Step I Chronic Rejection Question?

[MissMedicine]

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Hi I was wondering if you guys could tell me whether chronic rejection is Ab or cell mediated... FA says Ab mediated damage to the endothelial cells, but I kinda remember learning that its cell-mediated, and then I just did a question (the pt with Hep B with a liver transplant) and it too says its t-cell mediated.

please advise. 😍

 

[MissMedicine]

also, are virally infected cells/tumor cells killed by cd8 cells, or cd16 (NK cells)... in FA diagram, they show a cd8 attack, but i just did a qbank question that says NK cells kill virally infected bac and tumor cells post saturation with Ab... so are both methods used??!

 

[FoxyDoc]

All rejection is T cell mediated except for hyperacute which is due to preformed antibodies.

 

[phllystyl]

also, are virally infected cells/tumor cells killed by cd8 cells, or cd16 (NK cells)... in FA diagram, they show a cd8 attack, but i just did a qbank question that says NK cells kill virally infected bac and tumor cells post saturation with Ab... so are both methods used??!

MHC Class I molecules are linked to viral Ags in the RER and presented to CD8+ cytotoxic T cells.

NK Cells are a non-specific defense involved in viral protection as well. Often they are involved in Ab-dependant cytotoxicity rxns, as I recall.

 

[MissMedicine]

All rejection is T cell mediated except for hyperacute which is due to preformed antibodies.

Ok thanks foxy, thats what I thought, so then is this another FA mistake? 😡

 

[MissMedicine]

do ya'll know what type of t cell does delayed-type hypersensitivity? is it Th1 or Th2?

 

[MissMedicine]

MHC Class I molecules are linked to viral Ags in the RER and presented to CD8+ cytotoxic T cells.

NK Cells are a non-specific defense involved in viral protection as well. Often they are involved in Ab-dependant cytotoxicity rxns, as I recall.

THANKS!!

 

[fernj1975]

Th1 cells activate the cell mediated immunity response thus they are the cells responsible for type IV hypersensitivity response. Th2 cells are responsible for the humoral response. interferon gamma from Th1 cells inhibit th2 cells and IL10 from Th2 cells inhibit Th1 cells.

 

[phllystyl]

my fav example of Th1 v Th2 is M. Leprae... If your body mounts a Th2 response against it, you get leprosy.

If your body mounts a Th1, you get a milder tuberculoid illness without the horrible disfiguration.

Most people have a CMI response (Th1), and avoid leprosy

 

[MissMedicine]

Ok thanks foxy, thats what I thought, so then is this another FA mistake? 😡

so is this a mistake??!

 

[MissMedicine]

hello?hello??

so is the chronic rejection being ab mediated another mistake in FA?

 

[-=UberSharky=-]

All rejection is T cell mediated except for hyperacute which is due to preformed antibodies.

not to add to the confusion..but BRS path (p.81) says chronic is "Ab-mediated vascular damage". i think FA is correct.

 

[scully]

It is both -- ab in the blood vessel walls and cytotoxic Ts.