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188 Cards in this Set
- Front
- Back
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What are the functions of the lymph node? |
Nonspecific filtration by macrophages, storage and activation of B and T cells, antibody production.
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Within the lymph node, where are B cells located?
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Follicles.
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What is contained within the medulla of the lymph node?
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Macrophages, reticular cells, plasma cells.
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Which structure in the lymph node houses T cells? In which disease is this structure poorly developed?
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Paracortex. DiGeorge syndrome.
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Under what circumstances would you see an enlarged paracortex?
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Extreme cellular response (e.g., viral).
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Name some of the MALT structures.
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Palatine tonsils, Peyer's patches, M cells of the GI tract, appendix.
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To which lymph nodes do the upper limb and lateral breast drain?
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Axillary.
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To which lymph nodes does the stomach drain?
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Celiac.
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To which lymph nodes does the duodenum and jujenum drain?
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Superior mesenteric.
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To which lymph nodes does the sigmoid colon drain?
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Colic --> Inferior mesenteric.
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To which lymph nodes does the rectum (lower portion above the pectinate line) drain?
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Internal iliac.
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To which lymph nodes does the anal canal (below the pectinate line), scrotum, and thigh (superficial) drain?
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Superficial inguinal.
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To which lymph nodes do the testes drain?
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Para-aortic!
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Where does the thoracic duct drain into?
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The junction of the left subclavian vein and internal jugular vein.
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B cells, T cells, and APCs all arrive in the spleen via this vessel.
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Central arteriole of the spleen.
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Where in the spleen are T cells located?
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PALS (periarterial lymphatic sheath) and in the white pulp.
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Where in the spleen are the B cells located?
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Follicles within the white pulp.
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Where in the spleen do macrophages live?
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In the red pulp at the periphery of the spleen.
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Describe the path of splenic dysfunction that increases risk of infection by encapsulated bugs.
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Decreased IgM --> Decreased complement activation --> Decreased C3b opsonization --> susceptibility to encapsulated organisms.
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Which bugs specifically are troublesome in patients without a spleen?
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E. coli, Salmonella, Klebsiella pneumoniae, H. influenzae (Type B), Pseudomonas aeruginosa, Neisseria meningitidis, Cryptococcus.
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Which vaccines should be given to patients without a spleen?
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H. influenzae, N. meningitidis, S. pneumoniae.
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In which disease does autosplenectomy occur?
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Sickle cell disease.
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What hematologic changes would you see in a patient without a functional spleen?
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Howell-Joly bodies (nuclear remnants usually cleared by macrophages), target cells, thrombocytosis.
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Where do T cells mature and get their diploma?
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Thymus.
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From which embryological structure is the thymus derived?
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Epithelium of the third branchial POUCH.
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Where does positive and negative selection of T cells occur?
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Corticomedullary junction of the thymus.
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Describe negative selection of maturing T cells in the thymus.
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Maturing T cells that bind MHC TOO STRONGLY or not at all are signaled to undergo apoptosis.
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Name the cells/molecules that are involved in the innate immune response.
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Neutrophils, macrophages, dendrites, NK cells, complement.
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Describe the innate immune response.
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Fast, nonspecific, poor memory.
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Describe adaptive immunity. Which cells/molecules are involved in adaptive immunity?
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Response is slow on first exposure, but memory response is faster and better. T cells, B cells, and circulating antibody.
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Which genes encode for MHC-I? MHC-II?
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MHC-I: HLA-A, HLA-B, HLA-C.
MHC-II: HLA-DP, HLA-DQ, HLA-DR. |
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Which MHC class is expressed on almost all nucleated cells? Which cells don't express this class (or any class)?
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MHC-I; red blood cells.
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What does MHC-I bind? What type of immunity does it mediate?
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TCR and CD8; mediates viral immunity (tattle tale of the cell!).
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Where is MHC-II expressed? What does it bind? What type of immunity does it mediate?
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APCs; TCR and CD4; mediates humoral immunity.
