Chapter 18 Flashcards
disorders of the immune system may be the result of ___ or ___
over-reacting, under-reacting
Hypersensitivity
an over reaction of an immune respomse against a foreign antigen
the 4 types of hypersensitivity are…
I-immediate,
II-cytotoxic,
III-immune-complex mediated,
IV-delayed or cell mediated
Type I(immediate) hypersensitivity:(localized or systemic)
Reaction that results from the release of inflammatory molecules in response to an antigen
Type I hypersensitivity is commonly called…
an allergy
The antigens that stimulate a type I hypersensitivity are called…
allergens
Mechanisms of a type I hypersensitivity reaction are
Antigen presenting cell, engulfs allergen, and exfposes the antigen to Th2, Th2 releases IL4 to create B cell which creates plasma cell that secretes IgE. The Fc portion of IgE bind to mast cells, basophils and eosinophils, sensitizing them to subsequent responses.
Subsequent exposure to the same allergen, binds to IgE on the surface of mast cells, basophils and eosinophils. these cells release infammatory chemicals from granules…called ___
degranulation
Degranulation releases…..
histamine,
kinins,
proteases,
leukotrienes, and prostaglandins
Degranulation occurs after ___
cells sensitized
Mast cells…
derived from stem cells i bone marrow, distributed throughout body (not WBC’s)
Basophils…
least numerous wbc, (granular WBC)
Histimine…
dialates blood vessels, tears, mucous, contractions ofsmooth muscle(swollen)
Kinins…
inflammation
Proteases
degrades proteins, activates complement
Leukotrines…
inflammation, vascular permeability
Prostglandins…
contract smooth muscle
Eosinophils…
function primarily for parasitic worms, release leukotrines which increase vascular permeability, and muscular contraction
Clinical signs of localized alleergic reaction:localized
Site of reaction depends on portal of entry, small inhaled allergens may reach lungs and cause asthma
Asthma
Constriction of bronchi
Some foods contain allergens:
May cause diarrhea and other gastrointestinal signs and symptoms
Local dermatitis may produce ___ (hives)
urticaria
Urticaria(hives)
Raised red areas of skin, itchy b/c histimine affects nerve endings in area
Common allergens:
pollen, dust mites, spores
If lots of mast cells degranulate at once releasing large amounts of histramine or inflammatory mediator this could exceed the body’s ability to adjust causing…..
Acute anaphylaxis or anaphylactic shock
Clinical signs of acute anaphylaxis or anaphylactic shock
Those of suffocation
Diagnosis of type I hypersensitivity
Based on detection of high levels of IgE against specific allergen, sample of blood is taken, and mixed with antigen to determine the IgE quantity in blood.
Immuno CAP specific IgE blood test…
Sample of blood is taken, and mixed with antigen to determine the IgE quantity in blood.
Alternative diagnoses can involve using skin tests..
Inject dilute allergen into skin of forearm, observe for any inflammation
Prevention of type I hypersensitivity..
Identification and avoidance of allergens
Food allergens are identified using an ___
elimination diet
Immunotherapy
“allergy shots” can help prevent allergic reactions
Antihistamine treatment of type I hypersensititvity
is administeration of drugs that counteract inflammatory mediators by neutralizing histamine
threatment of type I hypersensitivity Asthma with a ___(counteracts a inflammatory mediator) and a ___
bronchodialator
Epinephrine treatment of type I hypersensitivity …
neutralizes many mechanisms of anaphylaxis
what epinephrine does
relaxes smooth muscle, reduces vascular permeability(used in emergencyt treatment of allergic reactions
Type II(cytotoxic) hypersensitivity:
Results when cells are destroyed by an immune response
Type II hypersensitivity….
Often the combined activities of complement and antibodies, A component of many autoimmune diseases
2 examples of Type II
Destruction of blood cells following an incompatible blood transfusion, destyruction of fetal red blood cells in hemalytic disease of the newborn.
