Flashcards in White blood cell disorders Deck (73)
What is the starting cell for hematopoiesis?
- CD-34+ hematopoietic stem cells
What are the causes of neutropenia?
- Drug - especially chemotherapy alkylating agents--> decrease in WBC count especially neutrophils.
- Infection leading to aggregation of neutrophils in the tissue--> decrease in circulating neutrophils
What are the causes of leukopenia?
- Immunodeficiency (DiGeorge or HIV)
- Autoimmune destruction (SLE)
- High cortisol (exogenous or Cushings)
- Whole body radiation
What is the pathogenesis of acute leukemia?
- Increased production of blast cells crowds out normal hematopoiesis leading to anemia, thrombocytopenia and neutropenia.
- Elevated levels of immature blast (large, immature with punched out nuclei.
- Type depends on the phenotype of the blast.
What are the two types acute lymphocytic leukemia (ALL) and their markers?
- B-ALL - most common TDT+, CD-10,19,20
- T-ALL - TDT+, CD-2-8, no CD-10
How is lymphoblastic leukemia differentiated from myeloblastic (marker)?
What is the epidemiology of ALL?
- Typically arise in children, down syndrome is a risk factor.
- T-ALL arises in teenagers.
What abnormalities are associated with B-ALL? What are their prognosis?
- t(12,21) - children, good prognosis, chemo, prophylaxis to scrotum and CNS.
- t(9,22) - PH chromosome, adult, poor prognosis.
How do teenagers present with T-ALL?
- Mediastinal (thymic) mass.
How is acute myeloid leukemia (AML) identified?
- Myeloperoxidase (MPO) which may seen as Auer rods.
What are the high yield subtypes of AML?
Describe acute promyelocytic leukemia
- t(15;17) Retinoic acid R (RAR) translocation 17-->15. Disruption blocks maturation and cells build up>
- Immature promyelocytes have increased primary granules--> increased risk for DIC
How is acute promyelocytic leukemia treated?
- Treatment with all- trans- retinoic acid (ATRA)--> binds altered receptor causing cells to mature.
Describe acute monocytic leukemia
- Increase in monocytes, MPO negative
- Characteristically infiltrates gums.
Describe acute megakaryocytic leukemia?
- Increased megakaryocytes, MPO negative
- Associated with down syndrome arises before the age of 5.
What are the risk factors for AML?
- May arise from pre-existing dysplasias (Myelodysplasic syndromes) especially with alkylating agents and radiation therapy.
How do Myelodysplasic syndromes usually present and how do they die?
- Cytopenias, hypercelluar bone marrow, increased blasts
and abnormal maturation cells.
- Most die from bleeding or infection but some progress to acute leukemia
What is the pathogenesis of chronic leukemia?
- Neoplastic proliferation of mature circulating lymphocytes
- Usually insidious onset in older adults.
What are the characteristics of chronic lymphocytic leukemia (CLL)?
- The most common leukemia in US
- Increased proliferation of naive B cells co-expressing CD5 and 20
- Increased lymphocytes and smudge cells on blood smear
- Involvement of lymph nodes leads to lymphadenopathy and is called small cell lymphoma
What are the complications with CLL?
- Hypogammaglobulinemia- infection is the most common cause of death
- Autoimmune hemolytic anemia
- (Richter) transformation to diffuse large B cell lymphoma, enlarged lymph nodes and spleen.
What are the characteristics of hairy cell leukemia?
- Chronic leukemia
- Neoplastic proliferation of mature B cells characterized by hairy cytoplasmic process.
- Cells are positive for tartrate-resistant acid phosphatase (TRAP)
How do patients present with hairy cell leukemia?
- No lymphadenopathy
- Splenomegaly (infiltration of red pulp)
- Dry tap on bone marrow aspiration due to marrow fibrosis.
How are patients treated with hairy cell leukemia?
- Patients respond to 2-CDA (cladribine), adenosine deaminase inhibitor, adenosine accumulates to toxic levels in neoplastic B cells.
What is Adult T cell leukemia/ lymphoma (ATLL)?
- Chronic leukemia
- Neoplastic proliferation of mature CD4+ T cells
What is ATLL associated with and how does it present?
- HTLV-1, japan and caribean
- Lymphadenopathy and hepatosplenomegaly
- Lytic bone lesions with hypercalcemia
What is mycosis fungoides?
- Chronic leukemia
- Neoplastic proliferation of mature CD4+ T cells that infiltrate the skin producing rash, plaques and nodules (Pautrier microabscesses)
What occurs when mycosis fungoides infiltrates the blood?
- Sezary syndrome
- Lymphocytes with cerebriform nuclei
What are the myeloproliferative disorders?
- Chronic myeloid leukemia (CML)
- Polycythemia Vera
- Essential thrombocytopenia
What are the complications with myeloproliferative disorders?
- Increased risk for hyperuricemia and gout due to high cell turnover (nucleotides--> uric acid)
- Progression to bone marrow fibrosis or transformation to acute leukemia.