Hypersensitivities Flashcards
Acute inflammation progresses either to…. or …….
resolution
or
Chronic Inflammation
Resolution of Acute
1) supression of neutrophil recuritment
- stop inflammatory signaling
2) increase macrophage recruitment
- to clean up dead cell debri and pathogens
3) Scavenger function
4) tissue reapir
Acute leading to chronic
1) initiation of adaptive
2) fail to resolve, leads to chronic inflammation
What occurs with chronic inflammation that has to do with your vessels
angiogenesis
Outcomes of acute inflammation
1) resolution
2) healing by fibrosis
3) chronic inflammation
Major cells involved in Acute
1) Neutrophils
2) Mononuclear cells
- monocytes
- macrophages
Primary mediators of Acute
1) Vasoactive amines
2) PGs
3) activated complement
Major cells involved in Chronic
1) mononuclear cells
- macrophages, dendritic cells, monocytes
- the reason is we need these apc cells to stimulate our naive T cell and B cell population to initiate humoral and cellular immunity
Primary Mediators of Chronic
Cytokines
1) IFN-gamma
2) TNF-alpha
3) other cytokines
4) growth factors
- so maybe for angiogenesis
5) ROS species
6) hydrolytic enzymes
Summarize primary mediators of chronic
cytokines such as
1) IFN gamma
2) TNF alapha
other cytokes
growth factors
ROS
hydrolytic enzymes
Name 4 histological patterns of chronic inflammation
1) Mononuclear
- disordered
- has fibrosis
2) Granulomatous
- foreign body rxn, TB
- ORDERED pattern of macrophages/mononuclear cells
3) Eosinophilic
- parasites
- allergic, dominated by eosinophils with FIBROSIS
4) lymphoid neogenesis
-typically autoimmune disease
-spontaneous organization of new lymphoid structures
examples
-HEV, B lymphocytefollicles/germinal centers
Disorder, accompanied by fibrosis
Mononuclear histology
Parasites
allergic dominated by eosinophils with FIBROSIS
Eosinophilic
Typically in autoimmune disease
spontaneous org of new lymphoid structures HEV, B lymph/germinal centers
Lymphoid neogenesis
Foreing body rxn TB
ordered pattern of macrophages and other mononucelar cells
Granulomatous
Mononuclear histology
disordered
accompanied by fibrosis
Eosinophilic histology
parasites
allergic dominated by EOSINOPHILS with FIBROSIS
Granulomatous histology
FB, TB
ORDERED pattern of macrophages and other mononuclear cells
Lymphoid neogenesis
typically autoimmune
spontaneous organization of NEW lymphoid structures
HEV, B lymph follicles/germinal centers
Macrophages and Dendritic Cells are derived from what stem cell?
Myeloid stem cell
Immature Macrophages and Dendritic cells that haven’t left circulation and specialized into their tissues
MONOCYTES
Monocytes and granulocytes are distinct categories of progeny from myeloid stem cell
True
Moonocyte/macrophage progression
1) blood monocyte
2) tissue monocyte
3) activated macrophage/histiocyte
4) granulomatous inflammtion
multiNUCLEATED giant cell
Different activators of macrophages induce different phenotypes
IFN-y > GRANULOMA
IL4/IL13 > FOREIGN BODY GIANT CELL
TNFalpha> DENDRITIC CELLS
Macrophage effector functions
chemokines
cytokines
GF for tissue recovery
antimicrobial like hydrogen peroxide respiratory burst
Respiratory burst
also called oxidative burst
is the rapid release of reactive oxygen species (superoxide anion and hydrogen peroxide) from different types of cells
*hypersensitivity rules
1) are disease of ANTIGEN REENCOUNTER
2) No one has hypersensitivity rxn the FIRST TIME ag is ENCOUNTER
3) too much or inappropriate adaptive immunity
4) adaptive immunity inappropriately recruits innate mech that cause damage to our own bodies
Allergy
common disease of too much immune response
an overeaction, disproprotinate reponse to th danger of antigen
list 4 igE mediated allergic rxn
1) systemic anaphylaxis
- drugs
- serum
- venoms
- peanuts
2) acute urticaria (wheel and flare)
- animal hair
- insect bites
- allergy testing
3) allergic rhinitis (hay fever)
- pollens (ragweed, timonthy, birch)
- dust mite feces
4) asthma
- danders (cat)
- pollens
- dust-mite
5) food allergy
- tree nuts
- peanuts
- shellfish
- milk
- eggs
- fish
actopic
allergy prone
non-atopic
non-allergy prone
3 factors that contribute to allergy prone
1) genetic predisposition
2) antigen disproportionately favor Th2/IgE induction
3) genetic/environment predisposition to express Th2’IgE promoting cytokines with prolonged kinetics or greater magnitude than avg
Primary effector mech in allergy
1) immediate release of mast cell granules (histamine)
2) production of chemical mediators of inflammation
only….induce T cell reponses
Proteins or Peptides
Allergens are often….
proteases
low dose allergens favors activation of …..
IL-4 producing CD4 T cells
……are of low molecular weight so it can diffuse out of particle into mucus
low molecular weigh
Allergans are ……so can be readily eluted from particle
highly soluble
Allergens contain peptides that bind host MHC class……
MHCII required for T cell priming
Allergic rxn can be divide into 2 phase
1) Immediate
- release mediators in granules
2) Late Phase
downstream casacasde from ARACHADONIC ACID
Allergic rxn immediate response
release of preformed mediators in granules
Allergic rxn late phase resposne
downstream casacade form arachadnoc acid
….stabilizes granules preventing histamine relase
sodium cromoglycate
Wheal-and-flare type I hypersensitivity
Type I allergic reactions. Called a wheal-and-flare reaction, it includes swelling, produced by the release of serum into the tissues (wheal), and redness of the skin, resulting from the dilation of blood vessels (flare)
How is allergy treated? Four ways
1) reverse TH2 and Th1 balance
2) block co-stimulation to inhibit TH2 cytokines
- inhibit CD40-L
- inhibit IL-4 or IL-13
3) inhibit IgE binding to mast cell
- block IgE receptors
4) inhibits mediator effects on specific receptors, inhibit synthesis of specific mediators
- antihistamine drugs
- LOX inhibitors
5) block cytokine and chemokine receptors that mediate eosinophil recruitmnet and cativation
Which type of Ig or T cell is associated with Type 1 hypersensitivity?
IgE
Which type of Ig or T cell is associated with Type 2 hypersensitivity?
IgG
Which type of Ig or T cell is associated with Type 3 hypersensitivity?
IgG
Which type of Ig or T cell is associated with Type 4 hypersensitivity?
TH1
TH2
CTL
What is Type I hypersensitivity?
Immediate hypersensitivity
IgE mediate atopic (allergic) and anphylactic rxn in previously exposed individuals (Sensitized)
Type I hypersensitivity mechanism
1) INITIATION: cross-linkage by antigen of IgE bound to Rc receptors on mast cells and basophils after reexposure of sensitized host to allergan
2) EFFECTOR mech: degranulation of mast cells and basophils releasing vasoactives/other mediators like histamine and SRS-A is a mixture of LTC4, LTD4, LTE4
3) clinical manifestation:
- shock, vascular collapse, respiratory collapse
- chronic localized rxn: asthma, allergic rhinitis (hay fever) and wheal and flare (hives)
4) desensitization therapy: repeated injections of increasing doses of allergen induce production of IgG which binds lalergen and prevents its binding to igE on sensitized cells
Define Type I immediate hypersensitivity
IgE-mediated atopic (allergic) and anaphylactic reactions in previously exposed (sensitized) individuals