Hypersensitivity reactions (most important ) Flashcards by bahlz deip

Type I – Anaphylactic type, Allergy

In Type 1, there is release of vasoactive amines and other mediators derived from the mast cells or basophils and affecting vascular permeability and smooth muscles in various organs

How well did you know this?

Not at all

Perfectly

Type I – Anaphylactic type, Allergy First encounter

Most commonly via inhalation (ex. pollen)
Immune response – IgE immunoglobins (antibodies) produced on
mast cells, which contain granules filled with histamine
No physiological reaction

How well did you know this?

Not at all

Perfectly

Type I – Anaphylactic type, Allergy second encounter

Antibodies produced from first encounter bind to the antigen
(allergen) forming the antigen-antibody complex
Mast cells undergo degranulation  histamine released
Pathophysiological reaction

How well did you know this?

Not at all

Perfectly

Histamine effects on the body

Vasodilation
 Bronchospasm
 Mucus production
increase permeability of blood vessels

How well did you know this?

Not at all

Perfectly

Systemic anaphylaxis

–#1 cause of death in Type I\
– paranthyl (injection/appearance) of allergen
- Results in itching
- Hives (aka Urticaria)
- Bronchospasm
- Laryngeal edema – swelling leads to closing of the laryngeal
opening  strangulation (puncture above episternal notch)
- Abdominal cramps, diarrhea, vomiting
- Vascular (anaphylactic) shock – sudden systemic vasodilation,
blood follows gravity  no blood to brain, pass out  death

How well did you know this?

Not at all

Perfectly

Local reaction

– reaction depends on how allergen is contacted
- Urticaria (via skin contact)
- Hay fever, AKA acute allergic conjunctivitis (via inhalation) or
acute rhinoitis
- Atopy – familial predisposition to Type I
- Atopic bronchial asthma – serious, 2 different pathological mechanisms, only 1 of which is associated with allergy
 Extrinsic bronchial asthma
o Via type I allergic reaction
o Common in kids, familial predisposition to localized
type I hypersensitivity reactions
o NOT ASSOCIATED WITH TYPE I HYPERSENSITIVITY
 Intrinsic bronchial asthma o Autoimmune
 Genetic predisposition
 Diarrhea, vomiting
 Contact allergic dermatitis - blistering

How well did you know this?

Not at all

Perfectly

Type II – Antibody Dependent

Mediated by antibodies directed against target antigens on the surface of cells or other tissue components
 3 subtypes:
-1) Complement-Dependent Reactions
-2) Antibody-Dependent Cell-Mediated Cytotoxicity
-3) Antibody-Mediated Cellular Dysfunction

How well did you know this?

Not at all

Perfectly

Complement-Dependent Reactions

Autoimmune disease – antibodies for target (self) cells
Cascade of complement activation
Complement activation via classical pathway – DIRECT LYSIS
Seen in glomerulonephritis

How well did you know this?

Not at all

Perfectly

extrinsic bronchial asthma

type 1

common in kids

How well did you know this?

Not at all

Perfectly

intrinsic bronchial asthma

NOT type 1

autoimmune

How well did you know this?

Not at all

Perfectly

Complement-Dependent Reaction disorders

—Hemotransfusin reactions – occur with blood transfusions
where the blood types are not matched (blood types: O, A,
B, AB) 
—Erythroblastosis fetalis – 85% of people have Rh antigen
on their RBCs, Rh(+)

How well did you know this?

Not at all

Perfectly

Autoimmune hemolytic anemia

– ex. hemosiderosis  Certain drug reactions – can lead to production of
antineutrophil antibodies  decreased neutrophils
death)

How well did you know this?

Not at all

Perfectly

Pemphigus vulgaris (most common type)

– blister
formation in epidermis
o Pemphix = blister, bubble
o Desmosomal proteins hold/adhere cells together
o Production of antidesmosomal antibodies results
in disruption of intercellular junctions

How well did you know this?

Not at all

Perfectly

type III Antibody-Dependent Cell-Mediated Cytotoxicity

Macrophages, neutrophils, eiosinophils, and natural killer (NK)
cells are non-T and non-B lymphocytes → don’t have specific
receptors
Have receptors for FC fragment of IgE (? IgG & IgM, rarely IgE)
Mechanism
 — Antigen-antibody complex formed (FAB fragment of IgE
binds to target cell) 
— Non-T/non-B cells bind to the free FC portion  cell death
Parasites, virus-infected cells, tumor cells

How well did you know this?

Not at all

Perfectly

type III Antibody-Mediated Cellular Dysfunction

Myasthenia graves
Hashimoto’s Thyroiditis
Grave’s Disease
pernicious anemia

How well did you know this?

Not at all

Perfectly

Myasthenia gravis

– progressive muscle weakness
- Antibodies against Ach receptors on the muscle prevent
muscle contraction

How well did you know this?

