chapter 10 Flashcards
excessive immune response
hypersensitivity
mechanisms of hypersensitivity
type 1: igE mediated
type 2: tissue specific reactions
type 3: immune complex mediated
type 4: cell mediated.
type 1 hypersensitivity
IgE mediated
immediate hypersensitivity: 12-10 minutes after exposure to antigen (allergy) s/s appear
primary effector cells of type 1
mast cells
basophils
- release chemicals that trigger immune response
primary mediators of type 1
histamine
proteases
chemotactic factors: ECF, NCF
s/s of type 1 hypersensitivty
hives. allergic rhinitis
eczema. bronchoconstriction
localized edema wheezing
tachycardia anaphylaxis
type 2 hypersensitivity
tissue specific, IgG, IgM mediated
- antibodies attack antigens on specific cells or tissues
examples of type 2 hypersensitivity
ABO transfusion reactions
hemolytic disease of newborn
myasthenia gravis
alloimmunity
immune system attacks antigens on tissues from other members of the same species.
type 3 hypersensitivity
immune complex reaction, IgG, IgM
- not tissue specific
- results from failure to remove complexes effectively.
deposits in tissues
3 scenarios for type 3
recent infection or persistent low-grade fever
- weak antibody response
- circulating antigen forms chronic immune complex production
extrinsic environmental antigen: mold, plants, animals
- inhaled, exposed to antibody in body fluid
- complex formation in alveoli
autoimmune process
- antibodies attack self antigens
- chronic immune complex production
type 4 hypersensitivity
delayed hypersensitivity reaction: T-cells.
cytotoxic T cells: activate apoptosis
helper t cells: activate phagocytic cells
examples of type 4
contact dermatitis
graft rejection
autoimmunity
immune system recognizes self as foreign, amounts immune response
autoimmunity can be caused by failure of
central or peripheral tolerance with T cells.
genetic factors and autoimmunity
females increased risk
gene factors
environmental triggers and autoimmunity
chronic or multiple viral/bacterial infections may trigger autoimmune disease in susceptible person.
immunodeficiency
decrease in one of more components of immune system
- lymphocytes
- antibodies
- phagocytes
- complement proteins
primary immunodeficiency disorders
congenital or acquired
secondary immunodeficiency disorders
consequence of non-immune system disorders/treatments: secondarily affects immune function.
- stress
- dietary insufficiencies
- malignancies
- physical trauma/burns
- medical treatments
- infections
- AIDS
Hallmark sign of immunodeficiency
recurrent infections, often with opportunistic organisms.
B & T cell combined disorder
severe combined immunodeficiency disorder (SCID)
- common stem cell for all WBC is missing
- will need stem cell transplant
T cell immunodeficiency disorders
- viral, fungal, yeast, and atypical microorganisms
- diGeorge syndrom: deletion syndrome: dec. or no thymus
- chronic mucocutaneous candidiasis
- genetic, T-cells doens produce cytokines needed for immune response to c. albicans.
B cell and phagocyte disorders
microorganisms requiring opsonization
- agammaglobulinemia: genetic disorder, lack of normal B cell development in bone marrow
- common variable immunodeficiency: low titers of immunoglobulins, inability to differentiate into plasma cells
complement immunodeficiency disorders
present like antibody deficiencies
most severe is : C3 deficiency: links all complement pathways.
