Acute Transplant Rejection

Summary

Acute Rejection is a type of transplant rejection that occurs within weeks (acutely) after receiving a new graft. It is caused by T-cells attacking the donor MHCs, and is characterized by vascular damage. Biopsy of the affected organ will reveal dense interstitial lymphocytic infiltrates in the graft. Although serious, acute transplant rejection can be prevented or reversed with immunosuppressive drugs like corticosteroids or calcineurin-inhibiting drugs. 

Key Points

• Acute Rejection
  • Occurs weeks after transplant (acute)
    • Usually occurs 1-2 weeks after receiving a transplant
  • Mechanism
    • T-cells activate against graft
      • Cytotoxic T-cells and Helper T-cells activate against donor MHCs
      • Example of Type IV Hypersensitivity Reaction
    • B-cells make antibodies against graft
      • Less important than T-cell action
      • Antibodies are not premade (contrast vs. Hyperacute Rejection)
      • Example of Type II Hypersensitivity Reaction
  • Biopsy reveals dense interstitial lymphocytic infiltrate
    • perivascular and peribronchial lymphocytic infiltrates seen under light microscopy
  • Prevent or treat with immunosuppression
    • e.g. Cyclosporine, Tacrolimus, Sirolimus