Hypersensitivity Flashcards
Excessive reaction to antigenic stimulus
Hypersensitivity
Immediate reaction lang ang meron sa Type I hypersensitivity. True or False?
False. May late phase din, 2-24 h later. May last for several days.
Individuals who have been previously exposed to an antigen may trigger a pathologic reaction when exposed to the same antigen. T or F?
T. This is called sensitization
Eosinophils are recruited to infection site by ___
Chemokines
Two proteins liberated by eosinophils
Basic protein
Cationic protein
Eosinophils direct which immune cells to release mediators?
Mast cells
Mast cells are activated by what cross linking?
Cross linking of high affinity IgE-FC receptors
Which complement proteins are involved in the activation of mast cells?
C5a, C3a
Mast cells have these kind of preformed mediators, except
a. vasoactive amines
b. proteoglycans
c. enzymes
d. leukotrienes
D
Leukotrienes are lipid mediators that are synthesized by sequential reactions in the mast cell membranes
Phospholipase A2 is an enzyme that an enzyme that acts on membrane
phospholipids to yield ___
arachidonic acid
What is atopy?
predisposition to develop localized immediate
hypersensitivity reactions
In atopy, there is higher serum IgE levels and more ___producing TH2 cells
IL-4
Non-atopic allergy is triggered by __
triggered by temperature extremes and exercise
Which is not consistent with the Hygiene Hypothesis?A.decreasing incidence of immediate hypersensitivity
diseases in developed countries
B.appears to be related to a decrease in infections during
early life
C.immune system is rest such that TH2 responses develop
more readily against common environmental antigens
A
What kind of hypersensitivity are transfusion reactions?
II
What is Erythroblastosis Fatalis?
there is antigenic difference between the mother
and the fetus, and IgG antibodies from the mother
cross the placenta and cause destruction of fetal
red cells
Differentiate Type II from Type III hypersensitivity
Type II is mediated by antibodies AGAINST antigens
Type III is mediated by antigen-antibody complexes
What are the phases of systemic disease for Type III hypersensitivity?
formation of immune complexes
deposition of immune complexes
injury caused by immune complexes
Which is true about deposition of immune complexes? A.Deposition is greatest with medium sized complexes. B.Deposition is great in glomerulus. C.Deposition is great in synovium. D.All are true.
D
False about Arthus reaction
A.Localized area of tissue necrosis resulting from
acute immune complex vasculitis
B.As the antigen diffuses into the vascular wall, it
binds the preformed antibody, and large complexes
are formed locally
C.These complexes precipitate in the vessel walls and
cause caseous necrosis, and superimposed
thrombosis worsens the injury
C
Fibrinoid, not caseous
