WBC Disorders - Leukopenia and Leukocytosis

Question 1

Neutropenia

Answer 1

Decreased circulating neutrophils
Causes:
-drug toxicity –> damage to stem cells
-severe infection –> increased mov’t neutrophils into tissues
Tx: GM-CSF or G-CSF to boost granulocyte production

Question 2

Lymphopenia

Answer 2

Decreased circulating lymphocytes.
Causes:
-Immunodeficiency
-High cortisol state –> induces apoptosis
-Autoimmune destruction
-Whole body radiation - lymphopenia is earliest change

Question 3

Neutrophilic leukocytosis

Answer 3

Increased circulating neutrophils.
Causes:
-Bacterial infection or tissue necrosis –> induces release of neutrophils, including immature forms with decreased Fc receptor (CD16) - left shift
-High cortisol state –> impairs leukocyte adhesion –> release from pool of neutrophils

Question 4

Monocytosis

Answer 4

Increased circulating monocytes.
Causes:
-chronic inflammation
-malignancy

Question 5

Eosinophilia

Answer 5

Increased circulating eosinophils.
Causes:
-allergic rxns
-parasites
-Hodgkin lymphoma (due to ^ IL-5)
Driven by ^ eosinophil chemotactic factor.

Question 6

Basophilia

Answer 6

Increased circulating basophils.

Seen in CML

Question 7

Lymphocytic leukocytosis

Answer 7

Increased circulating lymphocytes.
Causes:
-viral infections: T lymphocyte hyperplasia in response to virus
-Bordatella pertussis infection: bacteria produce lymphocytosis-promoting factor - blocks lymphocytes from leaving blood and entering lymph node.

Question 8

Infectious Mononucleosis

Answer 8

EBV infection (saliva transmission - kissing disease in teens) –> lymphocytic leukocytosis of reactive CD8+ T-cells.
CMV less common cause.
EBC infects: oropharynx, liver, B cells.
CD8+ T cell response –> generalized LAD (bc T-cell hyperplasia in lymph node paracortex), Splenomegaly (T-cell hyperplasia in periarterial lymphatic sheath), High WBC count w atypical lymphocytes (reactive CD8+ T cells)
Monospot test for screening.
Serologic test for EBV viral capsid antigen for diagnosis.
Complications: splenic rupture (avoid contact sports 1 year), rash if exposed to ampicillin, dormancy in B-cells–> recurrence and B-cell lymphoma (esp in immunodeficient)

Question 9

Monospot Test

Answer 9

For screening of IM.
Detects IgM antibodies that cross-react with RBCs of different animal (heterophile antibodies).
Positive within 1 week.
Negative result –> CMV.
Definitive diagnosis w serologic test for EBV viral capsid antigen.