Objective:

To analyze factors influencing allosensitization and waiting time for kidney retransplantation, focusing on maintenance immunosuppression.

Approach:

• Study Design: Retrospective single-center study of kidney retransplant recipients at the University Hospital of Zurich from 2012 to 2023.
• Cohort Characteristics: Included 191 retransplantations out of 1,040 kidney transplants, with 27 living donations.
• Data Analysis: Evaluated the impact of maintenance immunosuppression on allosensitization and calculated panel reactive antibodies (cPRA).

Key Findings:

• 16% of kidney transplants were retransplantations.
• The burden of immunosuppression decreased from graft failure to retransplantation (triple IS 54% vs. 12%, p < 0.05).
• Allosensitization increased significantly with a higher number of HLA-antibodies (MFI > 1,000/patient 5.8 vs. 12.45, p > 0.001).
• Intake of calcineurin inhibitors was associated with lower cPRA (27% vs. 78% no CNI, p < 0.001).
• Intake of antimetabolites was associated with lower cPRA (23% for azathioprine, 20% for mycophenolic acid, and 88% for no antimetabolite, p < 0.001).
• First retransplantation had a lower cPRA compared to subsequent retransplantations (41% vs. 78% vs. 88%, p = 0.02).

Interpretation:

Intake of antimetabolites at retransplantation is associated with reduced allosensitization, while waiting time has a weak correlation with allosensitization.

Limitations:

• Single-center study may limit generalizability.
• Retrospective design may introduce bias.

Conclusion:

The intake of antimetabolite at retransplantation showed a protective effect against allosensitization, while waiting time had only a weak correlation with allosensitization.