Abstract: SA-PO470

De Novo Donor Specific Antibody (dnDSA) and Biopsy Proven Acute Rejection (BPAR) Are Associated with Higher Intrapatient Variability (IPV) in Tacrolimus Trough Levels Following Renal Transplant

Session Information

Category: Transplantation

  • 1702 Transplantation: Clinical and Translational

Author

  • Goldsmith, Petra M, Royal Liverpool Hospital, Lymm, United Kingdom

Group or Team Name

  • UK Transplant Audit Collaborative
Background

High IPV in Tacrolimus trough levels has been associated with poorer kidney transplant outcomes, including the occurrence of BPAR. However, there is a paucity of information in the published literature about any association between high IPV and the development of dnDSA.

Methods

We performed a single centre retrospective cohort study with the hypothesis that patients identified as having BPAR or dnDSA at any timepoint would have a greater mean IPV than those who did not. Patients transplanted in our centre between 2009-2014 and receiving standard preparation Tacrolimus based immunosuppression were included. Patients receiving other primary immunosuppression, who were in receipt of organs other than kidneys and who did not have a functioning transplant at 2 years were excluded. One hundred and seventy one patients were identified with IPV data collected at 2 predetermined time points: 6-12 months post-transplant (T1) and the most recent 12 months (T2).

Results

IPV values were compared using Mann Whitney U tests between patients developing a) BPAR and b) dnDSA with those who did not, at both T1 and T2. The results are shown in table 1.

There is a clear association between BPAR and high IPV at T1 (p=0.01) which reverses at T2 but fails to reach statistical significance. For dnDSA, we observe a higher IPV for both T1 and T2 although in both cases it is not statistically significant.

Conclusion

As most episodes of BPAR occur early post-transplant, it is possible that the observed reversal in IPV at T2 reflects more precise monitoring and control of Tacrolimus exposure in these patients following rejection. In respect of the observation of higher IPV at both T1 and T2 for dnDSA, the small sample size who developed antibodies may have contributed to the failure to reach significance and it is anticipated that this analysis will be expanded to a multicentre cohort in the future.

Table 1: Mann Whitney U Test to compare BPAR and DnDSA
 Mean Rank T1T1 P ValueMean Rank T2T2 P Value
BPAR (N=24)
No BPAR (N=147)
108.3
82.4
0.0171
88.5
0.05
DnDSA (N=16)
No dnDSA (N=155)
84.6
99.3
0.1384.8
97.2
0.17