Immuno physiology Flashcards
What type of Hypersensitivity reaction is Acute Hemolytic Transfusion Reaction
Type II (antibody-mediated)
Describe the clinical presentation of a patient with acute hemolytic transfusion reaction
fever and chills, hypotension, chest/back pain and hemoglobinuria (red- to brown-colored urine) after blood transfusion
What is the mechanism behind acute hemolytic transfusion reaction?
Recipient Anti-ABO antibodies bind donor erythrocyte antigens. Activate complement-mediated cell lysis (C5-C9)
Hemolytic disease of the newborn is what type of hypersensitivity reaction?
Type II
Which humoral components are involved in a Type II hypersensitivity reaction?
IgG and IgM autoantibodies and complement
What is the etiology of hyperacute transplant rejection
Preformed antibodies against graft in recipient’s circulation
What is the morphology of hyperacute transplant rejection reaction
Gross mottling and cyanosis; arterial fibrinoid necrosis and capillary thrombotic occlusion
What is the etiology of acute transplant rejection?
Exposure to donor antigens induces humoral/cellular activation of naive immune cells in recipient
What is the morphology of humoral mediated acute transplant rejection?
C4d deposition, neutrophilic infiltrate, necrotizing vasculitis
What is the morphology of cellular acute transplant rejection?
Lymphocytic interstitial infiltrates and endotheliitis
What is the etiology of chronic transplant rejection?
Chronic, low-grade immune response refractory to immunosuppressants
What is the clinical presentation of chronic renal allograft rejection?
Worsening hypertension, progressive rise in serum creatinine and proteinuria with normal urinary sediment
What is the morphology of chronic transplant rejection?
Vascular wall thickening and luminal narrowing; interstitial fibrosis and parenchyma atrophy (obliterative vascular fibrosis)
Which bacterial genus lacks peptidoglycan cell wall?
Mycoplasma (including Ureaplasma urealyticum)
What is the best treatment for Mycoplasma infections?
Anti-ribosomal agents (tetracycline, macrolides)
Why does blood in left atrium and ventricle have slightly lower pO2 than in pulmonary capillaries?
Mixing of deoxygenated blood from pulmonary veins carrying blood from bronchial blood supply and cardiac (thesbian) blood supply
List 4 causes of diffusion limited exchange
pulmonary fibrosis, ARDS, emphysema, hyaline membrane dz in infant
What is the function of IL-3 secreted by helper T cells
promote growth and differentiation of bone marrow stem cells
Function of IL-1 secreted by macrophage
stimulates T cells to proliferate and secrete cytokines
Which cytokine is responsible for fibrosis?
TGF-beta
IFN-gamma
activates macrophages and may stimulate CD8 T cells
What is the structure of MHC I
Heavy chain and beta 2 microglobulin
What is the structure of MHC II
alpha and beta polypeptide chains
Which MHC molecules respond to tumors
MHC I
What does antigen presentation by MHC I result in
apoptosis of presenting cell
What does antigen presentation from MHC II result in
Activation of TH cells, which stimulate humoral and cell-mediated response
How do a mainstem bronchus obstruction and pleural effusion present on CXR
entire lobe white opacities with tracheal deviation (completely opacified hemithroax)
How to distinguish between mainstem bronchus lung collapse and pleural effusion
In lung collapse, trachea shifts towards injured lung (white); in pleural effusion, trachea shifts away from injured lung
Viruses that lose their infectivity upon exposure to ether are likely
Enveloped
Which part of the immune response is integral to response against mycobacteria?
Cell-mediated (macrophage, neutrophils, etc)
Which fungal infection found in the Central US appears as ovoid cells within macrophages?
Histoplasma capsulatum
Which fungal infection endemic to SW US appears as multinucleated spherules?
Coccidiodes
Which fungi takes form of budding yeast with thick capsule
Cryptococcus neoformans
Which yeasts form pseudohyphae and blastoconidia
Candida species
Which fungus is seen in tissue sections as septae hyphae and dichotamous branching
Aspergillus
Which enzyme is mutated in chronic granulomatous disease?
NADPH oxidase
NADPH oxidase deficiency in CGD leads to
impaired respiratory burst (intracellular killing)
Three primary clinical manifestations of Chronic Granulomatous Disease
Recurrent infections by catalase-positive organisms, infections of skin and lymph nodes; diffuse granuloma formation
Dihydrorhodamine flow cytometry testing that reveals an absence of green fluorescnece characteristic of normal neutrophils likely diagnoses
Chronic Granulomatous Disease
A Nitroblue tetrazolium test that does not turn blue likely confirms
Myeloperoxidase deficiency
Which yeast species gives rise to “germ tubes”
Candida (colonizes mucous membranes of mouth, vagina, skin, intestine)
Which yeast forms a “fungus ball” in lung cavities and causes cough and hemoptysis
Aspergillus fumigatus
Which parts of the pulm system are normally sterile?
Trachea and small bronchi
What is the tetrad of septic shock?
Hypotension, tachycardia, tachypnea and fever
Which molecule is the mediator of septic shock?
TNF-alpha
TNF-alpha (cachectin) mediates which consequence of inflammation?
Necrosis of tumors and cachexia (generalized muscle wasting) of host
Which cytokine mediates sepsis and causes hepatic release of acute-phase reactants
TNF-alpha
Which cytokine has antiviral and antitumor activity
Interferon alpha
