Type III Immunopathology Flashcards
What three requirements must be met in order to see a type III immunopathology?
The immune complex must…
- Be to small to removed by RED
- Large enough to activate complement
- Too large to readily pass through basement membrane
What components of complement recruit neutrophils?
C3a and C5a
Name somethings that neutrophils release upon arrival to immune complexes stuck in a basement membrane.
Inflammatory factors like proteases cathepsin G and elastase and hydrogen peroxide
What activates metalloproteinases?
Hydrogen peroxide
What three things contribute to degradation of the basement membrane?
Proteases cathepsin G (produced by neutrophils)
Elastase (produced by neutophils)
Metalloproteinases
What helps release histamine from mast cells?
C3a and C5a
Type III immunopathology causes what?
Widespread small vessel vasculitis
Polyarteritis nodosa can be caused by what virus?
Hepatitis B and C
-Viral proteins + antibodies embed in medium sized arteries
Can an antigen that is quickly cleared by the body cause Type III?
No. The antigen needs to be given in a high enough quantity so it can be around when the antibody is finally made by the B cells
What is the onset of serum sickness?
10-14 days after exposure. Need time for the antibodies to be released. 10-14 is the time it takes for the antigen to still be in a little bit of excess of the antibody -
What are the symptoms of serum sickness?
Fever
malaise
rash + itch
arthraligia
True or Flase
Serum sickness can happen after treatment with murine, chimeric, or humanized monoclonal antibodies
True
How can penicillin cause a type III reaction?
Penicillin can be know to bind to human peptides.
Complex taken up by B cells and digested and presented to T cells
T cells recognize penicillin + chewed up protein and activates B cell switching
B cell creates anti-penicillin antibodies
Complexes form
True or False:
Serum sickness-like symptoms can be seen in patients with viral infections like hepatitis
True. Lower-leg rash Malaise Fever Arthralgias
An 8 year old boy comes into the emergency room complaining of nausea, vomiting, fever, malaise, hypertension. reduced urine output,hematuria, and joint pain. What should be your next question?
Have you had a soar throat lately because it sounds like acute post-streptococcal glomerulonephritis.
What is the treatment for someone with acute post-streptococcal glomerulonephritis?
Antibiotics and supportive care
What would you see on the labs of a patient with acute post-streptococcal glomerulonephritis?
Hematuria
Decreased complement levels
A farmer comes in with a dry cough, malaise, fever and tachycardia. It has been raining lately What should be on your differential?
Hypersensitivity pneumonitis. caused by thermophilic Actinomycetes found in moldy hair. Aerosolized spores are inhaled complexes form in the lunges
What is the treatment of hypersensitivity pneumonitis?
Systemic glucocorticoids and avoidance
A booster immunization is given to a child. The injection site becomes inflammed. What has just occured?
Arthus reaction. Pre-existing antibody to immunogen complexes immediately begin to form locally.
Can antigens be endogenous?
Yes
Rheumatoid factor is an IgM anti-IgG, but it is just big enough to deposit in the BM. So what type of reaction it this?
Type III
Describe the pathogenesis of systemic lupus erythematosus.
Antibodies to double stranded DNA
HIstones H2, H3, and H4.
The antibody—dsDNA preferentially deposit in kidneys
Why do SLE patients develop facial butterfly rashes?
Sun-damaged DNA-releasing skin cells + reactive antibodies
