Transplant Immunology and Rejection Flashcards

Which complement pathway is primarily activated in antibody-mediated rejection?

Answer: Classical pathway

The classical complement pathway is activated when donor-specific antibodies bind to graft endothelium, initiating the complement cascade in antibody-mediated rejection.

C4d deposition on peritubular capillaries is a hallmark finding in which type of renal transplant rejection?

Answer: Antibody-mediated rejection

C4d deposition on peritubular capillaries is a pathologic marker of antibody-mediated rejection, indicating complement activation by donor-specific antibodies.

Which of the following is the most important factor in determining a patient's risk for rejection in the first year after transplant?

Answer: Number of HLA mismatches

The number of HLA mismatches between donor and recipient is the most important immunologic factor determining rejection risk in the first year post-transplant.

Which statement best describes tolerance in transplantation?

Answer: The recipient accepts the graft without ongoing immunosuppression

Operational tolerance means the recipient's immune system accepts the graft as self without requiring long-term immunosuppressive therapy.

Which cytokine plays the most central role in T-cell activation during acute rejection?

Answer: IL-2

IL-2 is the primary growth factor for T lymphocytes and plays a central role in T-cell proliferation during acute rejection episodes.

The direct pathway of allorecognition involves recipient T cells recognizing donor antigens presented by which cells?

Answer: Donor antigen-presenting cells

In the direct pathway, recipient T cells recognize intact donor MHC molecules presented directly on donor antigen-presenting cells.