Hypersensitivity Flashcards
1
Q
Hypersensitivity
A
altered immunologic response to an antigen that results in disease or damage to the host
2
Q
Allergy
A
- hypersensitivity to environmental antigens
- reactions happen after 1st exposure
- often allergen is contained within a particle too large to be phagocytized or is protected by non-allergenic coat
3
Q
Autoimmunity
A
- disturbance in the immunologic tolerance of self-antigens
- body recognizes self antigen as foreign
- antigenic mimicry – foreign antigen similar to body’s antigen
4
Q
Alloimmunity
A
- immune reaction to tissues of another individual
- transplant rejection and transfusion rejections
5
Q
Type I
A
- IgW mediated
- works against environmental antigens (allergens)
- IgE binds to antibody receptors on the surface of mast cells – sensitizes
- histamine release – H1 (respiratory, vasodilation) and H2 (GI)
- manifestations = itching, urticaria, conjunctivitis, rhinitis, hypotension, bronchospasm, dysrhythmias, GI cramps
- genetic predisposition
- tests = food challenges, skin tests, lab tests
- can cautiously desensitize someone
6
Q
Type II
A
- tissue specific
- cells are destroyed by antibodies and complement
- cell destruction through phagocytosis
- soluble antigen enters the circulation and deposits on tissue, tissue destroyed by complement and neutrophil granules
- antibody dependent cell mediated cytotoxicity – transplant rejection
- causes target cell malfunction
7
Q
Type III
A
- immune complex mediated
- antigen-antibody complexes are formed and later deposited
- systemic or localized
- Raynaud’s disease = caused by temperature dependent deposition of immune complexes, blocks circulation and causes pallor, numbness, cyanosis
8
Q
Type IV
A
- cell mediated
- no antibodies, antigens stimulate T-lymphocyte activity
- activities activated:
1. cytotoxic T-lymphocytes = attack and kill cells
2. cytokine producing Th cells = produce cytokines recruiting and activates phagocytic cells
9
Q
Immediate hypersensitivity
A
- occurs within minutes to 2-3 hours
- anaphylaxis = most rapid and severe, immediate reaction
- cutaneous (localized) = painful local reaction, redness/swelling
- systemic (generalized) = allergic reaction to bee stings
10
Q
Delayed Hypersensitivity
A
- may take several hours and are at peak severity days after re-exposure
11
Q
Graft Rejection
A
- hyperacute = immediate and rare, pre-existing antibody to antigens of the graft
- acute = cell mediated immune response against unmatched HLA antigens (anti-rejection drugs)
- chronic = months or years, inflammatory damage to endothelial cells of vessels as a result of a weak cell mediated reaction against HLA antigens
12
Q
Graft vs. Host Disease
A
T-cells in the graft are mature and capable of cell-mediated destruction tissues within the recipient
