Immunopathology Basics Flashcards
There are 2 divisions innate (natural) and adaptive (acquired) immunity. what are some characteristics of them?
Innate: Not ag specific and ready for immediate action
TNF,IL-1,IL-12,IFNgamma and chemokines
Adaptive: develops after exposure= response slower than innate (memory) (makes B and T cells) (includes humoral and cellular/cell mediated)
IL-2,IL-4,IL-5,IL-17,IFNgamma
Complement activation is mediated by classical and alternative pathway. what are some characteristics of both?
Classical: Ag/Ab complex Alternative: Microbe suface inflammation response via C3/5a anaphylatoxins opsonization via C3b = phagocytosis Lysis of microbe via MAC
Wha is the most important cell of the immune system?
Ag Presenting Cells(APCs)
—dendritic aka Langerhans: most important; located under epithelium
Adaptive (Acquired) immunity produces T lymphocytes, what are some features of T lymphocytes?
Thymus derived
Effector cells of cellular immunity
Stimulate Ab responses
Peripheral blood lymphocytes recognize Ags to MHC molecules on other cells
—-CD4 T cells bind class II MHCs expressed by mature Ts and helper Ts (Secrete cytokines that stimulate B cells)
—CD8+ T cells bind class I MHCs expressed by 30% of mature Ts (Cytotoxic Ts — kills directly)
Adaptive (Acquired) immunity produces B lymphocytes what some features of B lymphocytes?
Bone marrow derived
- -transform into plasma cells when stimulated = effector cells of humoral immunity
- -recognize Ags via surface IgM
- -Produce 1 of 5 classes of Ig: M, D, A, G ,E
What is a epitope, idiotype and isotype in regards to B lymphocytes?
Epitope: part of the Ag that is recognized by the immune system
Idiotype: unique Ag-binding site of an Ab molecules
Isotype: type of Ab: IgA, IgM, IgG, and IgE
What are features of MHC class I?
HLA: A, B, C
all nucleated cells
endogenous inside cell
elimination of abnormal (infected cells)
B-2 microglobulin: required for proper folding of MHC1
What are features of MHC class II?
HLA: DP,DQ,DR APCs, Ts, Bs, activated endothelial Exogenous outside cell Presentation of Ag Invariant chain: transiently binds MHCII
CD4 THO are considered master cells, what are TH1 cells?
Increase proliferation: IFNgamma and IL-12
Inhibited by: IL-4, IL-10 and cytokines released IL-2, TNF, and IFNgamma
what are TH2 cells?
Increased proliferation: IL-4
Inhibited by IFNgamma
Cytokines released: IL-4,5,6,10,13,TGF-Beta support Bs/humoral immunity
Type I HSR: IgE mediated is an interaction with IgE attached to surface of mast cell. Effector cells are what?
Masts, basophils and eosinophils
TH2 cells play a pivotal role
Role in parasitic infection
What are the two waves of rxn for Type I HSR?
- Sensitization: Ag presented to TH2 by APC — production of IgE and IgE binds masts
- Activation: re-exposure to allergen — allergen binds to IgE on masts — masts release granules
What are the two activation phases?
- Immediate response: immediately and release of mast cell contents
- Late phase response: PMNs, eosinophils, lmyphocytes
What are examples of type I HSR?
Atopic Extrinsic asthma
Allergic Aspergillosis: asthma, alveolitis, can lead to COPD if untreated; allergic rxn to fungi in bronchi
What are type II HSRxn?
Antibodies against Antigens present on cell surface or other tissue components
What are examples of type II HSrxn?
Autoimmune hemolytic anemia Hemolytic transfusion rxn Goodpasture syndrome Graves disease Myasthenia gravis Pemphigus vulgaris Kawasaki syndrome Wegener's Granulomatosis/G polyarteritis SLE
What are type III HSRxn?
Immune complex mediated
- -injury secondary to deposition of Ag-Ab immune complexes
- -Ag can be exogenous or endogenous
What are examples of type III HSRxn?
SLE
Post streptococcal Glomerulonephritis
PNA
Reactive arthritis
Serum sickness (foreign Ag as xenobiotic serum like abx)
Hypersensitivity Pneumonia aka Extrinsic allergic alveolitis–organic Ag (farmers)
Compare staining patterns of post strep glomerulonephritis and goodpasture syndrome
Post Strep: granular
Goodpasture syndrome: linear deposition of IgG, IgA, and IgM on alpha 3 collagen of BM
What is a type IV HSR?
T cell mediated: initiated by sensitized T lymphocytes
–broad range of offending Ags
What are the two mechanisms of type IV HSR?
Delayed Type HS (CD4 Ts react with Ag presented by MHC II on APCs)(TH1 and TH17) Direct Cytotoxicity (autoimmune diseases and viral infections)
What ares some delayed type HS rxn tests?
Tuberculin/Mantoux test: M. tuberculae for TB
Lepromatous Leprosy: negative lepra test
Tuberculoid Leprosy: positive
Sarcoidosis: anergy to skin tests with candida/PP b/c all CD4Ts are in alveoli/other
What are examples of type IV HSRxns?
TB Type I diabetes MS RA Contact dermatitis Giant cell/temporal arteritis Transplant rejection Graft vs host Hypersensitivity Pneumonia aka Extrinsic allergic alveolitis Sarcoidosis
SLE is a multisystem autoimmune disease with numerous antibodies against what?
Nuclear components + phospholipids (+others)
- –positive antinuclear Ab test
- –anti-phospholipid Ab syndrome: hypercoagulable state = increase in blood clots and thrombosis
What are the lab investigations for SLE?
Indirect IF for anti-nuclear Abs (ANA)
Specific Abs: anti-dsDNA, anti-Smith (RNA binding proteins) and anti-phospholipid
Systemic Sclerosis (Scleroderma) is excessive fibrosis throughout the body and affects females and also affects the fingers first. What humoral abnormalities are specific for SS?
Anti-topoisomerase I/anti-Scl 70: highly specific dx
Anti-centromere: highly specific for CREST
(Calcinosis, raynauds, esophageal dysfunction, sclerodactyly and telangiectasias)
