Flashcards in Hypersensitivities part 2 Deck (19):
Describe a Type 2 hypersensitivity response.
Responses characterized by IgG or IgM antibodies binding to tissues, cells or ECM leading to their damage; Antigen is NOT soluble.
What can the Type 2 antibodies bind to?
1. Self antigens on CM or collagen
2. Allergens absorbed onto cells.
3. Donor cells
4. Fetal cells
Discuss autoimmune hemolytic anemia.
Erythrocyte membrane proteins are opsonized by antibodies causing hemolysis and anemia
Discuss Thrombocytopenic purpura
Antibodies made for platelet membrane proteins; Presents as bleeding
Describe Grave's disease
Antibodies made for Thyroid stimulating hormone receptor; Hyperthyroidism
Describe Myasthenia gravis
Antibodies made for acetylcholine receptor; Muscle weakness and paralysis.
Discuss Rheumatic Fever
Antibody for strep cell wall antigen cross reacts with myocardial antigen; Myocarditis and arthritis
Discuss Type 2 diabetes
Antagonistic antibody against insulin receptor; Insulin resistance and obesity.
What is the main concern in an ABO incompatibility in pregnancy?
Can affect the first pregnancy
Discuss Type 3 hypersensitivity
Formation of soluble immune complexes (IgG or IgM) that get stuck in small vascular spaces and cause tissue damage.
What are type 3 hypersensitive antibodies binding to?
1. Soluble self antigens
3. Bacterial or viral antigens
4. Antibodies for immunotherapy.
Discuss Systemic Lupus Erythematosus
Antibody against DNA and nucleoproteins. Causes nephritis.
Describe strep glomerulonephritis
Antibody to strep cell wall antigen; Nephritis
Discuss Serum sickness
Antibodies against foreign antibodies; Systemic vasculitis
What are the treatments for antibody mediated hypersensitivities?
1. Anti-inflammatory pharmaceuticals
2. Anti-microbial treatments
3. Plasmapheresis to reduce the level of circulating immune complexes (severe cases)
Describe Type 4 hypersensitivity
Caused by Th1 or Th17 cells attacking self-antigens. Can be acute or chronic.
What are the TCRs binding to in Type 4?
1. Unmodified/Modified self protein
2. Bacterial/viral proteins
3. Donor proteins in transplants
Describe a contact hypersensitivity clinically