Four types of hypersensitivity reactions
Type one?
Type two?
Type three?
Type four? correct answer: Type 1; IgE or complement mediated anaphylactic, atopic reactions (early & late phase)
Type 2; Autoantibody, C3b opsonization of normal cells activate cytotoxic cells.
MAC
Type 3; Immune...
2022 Board Review Allergy & Immunology QUESTIONS
WITH COMPLETE SOLUTIONS
Four types of hypersensitivity reactions
Type one?
Type two?
Type three?
Type four? correct answer: Type 1; IgE or complement mediated anaphylactic, atopic reactions (early & late phase)
Type 2; Autoantibody, C3b opsonization of normal cells activate cytotoxic cells. MAC
Type 3; Immune-complex mediated; Vasculitis
Type 4; T cell mediated "delayed type"
Associations
1. Tryptase
2. Klebsiella ozaenae
3. 22q12.2 deletion
4. CATCH22 correct answer: 1. Type 1 anaphylaxis, immediate hypersensitivity reaction. Released from mast cells.
2. Atrophic rhinitis
3. DiGeorges syndrome 4. DiGeorges syndrome
Associations
1. Darier sign
2. Urticaria pigmentosa
3. Tryptase
4. 22q11.2 deletion
5. Reactivation human herpes 6 virus
6. CATCH-22
7. Lectin correct answer: 1. Cutaneous mastocytosis
2. Cutaneous mastocytosis
3. Released by mast cells. Useful in diagnosis of mastocytosis and anaphylaxis
4. DiGeorge syndrome
5. DRESS; drug rash eosinophilia with systemic signs
6. DiGeorge syndrome
7. One of the 3 complement activation pathways; lectin binds mannose on the surface of pathogens
Corrected ESR and CRP for age and sex ESR; age/2 for men and (age +10)/2 for women
CRP; age/50 for men and age/50 + 0.63 for women correct answer: In a patient with IgA deficiency which test will you use as a pregnancy test; urine or serum? correct answer: Urine pregnancy test
The serum test can yield a false positive result.
IgA is a "dimmer" with a secretory component
Which complement deficiency is associated with SLE? correct answer: C2
Hypersensitivity reactions
What lab test can you order to confirm an anaphylactic reaction; Type 1, immediate hypersensitivity? correct answer: Tryptase; released from mast cells, unlike histamine which is broken down rapidly, is stable for a few hours after mast cell degranulation.
RBCs present immune complexes to the spleen and liver for removal.
The complement systems C3b attaches to the Fc portion of the antibody located on RBC membrane surface (opsonization), making the immune complex more soluble-less likely to precipitate and cause cell damage. True or false? correct answer: True.
Associations
1. Five minute skin "ice cube challenge"
2. Tryptase
3. Human herpes 6 reactivation
4. Nikolsky's sign
5. He/vein
6. Klebsiella ozaenae correct answer: 1. Acquired cold urticaria
2. Diagnosis of anaphylaxis, mastocytosis; mast cell degranulation
3. DRESS syndrome; Drug reaction with eosinophilia and systemic symptoms. Type IVb delayed T cell mediated
4. Stevens Johnson syndrome/toxic epidermal necrolysis; Sloughing of epidermis with slight tangential pressure
5. A protein on the surface of latex products responsible for the allergic reaction
6. Atrophic rhinitis
Associations
1. Ecall/antide
2. Ica/tibant
3. PKB PACT ("peekaboo pact")
4. MAC; membrane attack complex, C3,C4,C5 anaphlaxatoxins correct answer: 1. Acute treatment of hereditary angioedema 2. Acute treatment of hereditary angioedema
3. Fruits and vegetables cross react with latex Papaya, Kiwi, bananas
Potato, avocado, chestnut, tomato
4. Type 2 hypersensitivity reaction
Associations
1. Atypical/"spindle-shaped" cells in bone marrow or other extracutaneous tissue
2. c-kit gene point mutation
3. Expression of surface markers CD2, CD25, or both
4. Six food elmination diet
5. Ecall/antide
6. Icati/bant correct answer: 1. Mastocytosis
2. Mastocytosis
3. Mastocytosis
4. Eosinophilic esophagitis
5. Treat Hereditary Angioedema
6. Treat Hereditary Angioedema
Associations
1. Transcription factor FOXP3 correct answer: 1. Controls development and function of Treg (T regulatory) cells p2-18
Hypersensitivity reactions
Type 1; Immediate hypersensitivity
Mechanism of action
Early phase; mast cell degranulation- IgE or complement (C3,C4,C5 anaphylactoids) mediated
Late phase; mast cell degranulation of cytokines; recruit eosinophils and basophils; example- asthmatic bronchspasm correct answer: IgE mediated; is antigen specific, occurring only in response to previous exposure to same antigen.
Fc portion of IgE binds to nonspecific receptors on mast cells. Two IgE antibodies attached by their specific sites to an antigen interlinking causing degranulation of mast cells releasing histamine, leukotrienes, prostaglandins, cytokines, chemotactic factors (tryptase)
Histamine; short half-life.
Tryptase; long half life (used for diagnosis)
IgE correct answer: Hypersensitivity reactions
Type 1; Immediate hypersensitivity
Mechanism of action?
May be initiated by IgE or C3, C4, C5 (anaphylactoids) Refer to image insert correct answer: Which is the only antibody capable of crossing the placenta? correct answer: IgG
In which type of immunoglobulin deficiency is IVIG and RBC transfusion contraindicated? correct answer: IgA deficiency
Dimer, Secretory component
Hypersensitivity reactions
Which hypersensitivity reaction type is responsible for airway hypersensitivity in asthmatic persons? correct answer: Type 1, late phase response
The initial immediate IgE or complement (C3,C4,C5- anaphylactoids) reaction (mast cell degranulation) releases cytokines, prompting cellular recruitment of eosinophils and basophils, resulting in an eosinophilic inflammatory infiltrate
Hypersensitivity reactions
Type 1-anaphylaxis
Can be IgE mediated or mediated by complement- activated C-3, C4, C5 (anaphylactoids)
Examples of non-IgE mediated anaphylaxis? correct answer: T cells and HLA antigens
HLA antigens expressed on cell surfaces help the immune system surveillance to identify self versus non-self.
HLA Type 1 antigens are not specific and are expressed on the cell membrane of virtually every nucleated cell.
CD8 killer cells are not specific, they will phagocytize any antigen presented by
HLA Type 1.
What about HLA Type II antigens and CD 4 helper cells?r correct answer: HLA Type II molecules are highly specific with antigen presentation to CD4 T-helper cells, which are highly specific regarding antigens they accept and activate B cells to become plasma cells forming very specific antibodies to the specific antigen.
HLA Type 1; nonspecific, CD8 killer cells
HLA Type 2; specific, CD4 helper cells
Actions of various components of the complement system
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