Heme/Onc Flashcards
What are the dense granules of thrombocytes?
ADP, Ca+2
What are the alpha granules of thrombocytes?
vWF, fibrinogen, fibronectin
Where is 1/3 of platelet pool synthesized?
Spleen
Which leukocytes are granulocytes?
Neutrophils, eosinophils, basophils
Which leukocytes are mononuclear cells?
Monocytes (macrophage in tissue), Lymphocytes (T and B cells)
In an acute inflammmatory response, which leukocyte is predominant?
Neutrophil
List 5 chemotactic factors for neutrophils
IL-8, LTB-4, kallikrein, platelet-activating factor, C5a
Which cytokine activates macrophages in tissues?
gamma-interferon
which leukocyte is important in granuloma formation?
macrophage
How do macrophages initiate septic shock?
CD14 binds Lipid A from bacterial LPS
Which cells do macrophage present antigens to/
CD4 (via MHC II)
List the causes of eosinophilia (NAACP)
Neoplasia, Asthma, Allergies, Chronic Adrenal Insufficiency, Parasites
Basophilia can be a sign of which hematologic problem?
CML (myeloproliferative disease)
Which leukocyte produces major basic protein?
Eosinophil
Describe Type I hypersensitivity reaction (allergic response)
Mast cell binds Fc portion of IgE, IgE cross-links, degranulation, release of histamine, heparin, tryptase and eosinophil chemotactic factors
Cromolyn sodium is used to prevent
Degranulation of mast cells (allergic prophylaxis)
Which cell serves as the link between innate and adaptive immunity?
Dendritic cell
Which MHC do dendritic cells express?
MHC II
Which blood cell is affected in multiple myeloma?
plasma cell
Which blood cells make up the majority of circulating lymphocytes
T cells
Which blood type is a universal donor of plasma?
AB
Which blood type is universal recipient of plasma?
Type O
What is the purpose of administering RhoGAM to mothers/
prevents maternal anti-d IgG production in Rh- mothers against Rh+ positive fetus (prevents hemolytic disease of newborn)
What is ABO hemolytic disease of newborn
Hemolytic anemia of A, B, or AB fetus in type O mother. Presents as mild jaundice in first 24 hours of birth, treatment is phototherapy or exchange transfusion
Why can ABO hemolytic disease of newborn happen in first pregnancy and not Rh disease?
Anti-ABO antibodies are formed early in life while anti-D IgGs usually form after exposure to Rh
Which aspects of inflammation does PGE4 mediate?
Vasodilation, increased vascular permeability, pain and fever
Leukotrienes are primarily involved in which inflammatory response?
Anaphylaxis
What is the immediate response of mast cells in acute inflammation?
Release histamine to increase vasodilation of arterioles and vascular permeability
What is the delayed response of mast cells in acute inflammmation?
production of arachidonic acid metabolites, especially Leukotrienes
Which factors are involved in the Classical pathway for Complement activation?
IgM and IgG bound to antigen (bind C1)
Which factors activate the alternative pathway
microbial products
Which factors activate the Mannose-binding lectin pathway
MBL binds mannose on microorganisms to activate complement
Which complement factors are part of the MAC complex
C5b, C6-C9
Which complement protein is chemotactic for neutrophils
C5a
Which complement protein is an opsonin for phagocytosis?
C3b
Describe the function of Hageman factor (Factor XII)
Activates coagulation and fibrinolysis, complement and kinin system
Which inflammatory molecules are responsible for redness and warmth?
Histamine, Prostaglandins D2, E2 and I2, and bradykinin (vasodilators)
What are the key mediators of swelling in inflammmation?
Histamine (endothelial cell contraction) and tissue damage
Key mediators of pain in inflammation
Bradykinin and PGE2 (sensitize sensory nerve endings)
Key mediators of fever in inflammation?
Pyrogens that cause macrophage to release IL-1 and TNF (increase COX in perivascular cells of hypothalamus)
Which prostaglandin mediates fever in the hypothalamus?
PGE2
What are the features of autosomal recessive integrin deficiency? (CD18)
Delayed separation of umbilical cord, increased circulating neutrophils and recurrent bacterial infections that lack pus formation
What are the features of Chediak-Higashi syndrome?
