Quiz 2 Exam 4 Flashcards
Hypersensitivity and allergies
Hypersensitivity is an _____________ of the immune system
Over-reaction
Hypersensitivity reactions are immune reactions that are __________ against an _________.
Exaggerated
Antigen
In the classification of hypersensitivity reactions by Coombs and Gell, what is the mechanism behind type I/ immediate type hypersensitivity reactions?
Type 1 hypersensitivity reactions are IgE mediated with mast cells and basophils. This response can be rapid or delayed
In the classification of hypersensitivity reactions by Coombs and Gell, what is the mechanism behind type II/ antibody-mediated cytotoxic hypersensitivity reactions?
Type II hypersensitivity reactions are IgG and IgM mediated. This response can be from hours to days.
In the classification of hypersensitivity reactions by Coombs and Gell, what is the mechanism behind type III/ immune complex mediated hypersensitivity reactions?
Type III hypersensitivity reactions are mediated by antigens and antibodies as well as IgG and IgM. This response can take hours to weeks.
In the classification of hypersensitivity reactions by Coombs and Gell, what is the mechanism behind type IV/ T cell-mediated hypersensitivity reactions?
Type IV hypersensitivity reactions are mediated by T lymphocytes and cytokines. This reaction can last days to weeks.
The initial exposure in type I hypersensitivity reactions is due recognition of T cells and presentation of MHC molecules which stimulates plasma cells to produce __________. That will binds to basophils and mast cells and stimulate the release of granules with inflammatory mediators.
IgE
When IgE binds to mast cells and basophils in the type I hypersensitivity reaction, what mediators are released in response?
Granules and inflammatory mediators
What are some of the different mediators released by mast cells?
They release preformed mediators like histamine, heparin, proteases, and TNF. THey release lipid mediators like prostaglandins and leukotrienes, and they release cytokines and chemokines.
What are the main actions of the different mediators released by mast cells in a type I hypersensitivity reaction?
Vasodilation, increased vascular permeability, smooth muscle spasms, and leukocyte extravasation.
Cytokine releases increases vascular permeability which shifts fluid from intravascular to extravascular space. What is the result of intravascular depletion?
This results in decreased perfusion of tissues and organs. It also decreased blood pressure and reflexively increases heart rate.
Cytokine releases increases vascular permeability which shifts fluid from intravascular to extravascular space. What is the result of extravascular accumulation?
Edema
Allergy is a hypersensitivity reaction in which ________________ mediated hypersensitivity is prominent.
IgE
Thinking about drug allergies, what is the main thing to determine in patients?
Identify patients at risk for hypersensitivity reactions.
What is the physiology surrounding anaphylaxis?
Mast cells suddenly release a large amount of histamines and leukotrienes which leads to intense bronchospasms, laryngeal edema, cyanosis, hypotension, and shock.
In a very basic sense, anaphylaxis is a very severe __________ hypersensitivity reaction.
Type I
What is the clinical criteria for an anaphylaxis diagnosis?
- Acute onset of the illness with involvement of skin, mucosal tissue, or both
- ONE OF THE FOLLOWING
A. Respiratory compromise
B. Reduced BP or symptoms of end-organ dysfunction
C. Severe GI symptoms
What are the 3 goals in the management of type I hypersensitivity reactions?
- Inhibit mast cell degranulation
- Antagonize mast cell mediators
- Reduce inflammation
What is the main drug given in anaphylaxis?
Epinephrine
What are the effects of epinephrine?
VAscular smooth muscle cell contraction, increases cardiac output, inhibits bronchial smooth muscle cell contraction
How is anaphylaxis managed long-term?
Identify the triggers and create a written action plan. Educate the patient and makes sure they have epi pens. All about preventing the recurrence to prevent death.
What is the pathophysiology behind a type II hypersensitivity reaction?
Type II hypersensitivity reactions are antibody-mediated cytotoxic reactions. It is when IgG and IgM antibodies produced by immune responses bind to antigens on the individuals own cell surface. When these large immune complexes are formed, they can initiate the complement cascade.
Cellular destruction in type II hypersensitivity reactions occur via what 3 mechanisms?
Phagocytosis
Complement-dependent cytotoxicity (CDC)
Antibody-dependent cellular toxicity (ADCC)
What is the pathophysiology behind type III immune complex mediated hypersensitivity reactions?
There is an accumulation of antigen-antibody complexes (immune complexes) that are NOT cleared by innate immune cells. The immune complexes lead to complement activation and inflammatory responses mediated by neutrophils.
What is the pathophysiology behind type IV cell-mediated hypersensitivity?
This is triggered by autoimmune and exaggerated or persistent responses to environmental antigens.
