WBC Disorders Flashcards
Hematopoietic stem cells have what CD marker?
CD34+
Hematopoietic CD34+ stem cells differentiate into Myeloid or Lymphoid stem cells. What cells are included in the myeloid lineage?
Erythroblasts —> RBCs
Myeloblasts —> Neutrophils, basophils, eosinophils (granulocytes)
Monoblasts —> monocytes —> macrophages
Megakaryoblasts —> megakaryocytes
Hematopoietic CD34+ stem cells differentiate into Myeloid or Lymphoid stem cells. What cells are included in the lymphoid lineage?
B lymphoblasts —> naive B cells —> plasma cells
T lymphoblasts —> naive T cells —> CD8+ T cells, CD4+ T cells
Neutropenia is a decrease in circulating neutrophils. What are 2 classic scenarios in which this is seen?
Drug toxicity — classic example is chemotherapy (tx with GM-CSF or G-CSF; used to boost neutrophil count)
Severe infection
Immunodeficiency states, high cortisol states, autoimmune destruction, and whole body radiation are scenarios associated with leukopenia of what type of cell?
Lymphopenia
[Immunodeficiency example is DiGeorge syndrome. High cortisol induces apoptosis of circulating lymphocytes. Autoimmune example is SLE —> antibodies against cells in blood]
What is the most sensitive cell in the body to radiation exposure, aka which cells are the first to exhibit damage?
Lymphocytes
Neutrophilic leukocytosis is associated with bacterial infection, tissue necrosis, and a ______ cortisol state
High
[cortisol causes demargination]
In the setting of bacterial infection, an increase in immature neutrophils is released from the bone marrow in a phenomenon called left-shift. These immature neutrophils will have a decreased expression of _________, evidenced by low expression of CD_____. This indicates that they are less effective at fighting infection
Fc receptors; CD16+
In what 2 conditions might you see a monocytosis?
Chronic inflammatory state
Malignancy
3 clinical scenarios associated with eosinophilia include allergic reaction, parasitic infections, and _______ lymphoma due to an increase in ______ production
Hodgkin; IL-5
For all practical purposes, the one scenario in which you will see basophilia is ______
CML
Lymphocytic leukocytosis is classically associated with viral infections in which the primary cell fighting infection is CD8+ T cells. Most bacterial infections are associated with neutrophilia moreso than lymphocytic leukocytosis. The one bacteria that is an exception to this is _____ ____, which secretes lymphocytosis-promoting factor, which prevents lymphocytes from entering lymph nodes (thus they remain high in the blood)
Bordetella pertussis
Infectious mononucleosis is an EBV infection that results in a lymphocytic leukocytosis comprised of reactive _______ cells. CMV is a less common cause.
EBV primarily infects 3 tissues: ______, ______, and _____
CD8+ T cells
Oropharynx; liver; B cells
In response to mononucleosis infection, CD8+ T cells cause generalized LAD, splenomegaly, and high white count with atypical lymphocytes (large nucleus, abundant blue cytoplasm, look like monocytes).
Which areas of the lymph nodes and spleen are enlarged?
Lymph nodes = paracortex expansion
Spleen = periarterial lymphatic sheath (aka PALS - part of white pulp)
The monospot test is used for screening for mononucleosis. It detects ____________ and usually turns positive within _____ after infection. Definitive diagnosis is made by testing for ____________
A negative monospot test suggests _____ as the cause.
IgM heterophile antibodies; 1 week; EBV viral capsid antigen
CMV
Complications of infectious mononucleosis include increased risk for splenic rupture, rash if exposed to ________, and dormancy of virus in _______
Penicillin; B cells
[increased risk later on of B cell lymphoma due to latency in B cells]
Acute leukemia is a neoplastic proliferation of blasts, defined as an accumulation of >20% blasts in the bone marrow. Blasts “crowd-out” normal hematopoeisis, resulting in “acute” presentation with anemia, thrombocytopenia, or neutropenia. Blasts usually enter the blood resulting in a high WBC. How do blasts appear on blood smear?
Large, immature cells, often with punched out nucleoli
If blasts are identified on peripheral smear indicating an acute leukemia, they may be of either myeloid or lymphoid origin.
If they are of myeloid origin, it is called AML. Myeloid blasts will stain positive for _______ enzyme in the cytoplasm, which may be detected in 2 ways: one is to do a chemical study, and the other is to view the cell under a microscope as _____ ______, which may be visualized as crystallized structures.
If they are of lymphoid origin, it is called ALL. Lymphoid blasts will stain positive for ______ in the ______, which is a compound found NOT found in mature lymphoid cells or myeloblasts.