Increased risk of pyogenic infections, neutropenia, giant granules on leukocytes, albinism, peripheral neuropathy, defective primary hemostasis
Which cellular mechanism is defective in Chediak-Higashi syndrome?
Cell-trafficking and phagolysosome formation
Which enzyme is defective in Chronic Granulomatous Disease?
NADPH Oxidase (converts O2 –> Superoxide radical)
People with CGD are prone to infections by which organisms?
Catalase-positive (S. aureus, Pseudomonas, Serratia, Nocardia, Aspergillus)
Which test is used to screen for CGD
Nitroblue tetrazolium (leukocytes turn blue if normal, stay colorless if NADPH oxidase is defective)
MPO deficiency increases risk of which infections?
Candida infections
What are the anti-inflammatory cytokines produced by macrophages?
IL-10 and TGF-beta
Which cytokine from macrophages recruits additional neutrophils?
IL-8
Which leukocytes mediate abscess formation?
Macrophages via fibrosis
Which T cells are involved in chronic inflammation?
CD4+ T cells activated by MHCII of macrophages
Which cells express MHC I and what do they present?
All nucleated cells, intracellular antigens (viruses)
Which cells express MHC II and what do they present?
Antigen-presenting cells (dendritic, macrophage), extracellular antigens (parasites, bacteria, etc)
Which two interactions activate CD4+ helper T cells?
B7 on APC to CD28 on T cell and MHCII on APC to TCR (+CD3) on T cell
What are the two subsets that helper T cells divide into?
TH1 and TH2
Which cytokines are secreted by TH1 cells?
IFN-gamma to activate macrophage and promote B cell class-switch to IgG, IL-2 to activate CD8+ T cells (and inhibit TH2)
Which cytokines do TH2 cells secrete and what is their function?
IL-4 (B cell class switch to IgE); IL-5 (recruit eosinophils); IL-13 (B cell class switch); IL-10 (inhibit TH2)
What is the second activation signal for CD8+ T cells?
IL-2 secreted by TH1 cells
How do CD8+ T cells kill infected cells? (2 ways)
Secrete perforin and granzyme to activate apoptosis; express FasL to bind Fas on target cells and activate apoptosis
List 3 ways to activate apoptosis
cyt c, Fas-FasL, granzyme via CD8+
Which two signals activate B cells to become plasma cells?
CD40 on B binds CD40L on helper T cell; BCR-MHCII
What 2 cytokines released by helper T cell promote B cell class switch?
IL-4 and IL-5
Describe what a granuloma looks like
epithelioid histiocytes (macrophage with abundant pink cytoplasm) surrounded by giant cells and rim of lymphocytes
Difference between caseating and non-caseating granulomas
Non-caseating granulomas lack central necrosis; caseating granulomas are characteristic of tuberculous and fungal infections
Which cytokine induces helper T cells to turn into TH1 subtype?
IL-12
Describe how granulomas form
Macrophage ingest pathogen and present to CD4 T cell on MHC II–> macrophage secrete IL-12 to differentiate T cell into TH1 cell–> TH1 cell secretes IFN-gamma to activate macrophages into epithelioid histiocytes and giant cells
List the clinical presentation of DiGeorge syndrome
T-cell deficiency (thymic aplasia), hypocalcemia (parathyroid aplasia), abnormalities of heart, great vessels and face
What are three major causes of SCID?
Cytokine receptor defects (most common); ADA deficiency (leads to oxidative death of lymphocytes); MHC II deficiency (cannot activate T cells and cytokine production)
X-linked agammaglobulinemia is a mutation in which enzyme?
Bruton tyrosine kinase
What is the defect in X-linked Agammaglobulinemia?
Pre- and pro-B cells cannot mature to plasma cells (complete lack of immunoglobulins)
Presentation of X-linked Agammaglobulinemia
presents after 6 months of life with recurrent bacterial, enterovirus and Giardia infections
Why does X-linked agammaglobulinemia present after 6 months?
Infant no longer has protective maternal IgGs
Patients with Common variable immunodeficiency are at increased risk of which diseases?
Autoimmmune diseases and lymphoma
What is the difference in presentation between X-linked agammaglobluinemia and common variable immunodeficiency?
