CCTN Transplant Immunology and Rejection 2 — Questions and Answers
Question 1: Which complement pathway is primarily activated in antibody-mediated rejection?
- Alternative pathway
- Lectin pathway
- Classical pathway (Correct answer)
- Terminal pathway only
Correct 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.
Question 2: C4d deposition on peritubular capillaries is a hallmark finding in which type of renal transplant rejection?
- Hyperacute rejection
- Acute cellular rejection
- Antibody-mediated rejection (Correct answer)
- Chronic cellular rejection
Correct answer: Antibody-mediated rejection
C4d deposition on peritubular capillaries is a pathologic marker of antibody-mediated rejection, indicating complement activation by donor-specific antibodies.
Question 3: Which of the following is the most important factor in determining a patient's risk for rejection in the first year after transplant?
- Recipient age
- Number of HLA mismatches (Correct answer)
- Donor BMI
- Cold ischemia time
Correct 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.
Question 4: Which statement best describes tolerance in transplantation?
- The recipient's immune system is permanently suppressed
- The recipient accepts the graft without ongoing immunosuppression (Correct answer)
- The graft is rejected slowly over years
- The donor kidney functions normally without HLA matching
Correct 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.
Question 5: Which cytokine plays the most central role in T-cell activation during acute rejection?
- IL-4
- IL-10
- IL-2 (Correct answer)
- TNF-alpha
Correct 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.
Question 6: The direct pathway of allorecognition involves recipient T cells recognizing donor antigens presented by which cells?
- Recipient antigen-presenting cells
- Donor antigen-presenting cells (Correct answer)
- Natural killer cells
- Recipient B cells
Correct answer: Donor antigen-presenting cells
In the direct pathway, recipient T cells recognize intact donor MHC molecules presented directly on donor antigen-presenting cells.
CCTN Transplant Immunology and Rejection 2
Which complement pathway is primarily activated in antibody-mediated rejection?