12: Autoimmunity

Question 1

autoimmune hemolytic anemia

Answer 1

• RBC antibodies produced against RBC membrane proteins

- Intravascular hemolysis or extravascular hemolysis

Question 2

goodpasture’s syndrome

Answer 2

• autoanitbodies against type IV collagen of lung and kidney
• complement activation leads to kidney damage, pulmonary hemorrhage and death
• smooth, ribbon-like appearance

Question 3

Pernicious anemia

Answer 3

• autoanitbodies to intrinsic factor and/or gastric parietal cells
• decreased absorption of vitamin B12 leads to anemia

Question 4

Hashimoto’s thyroiditis

Answer 4

• hypothyroid state

- autoantibodes and autoreactive t cells to thyroid gland proteins

Question 5

Idiopathic thrombocytopenia purpura (ITP)

Answer 5

• platelets destroyed by autoantibodies to platelet membrane proteins
• pupura: skin lesions due to epidermal hemorrhage
• IVIG (intravenous immunoglobulin) can prevent destruction of platelets

Question 6

Vitiligo

Answer 6

• depigmentation of the skin by destruction of melanocytes

Question 7

Grave’s disease

Answer 7

• autoantibodies against TSH receptor, antibody stimulates receptor without ligand
• hyperthyroidism

Question 8

Myasthenia gravis

Answer 8

• autoantibodies to nAch receptor on skeletal muscle cells
• blockage of neuromuscular transmission leads to muscle weakness and paralysis
• antibody inhibits binding of ligand to receptor

Question 9

Type 1 diabetes

Answer 9

• glucose intolerance and hyperglycemia through immune-mediated destruction of insulin-secreting beta cells in the pancreas
• autoreactive T cells mediate the destruction of b cells, autoantibodies to b cells are diagnostic

Question 10

Multiple scelorsis

Answer 10

• demyelinating disease of the CNS
• TH1 and TH17 cells specific for myelin antigens become activated which drives macrophage activation and subsequent damage to myelin-containing nerve cells
• therapy: INFbetaB on alternate days, INFbetaA weekly and IV steroids

Question 11

SLE systemic lupus erythematosus

Answer 11

• systemic constellation of autoantibodies stemming from a broad loss of regulatory control that sustains self-tolerance
• Most commonly skin, joints, and kidney
• damage from immune complexes (can deposit on renal podocytes because they express CR1)
• may develop type II hypersensitivity as well against RBC, WBC and platelets

Question 12

RA rheumatoid arthritis

Answer 12

• systemic
• destruction of joint cartilage and inflammation of synovium (also pulmonary, cardiac, and ocular manifestations)
• associated withi HLA-DR4 haplotype
• cell-mediated type IV hypersensitivity

Question 13

Controlling the role of TNFalpha in RA

Answer 13

• etanercept: TNFalpha type II receptor fused to IgG1 antibody sponges up free TNFalpha
• infliximab:mouse/human anti-TNFalpha antibody
• adalimumab: recombinant human anti-TNF antibody

Question 14

Sjogren’s syndrome

Answer 14

• dry eyes and mouth due to the destruction of lacrimal and salivary glands
• B and T cells influx into glands, don’t know which causes the damage

Question 15

Scleroderma (progressive systemic sclerosis)

Answer 15

• excessive deposition of collagen in skin, kidney, GI, heart, muscles, lungs
• antinuclear antibodies
• cyclical pattern: T cells hypersensitive to collagen release IL1 and TNFalpha which leads to the production of more collagen

Question 16

polymyositis-dermatomyositis

Answer 16

• muscle injury brought about by CD4 and CD8 t lymphocytes infiltrating the muscles
• diagnosis: autoantibodies against histidyl tRNA synthetase
• could be involved with coxsackie B viruses

Question 17

Corticosteroid therapy

Answer 17

• nonspecific immmunosuppresion to decrease tissue damage
• anti-inflammatory effects
• side effects: bone mineral loss, weight gain, diabetes, fluid retention, skin thhinning

Question 18

Asathioprine and cyclophosphamide

Answer 18

• nonspecific immunosuppresion to decrease tissue damage
• interferes with DNA synthesis to eliminate dividing lymphocytes
• side effects: bone marrow suppression and damage to intestinal epithelium

Question 19

cyclosporine and tacrolimus

Answer 19

• nonspecific immunosuppresion to decrease tissue damage
• block activity of calcineurin to block transcription of IL2 and INFgamma
• nephrotoxic

Question 20

plasmapheresis

Answer 20

nonspecific immunosuppresion to decrease tissue damage

- removes Ag-Ab complexes for short term alleviation of symptoms