CVID arises in late childhood (not after 6 months) and blood tests show low Ig count
Which protein is mutated in hyper-IgM syndrome?
CD40L (on helper T cells) or CD40 receptor (on B cells)
What is the Ig presentation of hyper-IgM syndrome?
elevated IgM, low IgA, IgG and IgE (recurrent pyogenic infections) at mucosal sites
Which gene is mutated in Wiskott-Aldrich syndrome?
WASP (XLR)
Clinical presentation of Wiskott-Aldrich Syndrome?
Eczema, thrombocytopenia (low platelet count), and recurrent infections
What is the major cause of death in Wiskott-Aldrich syndrome?
Bleeding
Patients who are prone to Neisseria infections are deficient in which immune component?
Complement C5-C9 (MAC complex)
What causes hereditary angioedema (inflammation around orbitals)
C1 deficiency (persistent vasodilation)
What does central tolerance lead to?
T cell apoptosis or generation of regulatory T cells
Which mutation leads to autoimmune polyendocrine syndrome (hypoparathyroidism, adrenal failure, chronic candida infections)
AIRE
Which 2 autoimmune conditions are polymorphisms in CD25 associated with?
MS and T1DM
What is a the phenotype of Treg cells?
CD3+ CD4+ CD25+ FOXP3+
IPEX syndrome is a mutation in which protein?
FOXP3 on Treg cells
Describe symptoms of IPEX syndrome
Immune dysregulation
Polyendocrinopathy
Etneropathy
X-linked
What type of Hypersensitivity reaction is SLE?
Type III (Antigen-Antibody complexes)
Deficiency of which complement proteins associated with SLE?
C1q, C4 and C2 (needed to clear Ab-Ag complexes)
Which antibodies are highly specific for SLE?
Anti-Sm (mitochondrial) and Anti-dsDNA
Which antiphospholipid antibodies are elevated in SLE?
anticardiolipin, anti-beta2-glycoprotein I, and lupus anticoagulant (falsely-elevated PTT)
What is a complication of antiphospholipid syndrome?
recurrent miscarriages
What is antihistone antibody specific for?
Drug-induced lupus
anti-SSA/Ro and anti-SSB/La associated with which disorder
Sjogren syndrome
What type of HS reaction is Sjogrens
Type IV Lymphocyte-mediated damage with fibrosis
Which malignancy commonly presents with Sjogrens
Rheumatoid arthritis
What risks exists for babies with mother’s who have anti-SSA?
neonatal lupus, congenital heart block
B cell (marginal) zone lymphoma risk is increased in which condition?
Sjogren’s
What is the diagnostic criteria for Sjogren’s?
Lymphocytic sialedenitis on lip biopsy
What are the two types of scleroderma and what are their antibodies?
Limited type (CREST syndrome): anti-centromere Diffuse type (any organ, especially lungs): anti-Scl70 (DNA Topoisomerase I)
What is primary intention?
Wound edges brought together, minimal scar formation
What is secondary intention wound healing?
Edges not approximated–granulation tissue fills defect; myofibroblasts contract–scar formation
Deficiencies that cause delayed wound healing?
Vitamin C (hydroxylation of proline and lysine of procollagen– collagen cross-linking)
Copper (cofactor for lysyl oxidase to cross-link collagen)
Zinc (cofactor for collagenase)
How do disorders in primary hemostasis typically manifest?
Mucosal or skin bleeding
What is the most common symptom of primary hemostasis disorders
epistaxis
List symptoms of mucosal and skin bleeding common to primary hemostasis disorders
epistaxis (nosebleeds), hemoptysis, GI bleeds, petechiae, purpura, easy bruising, echhymoses
What is Immune Thrombocytopenic Purpura?
Splenic generation of autoantibodies against platelets (IgG)
What are the two forms of ITP?
Acute (in children, usually after viral infection)
Chronic (in women, usually pregnant, secondary to autoimmune dz, can lead to ITP in kids)
Lab findings of ITP?
thrombocytopenia (<50k), normal PT/PTT, megakaryocytosis
What is treatment of ITP for refractory cases?