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What type of lymphocyte makes up the majority of circulating lymphocytes?
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T cells (80%!).
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What molecule is expressed on all T cells (both CD4+ and CD8+)?
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CD3.
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Which MHC is found on helper T cells? Which MHC is found on cytotoxic T cells?
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MHC-II; MHC-I.
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What type of diseases are associated with HLA-B27 subtypes?
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Arthropathies that are sero-negative (e.g., no Rho factor): Psoriatic arthritis, ankylosing spondylitis, IBD, Reiter's syndrome.
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Which HLA subtype is associated with DMT1?
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DR3 and DR4.
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Which HLA subtype is associated with hemochromatosis?
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A3.
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What is the purpose of dendritic cells?
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Capture antigen in one location (the periphery), migrate and present antigen in another location (lymph nodes).
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How do dendritic cells capture their antigens?
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Phagocytosis, pinocytosis, receptor-mediated endocytosis (clathrin!).
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Which MHC class do they express? Any co-stimulatory molecules?
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Both, but largely MHC-II. B7 family of co-stimulatory molecules (CD80, CD86), and CD40 (T cells!).
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Name the different types of dendritic cells.
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Langerhans (skin), plasma-derived, monocyte-derived, bone marrow, follicular (help mature B cells).
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What is pathognomonic for Langerhans cell histiocytosis (LCH)?
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Birbeck granules -- they look like tennis rackets on EM!
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What's the problem in Langerhans cell histiocytosis (LCH)?
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Proliferative disorder of Langerhans cells from monocyte lineage. Cells don't mature and thus can't stimulate T cells via antigen presentation. They're just bunk.
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What are three cell types that are known for presenting antigens to T cells?
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Macrophages, dendritic cells, B cells.
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Which cytokines are produced by TH1 cells?
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IL-2, IFN-gamma.
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Which cytokines are produced by TH2 cells?
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IL-4, IL-5, IL-10.
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Which cytokine inhibits TH1 cells?
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IL-10.
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Which cytokine inhibits TH2 cells?
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IFN-gamma.
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What types of cells do TH1 cells activate?
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Macrophages, Cytotoxic T cells (CD8+) -- CELL-MEDIATED response.
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What types of cells do TH2 cells activate?
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B cells to make antibody (IgE>IgG) -- HUMORAL response.
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How is a helper T-cell activated?
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Antigen phagocytosed by APC --> presentation on MHC-II + recognition by TCR on TH cell --> costimulation of B7:CD28 --> activated TH cell makes cytokines.
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How is a cytotoxic T-cell activated?
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Endogenous antigen presented on MHC-I --> recognized by TCR on cytotoxic T-cell --> IL-2 from TH1 cell activates cytotoxic T-cell to kill virus-infected cell.
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What types of things do cytotoxic T-cells kill?
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Virus-infected cells, neoplastic cells, donor graft cells.
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How do cytotoxic T-cells kill?
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Induce apoptosis by using perforin and granzymes.
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How are B cells activated?
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Antigen presentation via MHC-II to TH cell --> IL-4, IL-5, from TH2 cell --> CD40L (T cell) + CD40r (B cell) --> co-stim signal B7:CD28 --> class switching + antibody production.
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What do regulatory T cells do?
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When activated they have an ANTI-INFLAMMATORY effect and secrete anti-inflammatory cytokines IL-10 and TGF-b.
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What is the only lymphocyte member of the innate immune system? How does it do it's job?
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Natural killer cells! Kills cells w/o MHC-I on target cell surface. Uses perforin and granzymes. THESE GUYS ARE LIKE QUALITY CONTROL SCANNERS!
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What are monocytes of the kidney called? Liver? Connective tissue? Bone? Brain?
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Mesengial cells; Kupfer cells; A-cells/Histiocytes; Osteoclasts; Microglia.
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What cytokine more than any other should be known as the macrophage-activating cytokine? Who secretes this cytokine?
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IFN-gamma; TH1 cells.
