Autoimmunity

Question 1

factors contributing to development of autoimmune diseases

Answer 1

immune factors, genetic factors, environmental factors

Question 2

all autoimmune diseases involve

Answer 2

breakdown of T and B cell tolerance and the production of autoantibody and/or inflammatory autoreactive T cells

Question 3

breakdown in B cell tolerance

Answer 3

breakdown in: central B cell tolerance, peripheral B cell tolerance

Question 4

breakdown in central T cell tolerance

Answer 4

defects in AIRE (autoimmunre regulator)

Question 5

breakdown in peripheral T cell tolerance

Answer 5

insufficient control of T cell costimulation (CTLA-4, B7), lack of regulatory T cells may contribute to autoimmune disease

Question 6

Th 17

Answer 6

may be link between infection and autoimmunity, helper T cell that secrete IL-17

Question 7

genetic factors

Answer 7

HLA is the dominant genetic factor affecting susceptibility to autoimmune disease

other factors include AIRE, Fas, FasL, bcl-2, TNF, FoxP3

Question 8

sympathetic ophthalmia

Answer 8

example of a release of sequestered antigens

trauma to sites of immune privilege - self antigens may be exposed to circulation by wound or infection and effector cells can gain access

Question 9

celiac disease

Answer 9

example of self proteins may be modified to appear foreign

result is diarrhea, malabsorption of nutrients, IgG or IgA to tissue

Question 10

molecular mimicry

Answer 10

may contribute to role of infections, pathogen derived peptides structurally similar to a self antigen stimulate a T cell response directed against the self-antigen

Question 11

hashimoto’s disease

Answer 11

infection may lead to increased antigen presentation, upregulation of Class 1 and 2 expression, thyroid gland resembles secondary lymphoid tissue with B and T cells present

Question 12

additional factors that may contribute to disease mechanisms in genetically susceptible individuals

Answer 12

chemicals, metals, hormones, stress, diet, age

Question 13

hemolytic anemia

Answer 13

IgG autoantibodies bound to Rh or I antigens may promote antibody dependent cell mediated cytotoxicity (ADCC) or complement fixation.

antibody mediated autoimmune disease (Type 2 hypersensitivity)

Question 14

Graves disease

Answer 14

autoantibodies bind to the TSH receptor of thyroid cells mimicking the action of TSH so more thyroid hormones are released

can be transferred in utero (to fetus while pregnant)

Question 15

Myasthenia gravis

Answer 15

anti-acetylcholine receptor antibodies binds to the receptors so muscles cannot contract, leads to muscle weakening

Question 16

autoimmune diseases that can be transferred in utero

Answer 16

only IgG-mediated diseases (Type 2 and 3 hypersensitivity), T cells cannot cross placenta so no Type 4 hypersensitivity

Question 17

Systemic Lupus erythematosus (SLE)

Answer 17

type 3 hypersensitivity, immune complex-mediated autoimmune disease, immune complexes contain anti-DNA, anti-nucleosome antibodies, butterfly rash

Question 18

Juvenile (Type 1) diabetes

Answer 18

type 4 hypersensitivity, beta cells in pancreas produce little or no insulin due to destruction by CD8 cells

Question 19

Rheumatoid arthritis (RA)

Answer 19

type 4 hypersensitivity, caused by production of antibodies that react with constant regions of other antibodies (rheumatoid factor) and infiltration of joint synovium by inflammatory CD4 and CD8 cells

Question 20

Multiple sclerosis (MS)

Answer 20

type 4 hypersensitivity, myelin sheath covering cells of spinal cord and brain destroyed due to TH1, macrophages, mast cells, and complement activtation

Question 21

Treatment for autoimmune diseases

Answer 21

removal of antigen, intravenous IgG, anti-inflammatory drugs, depletion of immune cells, blocking activation of immune cells, replacement therapy, hormones, diet, exercise