Human Immunology (Videos Available)

Tuesday July 03, 2018 from 08:30 to 09:30

Room: N-106

403.2 Single-cell analysis of NFATc1 amplification in T cells for pharmacodynamic monitoring of tacrolimus (Video Available)

Carla C. Baan, Netherlands

Head of laboratory
Internal Medicine
Erasmus MC


Single-Cell Analysis of NFATc1 Amplification in T Cells for Pharmacodynamic Monitoring of Tacrolimus

Nynke Kannegieter1, Dennis Hesselink1, Marjolein Dieterich1, Gretchen de Graav1, Rens Kraaijeveld1, Carla Baan1.

1Internal Medicine, Erasmus Medical Center, Rotterdam, Netherlands

Introduction:Therapeutic drug monitoring (TDM) of the calcineurin inhibitor tacrolimus (TAC) is based on blood concentrations that show an imperfect correlation with the occurrence of acute rejection. A pharmacodynamic method that reflects the direct inhibitory effects of TAC may therefore be preferable over traditional pharmacokinetic TDM. Here, we tested whether measuring the amplification of NFATc1, a member of the calcineurin pathway, is suitable for TDM of TAC.
Materials and Methods:NFATc1 amplification was monitored in T cells of kidney transplant recipients who received either TAC- (n = 11) or a belatacept (BELA)-based (n = 10) immunosuppressive therapy. Heparinized blood samples were collected at days 0 (pre-transplantation), 4, 30, 90, 180 and 360 after transplantation and stimulated with PMA/ionomycin. In addition, individual drug effects on NFATc1 amplification were studied in vitro, after spiking blood samples of healthy volunteers with either TAC, BELA or mycophenolate mofetil.
Results and Discussion: In TAC- treated patients, at day 30 after transplantation, NFATc1 amplification was significantly inhibited in CD4+ T cells expressing the co-stimulation receptor CD28 (mean inhibition 37%; p = 0.01) and in CD8+CD28+ T cells (mean inhibition 29%; p = 0.02), while this was not observed in CD8+CD28- T cells or in BELA-treated patients. The TAC pre-dose concentrations of these patients correlated inversely with NFATc1 amplification in CD28+ T cells (rs = -0.46; p < 0.01). The in vitro study revealed a dose dependent effect of TAC on NFATc1 amplification in all three tested T cell subsets (mean inhibition 58% at 50 ng/ml TAC; p = 0.02), while belatacept and mycophenolate mofetil did not show an effect.
Only one patient under TAC-based therapy suffered from a rejection and, as a consequence, no conclusions could be drawn on the association between NFATc1 amplification and rejection risk.
Conclusion: In conclusion, measuring NFATc1 amplification is a promising tool for monitoring the biological effects of TAC on T cell subsets directly, which might be useful for further transplantation diagnostics.

© 2024 TTS2018