Leukopenia And Leukocytosis Flashcards
What is the hematopoietic stem cell and what are the two stem cells/lineages that come from it?
HP cd34 positive stem cell.
Makes a myeloid stem cell lineage
Makes a lymphoid stem cell lineage
Explain the lymphoid stem cell lineage and what it can make?
Makes a B lymphoblast and a T lymphoblast
Each ones makes a naive B cell and naive T cell respectively
Naive B cells turn into plasma cells and naive T cells make either a cd 8 or cd 4 T cell.
Explain the myeloid lineage and what is made?
Myeloid stem cell makes 4 different cells: erythroblast, myeloblast, monoblast, and a megakaryoblast.
E makes RBCS; Mye makes neutrophils, basophils and eosinophils; monoblasts make monocytes and mega makes megakaryocytes.
What is the normal white blood cell count and what levels define leukopenia and leukocytosis? Also, what is the general principle behind a low or high white blood cell count?
5-10k
Less than 5k
Greater than 10k
A low or high WBC count is usually due to a decrease or increase in one cell type.
Top two causes of neutropenia, explain how each one causes neutropenia, and how would we treat the leukopenia?
Drug toxicity, example is chemotherapy. Not only are they taking out the cancer cells, but also rapidly dividing normal cells, so the stem cells. Treat with GMCSF or GCSF.
Severe infection. The idea here is that there are far more neutrophils migrating out of the blood and into the tissue than usual because the infection is so bad.
4 causes of lymphopenia, and give examples or explain why it is a cause?
- Immunodeficiency, Digeorge or HIV
- High cortisol state like cushings or exogenous use, cortisol induces apoptosis in lymphocytes
- Autoimmune like lupus, has antibodies against RBCs, WBCs, and platelets
- Whole body radiation, the lymphocyte is the most sensitive cell in the human body to radiation.
3 causes of neutrophilic leukocytosis?
Bacterial infection
Tissue necrosis
High cortisol state
What is the high yield point he made about a left shift in a bacterial infection?
The immature neutrophils have decreased Expression of Fc receptors (CD16), which bind immunoglobulin for phagocytosis.
Why does a high cortisol state cause high neutrophil levels?
Because the cortisol disrupts the marginal pool of neutrophils that are stuck to the endothelium of the blood vessels and dumps them back into the blood.
2 causes of monocytosis?
Chronic inflammation and malignancy
3 causes of eosinophilia?
Allergic reactions, parasitic infections, and Hodgkin lymphoma
What is the MOA that leads to a rise in eosinophils from Hodgkin lymphoma?
The lymphoma results in a rise in IL5
Basophils is classically seen in what disease?
Chronic myeloid leukemia
2 causes of lymphocytic leukocytosis, one normal and one cause that is unique and explain why and how it works?
Viral infections is the normal one. CD8 T cells fight infections.
Bordetella pertussis infection. This is unique because it is a bacteria, but the bacteria produces a lymphocytosis promoting factor that blocks lymphocytes from exiting the blood and going to the LN so you get a rise in lymphocytes.
How do we characterize/define infectious mononucleosis? What is the less common infection causing it as well?
EBV infection that results in a lymphocytic leukocytosis where CD8 T cells are reacting to the infection.
CMV is less common cause
EBV in IM primarily infects what 3 areas of the body causing what in each?
Oropharynx cousin pharyngitis
Liver causing hepatitis
B cells
Because of the CD8 T cell response, what 3 things do we see clinically in IM?
Generalized LAD due to tons of T cells in the paracortex of the LN
Splenomegaly due to tons of T cells in the periarterial lymphatic sheath
High WBC count with atypical CD8 T cells in the blood.
What is the screening test we can use for IM, what does it detect, what if the test is negative, and what confirmatory test do we do for a definitive diagnosis?
Monospot test.
Detects IgM antibodies that cross react with horse or sheep RBCs called heterophile antibodies
Did it too soon or it means CMV is the culprit
Serologic testing for EBV capsid antigen
3 complications of IM?
Spleen can rupture because its huge
Rash if exposed to ampicillin
Virus stays dormant in B cells so risk for recurrence or B cell lymphoma
