Ch 19: Disorders Associated with the Immune System Flashcards
What is a hypersensitivity reaction?
- Overreaction of the immune system to antigens, leading to damage
- Requires sensitization (a prior exposure)
- Allergies
How long after exposure to an antigen does each of the four types of hypersensitivity reactions occur?
- Anaphylactic → <30 mins
- Cytotoxic → 5-12 hours
- Immune complex → 3-8 hours
- Delayed cell-mediated/hypersensitivity → 24-48 hours
How do anaphylactic reactions begin?
- IgE to allergen trigger mast cells and basophils
- Mast cells and basophils release histamine, leukotrienes, and prostaglandin
Where are mast cells located?
Connective tissue
Mast cells play a role in ____ (5)
- Wound healing
- Angiogenesis
- Immune tolerance
- Defense against pathogens
- Allergy and anaphylaxis
What are some examples of localized anaphylaxis? (3)
- Hives
- Hay fever
- Asthma
97% of food allergies are due to what 8 foods?
- Eggs
- Peanuts
- Tree nuts
- Milk
- Soy
- Fish
- Wheat
- Peas
Systemic anaphylaxis results from _____
Injection or ingestion
Cytotoxic reactions are caused by _______ and lead to _____
- Complement activation
- Cell lysis
Blood transfusion reactions are which type of hypersensitivity reaction?
Type II (cytotoxic)
How do antibodies against A and B blood group antigens arise?
- Presumed to arise in response to microorganisms in ingested food
- Have antigenic determinants very similar to blood groups (sugars)
Which blood type is more susceptible to cholera?
Type O
Populations with low type ____ blood type(s) may be more susceptible in smallpox epidemics
Type A and AB
Which blood type is less severely affected by malaria?
Type O
In hemolytic disease of a newborn (HDNB), what are the blood types of mother vs fetus?
- Mother Rh-
- Fetus Rh+
In HDNB, what drug is given to pregnant women to bind fetal RBCs and keep them from mounting an immune response to Rh
RhoGAM (antibodies to Rh antigen)
In drug-induced cytotoxic reactions, upon second exposure the drug binds to the surfaces of platelets, granulocytes, and RBCs. What do they each causing ____(3).
- Platelets → thrombocytopenic purpura
- Granulocytes → agranulocytosis
- RBCs → hemolytic anemia
Explain type III hypersensitivity reactions.
- IgG antibodies and antigens for immune complexes
- Lodge at basement membrane
- Attracts neutrophils which release enzymes that cause damage
Type IV hypersensitivities are delayed due to?
T-cell and macrophage infiltration takes time
What are some examples of type IV hypersensitivity reactions?
- Allergic contact dermatitis
- Hives
True or false. Having autoantibodies guarantees autoimmune disease.
False. Only certain disease of the immune system generate significant amounts of autoantibodies
Cytotoxic autoimmune diseases are caused by?
- Antibodies reacting with cell-surface antigens
- (Ex: Graves’ disease & myasthenia gravis)
_____ is caused by autoantibodies that stimulate thyroid gland receptors, thus increasing levels of thyroid hormone.
Graves disease
____ is caused by autoantibodies that bind acetylcholine receptors, making muscles effectively weaker.
Myasthenia gravis
____ is caused by immune complex deposition in the kidney.
Systemic lupus erythematosus
_____ is caused by immune complex deposition in the joints.
Rheumatoid arthritis
_______ is caused by a T-cell mediated attack on myelin in the CNS
Multiple sclerosis
Organ transplant requires matching ______
HLA types
Where are the “privileged sites” for transplants? (4)
- Cornea - no circulation
- Brain - blood brain barrier
- Heart valve - xenografts are successful
- Fetus - in part, due to placent’s HLA molecules
What does “pluripotent” mean?
Describes a cell that can differentiate into any cell type
What is an isograft?
Use of an identical twin’s tissue
What is an allograft?
Use of tissue from another person
What is a xenograft?
Use of nonhuman tissue
_______ can result from transplanted bone marrow that contains immunocompetent cells.
Graft-versus-host disease
Immunosuppression involves suppression of what cytokine? Why?
- IL-2
- Major growth factor for T-cells
_____ is a drug that is used to down-regulate the expression of IL-2 in T-cells
Cyclosporine
______ cells lyse abnormal cells, such as cancer cells.
CTL (activated TC)
What is Coley’s toxin?
- Endotoxin of gram-negative bacteria that cause typhoid fever
- Stimulates TNF-production of macrophages
- Potential immunotherapy for cancer
______ is caused by a deletion on chromosome location 22q11.2, which results in patients missing a thymus gland
DiGeorge syndrome
Nude mice lack ______, a transcription factor needed for development of many organs, including the thymus and hair follicles
FOXN1
HIV primarily infects ______ cells
CD4+ T-cells
Which surface protein on HIV allows it to enter a cell?
gp120
Explain the 3 phases of HIV infection.
- Asymptomatic or chronic lymphadenopathy (~3 years)
- Symptomatic; early indication of immune failure
- AIDS indicator conditions; extremely low T-cells
What is HAART therapy?
- Highly active antiretroviral therapy
- Combinations of nucleoside reverse transcriptase inhibitor plus
- Non-nucleoside reverse transcriptase inhibitor OR
- Protease inhibitor
