transplant rejection



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  • Adequacy

    • at least 3 fragments
    • minimal 3 levels each

  • Grading

    • Nonrejection
      • ischemic injury
        • 2004: early (0-6 weeks post-transplant), late (related to allograft CAD)
        • 1990: A (0-3 weeks post-transplant), B (late ischemia)
        • histology
          • early: contraction band, necrosis, myocyte vacuolization, mixed inflammatory infiltrate
          • late: vacuolization, microinfarcts
        • ischemia predominance over inflammation
      • quilty effect
        • 1990 A: endocardium only, no myocyte encroachment
        • 1990 B: myocyte encroachment
        • subyping A vs B has no clinical significance
        • B cells, plasma cells
        • background fibrosis and vascularity favors quilty
        • CD21 highlights follicular dendritic cell network
      • infection
      • lymphoproliferative disorder
    • acute cellular rejection
      • 0R: no acute cellular rejection
        • no mononuclear infiltrate
        • no myocyte damage
      • 1R: mild acute rejection
        • mononuclear infiltrate (perivascular, interstitial)
        • up to 1 focus of myocyte damage
        • encompasses 1990 grade 1A, 1B, 2
          • 1A: focal infiltrate, no myocyte damage
          • 1B: diffuse infiltrate, no myocyte damage
          • 2: focal infiltrate with myocyte damage
      • 2R: moderate acute rejection
        • multiple mononuclear infiltrates with myocyte damage
        • may have eosinophils
        • foci may be in same or different fragments
        • encompasses 1990 grade 3A
      • 3R: severe acute rejection
        • diffuse inflammation with myocyte damage
        • mononuclear or PMNs
        • in multiple fragments
        • encompasses 1990 grade 3B, 4
    • Humoral / antibody-mediated rejection (AMR)
      • histology
        • endothelial cell swelling
        • intravascular macrophages
        • edema, hemorrhage
        • PMNs within and around small vessels
      • confirmatory IF/IHC
        • IF: C3d, C4d deposition in capillaries
        • IHC: C3d, CD68
        • donor-specific antibodies in serum
      • AMR0
        • no histologic or immunopathologic features of AMR
      • AMR1
        • 2004: histologic features of AMR confirmed by positive immunofluorescence or immunoperoxidase staining for AMR (CD68, C4d)
        • 1990: immunofluorescence, vasculitis, severe edema in the absence of cellular infiltrate
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