6.1 Leukopenia and Leukocytosis

Question 1

What is the cell marker (CD) on the hematopoietic stem cell and what are the two main cell lineages that come from this cell?

Answer 1

CD34+
This is the starting cell for all blood cells
Myeloid Stem Cells
Lymphoid Stem Cells
Both come from this one stem cell

Question 2

What are the blast cells that come from the Myeloid Stem Cell and what do these blasts give rise to?

Answer 2

Erythroblast: RBC’s
Myeloblast: Granulocytes
Monoblast: Monocytes
Megakaryoblast: Megakaryocytes

Question 3

What cells come from the Lymphoid Stem Cell?

Answer 3

B lymphoblast–> Naive B cell–> Plasma cell

T lymphoblast–> Naive T cell–> CD8+, CD4+

Question 4

What are some causes of neutropenia?

Answer 4

Drug toxicity: chemotherapy, damages stem cells

Severe infection: G(-) sepsis moves PMN’s into tissues

Question 5

Causes of Lymphopenia?

Answer 5

Immunodeficiency: DiGeorge, HIV
High Cortisol: Cushing’s, exogenous cortisol, causes apoptosis of lymphs
Autoimmune: SLE
Whole Body Radiation: lymphs very sensitive, first change seen after radiation

Question 6

What are leukocytes?

Answer 6

WBC’s
Anything other than RBC’s
This includes granulocytes and lymphocytes
Leukopenia can mean neutropenia or lymphopenia

Question 7

What are 2 causes of neutrophilia?

Answer 7

Bacterial infection or tissue necrosis: releases marginated pool and from marrow, left-shift possible

High cortisol: impairs leukocyte adhesion causing release from marginated pool

Question 8

What is a characteristic finding of immature neutrophils?

Answer 8

Decreased Fc receptors (CD16)

Question 9

Causes of Monocytosis

Answer 9

Chronic inflammatory state: autoimmune or infection, malignancy

Question 10

Causes of Eosinophilia

Answer 10

Allergic reactions
Parasitic infections
Hodgkin lymphoma

Question 11

What factor drives eosinophilia?

Answer 11

Eosinophil chemotactic factor

Question 12

Causes of Basophilia

Answer 12

Classically in Chronic Myeloid Leukemia

Question 13

What granulocyte cell type tends to be extra high in Hodgkin Lymphoma?

Answer 13

Eosinophils

Question 14

What cell type is high in Chronic Myeloid Leukemia?

Answer 14

Basophils

Question 15

Causes of Lymphocytic leukocytosis

Answer 15

Viral infections: T cells undergo hyperplasia

Bordetella pertussis: Bacteria produce lymphocytosis-promoting factor that prevents the cells from leaving the blood and entering the lymph nodes

Question 16

EBV causing infectious mononucleosis causes an increase in what cell type in the body?

Answer 16

Lymphocytes, especially reactive CD8+ T cells

Question 17

In mono, what is primarily infected by EBV?

Answer 17

Oropharynx–>pharyngitis
Liver–> hepatitis, hepatomegaly, elevated enzymes
B cells

Question 18

What causes the classic Sx in infective mononucleosis?

Answer 18

Classic Sx: generalized LAD, splenomegaly, atypical lymphs

All caused by the proliferation of reactive T cells

Question 19

What is the Monospot test with Mono?

Answer 19

Screening test looking for IgM against horse or sheep RBC’s
Usually (+) within 1 week of infection
Negative result suggests CMV cause
Dx made by presence of EBV viral capsid antigen

Question 20

Complications of mononucleosis

Answer 20

Splenic rupture
Rash with ampicillin
Dormancy of virus in B cells carries risk of recurrence and B cell lymphoma, especially if immune deficiency develops