Hypersensitivities Flashcards
Food, Drug, Bee sting allergies.
Asthma
Type __ HSR
1
Autoimmune- hemolytic anemia ITP Hemolytic Disease of Newborn Transfusion reactions Type \_\_ HSR
2
Antibody dependent Cellular Cytotoxicity
NK cell killing
Good Pasture Syndrome
Rheumatic Fever
Hyperacute Transplant Rejection
Type __ HSR
2
Complement system & Fc receptor-mediated Inflammation
Myasthenia Gravis
Graves Disease
Pemphigus Vulgaris (IgG-Desmoglein)
Type __ HSR
2
ABs bind to cell surface receptor and block or activate downstream processes.
SLE Polyarteritis Nodosa (Hep. B association) PSGN Serum Sickness Type \_\_ HSR
3
Poison Ivy
Nickel Allergy
Type __ HSR
4
Contact Dermatitis
Graft Vs Host Disease
PPD test for TB
Candida skin test
Type __ HSR
4
Hypersensitivity reaction does NOT involve Antibodies
Type 4
Delayed Type
What HSR is described?
Direct cell cytotoxicity via CD8+ T cells killing target
Type 4
Delayed Type
(+CD4+ releasing inflammatory cytokines)
Immune complexes (antigen-antibody) activate complement and neutrophils release lysosomal enzymes. Complexes are insoluble and may deposit onto tissue surfaces.
Type 3
Ag-Ab-C3 (3 things stuck together)
What HSR is described?
Antibodies bind to cell surface antigens causing cellular destruction, inflammation, and organ dysfunction.
Type 2
One mechanism is the cell is opsonized by antibodies leading to either, complement mediated phagocytosis or NK cell killing (ADCC).
Type 2
Detects Antibodies attached DIRECTLY to the RBC surface. + result means agglutination
Coombs
Detects the presence of unbound antibodies in the serum.
Indirect Coombs
ELISA blood test for allergen specific IgE to diagnose which HSR type?
Type 1
Anaphylactic & Atopic reactions occur in 2 phases:
The immediate reaction occurs in minutes when the antigen crosslinks ____ IgE on PRESENSITIZED Mast cells.
Pre-formed
Mast cell degranulation releases (2)
Histamine (increased permeability of capillary)
Tryptase
The second or delayed phase of Type 1 HSRs occur hours later when chemokines attract ___ and ___ causing inflammation and tissue damage.
Eosinophils
leukotrienes
Describe Type 1 HSR Type 2 HSR Type 3 HSR Type 4 HSR
Mast cell/ IgE mediated (Immediate)
Antibody mediated
Immune Complex mediated
T Cell mediated (Delayed)
(MACT)
This patient with recurrent episodes of abdominal pain and an episode of facial swelling likely has angioedema due to
C1 inhibitor (C1INH) deficiency
C1 inhibitor (C1INH) deficiency causes increased cleavage of C2 and C4 and results in inappropriate activation of the complement cascade. C1INH also blocks ____-induced conversion of kininogen to bradykinin
kallikrein
a potent vasodilator associated with angioedema due to increased permeability:
bradykinin
Direct Mast Cell Activation can be done by ____ which caused pruritis & urticaria
Opioids
Facial edema (without itchiness or rash) or laryngeal swelling caused by recent use of ACE-I is due to accumulation of _____
Bradykinin
Excess Bradykinin resulting in edema can be caused by
C1 inhibitor deficiency
ACE-I
Angiedema without urticaria or pruritis
Labs: low C4, High Bradykinin
indicative of
C1 inhibitor deficiency
High levels of activated C1
Low levels of C1 esterase inhibitor
Kallikrein converts what to proteins
Plasminogen to Plasmin
Kininogen to Bradykinin
Activated C1 inhibits what protein
Kallikrein
____ inhibitor suppresses activation of the C1 complement component and therefore the rest of the classic complement pathway.
C1 esterase
An erythematous area with indistinct margins over the skin. The area feels hot and indurated and is exquisitely tender.
Cellulitis
Myeloperoxidase is found predominately in
neutrophils
Drugs causing a nonimmunologic reaction that can cause itching, urticarial rash, wheezing, hypotension, and tachycardia that closely mimictrue IgE-mediated type 1 hypersensitivity (eg, anaphylaxis). (3)
Opioids
Vancomycin (red man syndrome)
radioiodine contrast
Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenase, which leads to increased _____ activity. This effect can precipitate bronchoconstriction and wheezing due to increased production of leukotrienes (ie, NSAID-exacerbated respiratory disease)
5-lipoxygenase
During initial allergen exposure, antibody class switching from IgM to IgE antibodies specific for the allergen occurs. IgE binds to high-affinity ____ on basophils and mast cells.
Re-exposure to the allergen results in cross-linking of bound IgE antibodies with subsequent degranulation and release of inflammatory mediators ( histamine, tryptase, leukotrienes, prostaglandins).
IgE Fc receptors
TH1 cells are responsible for inducing macrophage and ____ inflammatory reactions.
cytotoxic T lymphocyte-mediated (type IV)
__ is a cytokine produced by TH1 lymphocytes that increases proliferation and activity of helper, cytotoxic, and regulatory T cells as well as NK cells.
IL-2
IL-4 is responsible for driving the production of TH2 cells, which promote antibody-mediated (humoral) immunity and facilitate type __ hypersensitivity.
I
IL-4 is responsible for driving the production of __ cells
TH2
Dyspnea, hypotension, and tachycardia soon after administration of β-lactam antibiotics are suggestive of
anaphylactic shock
*give epinephrine
release of ___ causing widespread increased vascular PERMEABILITY aka Anaphylactic Shock
chemical mediators
histamine, prostaglandin, leukotrienes
In response to anaphylaxis-induced hypotension, an intact ____ reflex leads to increased sympathetic activity, tachycardia, and compensatory vasoconstriction.
baroreceptor
A toxin-mediated decrease in myocardial contractility and an increase in capillary permeability occur in
toxic shock syndrome (TSS)
TSS toxin 1 is capable of nonspecifically activating T cells (superantigen). The subsequent dramatic release of inflammatory cytokines results in increased capillary permeability and hypotension, as well as high fever and a diffuse, erythematous rash. In addition, the exotoxin can directly inhibit myocardial function.
Anaphylactic Shock is due to CHEMIACAL mediators (like Histamine) not TOXIN mediators like TSS.
Hypotension, Tachycardia, N/V, & Wheezing
are all signs of
Anaphylactic Shock
other signs: Edema, hoarseness, stridor, flushing, itchiness, rash, abdominal pain
Erythema
Pruiritis
Urticaria
characteristic of Type __ HSR
1
