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BIOS 255
April 7, 2024
Week 5 Case Study: Hypersensitivity Reactions
1. Hypersensitivity reactions are extreme immune responses against an antigen (Saladin, 2019).
2. Hypersensitivity reactions come in four types (Type I – IV). Type I refers to IgE-mediated and
systemic reactions, which include conditions like food or insect sting allergies and asthma. Type II
is an antibody-mediated response that causes agglutination in incompatible blood transfusions.
Type III is immune complex-mediated, which includes autoimmune diseases like rheumatoid
arthritis or systemic lupus. Lastly, Type IV is due to delayed or T-cell-mediated hypersensitivity,
which is seen in poison ivy, Type I diabetes, or multiple sclerosis (Saladin, 2019).
3. This hypersensitivity reaction from the bee sting is considered Type I. Type I is IgE-mediated and
stimulates basophils and mast cells to secrete histamine of inflammation and other mediators of
inflammation and allergies (Saladin, 2019).
4. This reaction is an antibody-mediated response, specifically antibody IgE (Saladin, 2019).
5. Epinephrine is both a hormone and neurotransmitter. As a hormone, epinephrine plays a role in
the sympathetic nervous system, which is also considered the body’s “fight-or-flight” response.
When someone is experiencing anaphylaxis shock, epinephrine helps by relaxing airway muscles,
increasing heart muscle contraction and heart rate, and overall reducing the severity of IgE-
mediated reactions via receptors on mast cells (Dalal & Grujic, 2023).
BIOS 255
April 7, 2024
Week 5 Case Study: Hypersensitivity Reactions
1. Hypersensitivity reactions are extreme immune responses against an antigen (Saladin, 2019).
2. Hypersensitivity reactions come in four types (Type I – IV). Type I refers to IgE-mediated and
systemic reactions, which include conditions like food or insect sting allergies and asthma. Type II
is an antibody-mediated response that causes agglutination in incompatible blood transfusions.
Type III is immune complex-mediated, which includes autoimmune diseases like rheumatoid
arthritis or systemic lupus. Lastly, Type IV is due to delayed or T-cell-mediated hypersensitivity,
which is seen in poison ivy, Type I diabetes, or multiple sclerosis (Saladin, 2019).
3. This hypersensitivity reaction from the bee sting is considered Type I. Type I is IgE-mediated and
stimulates basophils and mast cells to secrete histamine of inflammation and other mediators of
inflammation and allergies (Saladin, 2019).
4. This reaction is an antibody-mediated response, specifically antibody IgE (Saladin, 2019).
5. Epinephrine is both a hormone and neurotransmitter. As a hormone, epinephrine plays a role in
the sympathetic nervous system, which is also considered the body’s “fight-or-flight” response.
When someone is experiencing anaphylaxis shock, epinephrine helps by relaxing airway muscles,
increasing heart muscle contraction and heart rate, and overall reducing the severity of IgE-
mediated reactions via receptors on mast cells (Dalal & Grujic, 2023).
