Week 13: Blood, Immunity Flashcards
Define neutropenia, causes, consequences
abnormally low number of neutrophils
Causes: may be due to reduced production in the bone marrow or destruction of neutrophils elsewhere in the body
Consequences: inability to respond to bacterial infections
What is the infectious agent of mononucleosis?
Epstein-barr virus - replicates in epithelial cells then within B lymphocytes which stimulates T cytotoxic cells to target the infected B lymphocytes
Transmission, S/S (6) and prognosis of mononucleosis
Transmission: person to person by saliva
S/S: flu-like, fever, sore throat, fatigue; spleen enlargement, lymphadenopathy
Prognosis: self-limiting and does not usually require treatment
Define myelogenous leukemia
involves pluripotent myeloid stem cells in bone marrow, interferes with maturation of all blood cells including granulocytes, erythrocytes and thrombocytes
Define lymphocytic leukemia
immature lymphocytes and their progenitors that originate in bone marrow but infiltrate spleen, lymph nodes, CNS and other tissues
Define acute vs. chronic leukemia
Acute leukemia: rapid increase in # of immature blood cells, most common form in children
Chronic leukemia: buildup of relatively mature but abnormal WBC, generally takes months or years
Characteristics of ALL (3)
- Most common type in young children, but can affect adults usually over age 65
- Precursor B or T lymphoblasts, with most being pre-B
- Structural and numerical changes in chromosomes within leukemic cells such as translocations, deletions, hyperploidy or polyploidy that alter ability to regulate normal hematopoiesis
Characteristics of CLL (3)
- Clonal malignancy of B lymphocytes that most often affects adults over age 55 and does not affect children
- Most common form in adults and 2/3 of all cases are men
- See change in immunoglobulin gene resulting in low levels of CD markers like CD38 and zeta-associated protein (ZAP-70) involved in signaling T cells and natural killer cells do better, while individuals with higher levels of markers tend to do worse
Characteristics of AML (3)
- Occurs more commonly in adults than children and more commonly in men than women
- Diverse set of leukemias affecting myeloid precursors in the bone marrow and are most often associated with acquired genetic changes that inhibit myeloid cell differentiation
- Undifferentiated blast cells replace normal cells within bone marrow causing anemia, neutropenia and thrombocytopenia
Characteristics of CML (6)
- Mainly in adults, may be seen in a small # of children
- Pluripotent hematopoietic progenitor cell
- Characterized by excessive proliferation of marrow granulocytes, erythroid precursors and megakaryocytes
- Philadelphia chromosome
- Begins in a chronic phase that over several years progresses to an accelerated phase that ultimately enters a blast crisis phase = terminal phase where CML acts like AML
- CML treated with tyrosine kinase inhibitor drugs that have improved survival rates to over 95%
2 forms of CLL
- long term survival and eventual death from other causes
2. Rapidly fatal disease despite aggressive therapy
What happens in the formation of the Philadelphia chromosome?
creates a new fusion gene that acts like a tyrosine kinase
Activates the cell cycle - cell division rates increased, inhibition of DNA repair
What cells are affected in non-Hodgkin lymphoma, causes (5)?
Either B-cell or T-cell neoplasms, may originate from any lymphoid tissues but commonly from lymph nodes
Causes largely unknown, may include infection (EBV, HTLV-1, HIV), chemicals, medical treatment, genetic diseases, autoimmune diseases
What is the characteristic cell formation in Hodgkin Lymphoma? Where is it believed these cells originate from?
Reed-Sternberg cells - multinucleated cells
B cells within the germinal centers of the lymph node
Peaks of incidence for Hodgkin Lymphoma, treatment (3)?
Two peaks of incidence - age 15-35 and over 55
Treatment: radiation, chemo, hematopoietic stem cell transplantation
Define multiple myeloma; why it is called a “myeloma”?
B-cell cancer of the plasma cells that normally produce antibodies
Name comes from impact on all different kinds of cells - generates losses of myeloid function due to infiltration of bone marrow
What are Bence Jones proteins and which disease process do they accompany?
cells release protein part of the immunoglobulins
Multiple myeloma
Risk factors (4) and manifestations of multiple myeloma (6)
Risk factors: chronic immune stimulation, autoimmune disorders, exposure to ionizing radiation, occupational exposure to pesticides
Manifestations: anemia, neutropenia, thrombocytopenia, infection, renal failure, neurologic symptoms
Explain why liver dysfunction; vessel defects; and platelet defects can give rise to coagulation pathology
Liver dysfunction: clotting factor synthesis, bile synthesis and clearing of clotting factors disrupted
Vessel defects: exposure to subendothelial lining triggers the clotting pathway
Platelet defects: clotting factor reactions normally take place on the surface of platelets
What are examples of vessel defects (4) and platelet defects (3)
Vessel defects: marfan’s syndrome, vitamin C deficiency, inflammatory responses, atherosclerosis
Platelet defects: thrombocytopenia, splenomegaly, platelet destruction
What are examples of clotting disorders (5)
- Hemophilia
- DIC
- Vit K deficiency
- Fibrinolytic defects: increased circulating clotting factors, plasmin inhibitor deficiencies
- Inherited prothrombic disorders: AT III deficiency, protein C defects
What are the clotting dysfunction tests (3)?
- Platelet count
- aPTT (activated partial thromboplastin time): measures effectiveness of intrinsic pathway
- PT (prothrombin time): measures extrinsic pathway
How do aspirin, warfarin and heparin impact blood clotting?
Aspirin: inhibits cyclooxygenase
Warfarin: competes with vitamin K
Heparin: interacts with AT III to bind coagulation factors including thrombin and prevent hemostasis
Define DIC
complication of diseases that accelerate clotting, causing small blood vessel occlusion, organ necrosis, depletion of circulating clotting factors and platelets, activation of fibrinolytic system and consequent severe hemorrhage
Causes of DIC (4)
- disorders that produce necrosis - burns, trauma, hepatic necrosis, transplant rejection
- Infection - septicemia, fungal, protozoal, viral infection
- Neoplastic disease
- Other conditions - cardiac arrest, cirrhosis, shock
Patho of DIC
excessive clotting and consumption of clotting components, excessive circulating thrombin activates fibrinolytic system which dissolves clots
Define thrombocytopenia
Most common cause of what?
relative decrease in thrombocytes or platelets
Hemorrhagic disorders
Causes of thrombocytopenia (4)
- Blood loss
- Decreased platelet production - leukemia, aplastic anemia, drug toxicity
- Increased platelet destruction - liver cirrhosis, DIC, severe infection
- Sequestration - increased blood in limited vascular area like spleen
Define idiopathic thrombocytopenia
deficiency of platelets as a result of immune system destroying own platelets
What populations does idiopathic thrombocytopenia affect?
Acute: children ages 2-4
Chronic: adults under age 50, particular women between 20-40
Define Von Willebrand disease
Inheritance pattern
hereditary bleeding disorder characterized by prolonged bleeding time
Autosomal dominant