Mechanisms of Immune Injury Flashcards
What antigens attract women to men?
HLA
Haptens
molecules that bind to bodily proteins and becomes attacked by immune system
- cause of small molecule allergies (nickel, poison ivy)
What does adaptive immunity consist of?
B/T-lymphocytes
-specific and diverse receptors for antigens
Function of B-Lymphocytes
neutralization of microbe, phagocytosis, complement activation
Function of Helper T-lymphocytes (CD4)
Activation of macrophages, inflammation, activation/profileration of T/B lymphocytes
Function of cytotoxic T lymphocytes (CD8)
killing infected cells
- acute cellular rejection
Function of Regulatory T-lymphocytes
suppression of immune system
Function of NK cells
killing infected cells
- cells with no MHC I expression
What cytokine lines the medulla of the lymph node?
Dendritic Macrophages
What cytokines process antigens in outer skin?
Dendritic cells
What cytokines are produced to by Th1? To defend against what?
IFN-gamma for intracellular microbes
What cytokines are produced to by Th2? To defend against what?
IL-4, IL-5, IL-13 for helminthic parasites
What cytokines are produced to by Th17? To defend against what?
IL-17, IL-22 for extracellular bacteria, fungi
Where doe B-cells undergo maturation?
germinal follicles of lymph nodes
Where are plasma cells generally found?
Produce antibodies in tissue rather than blood
Hypersensitivity
disease caused by the immune system causing harm to the body
- failure of control through feedback mechanisms
Type 1 Immune Injury
in response to allergies/anaphylaxis (hay-fever, asthma)
- Th2 produces IgE and histamine from mast cells (high IL-5)
- later reaction is mediated by leukotrienes, PGD2
- symptoms: vascular dilation, sm. m. contraction, mucus production
What is a common cause for urticaria?
IgE/Type I immune injury
What is a common cause of eosinophilic gastroenteritis?
food allergy
Cause of anaphylaxis
massive IgE-mediated response
Cause of atopic dermatitis
people with allergies
- look for FCeRI and dendritic macrophages
What is chronic urticaria and it’s cause?
patches of skin that swell from local IgE/histamine
- from autoimmunity, food, “unknown”
Cold urticaria
get hives from cold temperatures
- non-immune mediated
Cholinergic urticaria
hives from wet heat (sweating, shower)
- non-immune mediated
Dermatographism
skin gets inflamed where it is scratched
Type II Immune Injury
antibody mediated
- antibodies attack antigen (autoimmune hemolytic anemia, goodpasture syndrome)
- IgG, IgM
Coomb’s test
test for antibodies in patient’s blood
Goodpasture’s disease
antibodies against basement membrane of lungs and kidney
Why are men preferentially used as plasma donors?
Women can have antibodies in the plasma against HLA antigens from previous pregnancy
What is the most common cause of hypothyroidism?
Autoimmunity (hashimoto’s thyroiditis)
- antibodies and T/B-cells
Type II immune response in adrenal
Addison’s disease
- T-cell destruction
Type II immune response in pancreas
Type I Diabetes Mellitus
- t-cells destroy islet of langerhans
What clotting factor do hemophiliacs develop antibodies against?
Factor VIII
What receptors do antibodies in Graves’ disease bind to?
TSH receptors causing hyperthyroidism
Isaac’s antibodies
Ab against muscles
- keeps muscles firing and causes pain
Type III immune injury
immune complex-mediated (vasculitis, arthritis, glomerulonephritis)
- Ag + Ab + Complement
- deposits into vascular intima (feel bad all over)
- ends when antibody becomes more abundant and immune complexes leave
What type of immune injury is associated with fibrinoid necrosis ?
Type III
Arthus Reaction
sore muscles from injection of something that you already have Ab for
What type of immune injury is associated with hyperacute rejection of donor kidney?
Type III
Type IV immune injury
T-cell mediated (contact dermatitis, MS, rheumatoid arthritis, psoriasis)
- inflammation –> cytolysis
- Th1/Th17
Anergy
no immune response to things you have already encountered
- dysfunction in T-helper cells
(sarcoidosis, lymphomas, cancers, HIV, measles)
Halo nevus
T-cells destroy melanocytes around nevus
What cells are responsible for granuloma formation?
Th1 (no Ab necessary)
- miliary TB
What is responsible for acute humoral rejection?
antibodies
- intimal hyperplasia in arteries
Hyperacute rejection
Type III response
- IgG precipitates
- fibrinoid in arterial walls (lymphocytes)
What is responsible for acute cellular rejection?
CD8
- destroy heart transplant
- tubulitis, endotheliitis
Chronic transplant rejection
vessels narrow or totalled
- intima is thickened (concentric)
- T-cells cause thickening of intima/media
Signs of acute graft v host disease
days to weeks after transplant
- attack by CD8, Type IV immune response
- generalized rash, loss of epidermis (starts in palms)
- jaundice from bile duct damage
- ulcers along GI tract/orally
Signs of chronic graft v. host disease
appears after ~100 days
- more fibrosis, less necrosis
- fibrosis of dermis with loss of skin
- cholestatic jaundice from bile duct damage
- GI damage
- damage of host T-cells (immunocompromised)
- cytomegalovirus pneumonitis infection
