Quantitative WBC abnormalities

Leukocytosis

• any WBC over 11.5 ×10^9/L

• causes:

  • strenuous exercise

  • emotional stress

  • infection

  • hemolysis

  • etc

Leukopenia

• less then 4.5 ×10^9/L

• Causes:

  • infections

  • drugs

  • radiation

  • hematologic disorders

  • neonatal alloimmune neutropenia

Leukemoid Reaction

• Excessive leukocytosis > 50.0 ×10^9/L with a left shift

• causes:

  • infections

  • meds

  • splenectomy

Leucoerythroblastic

• immature neutrophils and nucleated RBC in PB

• PMF- primary myelofibrosis

Neutrophilia

• Increase in neutrophils greater then 8.1 ×10^9/L

• causes:

  • physiologic

  • acute infection

  • chronic inflammation

  • steroids

Neutropenia

• Decrease in neutrophils less then 2.3 ×10^9/L

• causes:

  • decreased BM production

  • shift from CGP to MGP (pools)

  • neonatal alloimmune neutropenia

Eosinophilia

• increase above 0.6 ×10^9/L

• causes:

  • allergic rxns

  • parasitic infection

Basophilia

• Increase above 0.2 ×10^9/L

• causes:

  • CML

Monocytosis

• increase above 1.2 ×10^9/L

• causes:

  • hematologic disorders

  • connective tissue disorders

  • infections

Monocytopenia

• decrease in monocytes

• hairy cell leukemia

Lymphocytosis

• Increase above

  • adults: 4.8 ×10^9/L

  • kids: 11.1 ×10^9/L

• causes:

  • infectious mononucleosis

  • infection

Lymphopenia

• decrease below

  • Adults: 0.8 ×10^9/L

  • kids: 1.5 ×10^9/L

• causes:

  • immunologic disorders

  • chemotherapy

Shift to left

shift in maturation stage that is being pushed out (ex: myelocytes and metamyelocytes show up)

How can the movement of neutrophils from one pool to another can affect lab values

can increase it or decrease

Physiologic factors that can affect numbers and types of circulating leukocytes

Exercise

Stress

Pregnancy

Leukemoid reaction vs Chronic myelogenous leukemia (CML)

Leukemoid:

• no increase in eos and baso

• normal platelets

• no 9:22 translocation

CML:

• increase in eos and baso

• giant platelets

• 9:22 translocation

Severe neutropenia

• <1.5 ×10^9/L

• increased risk of infection

More severe neutropenia

• < 1.0 ×10^9/L

• increased risk of auto-infection

Most severe neutropenia

• < 0.5 ×10^9/L

• very serious risk

• reverse isolation and/or prophylactic antibiotics

22qII.2 deletion syndromes

• most common microdeletion syndrome

• low T-cell counts and/or absent thymus

• TBX1 deletion: defective development of pharyngeal pouch system

• many die <1yr old

FISH methodology

uses biofluorescence to light up genes to see if there are additions/deletions

Steps of MLPA

1. denaturation of specimen DNA

2. Hybridization of probes

3. ligation

4. Amplification by PCR

5. Fragment separation

6. DNA analysis

why is MLPA better then FISH

more specific

Severe combined immunodeficiency (SCID)

• X linked mutation

  • most common

  • loss of cytokine receptors

• Somatic mutation

  • loss of ADA enzyme leads to accumulation of adenosine

• very low T cell counts leading to pronounced immunodeficiency (low CD3 counts)