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USMLE - Immunopath
USMLE - Goljan, Chapter 3 Immunopathology
Question | Answer |
---|---|
Name the two types of immunity | Innate and Acquired |
Name cells of the innate immunity | phagocytes (neutrophils, macrophages), NK cells |
Name cells of acquired immunity | B and T cells (antigen-dependent) |
If a newborn already has IgM at birth, what should you suspect? | Congenital infection because normally, IgM synthesis only begins at birth |
When does IgG synthesis begin? | 2 months old; IgG presence at birth is usually mom's IgG |
MHC complex | proteins that display self and non-self antigens to T cells |
MHC class 1 | bind to CD8 T cells |
MHC class 2 | bind to CD4 helper T cells |
HLA genes | subset of genes in the MHC region (on chromosome 6) |
HLA A, B, C | Belong to MHC class I group; present on all cells except RBCs; recognized by CD8 T cells and NK cells |
HLA DP, DQ, DR | belongs to MHC class II group; present on all antigen-presenting cells (B cells, macrophages, dendritic cells); recognized by CD4 helper T cells |
HLA-B27 | ankylosing spondylitis |
HLA-DR2 | MS |
HLA-DR3 and DR4 | Type 1 DM |
Name 3 functions of CD4 T cells | secrete IL-2 --> proliferation of CD4/CD8 T cells; secrete gamma-interferon --> activate macrophages; help B cells become antibody-producing plasma cells |
What do CD8 T cells do? | kill virus-infected, tumor (neoplastic), or foreign cells (donor) |
Do APC's interact with CD4 or CD8 cells? | CD4 T cells |
What type of cells do NK cells attack? | Virus-infected or tumor (neoplastic) |
What are dendritic cells? | APC's found in skin |
What Ig is involved in Type I hypersensitivity? | IgE --> activation of mast cells |
Atopic disorders -- what type of hypersensitivity rxn? | Type 1 |
Hay fever -- what type of hypersensitivity rxn? | Type 1 |
Eczema -- what type of hypersensitivity rxn? | Type 1 |
Hives -- what type of hypersensitivity rxn? | Type 1 |
Asthma -- what type of hypersensitivity rxn? | Type 1 |
anaphylaxis -- what type of hypersensitivity rxn? | Type 1 |
Drug allergy to penicillin -- what type of hypersensitivity rxn? | Type 1 |
Mnemonic for Type 1 Hypersensitivity Rxns | ANAPHYLAXIS Annie's ASTHMA FLAREs when her FOOD contains HAY. FLARE = wheal/flare (insect stings, allergy testing); FOOD = food allergies; HAY = hayfever |
Mnemonic for Type 2 Hypersensitivity Rxns | The BULLdog E.F. ARF the II HAd GOOD TaPas, while DuM MaG-Gie PAssed on them. |
Name the complement-dependent diseases associated with Type 2 Hypersensitivity reactions | Complement Dependent: BULL=Bullous pemphigoid; E.F.=Erythroblastosis Fetalis; ARF=Acute Rheumatic Fever; II=type 2; HA=hemolytic anemia; GOOD=Goodpasteur's Syndrome; TP=thrombocytopenic purpura (autoimmune). |
Name the complement-independent diseases associated with Type 2 Hypersensitivity reactions | Complement-independent: DM=Diabetes Mellitus; MG=Myasthenia Gravis; G=Graves; PA=Pernicious Anemia. |
Type II Hypersensitivity Rxns | Antibody-dependent |
ABO mismatch -- what type of hypersensitivity rxn? | Type II - antibody dependent, complement-dependent, by lysis (MAC) |
Hyperacute transplantation rejection -- what type of hypersensitivity rxn? | Type II - antibody dependent, complement dependent, by lysis (MAC) |
Goodpasteur's Syndrome -- what type of hypersensitivity rxn? | Type II - antibody dependent, complement dependent, by lysis (MAC) |
Warm IgG autoimmune hemolytic anemia -- what type of hypersensitivity rxn? | Type II - antibody dependent, complement dependent, by phagocytosis (macrophages) |
ABO and Rh disease of the newborn -- what type of hypersensitivity rxns? | Type II - antibody dependent, complement dependent, by phagocytosis (macrophages) |
helminth destruction by eosinophils -- what type of hypersensitivity rxn? | Type II - antibody dependent, complement INdependent, cell-mediated cytotoxicity |
Type III Hypersensitivity Rxns | Immune complex-mediated diseases |
Mnemonic for Type 3 Hypersensitivity Rxns | ARTHur was the 3rd PaGaN, RA in SLE with PNEUMONITIS in his PeNis!! ARTH=ArthusRxn; 3rd=Type III; PGN=Post-StrepGlomeruloNephritis; RA=RheumArthritis; SLE; Pneu=HypersensitivityPneumonitis; PN=PolyarteritisNodosum |
Serum sickness -- what type of hypersensitivity rxn? | Type III - immune complex dependent |
Type IV Hypersensitivity Rxns | T-cell mediated diseases |
Mnemonic for Type 4 Hypersensitivity Rxns | Don't CONTACT Ms. GUILLIAN HASHIMOTO FOR NEURo TrouBles because she's GraVid. D=IDDM; CONTACT=ContactDermatitis; Guillian Barre; HashimotoThyroiditis; Neuritis; TB=tuberculosis; GV=Graft vs. Host Dz |
What is delayed Type 4 Hypersensitivity? | CD4 T cell mediated; macrophage activation, cytokines released --> inflammation. |
What is cell-mediated cytolysis Type 4 Hypersensitivity? | CD8 T cell cytolysis |
IL-1 | Secreted by macrophages --> inflammatory mediators --> pyrogenic response |
IL-2 | Secreted by helper (CD4) T cells --> both helper and cytotoxic T cells --> make more T cells!! |
IL-3 | Secreted by helper (CD4) T cells --> stimulate bone marrow stem cells --> growth and differentiation of progenitors of all blood cells |
IL-4 | Secreted by Th2 (subset of CD4's) cells 1. B cells --> IgE/IgG production, 2. differentiation of naïve CD4's into Th2's, 3. suppress gamma-interferon actions of macrophages |
IL-5 | Secreted by Th2 (subset of CD4's) cells 1. B cells --> make IgA, 2. eosinophils --> activate to kill worms |
IL-6 | Secreted by Th2 (subset of CD4's) cells AND macrophages --> acute phase reactants and Ig's by hepatocytes; --> stimulates growth of plasma cells (antibody-producing B cells) |
IL-8 | Secreted at site of inflammation --> chemotasis of neutrophiles |
IL-10 | Secreted by Th2 (subset of CD4's) cells AND activated macrophages --> 1. block Th1 and activated macrophages; 2. stimulate Th2 |
IL-12 | Secreted by B cells to activate NK cells; secreted by macrophages to activate Th1 (IFN-gamma release and phagocytic ingestion of microbes) |
IFN-gamma | Secreted by Th1 (subset of CD4's) AND NK cells --> stimulate Th1's and macrophages, block Th2 |