Lecture 13- Immune dysfunction part 2 Flashcards
What are the ways to diagnose allergies?
- Symptoms
- Blood test
- Look at blood titers (IgE)
- Skin test
- Skin is exposed to allergen, look for wheal and flare lesion
What are the four ways to manage type 1 allergies?
- Avoid antigen
- Antihistamines (benadryl)
- Steroid treatments
- Antibody treatments (xolair)
How do these treatments work:
- antihistamines
- Steroid treatments
- antihistamines= block histamines from binding to host receptor
- steroid treatments= decrease symptoms, but cause immunosuppresion
How do antibody treatments work?
Bind host IgE so they cannot bind allergens
What is type 2 hypersensitivity?
IgG or IgM (antibody) binds non-soluble antigen.
- can be cell surface or extracellular tissue
How do type 2 hypersensitivity allergens cause damage?
-
Cytotoxic damage
- Complement dependent
- Complement independent
- non-cytotoxic damage
What does cytotoxic, type 2 hypersensitivity do?
What are some examples?
Cause lysis of cells.
- Blood transfusion reactions
- Hemolytic anemia
How does complement dependent, cytotoxic sensitivity work?
- (what binds to what)
- Antigens bind to host cell
- Antibodies bind to antigen
- complement porteins bind antibody
What causes host cells to lyse due to complement dependent hypersensitivities?
- Membrane attack complexes form in host cell
or
- Immune cell phagocytose host cell
How does complement independent hypersensitivity work?
(What binds to what)
- Antigens bind to host cell
- Antibodies bind to antigen
What causes the host cell to lyse due to complement independent hypersensitivity?
Natural killer cells destroy host cell
What happens during non-cytotoxic damange by type 2 hypersensitivity?
Cell does not lyse.
antibodies bind to host cell receptor.
What two things can occur due to non-cytotoxic, type 2 hypersensitivity?
- Inactivates natural host receptor
- Over-stimulate natural host receptor (overactive thyroid)
What dictates the difference in blood types?
- A, B, and O
- Rh factor (positive or negative)
- A, B, and O are carbohydrate based
- Rh factor is protein based
compatibility is based on surface antigens
What is hemolytic transfusion reaction?
When blood transfusions are not a match and cause immune cells to lyse RBC.
What is the universal acceptor blood type?
What is the universal donor blood type?
Universal acceptor= AB+
Universal donor= O-
What happens if a baby’s Rh factor is different from a mother’s in a second pregnancy?
Mother’s antibodies cross placenta and target baby’s RBC
What is type 3 hypersensitivity?
IgG or IgM antibodies bind soluble antigens and make antigen-antibody complexes
- complexes collect in tissue and cause massive inflammation
What are the two types of type 3 hypersensitivities?
- Autoimmune type (lupus)
- Non-autoimmune type (venom)
What are type 4 hypersensitivities?
- What is it also known as?
T-cell mediated (not antibody mediated)
- called delayed hypersensitivity as it can take up to 3 days for reaction
What are the 2 types of Type 4 hypersensitivity?
- Autoimmune type (multiple sclerosis)
- Non-autoimmune type (TB skin test)
- What occurs during an autoimmune type 4 hypersensitivity?
- Multiple sclerosis?
T-cell attacks localized (not systemic) specific tissue
- T-cell see normal self antigen on myelin sheath, attack and destroy cell
What are non-autoimmune type 4 hypersensitivities caused by?
Caused by haptens
- molecules too small to cause reaction but bind host cell proteins to cause reaction
What are type of hypersensitivity are transplant rejections?
Type 4, non-autoimmune
Name these types of transplants:
- Between same species
- From identical twins
- Allograft
- Isograft (least chance of rejection)
Name these types of transplants:
- From different species
- From same person
- Xenograft
- Autograft (least chance of rejection