Not at all

Perfectly

Hashimoto’s Thyroiditis

Study These Flashcards

– most common cause of hypothyroidism
(where iodine levels in the diet are normal)
-overproduction of auto-antibodies
against TSH receptors on thyroid gland

Graves’ Disease

Study These Flashcards

-Autoimmune disease, more common in females 8:1 
- Overproduction of auto-antibodies that bind and
stimulate TSH receptors (mimic TSH)  overproduction of
thyroid hormones  hyperthyroidism 
-Exophthalmus – bulging eyes

Pernicious anemia



Study These Flashcards

Autonomic binding antibody against the intrinsic factor

receptors

Immune Complex Mediated Type

Study These Flashcards

hypersensitivity is Mediated by deposition of antigen-antibody (immune) complexes, followed by complement activation and accumulation of polymorphonuclear leukocytes.

Immune Complex Mediated Type Phase 1

Study These Flashcards

immune complex formation
 —- Antigen is present in the blood (ex. bacterium)
 —- Antigen and antibody bind to form immune complex
—- Production of antibodies

Immune Complex Mediated Type Phase 2

Study These Flashcards

immune complex deposition

— Immune complex attaches to the vessel wall

Immune Complex Mediated Type Phase 3

Study These Flashcards

complex-mediated inflammation
—- Phagocytic cells (ex. neutrophil) CANNOT engulf and phagocytize the immune complex because it is attached to the vessel wall
—- Instead the phagocyte releases proteolytic enzymes to digest the
antigen  damage to the vessel wall also occurs  vasculitis 
inflammation and narrowing of the lumen
—- Vasculitis – increases vessel permeability

Most common sites of immune complex deposition:

Study These Flashcards

o  Small vessels 
o  Kidneys 
o  Joints  arthralgia
 o  Heart 
o  Skin 
o  Serousal surfaces – fibrous layers lining body cavities
---  Very sensitive to deposition
---  Results in accumulation of fluid in the cavities

Serum sickness | 

``` - Injection of serum containing antibodies and proteins from one person into another person  - injectee develops antibodies against the non-self proteins - resulting in serum sickness 10 – 14 days post injection ```

Serum sickness symptoms

- fever - itching - rash - urticaria - arthralgia - increased lymph node size - vascular shock (uncommon)

Farmer’s Lung | 

- Inhale a large amount of antigens from hay, dust, mold - Leads to lung necrosis - Not very common

pigeon fanciers lung

dung in lungs

Type IV – Cell-Mediated Type

hypersensitivity reaction, Cell-mediated immune response (no antibodies or complement involved) with sensitized lymphocytes ultimately leads to cellular and tissue injury  2 subtypes: A) Delayed Type Hypersensitivity reaction B) T cell-mediated Cytotoxicity

Delayed Type Hypersensitivity reaction | 

Antigen activates CD4+ T-cells of the TH1 type (TH1 type—not T h type 2 in alergy)  production and release of cytokines  recruitment of macrophages -ex tuberculosis

Mantoux reaction

-aka PPD test= purified protein derivative) -Used to determine if a person has or has had TB and to begin treatment with izoniazid if necessary

Chronic Granulomatous Infection

- most common in upper lobes of lungs - macrophages build a wall around the antigen - interferon gamma leads to epithelioid coalescence which causes giant multinucleate cells

Contact dermatitis | 

-Poison ivy or poison oak, reaction ~ 2 days post contact  - Chemical reaction to urushiol** (active substance) found in the plant  - Looks like a second degree burn – blistered

T cell-mediated Cytotoxicity (not associated with T helper cells) 

``` -Associated w/ T8 – cytotoxic cells(don’t need antibody, immediate response?) Account for: o Antiviral immunity o Antitumorous immunity o Graft rejection ```

Neoplasia

= tissue formation, involves overgrowth of a tissue to form a neoplastic mass or neoplasm, called a tumor -

Hypoplasia

– inadequate development, so that the resulting tissue is immature and functionally deficient

Aplasia

– lack of organ/tissue development

Hypertrophy

– cell and organ enlargement that occurs in response to an increased demand of that tissue o Not an increase in the number of cells o Increase in the size of the cells o Heart enlargement due to hypertension – increased demand on the heart pump, enlarged myofibrils

Metaplasia – a change of the cell type

o Not from normal to abnormal (pathological) o Change from normal to normal of a different tissue type o A more serious adaptive response, but it is reversible o Chronic bronchitis in smokers  Normal lung epithelial lining – composed of goblet cells (mucous- producing cells) and columnar cells with villi; mucous traps particles from the air and the villi remove it  With chronic irritation from smoking, columnar cells are replaces by squamous epithelial cells  full loss of normal function and more vulnerable to infection

Dysplasia

o Loss in the uniformity of the individual cells as well as a loss in their architectural orientation o More serious, but can be reversed o Dysplasia still has some normal cells present along with pleomorphic cells -- Pleomorphism

Pleomorphism | 

Characterized by: o Variability in cell size and shape in contrast to the regularity of the cell structure seen in normal tissue o Larger, more darkly-staining nuclei, with abnormal shape o Increased mitosis rate  Found in malignant tumors  - Results from metaplasia with continuous, chronic irritation

Hypersensitivity reactions (most important ) Flashcards

(41 cards)