abnormal immune response Flashcards
what are the 3 types of abnormal immune responses
- immunodeficiency
- hypersensitivity
- autoimmunity
what is an immunodeficiency
a partial or complete loss of immune response
what is a primary immunodeficiency
- genetic or congenital
- the immune system fails to develop
what is a secondary immunodeficiency
- acquired post natal
- the IR is triggered by something else
what are the 5 types of immunodeficiency disorders
- B cell
- T cell
- T & B cell
- complement
- phagocytosis
what is a B cell immunodeficiency disorder
impaired antibody production
what is a T cell immunodeficiency disorder
impaired T cell function
what is someone with a T cell immunodeficiency disorder at risk of
cancer
what is a T & B cell immunodeficiency disorder
complete impaired immune response (basically no immune system)
what is a complement immunodeficiency disorder
the innate response is inhibited
what is a phagocytosis immunodeficiency disorder
disruption of phagocytosis which makes them prone to infection
what is the treatment for immunodeficiency disorders
- replacement therapy (Ab’s to supplement the immune system)
- marrow transplant (last resort)
what is a hypersensitivity
exaggerated/inappropriate immune response
what are the 4 types of hypersensitivity
- allergy (IgE mediated)
- cytotoxic
- immune complex
- delayed (T cell mediated)
what type of hypersensitivity is the most common
type I (allergy)
what is a type I hypersensitivity triggered by
allergens
what is a type I hypersensitivity mediated by
IgE
what are the 2 phases of type I hypersensitivity
- mast cell sensitization
- re-exposure
during what phase of type I hypersensitivity will an allergic reaction present
phase 2 (re-exposure)
what happens during the first phase of type I hypersensitivity
after exposure to the allergen, TH2 cytokines are produced which stimulate B cells and plasma cell formation
plasma cells produce IgE which attaches to and sensitizes mast cells
what cells are involved with type I hypersensitivity
- B cells & plasma cells
- mast cells
what happens during the second phase of type I hypersensitivity
the allergen binds to IgE on already sensitized mast cells
this forms an immune complex
inflammation mediators are released (histamine, prostaglandin)
inflammation occurs at site of contact
what is shock
failure of the cardiovascular system and inability to perfuse
what are the 4 types of shock
- cardiogenic (heart fx impaired)
- hypovolemic (low blood volume)
- obstructive (obstruction of vessels)
- distributive (dilated vessels decreases patency)
what is anaphylactic shock
a severe type I hypersensitivity reaction
what happens during anaphylactic shock
an allergen causes systemic mediator release
mediators cause increased systemic vasodilation and capillary permeability
this causes systemic edema
distributive shock occurs due to low vessel patency
what is type II hypersensitivity mediated by
antibodies (IgG or IgM)
what happens during type II hypersensitivity
endogenous and exogenous antigens are mistargeted by antibodies - loss of self recognition
any cell bearing the immune complex is destroyed
what is an example of type II hypersensitivity
incompatible blood transfusion
what happens during type III hypersensitivity
some immune complexes are not degraded and move through the body depositing in tissues
why does type III hypersensitivity occur (2 reasons)
- some immune complexes are too small to be recognized
- some immune complexes are resistant to breakdown
what are 2 examples of type III hypersensitivity
- glomerulonephritis (inflammation of the kidney)
- rheumatoid arthritis (one part of this is type III)
what is type IV hypersensitivity mediated by
T cells
what happens during type IV hypersensitivity
any cell bearing an antigen the T cell is responding to will be destroyed (self and foreign)
what are the 2 types of type IV hypersensitivity
direct
delayed
why does delayed type IV hypersensitivity occur
the production of lymphokines takes a few days
what is a TB test an example of
a type IV hypersensitivity
what is an autoimmunity
a chronic disease where the immune system targets self antigens
what is lost during autoimmunity
self tolerance
during autoimmunity the self is recognized as
foriegn
what are the 3 ways self tolerance is lost during autoimmunity
- molecular mimicry
- abnormal T cell function
- exposure of sequestered antigens
what is molecular mimicry (autoimmunity)
a cell shares a similar epitope with bacteria,
T cells get confused, antigen is mis-identified, T cell destroys the cell bearing the epitope
what is abnormal T cell fx (autoimmunity)
suppressor T cell function is not optimal
cytotoxic T cells are continuously produced and target self components
what is exposure of sequestered antigens (autoimmunity)
a self antigen that was hidden during development becomes exposed due to disease
exposure for the first time triggers an immune response
what is SLE
lupus
what is lupus
antibodies target nuclear components (widespread targeting of cells)
what type of test can be done for lupus
ANA (anti-nuclear antibodies) test
what is neoplasia
abnormal cell growth
what is a neoplasm
a tumor (abnormal mass)
characteristics of malignant neoplasms
- undifferentiated
- invasive, damaging
- rapid, disorderly, continuous growth
- metastasis
characteristics of benign neoplasms
- uncontrolled slower growth (than malignant)
- sometimes encapsulated
- differentiated
- may stop growing
- don’t spread by metastasis
genes code for
proteins which carry out functions
what are DNA repair genes
- “spell check” genes
- read genetic code looking for errors and fixing them to avoid mutation
targeting of DNA repair genes by carcinogens allows what
mutations to pass through
what are proto-oncogenes
- Go genes
- promote cell growth
- mutation = excessive cell growth = tumor
what are tumor suppressor genes
- stop genes
- inhibit cell growth/division
- mutation = excessive cell growth = tumor
what are oncogenes
any cancer associated gene that is mutated
cause malignant growth
