Hypersensitivity Flashcards
Type 1
Anaphylactic
Type 2
Cytotoxic
Type 3
Immune Complex
Type 4
Delayed/ Cell Mediated
Mediators of Early Type 1
Histamine, Heparin, ECF-A, Neutrophils (IL-8)
Heparin
anticoagulant
Mediators of Late Type 1
Prostaglandins, Thromboxanes, Leukotrienes
Early Phase Type 1
allergen activates B cells, IgM switches to IgE
IgE docks to mast cells and causes degranulation
early mediators released
Late Phase Type 1
2-4 hrs post
release prostaglandins and leukotrienes
Leukotrienes
1000x more potent than histamine
IL-4
drives class switch from IgM to IgE or IgG
IL-5
activates eosinophils
switches IgM to IgA
IL-13
IgE production
mucus secretion in epithelial cells
enhances smooth mm contraction
Early Phase T1 driven by
histamine
Late Phase T1 driven by
leukotrienes and prostaglandins
Manifestations of T1
anaphylaxis, atopy, asthma, rhinitis, hives, angioedema
Triggers for T1
foods
drugs
insects
Difference between eosinophil and mast cell action
worm coated in Ab, eosinophil binds thru Fce receptor
MC have Ab on them and wait for things to collide with them
Mechanism of T2
IgG binds to cell membrane, causing opsonization, inflammation, or cellular dysfunction
Opsonization
cellular destruction
leads to activation of phagocytosis (MAC attack), NK cell killing, and inflammation- necrosis
Cellular Dysfunction
Ab bind and cause abnormal blockade or activation
Clinical Manifestation of T2
autoimmune hemolytic anemia thrombocytopenic purpura- platelet lysing transfusion reactions- RBC lysing transplant rejection rheumatic fever
Corneal transplant rejection
T4
most rejection types are T2
Coombs Serum
antihuman IgG
rabbit + human
Direct Antiglobulin Test
detects Abs attached to RBCs using Coombs serum
Indirect Antiglobulin Test
detects plasma Abs that might bind to cells and cause lysing
uses Coombs serum
Diseases found using DAT
HDN, anemias, transfusion reactions
Uses of IAT
bloodbank antibody screening
Mechanism of T3
Ag/ Ab complex (IgM/ IgG) lodge in vessels and tissues
complement activated, phagocytes destroy
tissue damage
Clinical Manifestation of T3
systemic and localized inflammation and dammage
Examples of T3
Arthus reaction
serum sickness
rheumatoid arthritis
lupus
Arthus Reaction
Ab against vaccine
local
Serum Sickness
form haptins that bind to membranes in response to oral drugs
systemic
Activating complement in T3
anaphylotoxins degranulate mast cells
PMN chemotaxis
stim release of lytic enzymes from PMNs
Mechanism of T4
Ag binds to CD4
CD4 release cytokines that attract macrophages and CD8 and cause tissue damage
no Ab
Examples of T4
contact dermatitis
Tb skin test
corneal transplant rejection
autoimmune
Phlyctenular Keratoconjunctivitis
PKC
blister forming keratoconjunctivitis from T4 in response to bacterial infection
Causes PKC
Staph aureus
Scrapings from PKC show….
CD4, CD8, Langerhans cells
Penicillin T1 have what Ab types?
IgE, mast cells, eosinophils
Penicillin T4 have what Ab types
Th1 and macrophages
