Nuclear factor of activated T cells as potential pharmacodynamic biomarker for the risk of acute and subclinical rejection in de novo liver recipients

Pharmacodynamic monitoring by residual gene expression of the nuclear factor of activated T cell-regulated genes in lung transplant recipients and its correlation with tacrolimus blood levels

Introduction

Trough blood levels (C0) of tacrolimus are used to adjust drug dosage, but they do not consistently correlate with clinical outcomes. Measurement of residual gene expression of nuclear factor of activated T cell (NFAT)-regulated genes (NFAT-RGE) has been proposed as a pharmacodynamic biomarker to assess the degree of immunosuppression in certain solid organ transplantations, but little is known regarding lung transplant recipients (LTR). Our primary objective is to correlate tacrolimus blood levels with NFAT-RGE.

Methods

NFAT-RGE and tacrolimus C0 and peak (C1.5) levels were determined in 42 patients at three, six and 12 months post-transplantation.

Results

Tacrolimus C0 did not exhibit a correlation with NFAT-RGE, whereas C1.5 did. Besides, over 20% of measurements indicated high levels of immunosuppression based on the below 30% NFAT-RGE threshold observed in many studies. Among those measurements within the therapeutic range, 19% had an NFAT-RGE<30%.

Conclusion

Consequently, a subset of patients within the tacrolimus therapeutic range may be more susceptible to infection or cancer, potentially benefiting from NFAT-RGE and tacrolimus peak level monitoring to tailor their dosage. Further quantitative risk assessment studies are needed to elucidate the relationship between NFAT-RGE and the risk of infection, cancer, or rejection.

Incidence and risk factors of subclinical rejection after pediatric liver transplantation, and impact on allograft fibrosis

INTRODUCTION

Subclinical rejection (SCR) is a common injury in protocol biopsy after pediatric liver transplantation (pLT), but its effect on the recipient is not clearly understood. We herein investigated the incidence and risk factors involved in SCR and analyzed the relationship between SCR and allograft fibrosis (AF).

METHODS

We retrospectively reviewed the biopsy results from 507 children between May 2013 and May 2019, and 352 patients underwent protocol biopsy 2 years after pLT, 203 underwent protocol biopsy 5 years after pLT, and 48 underwent protocol biopsy both 2 and 5 years after pLT.

RESULTS

The incidence of SCR in the 5-year group was higher than that in the 2-year group (20.2% vs.13.4%, respectively, p = .033). The number of patients with mild and moderate SCR in the 5-year group was also higher than that in the 2-year group (p = .039). Logistic regression analysis showed that acute rejection before liver biopsy and deceased donor liver transplantation (DDLT) were independent risk factors for SCR in the two groups, and that the incidence and severity of AF in protocol biopsies at both periods in the SCR group were higher than those in the non-SCR group (p < .05).

CONCLUSIONS

The incidence and severity of SCR increased with the prolongation of protocol biopsy time. We postulate that acute rejection and DDLT are independent risk factors for SCR after transplantation. As the occurrence of SCR also augmented the incidence and severity of AF.

Getting immunosuppression just right: the role of clinical biomarkers in predicting patient response post solid organ transplantation

INTRODUCTION

Actually, immunosuppression selection isn't based on individual immune alloreactivity, and immunosuppressive drug dosing is mainly based on the development of toxicity and the achievement of specific target concentrations. Since a successful outcome requires optimal patient risk stratification and treatment, several groups have evaluated candidate biomarkers that have shown promise in the assessment of individual immune responses, the prediction of personal pharmacodynamic effects of immunosuppressive drugs and the prognosis and diagnosis of graft outcomes..

AREAS COVERED

This review includes biomarkers that the Scientific Community in Solid Organ Transplantation currently considers to have potential as diagnostic and prognostic biomarkers of graft evolution. We have focused on recent scientific advances and expert recommendations regarding the role of specific and non-specific pharmacodynamic biomarkers that are mainly involved in the T-cell-mediated response.

EXPERT OPINION

Integral pharmacologic monitoring that combines pharmacokinetics, pharmacogenetics and predictive pharmacodynamic biomarkers may provide crucial information and allow personal adjustment of immunosuppressive drugs at an early stage before severe adverse events ensue. Multicentre, randomized, prospective and interventional trials are needed to fine tune the established cut-off values for each biomarker and the optimal monitoring frequency for each biomarker and to accurately evaluate possible clinical confounding factors to enable correct clinical qualification.

Monitoring of gene expression in tacrolimus-treated de novo renal allograft recipients facilitates individualized immunosuppression: Results of the IMAGEN study

AIMS

Calcineurin inhibitors (CNI) have a small therapeutic window, and drug monitoring is required. Pharmacokinetic monitoring does not correlate sufficiently with clinical outcome. Therefore, the expression of nuclear factor of activated T cells (NFAT)-regulated genes in the peripheral blood has been suggested as a potentially useful immune monitoring tool to optimize CNI therapy. NFAT-regulated gene expression (RGE) was evaluated in renal allograft recipients as predictive biomarker to detect patients at risk of acute rejection or infections.

METHODS

NFAT-RGE (interleukin-2, interferon-γ, granular-macrophage colony-stimulating factor) was evaluated by quantitative real-time polymerase chain reaction in whole blood samples at day 7, day 14, month 1, 3, and 6 after transplantation in 64 de novo renal allograft recipients from 3 European centres. Immunosuppression consisted of tacrolimus (Tac), mycophenolic acid, and corticosteroids.

RESULTS

Tac concentrations (C0 and C1.5) correlated inversely with NFAT-RGE (P < .01). NFAT-RGE showed a high interindividual variability (1-61%). Patients with high residual gene expression (NFAT-RGE ≥30%) were at the increased risk of acute rejection in the following months (35 vs. 5%, P = .02), whereas patients with low residual gene expression (NFAT-RGE <30%) showed a higher incidence of viral complications, especially cytomegalovirus and BK virus replication (52.5 vs. 10%, P = .01).

CONCLUSIONS

NFAT-RGE was confirmed as a potential noninvasive early predictive biomarker in the immediate post-transplant period to detect patients at risk of acute rejection and infectious complications in Tac-treated renal allograft recipients. Monitoring of NFAT-RGE may provide additional useful information for physicians to achieve individualized Tac treatment.

Maintenance Immunosuppression in Solid Organ Transplantation: Integrating Novel Pharmacodynamic Biomarkers to Inform Calcineurin Inhibitor Dose Selection

Calcineurin inhibitors, the primary immunosuppressive therapy used to prevent alloreactivity of transplanted organs, have a narrow therapeutic index. Currently, treatment is individualized based on clinical assessment of the risk of rejection or toxicity guided by trough concentration monitoring. Advances in immune monitoring have identified potential markers that may have value in understanding calcineurin inhibitor pharmacodynamics. Integration of these markers has the potential to complement therapeutic drug monitoring. Existing pharmacokinetic-pharmacodynamic (PK-PD) data is largely limited to correlation between the biomarker and trough concentrations at single time points. Immune related gene expression currently has the most evidence supporting PK-PD integration. Novel biomarker-based approaches to pharmacodynamic monitoring including development of enhanced PK-PD models are proposed to realize the full clinical benefit.