T or F: Not all drug hypersensitivity reactions
can be classified with the system described by
Coombs and Gell.
True
T or F: All infusion-related reactions are allergic reactions.
False. They are often hypersensitivity related reactions but not always a true allergy.
What is an infusion-related reaction (IRR)?
Adverse reactions to an infusion of pharmacological or biological substances that can occur at anytime that patient is receiving it.
What is cytokine release syndrome?
A condition that may occur after treatment with some immunotherapies that stimulate an immune response via the release of cytokines. This results due to T cell activation.
What are the symptoms of cytokine release syndrome?
Fever, nausea, headache, decrease in BP, increased HR, and shortness of breath
What are immunotherapy-related toxicities (now called immune checkpoint inhibitor-related toxicities)?
This is the infiltration of normal tissue by activated T cells responsbile for autoimmunity due to inhibition of inhibitory receptors on T cells. Toxicities are related to autoimmunity and can happen in virtually an organ.
What are immune checkpoint inhibitor drugs?
In cancer, the inhibitory receptors on T cells can be upregulated. These drugs block their inhibitory receptors ramping up the immune system.
What mediates the immediate type I hypersensitivity reaction?
IgE
T or F: Cytokine release syndrome is an example of a type II hypersensitivity.
False
T or F: The diagnosis for anaphylaxis is clinical.
True
What are the strategies for the management of a hypersensitivity reaction?
Collect, Assess, Develop a plan for acute and delayed reactions and pick what drug therapy to use. Implement plan and communicate plan. Evaluate the impact of the plan and modify as needed.
Monoclonal antibodies are proteins with inherent ________________.
Immunogenicity.
Human MA are more immunogenic compared to chimeric then to mouse.
Monoclonal antibody hypersensitivity reactions may be due to ____________ __________.
Cytokine release (cytokine release syndrome)
How can symptoms of infusion-related reactions be prevented?
- Premedication of antihistamines, corticosteroids, and acetaminophen
- Titration of infusion and splitting of the infusion over several days
If someone begins have a reaction to an infused drug, what is the first thing to do?
Stop the drug
If someone has an immediate infusion toxicity, what are the steps to manage it?
- Stop the drug
- Assess clinical status of patient
- Supportive care
- Give meds based on clinical symptoms
Platinum agents like cisplatin, carboplatin, and oxaliplatin have a higher than usual risk of hypersensitivity reactions. By what infusion cycle are most reactions to these drug seen?
5 cycles
What is drug desensitization?
This is induction of a temporary state of drug tolerance in a patient with hypersensitivity to the drug. In order to maintain the temporary state of tolerance, the patient must continue to take the medication regularly. This is only acceptable if there are no known alternative drugs.
What are the medications given prior for desensitization?
Antihistamines and corticosteroids
T or F: Those who have penicillin allergies are likely not allergic to antibiotics with similar chemical properties to penicillin.
False. They will likely have an allergic reaction to those drugs as well.
What are some strategies to decrease cytokine release syndrome with agents known to cause this adverse reaction?
Premedication
Step-up dosing
Monitor in the hospital
Autoimmunity is a hypersensitivity response where the antigen is a _______ antigen.
self
What is immunological tolerance?
This is an unresponsiveness of the adaptive immune system to self antigens. Also known as self tolerance. It is the ability of the immune system to prevent itself from targeting self.
What are the 3 mechanisms of immune tolerance?
- Non-reaction of self-reactive lymphocytes induced by self-antigens
- Inactivation of self-reactive lymphocytes
- Death of self-reactive lymphocytes
_________________ play an important role in
maintaining immune tolerance.
Regulatory T cells
What is the role of regulatory T cells?
T reg cells may suppress immune response of other cells. They are like a self-check built into the immune system to prevent excessive reactions. They should prevent autoimmunity
T or F: T regulatory cells prevent autoimmunity.
True
Autoimmune diseases are a diverse
group of conditions characterized by
aberrant ______ and ______ reactivity to normal constitutions of the host.
B cell
T cell
Autoinflammatory diseases are a dysregulation of the _________ immune system that occurs in predisposed hosts, sometimes with secondary activation of adaptive immunity, resulting in inappropriate inflammation. There are no self-reactive ____________ here.
Innate
Lymphocytes
T or F: Inflammation against self tissues is always dependent on abnormal T and B cell responses.
False.
T or F: Not many autoimmune diseases are heterogenous and multifactorial.
False.
How do autoimmune diseases develop?
There are always a small number of self-reactive T and B cells that can leak out into the periphery. They will remain harmless unless there is a genetic predisposition or environmental trigger to break tolerance.
T or F: The inherited risk for most autoimmune disease is often attributable to one gene loci.
False. It is attributed to multiple gene loci.