chapter 12: disorders of the immune response Flashcards
what is hypersensitivity?
excessive or inappropriate activation of the immune response; damaged by immune response, NOT antigen
what is a hypersensitivity reaction?
abnormal immune response to not harmful substances –> tissue damage
what are the 4 types of hypersensitivity reactions?
1) allergic reaction
2) cytotoxic hypersensitivity
3) immune complex hypersensitivity
4) cell-mediated delayed hypersensitivity
what are the s/s of type 1 hypersensitivity?
local & atopic reactions (genetic):
1) urticaria (hives)
2) rhinitis (hay fever)
3) atopic dermatitis
4) bronchial asthma
what are the s/s of type 1 hypersensitivity?
local & atopic reactions (genetic):
1) urticaria (hives)
2) rhinitis (hay fever)
3) atopic dermatitis
4) bronchial asthma
what is the causative mechanism of type 1 hypersensitivity?
1) initial allergen exposure –> Ige antibody formation (fr B lymphocytes)
2) attach to mast cells
3) 2nd exposure –> antigen attach on mast cells –> histamine release
4) inflammatory response
what are the 2 types of type 1 hypersensitivity reactions?
1) primary/immediate phase
2) secondary/late phase
primary/immediate phase
1) mast cell degranulation releases HISTAMINE, PROSTAGLANDINS, KININS
2) vasodilation, vascular leakage, smooth muscle contraction
secondary/late phase
1) lipid mediators + cytokines release LEUKOTRIENES + PROSTAGLANDINS
2) infiltration of tissue w/eosinophils, tissue destruction
what is anaphylaxis?
a severe hypersensitive reaction (large mounts of chemical mediators released from mast cells into circulation quickly)
what happens as a result of anaphylactic shock?
1) vasodilation –> drop in BP
2) mucosa edema
3) bronchiole constriction
4) hives
5) itching
6) skin erythema
7) vomiting
8) abdominal cramping
what does the injection of epinephrine do?
1) vasoconstriction
2) increase RATE + STRENGTH of heartbeat
3) relaxes smooth bronchiole muscle
what are the 3 mechanisms for type 2 hypersensitivity?
1) complement and antibody mediated cell destruction: incompatible blood transfusion, hemolytic anemia from penicillin
2) complement and antibody mediated cell inflammation: organ rejection, tissues destroyed
3) antibody mediated cell destruction/activation: graves disease (change in cell function)
what is type 3 hypersensitivity?
free floating antigen + antibody
immune complexes deposit on bv walls and activates complement –> inflammation and bv damage
what are the 2 kinds of type 3 hypersensitivity?
1) systemic
2) local
what are the mechanisms of type 3 hypersensitivity?
1) formation of antigen-antibody complexes
2) deposition of immune complexes
3) attraction of inflammatory cells
what is type 4 hypersensitivity?
cell mediated: sensitized t cells attack antigen
what are the 2 types of type 4 hypersensitivity?
1) direct cell-mediated cytotoxicity
2) delayed-type hypersensitivity
what is the difference between delayed cell-mediated cytotoxicity and delayed-type hypersensitivity?
cmc: ctc directly kill antigen containing cell
dth: response to soluble protein antigen (poison ivy)
allograft
same species
isograft
identical twins
autograft
one part of body to another
xenograft
between different species
hyperacute rejection
patient has antibodies against transplant in them IMMEDIATELY
acute rejection
SEVERAL WEEKS AFTER; unmatched antigens cause a reaction
chronic/late rejection
SEVERAL MONTHS AFTER; bv’s in graft are gradually damaged
graft vs host disease
when donated stem cells or bone marrow wbc attack host body
the perfect storm
1) transplant must have a functional cellular immune component
2) recipient tissue: antigens foreign to donor t-lymphocytes
3) recipient tissue: compromised where it can’t destroy transplanted t cells
how do we prevent rejection of a transplant?
1) match hla/mhc
2) use of immunosuppressant drugs
autoimmune disease
self-tolerance breaks down
immune system attacks self-antigens –> destroys body tissues
immunodeficiency
loss of part or all function of immune system; acute or chronic
what are the two kinds of immunodeficiency?
1) primary: genetic, congenital disorders
2) secondary/aquired: malnutrition, drug induced, caused by infection (hiv)
what are some effects of immunodeficiency?
1) opportunistic infections
2) arise from normal flora
3) difficult to treat
4) increased risk of cancer
treatments of immunodeficiency disorders
1) antibody replacement
2) bone marrow/thymus replacement
hiv
human immunodeficiency virus: transmitted by body fluids (sexual contact, breast milk, blood-to-blood contact)
phases of hiv
1) primary infection: s of systemic infection are flu-like, antibodies against hiv appear (1-6 mo)
2) latency phase: virus replication, t helper cell count falls
3) overt aids: t helper cell count <200 cells
associated illnesses of aids
1) opportunistic infections (respiratory, gastrointestinal, nervous)
2) malignancies: kaposi sarcoma, non-hodgkins
3) wasting syndrome
4) metabolic disorders