Splenectomy
What types of cells can be seen in microangiopathic hemolytic anemia?
Schistocytes (helmet cells)
What are two major causes of Microangiopathic Hemolytic Anemia?
HUS and TTP
Mutation in which enzyme causes thrombotic thrombocytopenic purpura (TTP)
ADAMTS13
What is the function of ADAMTS13?
Cleaves vWF multimers (polymeric vWF cause abnormal aggregation and microthrombi)
How is deficiency of ADAMTS13 acquired?
Autoimmunity (autoantibody), more common in females
What causes hemolytic uremic syndrome (HUS)?
endothelial damage by drugs or infection
What is the most common cause of HUS?
E Coli O157:H7 (undercooked beef); verotoxin damages endothelial cells
Clinical findings of HUS/TTP
Skin/mucosal bleeding, hemolytic anemia (schistocytes), fever
Clinical finding specific to HUS
Renal insufficiency (elevated Creatinine/BUN)
Clinical finding specific to HUS
CNS involvement (hydroencephaly, confusion, etc)
Lab findings of HUS/TTP
Thrombocytopenia, longer bleeding time, normal PT/PTT, anemia with schistocytes, megakaryocytosis
What is the treatment for TTP/HUS?
Plasmapharesis (protein removal) and corticosteroids
What is the defect in Bernard-Soulier syndrome?
defective GPIb so platelet cannot adhere to endothelial cell
What is the defect in Glanzmann thrombasthenia?
GPIIb/IIIa deficient so platelet aggregation is impaired
How does aspirin affect platelet aggregation?
Inhibits COX irreversibly, impairing aggregation
What are the clinical features of secondary hemostasis disorders (coagulation cascade)
Deep tissue bleeding into muscles and joints; rebleeding after surgeries
Which pathway/factors does prothrombin time measure?
Extrinsic: 7; Common: 2, 5, 10, fibrinogen
Which pathway/factors does partial thromboplastin time measure?
Intrinsic (12, 11, 9, 8) and common (2, 5, 10, fibrinogen)
How is Hemophilia A inherited?
XLR or de novo
Which factor is deficient in Hemophilia A?
VIII of intrinsic pathway
Lab findings of Hemophilia A
Increased PTT; normal PT
Decreased Factor VIII
Normal platelet count and bleeding time
Symptoms of Hemophilia A
Deep tissue bleeding; rebleeding after surgical procedures
Which factor is deficient in Hemophilia B (Christmas disease)?
Factor IX
How to distinguish between Coagulation Factor Inhibitor and Hemophilia A?
In CFI, PTT does not correct after mixing normal plasma with patient’s plasma (bc antibodies impair VIII function, there is no deficiency)
What is von Willebrand Disease?
Genetic vWF deficiency, most common inherited coagulation disorder
How is the most common type of vWF disease inherited?
AD
Lab findings of vWF disease?
Increased bleeding time, increased PTT (decreased VIII deficiency), abnormal ristocetin test (impaired agglutination)
Describe the ristocetin test
Induces platelet agglutination by having vWF bind platelet GPIb; checks for vWF disease
Treatment for von Willebrand disease?
Desmopressin (ADH analogue that stimulates vWF production from Weibel-Palade bodies of endothelial cells)
Where is Vitamin K produced
gut flora
How does vitamin K deficiency lead to hemorrhage?
Vitamin K is needed to gamma carboxylate factors (activate) 2, 7, 9, 1 and Proteins C and S, all of which are needed for coagulation; deficiency keeps them inactive, so coagulation can’t occur
Who is at greatest risk of Vitamin K deficiency?
Newborns (sterile gut)
Pts with Malabsorption syndromes
Pts on long-term broad-spectrum antibiotics
How does liver failure lead to thrombocytopenia and abnormal hemostasis?
Decreased production of coagulation factors (monitor PT)
Laboratory findings of disseminated intravascular coagulation
thrombocytopenia (decreased platelet count)
increased PT/PTT
decreased fibrinogen
hemolytic anemia (schistocytes)
Which test confirms DIC dx?
Elevated D-dimer (split products of fibrin)
How is a clot removed?
fibrin broken down via plasmin, coagulation factors destroyed, platelet aggregation inhibited