MPO+; auer rods
TdT+ (DNA polymerase); nucleus
ALL can be subclassified into B-ALL or T-ALL, and this is based on surface markers (since both have tdt+). Which one is more common: B-ALL or T-ALL?
B-ALL
In B-ALL, lymphoblasts classically express what 3 cell markers?
CD10
CD19
CD20
B-ALL has an excellent response to chemotherapy, but requires what additional component of treatment?
Prophylaxis to scrotum and CSF (direct injection of chemo to those areas) — because chemotherapy does not cross those barriers
The prognosis for B-ALL is generally good, and is based on cytogenetic abnormalities (in this case translocations).
________ has a good prognosis — this is the type most are familiar with and is more commonly seen in kids.
________ has a poor prognosis and is more commonly seen in adults.
t(12;21)
t(9;22) — Ph+ (philadelphia chromosome)
T-ALL is identified based on lymphoblasts that express markers ranging from ____-_____.
CD2-CD8
T/F: T-ALL cells express CD10
False — CD10 is found on cells of B-ALL
How does T-ALL present clinically?
Presents as a mediastinal (thymic) mass in a teenager
Remember that this means it is referred to as Acute Lymphoblastic LYMPHOMA (not leukemia) since it is presenting as a solid mass
AML is a neoplastic proliferation of myeloblasts. Myeloblasts are characterized by staining for MPO. Crystal aggregates of MPO may be seen as Auer rods.
Is AML more common in children, adolescents, or older adults?
Older adults — average age is 50-60 years
AML can be subclassified in 3 ways: by cytogenetic abnormalities, by lineage of myeloblasts, or by surface markers. The predominant mechanism is by cytogenic abnormalities.
A classic type of AML is Acute Promyelocytic Leukemia, which is characterized by a _______ translocation. This results in disruption of the ______ receptor, leading to accumulation of promyelocytes.
Promyelocytes contain numerous Auer rods, which can activate the coagulation cascade, increasing the risk of ______.
t(15;17); Retinoic acid (RAR)
DIC
What is the treatment for acute promyelocytic leukemia and what does it do?
All-trans retinoic acid (ATRA) — causes the blasts to mature into neutrophils
AML can be subclassified in 3 ways: by cytogenetic abnormalities, by lineage of myeloblasts, or by surface markers. If there are no recurring cytogenic abnormalities, the lineage of myeloblasts is used to classify.
What type of leukemia, classified based on lineage, is characterized by a lack of MPO, and blasts that characteristically infiltrate the gums?
Acute monocytic leukemia
AML can be subclassified in 3 ways: by cytogenetic abnormalities, by lineage of myeloblasts, or by surface markers. If there are no recurring cytogenic abnormalities, the lineage of myeloblasts is used to classify.
What type of leukemia, classified based on lineage, is characterized by a lack of MPO and is associated with Down syndrome (before the age of 5)
Acute megakaryoblastic leukemia
Patients with Down syndrome are at increased risk for acute leukemia. What type of leukemia do they typically develop before the age of 5 vs. after the age of 5?
Before the age of 5 = Acute megakaryoblastic leukemia
After the age of 5 = Acute lymphoblastic leukemia
AML may also arise from pre-existing dysplasia, particularly seen with prior exposure to ________ or _________, resulting in a myelodysplastic syndrome.
While myelodysplastic syndrome may progress to acute leukemia, most patients with myelodysplastic syndromes die from ____ or ____
Alkylating agents; radiotherapy
Infection; bleeding
Define myelodysplastic syndrome
Cytopenia with hypercellular bone marrow — abnormal maturation with increased blasts (<20%)
[if it reaches the point of >20% blasts, it has progressed to acute leukemia]
A chronic leukemia is a neoplastic proliferation of mature circulating lymphocytes, characterized by a high WBC count. This usually insidious in onset and seen in older adults.
The prototypic chronic leukemia is CLL, which is a neoplastic proliferation of ______ B-cells. These cells co-express _____ and _____. It may be identified based on increased lymphocytes and _____ cells seen on blood smear
Naive; CD5; CD20; smudge
CLL may progress to cause generalized lymphadenopathy, at which point it may be called small lymphocytic lymphoma. What are the complications of CLL regarding immunoglobulin levels, anemia, and transformation?
Hypogammaglobulinemia (common cause of death is infection)
Autoimmune hemolytic anemia
Transformation to diffuse large B-cell lymphoma (presents with enlarging lymph node or enlarging spleen)
Hairy cell leukemia is a neoplastic proliferation of ______ B cells characterized by hairy cytoplasmic processes. These cells are positive for _______ enzyme.
Mature; TRAP (tartrate-resistant acid phosphatase)