See also these tables on transplant rejection pathologies from FA 2020.
Chronic allograft rejection of a transplanted organ occurs over months to years (the question was in the timeline of weeks). It is secondary to a CD4+ T lymphocyte response against donor peptides such as MHC. T cell activation leads to cytokine production and humoral and cellular hypersensitivity reactions (type II and IV). When you think Chronic rejection, you should be thinking VESSELS because this often leads to vascular arteriosclerosis and smooth muscle proliferation with parenchymal fibrosis and atrophy.
With acute rejection, you should be thinking of INFILTRATION, that is T-lymphocytes in the vasculature of the tubules and arterial walls leading to endothelitis. The primary histologic changes include interstitial infiltration with lymphocytic cells, in addition to the obliteration of the tubular basement membranes (as in this question with a kidney transplant).
submitted by โshak360(20)
See this question in block 1 about GVHD.
See also these tables on transplant rejection pathologies from FA 2020.
Chronic allograft rejection of a transplanted organ occurs over months to years (the question was in the timeline of weeks). It is secondary to a CD4+ T lymphocyte response against donor peptides such as MHC. T cell activation leads to cytokine production and humoral and cellular hypersensitivity reactions (type II and IV). When you think Chronic rejection, you should be thinking VESSELS because this often leads to vascular arteriosclerosis and smooth muscle proliferation with parenchymal fibrosis and atrophy.
With acute rejection, you should be thinking of INFILTRATION, that is T-lymphocytes in the vasculature of the tubules and arterial walls leading to endothelitis. The primary histologic changes include interstitial infiltration with lymphocytic cells, in addition to the obliteration of the tubular basement membranes (as in this question with a kidney transplant).