bone marrow derived but not found in the blood in health!
2. large cell with a round nucleus with fine magenta granules often found in the feathered edge

Question 14

when would you see mastocytosis? (3)

Answer 14

1. poor venipuncture if you only see a few
2. in dogs: mostly reactive so not super concerning, can be with GI disease or other inflam disease though
3. in cats: MAST CELL TUMORS!!!