NFAT-Dependent Cytokine and p70S6 Kinase Activity Assays as Immune Monitoring Tools for Transplant Patients on CNIs and mTOR Inhibitors
Kidney Transplant Service, UCSF, San Francisco, CA
Meeting: 2013 American Transplant Congress
Abstract number: A631
Objective: To compare NFAT-regulated gene expression and p70S6k activity in kidney transplant patients maintained on full-dose tacrolimus plus MPA versus reduced-dose tacrolimus and everolimus.
Methods: Peripheral blood was collected pre-dose (T0) and 1.5 hours post dosage (T1.5) of immunosuppression in control (Ctl) (full dose tacrolimus + MPA + steroids) and everolimus groups (Ever) (low dose tacrolimus + everolimus+ steroids) pre-, 3, 6, & 12 months post-transplant. Cells were stimulated with PMA/ionomycin. RT-PCR quantified NFAT-regulated genes IL-2, IFN-Γ & GM-CSF. The residual expression (RE) of each gene was calculated as T1.5/T0 x 100 & the average of the 3 genes as the mean RE (MRE). P70S6k activity was detected by flow cytometry & expressed as mean fluorescence intensity (MFI). The Mann-Whitney U test for comparison of medians was used.
Results: 5 patients were randomized to the Ctl arm & 6 patients to the Ever arm. All patients had 0,3,& 6 month data. 5 patients in the Ctl arm & 3 in the Ever arm had 12 month data. Median tacrolimus levels were higher in Ctls at 3 & 6 months but not SS at month 12. (P=0.036,0.022,0.177). MRE of NFAT regulated genes at month 3 was 21.4% (CI 10.6-65.8) in Ctls vs. 64.4% in Ever (CI 16.4-72.8 P=0.12). MRE at month 6 was 30.6% (CI 2.3-64.5) Ctls & 59.8% (CI 40-92.1) Ever (P=0.095). MRE at month 12 was 29.7% (CI 3.4-66.1) Ctls & 59.7% (CI 35.7-97.6) Ever (P=0.14). 3 month p70S6k activity at T1.5 in Ctls was 6251 MFI (CI 1340-9469) & 976 MFI (CI 461-1234) in the Ever arm (P=0.0081). 6 month p70S6k activity at T1.5 in Ctls was 6828 MFI (CI 1646-9324) & 1376 MFI Ever arm (CI 309-1855, P=0.022). 12 month p70S6K activity at T1.5 in Ctls was 6778 MFI (CI 4300-9464) &1406 MFI Ever arm (CI -2109-6151, P=0.036).
| NFAT- regulated Gene Expression (%MRE) | Controls | Everolimus | P value |
| 3M (n=11) | 21.4 | 64.4 | 0.12 |
| 6M (n=11) | 30.6 | 59.8 | 0.095 |
| 12M (n=8) | 29.7 | 59.7 | 0.14 |
| P70S6K Activity at T1.5 (MFI) | |||
| 3M (n=11) | 6251 | 976 | 0.0081 |
| 6M (n=11) | 6828 | 1376 | 0.022 |
| 12M (n=8) | 6778 | 1406 | 0.036 |
| Median Tacrolimus Trough Level (ug/L) | |||
| 3 M (n=11) | 8.2 | 5.1 | 0.036 |
| 6M (n=11) | 9.2 | 4.0 | 0.022 |
| 12M (n=8) | 6.3 | 5.0 | 0.177 |
Conclusions: Assays measuring NFAT- regulated gene expression and p70S6k activity accurately reflect the pharmacodynamics of tacrolimus and everolimus and may provide a more accurate assessment of the immune system than the limited value of drug levels.
Webber, A.: Grant/Research Support, Novartis. Vincenti, F.: Grant/Research Support, Novartis, Astellas, BMS, Alexion, Genetech, Pfizer.
To cite this abstract in AMA style:
Webber A, Hirose R, Leung C, Vincenti F. NFAT-Dependent Cytokine and p70S6 Kinase Activity Assays as Immune Monitoring Tools for Transplant Patients on CNIs and mTOR Inhibitors [abstract]. Am J Transplant. 2013; 13 (suppl 5). https://atcmeetingabstracts.com/abstract/nfat-dependent-cytokine-and-p70s6-kinase-activity-assays-as-immune-monitoring-tools-for-transplant-patients-on-cnis-and-mtor-inhibitors/. Accessed November 22, 2024.« Back to 2013 American Transplant Congress