NR507 Advanced Pathophysiology MidTerm
Hypersensitivity: Type 1 - ANS-Type 1: Allergic reaction, Mediated by IgE, Inflammation due to
mast cell degranulation
Local symptoms:
-itching
-rash
Systemic symptoms:
-wheezing
Most dangerous = anaphylactic reaction
systemic response of hypotension, severe bronchoconstriction
Main treatment: epinephrine reverses the effects
Hypersensitivity: Type 2 - ANS-Type 2: Cytotoxic reaction; tissue specific (ex: thyroid tissue)
Macrophages are the primary effectors cells involved
Can cause tissue damage or alter function
Grave's disease (hyperthyroidism) - example of altering thyroid function, but does not destroy
thyroid tissue
Incompatible blood type- example of cell/tissue damage that occurs; severe transfusion reaction
occurs and the transfused erythrocytes are destroyed by agglutination or complement-mediated
lysis.
Type 1 Hypersensitivity VS. Type 2 Hypersensitivity - ANS-Type 1 Hypersensitivity
Organ Specific
Antibody binds to the antigen on the cell surface
Type 2 Hypersensitivity
Not Organ Specific
Antibody binds to the soluble antigen outside the cell surface that was released into the blood or
body fluids, and the complex is then deposited in the tissues
Hypersensitivity: Type 3 - Examples - ANS-Rheumatoid arthritis: Antigen/antibodies are
deposited in the joints
Systemic Lupus Erythematosus (SLE)- very closely related to autoimmunity- antigen/antibodies
deposit in organs that cause tissue damage
, Hypersensitivity: Type 4 - ANS-Delayed response
Does not involve antigen/antibody complexes like Types 1, 2 and 3
Is T-cell mediated
Differentiating Between the Rash of a Type 1 vs. Type 4 Reaction: - ANS-Type 1: Immediate
hypersensitivity reactions, termed atopic dermatitis, are usually characterized by widely
distributed lesions
Type 4: Contact dermatitis (delayed hypersensitivity) consists of lesions only at the site of
contact with the allergen
The key determinant is the timing of the rash:
-Type 1 = Immediate
-Type 4 = Delayed: Several days following contact, ex would be poison ivy
Treatment of Type 4 Rash - ANS-A non-severe case of contact dermatitis would be treated with
topical corticosteroid.
Why not epinephrine or antihistamines?
-Epinephrine is for emergent Type 1 anaphylactic reactions. Antihistamines act on the H1
receptors. Type 4 does not involve mast cells and H1 receptors.
Antibiotics not appropriate since not an infection
Autoimmunity - ANS-Autoimmune disease can be familial, Affected family members may not all
develop the same disease, but several members may have different disorders characterized by
a variety of hypersensitivity reactions, These include autoimmune and allergic reactions
Associations with particular autoimmune diseases have been identified for a variety of major
histocompatibility complex (MHC) alleles or non-MHC genes
Alloimmunity - ANS-General term used to describe when an individual's immune system reacts
against antigens on the tissues of other members of the same species.
Examples: Neonatal disease where the maternal immune system becomes sensitized against
antigens expressed by the fetus, Transplant rejection, Transfusion reaction
Primary Immunodeficiency - ANS-Most primary immune deficiencies are result of single gene
defects
Something is lacking with the immune system itself.
Hypersensitivity: Type 1 - ANS-Type 1: Allergic reaction, Mediated by IgE, Inflammation due to
mast cell degranulation
Local symptoms:
-itching
-rash
Systemic symptoms:
-wheezing
Most dangerous = anaphylactic reaction
systemic response of hypotension, severe bronchoconstriction
Main treatment: epinephrine reverses the effects
Hypersensitivity: Type 2 - ANS-Type 2: Cytotoxic reaction; tissue specific (ex: thyroid tissue)
Macrophages are the primary effectors cells involved
Can cause tissue damage or alter function
Grave's disease (hyperthyroidism) - example of altering thyroid function, but does not destroy
thyroid tissue
Incompatible blood type- example of cell/tissue damage that occurs; severe transfusion reaction
occurs and the transfused erythrocytes are destroyed by agglutination or complement-mediated
lysis.
Type 1 Hypersensitivity VS. Type 2 Hypersensitivity - ANS-Type 1 Hypersensitivity
Organ Specific
Antibody binds to the antigen on the cell surface
Type 2 Hypersensitivity
Not Organ Specific
Antibody binds to the soluble antigen outside the cell surface that was released into the blood or
body fluids, and the complex is then deposited in the tissues
Hypersensitivity: Type 3 - Examples - ANS-Rheumatoid arthritis: Antigen/antibodies are
deposited in the joints
Systemic Lupus Erythematosus (SLE)- very closely related to autoimmunity- antigen/antibodies
deposit in organs that cause tissue damage
, Hypersensitivity: Type 4 - ANS-Delayed response
Does not involve antigen/antibody complexes like Types 1, 2 and 3
Is T-cell mediated
Differentiating Between the Rash of a Type 1 vs. Type 4 Reaction: - ANS-Type 1: Immediate
hypersensitivity reactions, termed atopic dermatitis, are usually characterized by widely
distributed lesions
Type 4: Contact dermatitis (delayed hypersensitivity) consists of lesions only at the site of
contact with the allergen
The key determinant is the timing of the rash:
-Type 1 = Immediate
-Type 4 = Delayed: Several days following contact, ex would be poison ivy
Treatment of Type 4 Rash - ANS-A non-severe case of contact dermatitis would be treated with
topical corticosteroid.
Why not epinephrine or antihistamines?
-Epinephrine is for emergent Type 1 anaphylactic reactions. Antihistamines act on the H1
receptors. Type 4 does not involve mast cells and H1 receptors.
Antibiotics not appropriate since not an infection
Autoimmunity - ANS-Autoimmune disease can be familial, Affected family members may not all
develop the same disease, but several members may have different disorders characterized by
a variety of hypersensitivity reactions, These include autoimmune and allergic reactions
Associations with particular autoimmune diseases have been identified for a variety of major
histocompatibility complex (MHC) alleles or non-MHC genes
Alloimmunity - ANS-General term used to describe when an individual's immune system reacts
against antigens on the tissues of other members of the same species.
Examples: Neonatal disease where the maternal immune system becomes sensitized against
antigens expressed by the fetus, Transplant rejection, Transfusion reaction
Primary Immunodeficiency - ANS-Most primary immune deficiencies are result of single gene
defects
Something is lacking with the immune system itself.
