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94 Cards in this Set

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What are the only immunologically specific components of the immune system?
T and B lymphocytes
Which of the following are nonspecific mediators of immunity?
a. T lymphocytes
b. B lymphoctyes
c. polymorphonuclear lymphocytes and monocytes
d. complement
e. interleukins
f. interferons
g. other cytokines
all except a and b
What are the two lines of differentiation from stem cells of the cellular immune system?
lymphoid and myeloid
What are components of the lymphoid cellular immune system? (3)
T-helper and suppressor cytotoxic cells
B cells and plasma cells
Null cells
What are components of the myeloid cellular immune system? (5)
platelets
eosinophils
neutrophils
basophils and mast cells
monocytes and macrophages
What are the two major sites of lymphopoiesis?
thymus
bone marrow
Which organ is critical for the development of major histocompatibility complex restriction?
thymus
What is the purpose of the primary lymphoid system?
proliferation and differentiation of lymphocytes
What is the purpose of the secondary lymphoid system?
to provide and environment that enhances antigen-effector cell interactions
What are some components of the secondary lymphoid system? (4)
Waldeyer's ring
lymph nodes
spleen
mucosa-associated lymphoid tissue (MALT - ie. Peyer's patches)
What three organs tracts can MALT be found?
the lamina propria and submucosa of the GI, respiratory, and urogenital tracts
What is the major immune function of the tonsil?
generation of antigen-specific B cells in the follicles; the B cells then produce specific secretory IgA
What CD antigen is found on helper T cells?
CD4
What CD antigen is found on cytotoxic/suppressor T cells?
CD8
Allergic inflammation is characterized by emphasis of Th2 response over Th1 response. True or false.
True
Do Th1 cells inhibit B cells or stimulate B cells?
Inhibit B cells.
What cytokines do Th1 cells produce?
IL-2
IFN-gamma
What cytokines do Th2 cells produce?
IL-4
IL-5
IL-6
IL-10
Are there more CD4+ T cells or CD8+ T cells?
CD4+ T cells: represent 60% of peripheral T cells
CD8+ T cells represent 20-30% of peripheral T cells
CD8+ T cells are the receptor for HIV. True or False.
False
Which MHC complex is associated with T-helper cells? What about T-cytotoxic cells?
Class II MHC - T-helper cells
Class I MHC - T-cytotoxic cells
Which MHC complex is carried on the surface of B cells?
Class II MHC
B cells comprise what percentage of circulating lymphocytes?
5-15%
What type of null cells have these characteristics?
a. 15% of blood lymphocytes
b. positive for CD16, 56
c. cytotoxic for virus-infected cells
d. have IgG receptors
Natural killer cells
What are the three major myeloid cell types?
macrophages, antigen-presenting cells, polymorphonuclear granulocytes
On what chromosome is the MHC in humans located?
Chromosome 6
Class I MHC antigens are what HLA subtypes? What about Class II MHC antigens?
Class I MHC: HLA-A, HLA-B, HLA-C
Class II MHC: HLA-DP, HLA-DQ, HLA-DR
Are endogenous or exogenous antigens associated with Class I molecules and B2 microglobulin?
Endogenous antigens
What are the 4 types of cytokines?
Interleukins
Interferons
Colony-stimulating factors
Tumor necrosis factors
What stimulates interferon production? (4)
viral infection
double-stranded RNA
endotoxin
mitogens
Which type of interferon is made by leukocytes?
alpha interferon
Which type of interferon is made by fibroblasts and epithelial cells?
beta interferon
Which type of interferon is a potent activator of eosinphils?
gamma interferon
What is the "late-phase response"?
Intense inflammatory reaction characterized by cellular infiltration of eosinophils, mononuclear cells, and neutrophils
When is the peak cellular accumulation of the "late-phase response"?
6-8 hours
What are the major cytokines involved in allergic inflammation? (3)
IL-4
IL-5
IL-13
What are the effects of IL-4?
1. induces switch recombination to IgG4 and IgE
2. enhances antigen presntation of B cells by the stimulation of class II antigen
3. induces differentiation of uncommitted T-cell precursors toward Th2-like phenotype
What is the difference between effects of IL-4 and IL-13?
IL-13, like IL-4 stimulates IgE isotype switching and B-cell growth but has no effect on T cells. IL-13 also induces adhesion molecules at the site of allergic inflammation, contributing to the selective accumulation of eosinophils and lymphocytes.
What are the effects of IL-5?
potent proliferation and differentiation factor for eosinophils. also a chemotactic factor
Which cytokine specifically inhibits IL-4 isotype switching of IgE?
gamma interferon
What are some typical antigen-presenting cells? (3)
macrophages
endothelial cells
glial cells
What cell produces IL-1 and what is its function?
Macrophages produce it.
It is a lymphocyte activating factor.
