autoimmunity

Question 1

define autoimmunity

Answer 1

immune reaction against self-antigen resulting in tissue injury

Question 2

two requirements to define pathologic autoimmunity

Answer 2

1. prrof that theres autoimmune reaction related to tissue injury
2. evidence that autoimmune reaction is not secondary to other diagnosis

Question 3

define immune tolerance

Answer 3

unresponsiveness to self-antigens

Question 4

central tolerance

Answer 4

destruction of self b or t-cells during maturation in primary sites.

Question 5

2 key mechanisms on central tolerance

Answer 5

(+): thymic cortex. test t-cell while they mature. tcell fails to recognize antigen/doesnt have mechanism; expressing incorrect # of receptors or not appropriate complex = destroyed by apoptosis

(-): in medulla. test antigen # and self-reactivity. fail = apoptosis

Question 6

peripheral tolerance

4 mechanisms

Answer 6

when central fails - back up.
ignorance = self -reactive t-cell never finds self-reactive antigen..

b. anergy AKA functional inactivation.
self-reactive t-cell binds to self-antigen = inactive bc additional mediating cell not activated.

c. phenotypic skewing. environment not allowing full response. non-pathogenenic cytokines = no activation
d. apoptosis - CD8 detects “odd” t-cell and destroys.

Question 7

causes of autoimmunity

Answer 7

genetic: multigenic patterns of susceptibility
environmental: infectious pathogen @ young age = acute genetic predisposition. women >males bc hormones.

Question 8

Molecular Mimicry

Answer 8

cause of autoimmunity. caused by Rheumatic fever - group A strep. bind to M proteins, produced by strep. M- protein also found in heart. antibody gets confused and acts on heart instead of on M-protein of strep.

Question 9

diabetes mellitus - type 1 (juvenile) 2 main mechanisms

Answer 9

1. CD4 and CD8 involved, both self-reactice. b-cell express self-reactive antigen. CD8 = apoptosis
2. innocent bystander. innate immunity; binding t-cell attracts innate & cytokines = inflammation - microtoxic enviro = death by apoptosis

Question 10

Graves disease

Answer 10

key effector: b-cell production of autoimmune Ab. sees “signal” as TSH receptor. binds = stimulation of receptor = produces T3&T4 = increase metabolism, increase inflammation

Question 11

pernicious anemia

Answer 11

destruction of gastal parietal cells - no longer produce IF needed for vit b12 absorp. no hematopoeisis.

Question 12

rheumatoid arthritis

Answer 12

systemic autoimmune.
destroy cartilage, infection, inflammation.
t-cell associates, cytokine released inappropriately = breakdown cartilage - remodeling = not proper. = thick fibroblasts

Question 13

SLE

Answer 13

non-organ specific. genetic and enviro factors. b-cell produce auto-ab, directed at nucleus = antinuclear antibody (ANA) immune complex increases = nephritis, vasculitis.

Question 14

diagnosis of autoimmune disease

Answer 14

general test: c reactive protein - check for inflammation
autoantibody titers - lupus checks for ANA
presence of Rheumatoid factor

desease specific - neuro = MS
fasting glucose = diabetes