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