Blood group antigens:
Surface molecules of red blood cells
Each person’s RBC’s have…
A antigen, B antigen, both antigens, or neither antigen
Transfusion reaction can result if an individual receives a ___
different blood type
Donor’s blood group antigens may stimulate the prodcution of ____
antibodies in the recipient that destroy the transfused cells.
If recipient has preexisting antibodies to foreign blood group antigens:
immediate destruction of donated blood cells(hemolysis) can occur, hb released in blood stream, kidney damage, clotting and diarrhea
Recipient has no preexisting antibodies to foreign blood group antigens:
Transfused cells intitially circulate and fucntion normally, eventually recipient’s immunme system mounts a primary response against the foreign antigens and destroys them
Transfused cells intitially circulate and fucntion normally, eventually recipient’s immunme system mounts a primary response against the foreign antigens and destroys them
Rh antigen:
an antigen common to RBC’s of humans and rhesus monkeys
About ___ of humans are Rh positive
85%
If Rh- woman is carrying an Rh+ fetus, the fetus may ___
be at risk of hemolytic disease
To prevent hemolytic disease of the newborn we …
administer anti Rh immunoglobulin, called Rhogam
Whem moms blood test are done during pregnancy, if mother is Rh-, she is treated to prevent…
hemolytic disease
Administration of an anti-Rh immunoglobulin, called __ is performed after childbirth, abortion, or miscarrige to……
Rhogam, kill any fetal RBC’s which enter mother’s immune system to prevent immune response
Drug induced cytotoxic reactions
Some drug molecules can form haptens
Haptens
Spontaneously bind to blood cells or platelets(acting as an antigen) stimulating the production antibodies
Haptens can produce various diseases
The cells or platelets that bind with the drugs, can then be destroyed by antibodies and complement proteins causing immune Thrombocytopenic purpura
Thrombocytopenic purpura
can affect blood clots, WBC’s, and RBC’s
Formation of antigens bound to antibodies form ____ which initiate several immunological process in type III hypersensitivity
immune complexes
These immune complexes are not phagocytized, howecver circulate in blood, and …..
travel throughout body
Prolonged inflammation can cause …
damage to blood vessels
can cause a localized reaction in type III
hypersensitivity pneumonitis, glomerulonephritis
Hypersensitivity pneumonotis
inhalation of antigens (spores) results in complexes that cause pneumonia in lungs
Glomerulonephritis
immune complexes deposit in glomerulus (vessels in kidney used for filtration) compromising kidney function
Can cause systemic reactions in type III
systemic lupus erhythematosus, rhematioid arthritis
Systemic lupus erythematosus
(lupus disease that affects multiple organs. immune system makes antibodies to multiple “self” antigens
Rhematioid arthritis
B-cells secrete IgM, that binds to IgG, froming complexes, These IgM-IgG complexes deposit in joints, causing inflammation, and destruction of cartilage
Type IV(delayed or cell-mediated) hypersensitivity
When antigens contact the skin to sensitized individuals, they provoke inflammation 12 to 24 hours after contact
Type IV hypersensitivity results from the interactin of
Antigens, antigen-presenting cells (APCs) and T-cells
The delay in types IV hpersensitivity reflects the time it takes for macrophagtes and T-cells to
Migrate to and proliferate at the site of the antigen
The tuberculin response in type IV hypersensitivity
Skin exposed to tuberculosis or tuberculosis vaccine reacts to an injection of tuberculin beneath the skin
Tuberculin response is used to
Diagnose contact with antigens of M.tuberculosis
There is ____ response to tuberculin when i ndividual has not been infected or vaccinated
No
There is a ____ that developse in individuals previously infected or immunized with TUberculin
Red hard swelling
Allergic contact dermatitis with type IV
Cell-mediated immune response resulting in an intesely irratating skin rash
