Autoimmunity Flashcards
What two mechanisms must be breached to develop autoimmunity?
Central and peripheral tolerance
What are the major factors that influence the development of autoimmune diseases?
Autoreactive CTLs
Microbial infections
Lymphocyte abnormalities
Genes
Can autoimmune diseases be tranferred to fetueses from their mothers (not genetically)?
Yes, but will be ~3 weeks long (IgG half life time)
What is epitope spreading? What begins this process?
Trauma induced spreading of self antigens not normally present in the blood (like d/t blood brain barrier)
How could viruses potentially play a role in the development of autoimmunity?
Similar antigens to self (“molecular mimicry”)
Allow for inflammation cytokines to be present when attempting to tolerize T cells
What can mycoplasma infections induce?
Transient autoimmunity d/t cross-reaction of antibodies to RBCs
What do the antibodies of rheumatic fever cross react with?
Heart tissue
How can inappropriate expression of MHC class I molecules lead to autoimmunity? What are the two example diseases for this?
Activate T cells inappropriately
Grave’s disease and DM I
What is vitiligo?
Autoimmune disease against melanocytes
How can expression of TCRs specific for MHC proteins on thymocytes bypass negative selection?
Expression of certain MHC proteins with self peptides during T cell selection in the thymus might allow enough binding to enable positive selection of autoreactive T cells, but might not bind with high enough affinity to elicit negative selection.
What are the three major ways that tissue injury can be brought about in an autoimmune disease?
- Autoreactie CTLs
- Circulating autoantibodies
- Immune complexes
What antibody type can cross the placenta?
IgG
What is the pathogenesis of autoimmune hemolytic anemia? (2)
RBC antibodies produced against RBC membrane proteins causes RBC lysis
Opsonization of RBCs prompt removal by spleen
What is Goodpasture syndrome?
Autoantibodies prodced against Type IV collagen, leading to lung and kidney damage, and death
What is the histological features of Goodpasture syndrome?
Smooth, ribbon like appearance to glomerulus
What is the pathogenesis of pernicious anemia?
Autoantibodies to intrinsic factor or gastric/parietal cells
What is the pathogenesis of hashimoto’s thyroiditis?
Hypothyroid state induced by autoantibodies and autoreactive T cells to thyroid glands proteins
What is idiopathic thrmobocytopenia (ITP)?
Platelets destroyed by autoantibodies to platelet membrane proteins, causing skin leasions/epidermal hemorrhage
What is the treatment for ITP?
IVIG
What is Grave’s disease?
Autoantibodies to TSH receptor, causing hyperthyroidism d/t over stimulation
What is myasthenia gravis?
Autoantibodies attack alpha chain of nicotinic acetylcholine receptors, blocking muscle signals
What is the pathogenesis of DM I?
Autoantibodies to Beta cells in pancreas, cause CTLs to kill (type IV)
What type of hypersensititivty is myasthenia gravis?
Type II
What is the pathogenesis of MS?
Th1 and Th17 cells specific of myelin antigens become activated, and attack myelin nerve cells
