NR 507-Advanced Pathophysiology
Hypersensitivity: Type 1 - answer Allergic reaction
•Mediated by IgE
•Inflammation due to mast cell degranulation
•Local symptoms: itching, rash
•Systemic symptoms: wheezing
•Most dangerous form is an anaphylactic reaction-systemic response-hypotension,
severe bronchoconstriction
•Main treatment: epinephrine reverses the effects
Hypersensitivity: Type 2 - answer Cytotoxic reaction; tissue specific (e.g. 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.
Difference Between Type 2 and Type 3 - answer•Type 2 is organ specific
•The antibody binds to the antigen on the cell surface
•Type 3 is not organ specific
•the antibody binds to 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 - answer•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
Scope of Damage of SLE-Type 3-autoimmune response - answer•Facial rash confined
to the cheeks (malar rash)
•Discoid rash (raised patches, scaling)
•Photosensitivity (development of skin rash developed as a result of exposure to
sunlight)
•Oral or nasopharyngeal ulcers
•Hematologic disorders (hemolytic anemia, leukopenia, lymphopenia, or
thrombocytopenia)
, •Immunologic disorders (antibodies against double-stranded DNA [dsDNA] or Smith
[Sm] antigen, false-positive serologic test for syphilis, or antiphospholipid antibodies
[anticardiolipin antibody or lupus anticoagulant])
•Non-erosive arthritis of at least two peripheral joints
•Serositis (pleurisy, pericarditis)
•Renal disorder (persistent proteinuria of >0.5 g/day or >3 g/day on dipstick or cellular
casts)
•Neurologic disorders (seizures or psychosis in the absence of known causes)
•Presence of antinuclear antibody (ANA)
A Word About Autoimmunity - answer•Autoimmune diseases 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.
•Ch. 9- p. 267
Alloimmunity - answer•General term used to describe when an individual's immune
system reacts against antigens on the tissues of other members of the same species
Alloimmunity Examples - answer-Neonatal disease where the maternal immune system
becomes sensitized against antigens expressed by the fetus
-Transplant rejection
-Transfusion reaction
Hypersensitivity: Type 4 - answer•Delayed response
•Does not involve antigen/antibody complexes like Types I, II and III
•Is T-cell mediated
Relationship between Type II and Type IV Hypersensitivity Reactions - answer•Organ
rejection involves cytotoxicity (Type II)
•Also, T-cells play a major role in organ rejection (Type IV-completely T-cell mediated)
• Antigens from target cells stimulate T-cells to differentiate into cytotoxic (Type II) T-
cells
•These T-cells have direct cytotoxic activity along with help T-cells involved in delayed
hypersensitivity (type IV).
Treatment of Type IV Rash - answer•A non-severe case of contact dermatitis would be
treated with a topical corticosteroid
•Why wouldn't we use epinephrine or antihistamines?
•Epinephrine is for emergent Type 1 anaphylactic reactions
•Antihistamines act on the H1 receptors
•Type IV doesn't involve mast cells and H1 receptors
•Antibiotics aren't appropriate since this is not an infection
Hypersensitivity: Type 1 - answer Allergic reaction
•Mediated by IgE
•Inflammation due to mast cell degranulation
•Local symptoms: itching, rash
•Systemic symptoms: wheezing
•Most dangerous form is an anaphylactic reaction-systemic response-hypotension,
severe bronchoconstriction
•Main treatment: epinephrine reverses the effects
Hypersensitivity: Type 2 - answer Cytotoxic reaction; tissue specific (e.g. 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.
Difference Between Type 2 and Type 3 - answer•Type 2 is organ specific
•The antibody binds to the antigen on the cell surface
•Type 3 is not organ specific
•the antibody binds to 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 - answer•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
Scope of Damage of SLE-Type 3-autoimmune response - answer•Facial rash confined
to the cheeks (malar rash)
•Discoid rash (raised patches, scaling)
•Photosensitivity (development of skin rash developed as a result of exposure to
sunlight)
•Oral or nasopharyngeal ulcers
•Hematologic disorders (hemolytic anemia, leukopenia, lymphopenia, or
thrombocytopenia)
, •Immunologic disorders (antibodies against double-stranded DNA [dsDNA] or Smith
[Sm] antigen, false-positive serologic test for syphilis, or antiphospholipid antibodies
[anticardiolipin antibody or lupus anticoagulant])
•Non-erosive arthritis of at least two peripheral joints
•Serositis (pleurisy, pericarditis)
•Renal disorder (persistent proteinuria of >0.5 g/day or >3 g/day on dipstick or cellular
casts)
•Neurologic disorders (seizures or psychosis in the absence of known causes)
•Presence of antinuclear antibody (ANA)
A Word About Autoimmunity - answer•Autoimmune diseases 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.
•Ch. 9- p. 267
Alloimmunity - answer•General term used to describe when an individual's immune
system reacts against antigens on the tissues of other members of the same species
Alloimmunity Examples - answer-Neonatal disease where the maternal immune system
becomes sensitized against antigens expressed by the fetus
-Transplant rejection
-Transfusion reaction
Hypersensitivity: Type 4 - answer•Delayed response
•Does not involve antigen/antibody complexes like Types I, II and III
•Is T-cell mediated
Relationship between Type II and Type IV Hypersensitivity Reactions - answer•Organ
rejection involves cytotoxicity (Type II)
•Also, T-cells play a major role in organ rejection (Type IV-completely T-cell mediated)
• Antigens from target cells stimulate T-cells to differentiate into cytotoxic (Type II) T-
cells
•These T-cells have direct cytotoxic activity along with help T-cells involved in delayed
hypersensitivity (type IV).
Treatment of Type IV Rash - answer•A non-severe case of contact dermatitis would be
treated with a topical corticosteroid
•Why wouldn't we use epinephrine or antihistamines?
•Epinephrine is for emergent Type 1 anaphylactic reactions
•Antihistamines act on the H1 receptors
•Type IV doesn't involve mast cells and H1 receptors
•Antibiotics aren't appropriate since this is not an infection
