Immunopathology1 Flashcards
What are the 4 types of immunopathologies?
ACID -
Anaphylactic and Atopic - Type I
Cytotoxic - Type II (Autoimmune)
Immune complex - Type III
Delayed (cell-mediated) - Type IV
What is a chronic frustrated response?
Immune system can’t get control of a foreign substance so it keeps going on and on trying to defeat it. A chronic response with no resolution
Explain the major mechanism for Type II tissue damage
Complement-mediated damage: Activation of complement leads to 1. lysis (C6-9) 2. Opsonization for phagocytosis (C3b) 3. Release of phagocytic lysosomal enzymes and ROS 4. Release of histamine (C5a, C4a, C3a)
What is stimulatory hypersensitivity?
Used to be called Type V
In this case, antibody that is made is able to mimic the ligand for a particular receptor. This leads to constitutive activation of the receptor and the breakdown of normal regulation methods.
Ex: LAST on the thyroid receptor –> Graves disease
Explain inappropriate tachycardia
Autoantibody is made to the beta-andrenergic receptor, which is stimulatory. Serves as a form of stimulatory hypersensitivity.
Seen mostly in women
Treat with beta-blockers
What are the 3 main mechanisms for TypeII tissue damage
- complement mediated damage (major)
- Stimulatory Hypersensitivity
- Antibody-Dependent Cell mediated cytotoxicity (ADCC)
Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC):
Stressed cells express surface molecules → NK recognizes them → natural killer (NK) cells have Fc receptor → can bind to the Fc portions of bound IgG → start apoptosiis
Example of Type II mechanism of disease of:
Muscle
Myasthenia Gravis
Example of Type II mechanism of disease of:
Lung and Kidney
Goodpasture Syndrome
Autoimmune Hemolytic Anemia
Rheumatic Heart Disease
& Dressler Syndrome
Example of Type II mechanism of disease of:
Red cells
Autoimmune Hemolytic Anemia
Example of Type II mechanism of disease of:
Platelets
Thrombocytopenic Purpura (ATP)
Example of Type II mechanism of disease of:
Thyroid
Graves’ Disease
Example of Type II mechanism of disease of:
Pancreatic islets
Juvenile diabetes
Type 1 diabetes
Myastenia Gravis
- Progressive muscle weakness because of Ab to AChR
- Complement- and neutrophil-mediated
- Becomes harder to stimulate the jxn because of what the neutrophils have barfed up on the end-plate