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Which acute phase cytokines do macrophages secrete and what are their actions?
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IL-1: fever
IL-6: fever TNF-alpha: mediates septic shock and + endothelium --> PMN recruitment and vascular leakage. |
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Where do B cells mature?
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Bone marrow.
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What are the B cell surface markers?
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CD19, CD20, CD21, IgM, IgD.
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Name all of the cell surface proteins found on T cells.
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TCR, CD3, CD28, CD4 (helper T cells), CD8 (cytotoxic T cells).
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Name all of the cell surface proteins found on B cells.
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CD19, CD20, CD21, IgM, IgD, CD40, MCH-II, B7
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CD21 acts as a receptor for which virus?
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EBV.
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What are the cell surface proteins of macrophages?
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CD14, CD40, MHC-II, B7, Fc and C3b receptors (enhance phagocytosis).
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What are the cell surface proteins of NK cells?
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CD16, CD56.
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Describe the cellular characteristics of the plasma cell.
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Clock-face chromatin, abundant RER, well-developed Golgi.
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What is the name of a plasma cell neoplasm?
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Multiple myeloma (bone marrow is making a TON of monoclonal antibodies -- i.e., ONE TYPE of antibody).
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What is an idiotype and which region of the antibody determines idiotype?
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The unique antigen-binding pocket; Fab region of the antibody.
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What is the isotype of an antibody? Which region of the antibody determines isotype?
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IgM, IgD, etc. Fc region of the antibody.
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Which region of the antibody recognizes antigen?
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Fab region, specifically the variable part of L and H chains.
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Which portion of the antibody fixes complement?
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The Fc portion of IgG and IgM.
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What type of bonds hold the antibody together in several locations?
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Disulfide bonds.
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What are the types of light chain? What is their relative ratio?
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Kappa and Lambda. 2:1.
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What are three major functions of the antibody?
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Opsonization, complement activation, neutralization (prevents bacterial adherence).
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What is the purpose of VDJ recombination?
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To generate antibody diversity.
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Which gene complex is responsible for initiating VDJ recombination? Which gene sequence does it interact with?
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RAG1 and RAG2 --> interact with RSS sequence flanking the V, D, and J coding regions.
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Which antibody isotype comprises 70-75% of the total immunoglobulin pool?
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IgG.
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Which antibody isotype crosses the placenta and confers immunity to neonates in the first few months of life?
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IgG.
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Which antibody can occur as a dimer?
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IgA.
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The predominant immunoglobulin in mucoserous secretions such as saliva, colostrum, milk, tracheobronchial secretions, and genitourinary secretions.
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IgA.
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This antibody can be a pentamer.
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IgM.
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Associated with allergies because it is bound by mast cells and basophils and causes them to degranulate and release their histamine.
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IgE.
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What type of hypersensitivity reaction does cross-linking of IgE cause?
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Type I hypersensitivity through release of histamine.
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The predominant early antibody frequently seen the immune response to infectious organisms with complex antigens.
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IgM.
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Describe passive immunity in terms of acquisition, onset, duration, and examples.
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Receiving preformed antibodies, quick onset, short duration of action (~3wks), IgA in breast milk, antitoxin, humanized monoclonal antibody.
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Describe active immunity in terms of acquisition, onset, duration, and examples.
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Exposure to foreign antigens; slow onset; long-lasting protection; natural infection, vaccines, toxoid.
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What type of vaccine initiates a CELLULAR response?
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LAIV vaccine.
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What type of vaccine initiates a HUMORAL response?
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Inactivated or killed vaccine.
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What are thymus-independent antigens?
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Antigens that lack a peptide component -- cannot be presented on MHC to T cells -- no immunologic memory.
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What are thymus-dependent antigens?
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Antigens that contain a protein component (e.g., conjugated H.flu vaccine). Direct contact of B cells with Th cells (CD40:CD40L) and release of IL-4,5,6 = immunologic memory!
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What are the live attenuated vaccines?
