Renal Transplant: T-Cell mediated Hypersensitivity

on 13.1.09 with 0 comments



Principles to understand

  • immediate graft rejection is mediated by ABO or preformed HLA antibodies. they attack vascular endothelium and provoke clotting

  • acute rejection (2 weeks) is mediated by T cells

  • late rejection (months to years) is due to both T cells and antibodies

  • recurrence of the original disease occurs after years

  • survival of grafts is best in identical twins, followed by HLA-matched siblings, HLA-matched living related donors, HLA-matched cadaveric donors, HLA-mismatched donors

  • bone marrow ablation before the graft, followed by hematopoietic stem cell transplantation, seems to produce permanent graft survival in NOD (non-obese diabetic) mouse model

  • this works best when you are young and your thymus is still working



T-cell-mediated autoimmune disease

  • insulin-dependent diabetes mellitus: autoantigen is against pancreatic β-cell. β-cell transplantation would be futile if autoimmune disease persists

  • rheumatoid arthritis: autoantigen is unknown synovial joint antigen leading to joint inflammation and destruction

  • experimental autoimmune encephalomyelitis (EAE), multiple sclerosis: autoantigen is antigen against myelin; leads to brain invasion by CD4 T cells and weakness


DR3/4in healthy controls and diabetics

  • DR3/4 phenotype is not directly related to diabetes

  • however, DR3/4 are linked to a DQ antigen that does present a particular pancreatic β cell peptide differently




Category: Pathology Notes

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