NR 507 Midterm Exam B
Hypersensitivity Type 1 - answer Type 1: Allergic Reaction
Mediated by IgE
Inflammation due to mast cell degranulation
local symptoms: Itching, rash
Systemic symptoms: wheezing
Most dangerous form: anaphylactic reaction-systemic hypotension, severe
bronchoconstriction
Main treatment: epinephrine
Hypersensitivity Type 2 - answer Type 2: Cytotoxic, tissue-specific (thyroid tissue)
Primary effector cells: Macrophages
Can cause tissue damage or alter the function
Example: Graves disease (alters thyroid function but does not alter tissue)
Example: Incompatible blood type (cell/tissue damage)- Severe transfusion reaction
occurs and the transfused erythrocytes are destroyed by agglutination or complement-
mediated lysis
Hypersensitivity Type 2 and 3 difference - answerType 2: Organ-specific, the antibody
binds to an antigen on the cell surface
Type 3: Not organ-specific, the antibody binds to soluble antigen outside the cell surface
that was released into the blood or body fluids and then the complex is distributed into
tissues
Hypersensitivity Type 3 Examples - answerRheumatoid 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
Scope of damage of SLE- Type 3 Hypersensitivity- autoimmune response - answerrash
confined to cheeks (malar rash)
discoid rash (raised, patchy, scaly)
photosensitivity
oral/nasopharyngeal ulcers
hematologic disorders
immunologic disorders
non-erosive arthritis
serositis
renal disorder (proteinuria)
neurologic disorders (seizures)
antinuclear antibody (ANA)
, Autoimmunity - answerFamilial
Affected family members may not have same dz, but several members may have other
disorders characterized by a variety of hypersensitivity reactions that include
autoimmune or allergic reactions
Associations with particular autoimmune diseases have been identified for a variety of
major histocompatibility complex (MHC) alleles or non-MHC genes
Alloimmunity - answerWhen an individual's immune system reacts against antigens on
the tissues of other members of the same species
Examples: neonatal dz where the maternal immune system becomes sensitized against
antigens expressed by the fetus, transplant rejection, transfusion reaction
Hypersensitivity Type 4 - answerdelayed response
does not involve antigen/antibody complexes like Type 1
T-cell mediated
Relationship between Type 2 and type 4 Hypersensisivity - answerOrgan rejection
involves cytotoxicity (type 2)
T-cells play a major role in organ rejection (Type 4- T-cell mediated)
Antigens from target cells stimulate T-cells to differentiate into cytotoxic (type 2) T-cells
These T-cells have direct cytotoxic activity along with help T-cells involved in delayed
hypersensitivity (type 4)
Difference between Type 1 and Type 4 Rash - answerType 1: Immediate
hypersensitivity reactions, termed atopic dermatitis are characterized by widely
distributed lesions
Type 4: contact dermatitis (delayed hypersensitivity) consists of lesions only at the site
of contact with the allergen
Key determinant is timing of rash:
Type 1- immediate
Type 4: delayed-several days following contact (poison ivy)
Treatment of Type 4 Hypersensitivity Rash - answerA non-severe case of contact
dermatitis would be treated with a topical steroid
Why would we not use epinephrine or antihistamine?
Epi is for emergent type 1 anaphylactic reactions
Antihistamines act on the H1 receptors
Type 4 doesn't involve mast cell and H1 receptors
Abx are not appropriate due to no infection
Primary Immunodeficiency - answerResult of single gene defects
Something is lacking with the immune system itself
Example: B-lymphocyte deficiency- one of the most severe forms of a primary
immunodeficiency
Hypersensitivity Type 1 - answer Type 1: Allergic Reaction
Mediated by IgE
Inflammation due to mast cell degranulation
local symptoms: Itching, rash
Systemic symptoms: wheezing
Most dangerous form: anaphylactic reaction-systemic hypotension, severe
bronchoconstriction
Main treatment: epinephrine
Hypersensitivity Type 2 - answer Type 2: Cytotoxic, tissue-specific (thyroid tissue)
Primary effector cells: Macrophages
Can cause tissue damage or alter the function
Example: Graves disease (alters thyroid function but does not alter tissue)
Example: Incompatible blood type (cell/tissue damage)- Severe transfusion reaction
occurs and the transfused erythrocytes are destroyed by agglutination or complement-
mediated lysis
Hypersensitivity Type 2 and 3 difference - answerType 2: Organ-specific, the antibody
binds to an antigen on the cell surface
Type 3: Not organ-specific, the antibody binds to soluble antigen outside the cell surface
that was released into the blood or body fluids and then the complex is distributed into
tissues
Hypersensitivity Type 3 Examples - answerRheumatoid 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
Scope of damage of SLE- Type 3 Hypersensitivity- autoimmune response - answerrash
confined to cheeks (malar rash)
discoid rash (raised, patchy, scaly)
photosensitivity
oral/nasopharyngeal ulcers
hematologic disorders
immunologic disorders
non-erosive arthritis
serositis
renal disorder (proteinuria)
neurologic disorders (seizures)
antinuclear antibody (ANA)
, Autoimmunity - answerFamilial
Affected family members may not have same dz, but several members may have other
disorders characterized by a variety of hypersensitivity reactions that include
autoimmune or allergic reactions
Associations with particular autoimmune diseases have been identified for a variety of
major histocompatibility complex (MHC) alleles or non-MHC genes
Alloimmunity - answerWhen an individual's immune system reacts against antigens on
the tissues of other members of the same species
Examples: neonatal dz where the maternal immune system becomes sensitized against
antigens expressed by the fetus, transplant rejection, transfusion reaction
Hypersensitivity Type 4 - answerdelayed response
does not involve antigen/antibody complexes like Type 1
T-cell mediated
Relationship between Type 2 and type 4 Hypersensisivity - answerOrgan rejection
involves cytotoxicity (type 2)
T-cells play a major role in organ rejection (Type 4- T-cell mediated)
Antigens from target cells stimulate T-cells to differentiate into cytotoxic (type 2) T-cells
These T-cells have direct cytotoxic activity along with help T-cells involved in delayed
hypersensitivity (type 4)
Difference between Type 1 and Type 4 Rash - answerType 1: Immediate
hypersensitivity reactions, termed atopic dermatitis are characterized by widely
distributed lesions
Type 4: contact dermatitis (delayed hypersensitivity) consists of lesions only at the site
of contact with the allergen
Key determinant is timing of rash:
Type 1- immediate
Type 4: delayed-several days following contact (poison ivy)
Treatment of Type 4 Hypersensitivity Rash - answerA non-severe case of contact
dermatitis would be treated with a topical steroid
Why would we not use epinephrine or antihistamine?
Epi is for emergent type 1 anaphylactic reactions
Antihistamines act on the H1 receptors
Type 4 doesn't involve mast cell and H1 receptors
Abx are not appropriate due to no infection
Primary Immunodeficiency - answerResult of single gene defects
Something is lacking with the immune system itself
Example: B-lymphocyte deficiency- one of the most severe forms of a primary
immunodeficiency