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Small pox, yellow fever, VZV, Sabin's polio virus, MMR.
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What are the killed/inactivated vaccines?
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Rabies, influenza, Salk polio, HAV vaccines.
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What are the recombinant vaccines?
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HBV, HPV.
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What is the immune response to polysaccharide antigen alone?
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No activation of T cells or class-switching. Only IgM antibodies are produced (e.g., Pneumovax).
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Anti-dsDNA, anti-Smith antibody.
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SLE
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Antinuclear antibodies.
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SLE, nonspecific.
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Antihistone antibodies.
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Drug-induced lupus (e.g., hydralazine).
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Anti-IgG (rheumatoid factor) antibodies.
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Rheumatoid arthritis.
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Anticentromere antibodies.
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Scleroderma (CREST).
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Anti-Scl70 (anti-DNA tompoisomerase I) antibody.
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Scleroderma (diffuse).
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Antimitochondrial antibody.
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Primary biliary cirrhosis.
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Antigliadan antibody.
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Celiac disease.
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Anti-basement membrane antibody.
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Goodpasture's syndrome.
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Anti-desmoglein antibody.
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Pemphigus vulgaris.
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Antimicrosomal, antithyroglobulin antibody.
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Hashimoto's thyroiditis.
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Anti-Jo 1 antibody.
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Polymyositis, dermatomyositis.
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Anti-SS-A antibody (anti Rho).
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Sjogren's syndrome.
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Anti-SS-B antibody (anti La).
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Sjogren's syndrome.
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Anti-U1 RNP (ribonucleoprotein) antibody.
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Mixed connective tissue disease.
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Anti-smooth muscle antibody.
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Autoimmune hepatitis.
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Anti-glutamate decarboxylase antibody.
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Type 1 DM.
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c-ANCA antibody.
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Wegener's granulomatosis.
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p-ANCA antibody.
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Other vasculitides.
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Anti-ACh receptor antibody.
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Myasthenia gravis.
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MPO-ANCA antibody.
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Cresentic glomerulonephritis.
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What are the PMN chemoattractants?
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IL-8, LTB4, C5a.
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What is the mechanism by which Interferons work?
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They place non-infected cells in an antiviral state. Induce production of ribonuclease --> inhibits viral protein synthesis by degrading viral mRNA (but not host mRNA!). Also increase MHC-I and MHC-II expression in all cells and activate NK cells.
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Describe hyperacute transplant rejection.
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Occurs within MINUTES of transplant. Antibody-mediated (HS type II) reaction d/t presence of pre-formed antibodies in transplant recipient.
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Describe acute rejection.
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Occurs weeks later d/t CTLs reacting to foreign MHC.
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Describe chronic rejection.
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Occurs months to years later. Irreversible. T cell and antibody-mediated vascular damage.
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How does graft versus host disease present?
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Maculopapular rash, jaundice, hepatosplenomegaly, diarrhea.
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How does cyclosporine work?
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Inhibits calcineurin and thereby blocks the differentiation and activation of T cells -- prevents production of IL-2 and its receptor.
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May prevent nephrotoxicity with mannitol diuresis when using this immunosuppressant.
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Cyclosporine.
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Binds to FKBP leading to loss of IL-2 production.
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Tacrolimus.
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Binds FKBP12 leading to inhibition of mTOR -- inhibition of T cell proliferation in response to IL-2.
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Sirolimus.
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Monoclonal antibody that binds IL-2 receptor on activated T cells.
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Daclizumab.
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Metabolized by xanthine oxidase and therefore increases allopurinol toxicity.
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Azathioprine.
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Precursor of 6-mercaptopurine.
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Azathioprine. Interferes with the metabolism and synthesis of nucleic acids.
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Antibody that binds CD3 on T cells.
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Muromonab-CD3.
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Inhibits inosine monophosphate dehydrogenase and thereby prevents the production of nucleoside guanine.
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Mycophenalate.
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Which recombinant cytokines are used in the recovery of bone marrow?