Which end of immunoglobulins is the variable region?
The N-terminal end or Fab fragment.
Where is IgA normally found? What conformation is it usually in?
Usually a dimer, this Ig class is found in seromucous secretions.
What is special about IgM? What conformation is it usually in?
Usually a pentamer, this is the predominant antibody in early immune response. It fixes complement by the classic pathway.
What are the characteristics of IgG? (3)
1. major antibody of secondary response
2. only Ig class that crosses the placenta
3. fixes complement by the classic pathway
What is the characteristic of IgD?
found in large quantities on circulating B cells
What is the characteristic of IgE?
Found on basophils and mast cells. Involved in response to helminthic infections and immediate hypersensitivity.
What are the mediators of a Gell and Coombs Type I reaction?
IgE
mast cells
heparin, histamine, prostaglandins, leukotrienes
What are the mediators of a Gell and Coombs Type II reaction?
IgM, IgG
complement
What are the mediators of a Gell and Coombs Type III reaction?
antibody-antigen complexes
complement
What are the mediators of a Gell and Coombs Type IV reaction?
macrophages
cytotoxic T cells
What are the steps involved in an immediate hypersensitivity response? (6)
1. Exposure to antigen
2. Deveopment of an IgE Ab response to antigen
3. Binding of the IgE to mast cells
4. Reexposure to antigen
5. Antigen interaction with antigen-specific IgE cound to the surface membrane of mast cells resulting in crosslinking.
6. mast cell degranulation
Serum level of IgE is a reflection of the amount of mast cell-bound IgE. True of False.
True.
What are the preformed mediators of immediate hypersensitivity? (4)
Histamine
Heparin
Tryptase, Beta-glucosaminidase
Eosinophil and neutrophil chemotactic factors
What are the general effects of histamine? (4)
1. Vasodilatation
2. Increased capillary permeability
3. Bronchoconstriction
4. Tissue edema
What are newly formed mediators of immediate hypersensitivity? (3)
1. leukotrienes D4, E4 from arachidonic acid via lipoxygenase pathway
2. prostaglandins and thromboxanes from AA vis cyclo-oxygenase pathway
3. platelet activating factor
What is relationship between platelet activating factor and eosinophils?
PAF is a chemotactic factor for eosinophils.
What are Dennie's Lines?
Fine horizontal lines in the lower lids.
What are perennial allergens? (5)
1. House dust - airborne allergen is > 10 microns and settles quickly
2. Dust mites - feces of Dermatophagoides pteronyssimus, absent at higher than 5000 feet altitude
3. Animal dander - cats: sebaceous gland production, 2-4 micron particles remain airborne for long time
4. Molds - damp, decaying matter
5. Cockroach - common in low-income housing
What are Thommen's postulates about effective allergens?
Must be:
windborne
light enough to be carried long distance (<38 microns)
produced in large quantities
abundantly distributed
What are the seasons for tree pollen?
Winter and Spring; Feb to May
What are the seasons for grass pollen?
Spring, Summer and Fall; April to frost
What are the seasons for weed pollen?
Summer and Fall; July to frost
What can be seen on nasal cytology and what are the diagnostic significances? (5)
1. Goblet cells: increased in allergy and infections, acute and chronic
2. Eosinophils: increased in inhalant allergy, nonallergic eosinophilic rhinitis, aspirin sensitivity syndrome
3. Mast cells and basophils: increased in food allergy and nasal mastocytosis
4. Neutrophils: suggest bacterial infection
5. Ciliocytophoria: result of viral damage to ciliated epithelial cells: apical ciliated portion separates from basal nucleated portion resulting in "bear's foot".
What are three kinds of skin tests? (3)
1. scratch: no longer used
2. prick: used in multitests
3. intradermal
For intradermal tests: what concentration of extract? What amount of injection? What gauge needle?
Concentration of extract - 1:500 - 1:1000
Amt of injection - 0.01 to 0.05ml
#26-gauge needle
What is the technique of serial dilution endpoint titration (SDET)?
Make serial fivefold dilutions of allergenic extracts #1-#6.
Start intratermal injection of 0.01ml of #6 dilution.
Determine the dilution that initiates progressive positive wheeling.
What is the defn of "initiating progressive poisitive wheeling"?
The first dilution that yields a wheal at least 2mm larger than the preceding negative wheal and is followed by a wheal at the next stronger dilution that is at least 2mm larger still (the confirming wheal).
How long before allergy testing must antihistamines be discontinued?
36 hours
Which of the following meds can affect skin test results:
decongestants
cromolyn
bronchodilators
corticosteroids
tricyclic antidepressants
tricyclic antidepressants
What are the advantages of in vitro allergy testing? (6)
1. eliminates variability of the skin response
2. eliminates drug effects
3. can be done in one blood test
4. more specific than skin testing
5. quantitative and can be used as basis for immunotherapy
6. safe for patients on beta blockers
Describe the radioallergosorbent test (RAST).