The allergic contact dermatitis is triggered by
Chemically modified skin proteins that the boyd regards as foreign
In severe cases of allergic contact dermatitis
Acellular fluid-filled blisters develop
Haptens include the
Oild or poision ivy
formaldehyde
cosmetics
chemicals used to produce latex
Allergic contact Dermatitis can be treated with
Corticosteroids
Graft rejection in type IV
rejection of tissues or organs that have been transplanted
In graft refection a normal immune respose against
Foreign MHC proteins present on graft cells
Likeihood of graft rejection depends on the
Degree to which the graft is foreign to the recipient (based on the type of graft)
Isograft
Genetically identical (sibiling or clone)
Allograft
Genetically different (member of same species)
Xenograft
Animals
Graft-verus-host disease
Donated bone marrow cells regard the patient’s cells as foregin
Donor and recipient differ in MHC class I molecules
Grafted T-cells attach recipient’s tissue
_____ can stop graft-versus-host disease
Immunosuppressive drugs
Donor-recipient matching and tissue typing
MHC compativility between donor and recipient difficult due to a high degree of bariability
Degree of variability
the more closely the doner and recipient are relate, the smaller the difference in their MHC
Preferable the grafts are donated by a ___ or ___
Parent
Sibiling
The actions of immunosupressive drug
imporatn to success of modern transplantation
Classed of immunosupressice drug
Glucocoriticoids
Cytotoxic drugs
cyclosporine
lymphocytedepleting therapies
Glucocorticoids
(Corticosteroids)
Steroids
supress T-cell to antigen
Cytotoxic drugs
Block cellular reproduction (prevents clonal expansion of B-cells and T-cells)
Cyclosporine
Prevents production of interleukins blocking helper T-cell responses
Lymphocyte-depleting therapies
Antiserum against lyphocytes
Autoimmune disease
May result when an indiviual begins to make autoantibodies or cytotoxic T-cells against normal body cells
Autoimmune diseases occur more often in
the elderly
Autoimmune disease are more common in
men than women
All autoimmune disorders are categorized into 2 major categories
Systemic autoimmune diseases, single-organ autoimmune diseases
Single-organ autoimmune diseases
Autoimmune hemolytic anemia, type I diabetes mellitus graves disease, multiple sclerosis, rheumatoid arthritis
Autoimmun hemolytic anemia
Produce antibodes against own RBCs
Type I diabetes mellitus
Immune attack on islets of angerhans, dont produce insulin (affects endocrine)
Grave disease
Autoimmune disorder on the thyroid gland (Affects endocrine)
Multiple sclerosis
Cell mediated response results in attack or degeneration of myelin sheaths of nervous system
Rheumatoid arthritis
Complexes in joints affect connective tissue
Conditions resulting from defective immune mechanisms (2 types)
Primar
Acquired
Primary
results from some genetic or developmental defect (develops in infants and young children)
Example of primary conditions
Chronic granulomatous disease
Sever conbined immunodeficiency disease (SCID)
Digeorge syndrome
Brutontype agammaglobulinemia
Chronic granulomatous disease
Inability of phagocytes to destroy bacter susceptible to infection
Severe combined immunodeficiency disease (SCID)
Dont develop lymphoid stem cells, B-cells nor T-cells not produced and cannot mount an immune response
DiGeorge syndrome
T-cell deficiencies (thymus doesnt develop)
Bruton-type agammaglobulinmia
B-cell deficiencies
cannot make immunoglobulins
Acquired
Develop as direct consequence of some other recognized cause (develop in later lif, number of causes)
Reasons we acquire immunodeficiency diseases
severe stress
malnutrition and environmental
acquired immunodeficiency syndrome
Severe stress
suppression of cell-mediated immunity results from an excess production of coricosteroids
Malnutrition and environmental facors
Inhibit production of B-cells and T-cells
Acquired immunodeficiency syndrome (AIDS)
Opportunistic infection
Low CD4 cells
Presence HIV