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Filgrastrim (granulocyte colony-stimulating factor), Sargramostim.
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What is the antidote for digoxin toxicity?
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Digoxin Immune Fab.
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This IgE antibody is used as an additional line of therapy for severe asthma.
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Omalizumab.
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What is the target of Abciximab?
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Glycoprotein IIb/IIIa.
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Rituximab targets CD 20 and is used to treat this disease.
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B-cell non-Hodgkin's lymphoma.
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What drugs are composed of antibodies against TNF? What is their clinical use?
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Infliximab, Etanercept, Adulamab. HLA-B27 arthropathies + Crohn's disease.
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What is a MAJOR consideration of Infliximab use?
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Reactivation of latent Tb infection.
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This drug targets TNF-alpha, is used as an immunosuppressant and phocomelia is a toxicity.
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Thalidomide.
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What are the two primary opsonins in bacterial defense?
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C3b and IgG.
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What inhibits complement activation on self cells?
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Decay-accelerating factor (DAF) and C1 esterase inhibitor.
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Which two complement components are responsible for anaphylatic shock
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C3a and C5a --> release histamine --> increase vascular permeability --> rapid decline in BP.
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What clinical feature does a deficiency in C1 esterase inhibitor cause?
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Hereditary angioedema.
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A deficiency in the C5-C8 complement predisposes to what?
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Recurrent Neisseria infections.
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Deficiency in DAF predisposes to this condition.
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Complement-mediated lysis of RBCs and paroxysmal nocturnal hemoglobinuria.
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What does a deficiency in C3 cause?
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Severe, recurrent pyogenic sinus and respiratory infections. Increased susceptibility to HS type III reactions.
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What type of reaction does Type I Hypersensitivity reaction cause?
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Atopic and Anaphylactic. FIRST and FAST! IgE gets cross-linked on pre-sensitized mast cells and basophils. Preformed antibody gets released. Yowza!
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What are some disorders associated with Type I hypersensitivity reactions.
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Anaphylaxis (e.g., bee sting, food allergy); Atopic and allergic disorders (e.g., rhinitis, asthma, hay fever, hives, eczema).
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What type of reaction does Type II Hypersensitivity reaction cause?
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AUTOIMMUNE, ANTI-SELF antibody-mediated. IgM and IgG bind to antigen on "enemy" cell --> lysis.
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What are some disorders associated with Type II hypersensitivity reactions?
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Specific to tissue or site where antigen is found; AIHA, pernicious anemia, TTP, erythroblastis fetalis, transfusion reactions, rheumatic fever, Goodpasture's, bullous pemphigoid, pemphigus vulgaris, Grave's, Myasthenia gravis.
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What type of reaction does Type III hypersensitivity cause?
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Immune-complex mediated. ICs activate complement, which attract neutrophils --> release lysosomal enzymes that cause trouble!
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What are some disorders associated with Type III hypersensitivity reactions?
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Can be associated with vasculitis and SYSTEMIC manifestations. SLE, RA, polyarteritis nodosum, poststreptococcal glomerulonephritis, serum sickness, arthus reaction, hypersensitivty pneumonitis (e.g., farmer's lung).
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Describe Type IV hypersensitivity reactions.
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DELAYED (T cell-mediated) type. Sensitized T lymphocytes encounter antigen and release lyphokines. NO ANTIBODY INVOLVEMENT.
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What are some disorders associated with Type IV hypersensitivity reactions?
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PPD test, contact dermatitis, Guillain Barre syndrome, Type I DM, multiple sclerosis, graft vs host disease.
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What are the causes of eosinophilia?
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"DNAACP": drugs, neoplasms, asthma, allergic processes, collagen vascular diseases, parasites.
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What type of HS reaction is the mast cell involved in?
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Type I.
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What does the mast cell release when it explodes? The mast cell is the tissue counterpart to what other myeloid cell?
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Histamine, heparin, eosinophil chemotactic factors; Basophil.