Paper disc with antigen of interest incubated with patient's serum. Washed. Incubated with radiolabeled IgE antibody. Washed. Gamma counter to quantitate amt of radiolabeled IgE bound.
What are indications for in vitro testing? (5)
1. in patients not responding to environmental control and conservative medical mgmt
2. in apprehensive children and infants in whom atopic sensitization seems likely
3. in symptomatic patients with conditions in which in vivo skin testing is contraindicated
4. in patients unable to stop medication adversely affecting skin testing
5. in patients doing poorly on immunotherapy
What are some contraindications for in vitro testing? (4)
1. in patients with poistive histories of sensitivity in whom nonspecific therapy is effective in alleviating symptoms
2. in asymptomatic atopic patients currently on immunotherapy
3. in symptomatic patients with negative skin tests
4. in patients with total IgE levels below 10U/ml
What are the three basic treatments for inhalant allergy?
1. environmental control
2. pharacotherapy
3. immunotherapy
What are precautions taken against mold exposure?
1. Avoid living near damp places
2. Avoid dense landscaping and mulch near house
3. Preventing moisture accuulation indoors around pipes, air conditioners
What are precautions taken against dust?
1. Use synthetic or no carpets
2. Regular and frequent vacuuming
3. Regular changes of filters on ACs
4. Avoiding large amounts of stored papers, clothing in house
What is the armamentarium of drugs for pharmacotherapy of inhalant allergy?
antihistamines
decongestants
mast cell stabilizers
corticosteroids
Why are first-generation antihistamines sedating?
lipophilic and cross the blood-brain barrier
What kind of patients are systemic decongestants contraindicated for?
Hypertensive patients. They act as alpha adrenergic agonists and can raise BP. They can also decrease appetite and produce tachycardia or palpitations.
What are short-acting, intermediate-acting, and long-acting oral steroids and what are their equivalences?
Short-acting:
cortisone 25mg
hydrocortisone 25mg
Intermediate acting:
prednisone 5mg
prenisolone 5mg
methylprednisone 4mg
triamcinolone 4mg
Long-acting
dexamethasone 0.75mg
betamethasone 0.75mg
What are specific changes observed with successful immunotherapy? (3)
1. a rise in serum IgG-blocking antibodies
2. a suppression of the annual seasonal rise in IgE antibody levels, followed by a decline in the level of specific IgG over the course of immunotherapy
3. an increase in IgA and IgG antibody levels in nasal secretions
What should the starting dose of immunotherapy be based on SDET or RAST?
SDET: 0.05ml of endpoint dilution
RAST: 0.05-0.1 ml of 1:200,000 for high-sensitivity allergens
0.05-0.1 ml of 1:20,000 for low-sensitivity allergens
What are some indications for immunotherapy? (7)
- symptoms initiated by IgE antibodies
- respiratory allergy
- severe symptoms not controlled by medications and avoidance
- long seasons
- multiple seasons
- perennial symptoms
- complications
What are some contraindications for immunotherapy? (10)
- mild symptoms readily controlled by simple methods
- easily avoidable allergen
- atopic dermatitis
- very short seasons
- non-compliant pts
- food allergies
- patients taking beta blockers
- HIV
- pregnancy
- autoimmune disease
What is the definition of a local reaction during immunotherapy?
erythema larger than 3cm at injection, accompanied by induration and lasting more than 24 hours
Aside from ABC's, what are meds given for anaphylaxis? (6)
1. epinephrine 0.3mg IM or SC; repeat PRN every 10-15 minutes for a total of 1mg
2. dopamine drip for hypotension
3. heparin 10,000units SC
4. benadryl 50mg IV
5. cimetidine 300mg slow IV
6. dexamethasone 4mg IV
What are the two types of food allergies?
Cyclic (60-95%) and Noncyclic (5-40%)
What are characteristics of a cyclic food allergy? (4)
1. severity depends on frequency and dose of ingestion
2. symptoms may not be apparent for 4-48 hours
3. little if any IgE mediation
4. in part an IgG-mediated, immune-complex disease
What are characteristics of a noncyclic food allergy? (4)
1. severity is fixed
2. does not depend on dose or frequency of ingestion
3. onset of symptoms within minutes
4. IgE-mediated
How is allergic fungal sinusitis identified? (5)
1. atopic individual
2. allergic mucin
3. nasal polyposis
4. radiographic features (hypercalcified speckling of sinus opacity, thickening of sinus walls, bony erosion)
5. eosinophils on biopsy
What kind of infections typically result from an Immunoglobulin or neutrophil defect?
bacterial infections
What kind of infections typically result from a T-cell defect?
Fungal, viral, protozoal