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What drug prevents mast cell degranulation? What disease is it used to treat?
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Cromolyn sodium. Asthma prophylaxis.
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If you see more than one basophil on a blood smear (and that's generous) what do you immediately think?
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CML.
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When should an Rh(-) mom be given Rhogam?
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At 28 weeks, at any traumatic event (e.g., MVA), and within 3 days of delivery.
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What is the inheritance pattern of Bruton's agammaglobulinemia?
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X-linked (Boys).
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A defect in BTK, a TYROSINE KINASE gene causes this.
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Bruton's agammaglobulinemia.
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Describe the pathogenesis and presentation of Bruton's agammaglobulinemia.
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Blocked maturation of pro-B cells to pre-B cells --> recurrent bacterial infections after age 6 months. Absence of thymic shadow.
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What causes hyper IgM syndrome?
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Defective CD40L on helper T cells --> inability to class switch.
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What is the most common type of Selective Ig deficiency?
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IgA deficiency.
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A patient develop an anaphylactic reaction to blood products that contain IgA. What's the defect?
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Selective IgA deficiency.
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What is the presentation of a patient with thymic aplasia (DiGeorge)?
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No T cells --> recurrent viral, fungal, protozoal infections; congenital defects in heart/great vessels; hypocalcemia --> tetany.
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What is the genetic and embryological defect in Thymic aplasia?
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Deletion at 22q11; failure to develop 3rd and 4th branchial pouches.
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What is the triad of symptoms in SCID?
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Severe recurrent infections (viral and fungal -- RSV, HSV, VZV, measles, flu, influenza, chronic candidiasis, PCP pneumonia), Chronic diarrhea, Failure to thrive. Also absent thymic shadow on CXR.
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What causes SCID?
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Defective IL-2 receptor --> no T cell activation. ADENOSINE DEAMINASE deficiency -- increased adenosin --> toxic to B and T cells. No MHC-II antigens either.
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What causes chronic mucocutaneous candidiasis?
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T-cell dysfunction.
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A defeciency in the IL-12 receptor predisposes to what type of infection?
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Mycobacterial infections. Decreased TH1 response --> decreased IFN-gamma.
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What is the presentation triad in Job syndrome (Hyper-IgE syndrome)?
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Eczema, Recurrent COLD S.aureus abcesses, coarse facial features. Also can have retained primary teeth.
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What is deficient in Job syndrome?
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IFN-gamma --> weak PMN response. Also high levels of IgE and eosinophils.
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Which immunoglobulin is deficient in ataxia-telangiectasia?
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IgA.
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What are the clinical symptoms of ataxia-telangiectasia?
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Cerebellar ataxia and poor smooth pursuit of moving target with eyes; telangiectasias of face; IgA deficiency.
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What is the triad of Wiskott-Aldrich syndrome?
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Infection (recurrent pyogenic), thrombocytopenic purpura, Eczema.
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List the X-linked immunodeficiencies.
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Wiskott-Aldrich syndrome, Bruton agammaglobulinemia, Hyper-IgM syndrome, chronic granulomatous disease.
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What is the presentation triad for Chediak-Higashi syndrome?
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Partial albinism, recurrent respiratory tract and skin infections (staph and strep), neuro problems (peripheral neuropathy and seizures).
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What is the genetic defect in Chediak-Higashi syndrome?
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LYST gene --> defect in lysosomal trafficking. Microtubule dysfunction in phagosome-lysosome fusion.
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What is pathognomonic for Chediak-Higashi?
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Giant cytoplasmic granules in PMNs are diagnostic.
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What is the defect in chronic granulomatous disease?
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Impotent phagocytes! Lack of NADPH oxidase --> decreased ROS and absent respiratory burst in PMNs.
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What infections is a patient with chronic granulomatous disease susceptible to?
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Catalase + bugs: S. aureus, E. coli, aspergillus.
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Which immunoglobulin is decreased in Wiskott-Aldrich syndrome?
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IgM.
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