Sirolimus vs mycophenolate moftile in Tacrolimus based therapy following induction with Antithymocyte globulin promotes regulatory T cell expansion and inhibits RORγt and T-bet expression in kidney transplantation

Netrin-1 reduces lung ischemia-reperfusion injury by increasing the proportion of regulatory T cells

Objective

Inflammation is the primary mechanism of lung ischemia-reperfusion injury (LIRI) and neurologic factors can regulate inflammatory immune responses. Netrin-1 is an axonal guidance molecule, but whether Netrin-1 plays a role in LIRI remains unclear.

Methods

A mouse model of LIRI was established. Immunohistochemistry was used to detect expression of Netrin-1 and to enumerate macrophages and T cells in lung tissue. The proportion of regulatory T cells (Tregs) was assessed by flow cytometry. Levels of apoptosis were assessed by terminal deoxynucleotidyl transferase dUTP nick end staining.

Results

Numbers of macrophages and T cells in the lung tissues of mice with LIRI were elevated, while expression of netrin-1 was significantly decreased. Flow cytometry showed that the proportion of Tregs in mice with LIRI was significantly decreased. The proportion of Tregs among lymphocytes was positively correlated with netrin-1 expression. In vitro experiments showed that netrin-1 promoted an increase in Treg proportion through the A2b receptor. Animal experiments showed that netrin-1 could inhibit apoptosis and reduce T cell and macrophage infiltration by increasing the proportion of Tregs, ultimately reducing LIRI. Treg depletion using an anti-CD25 monoclonal antibody blocked the effects of netrin-1.

Conclusion

Netrin-1 reduced LIRI by increasing the proportion of Tregs.

Evaluation of Thymic Output and Regulatory T Cells in Kidney Transplant Recipients with Chronic Antibody-Mediated Rejection

Background

Regulatory T cells (Tregs) and recent thymic emigrants (RTEs) have an essential role in the regulation of allogeneic immune responses. However, their mechanisms of action in chronic antibody-mediated rejection (cAMR) are still unclear. In this study, we aimed to compare Treg and RTE levels between stable graft function (SGF) patients and cAMR subjects after kidney transplantation.

Method

Mononuclear cells (MNs) were separated from peripheral blood, and flow cytometry analysis was performed for detection of CD4⁺ and CD25^high as Treg markers and CD4⁺, CD31⁺, and CD45RA⁺ as RTE immunophenotyping markers.

Result

The level of peripheral Treg cells was significantly lower in cAMR subjects in comparison to stable graft function patients. Moreover, SGF patients who had received cyclosporine A had a higher level of Treg in comparison to the tacrolimus recipients. Nevertheless, the RTE level between SGF and cAMR patients did not show any significant differences.

Conclusion

It seems that Treg cells are significantly associated with transplant outcomes in cAMR patients, and prescribed immunosuppressive drugs can influence the frequency of this crucial subset of T cells. Although these drugs are beneficial and inevitable for allograft maintenance, more investigations are needed to elucidate their complete effects on different immune cell subsets which some of them like Tregs are in favor of transplant tolerance. Besides, the thymic output is seemingly not a beneficial biomarker for predicting cAMR; however, more in vivo and in vitro studies are needed for revealing the precise role of Tregs and RTEs in the transplantation context.

Recent advances in precision medicine for individualized immunosuppression

PURPOSE OF REVIEW

The current tools to proactively guide and individualize immunosuppression in solid organ transplantation are limited. Despite continued improvements in posttransplant outcomes, the adverse effects of over-immunosuppression or under-immunosuppression are common. The present review is intended to highlight recent advances in individualized immunosuppression.

RECENT FINDINGS

There has been a great focus on genomic information to predict drug dose requirements, specifically on single nucleotide polymorphisms of CYP3A5 and ABCB1. Furthermore, biomarker studies have developed ways to better predict clinical outcomes, such as graft rejection.

SUMMARY

The integration of advanced computing tools, such as artificial neural networks and machine learning, with genome sequencing has led to intriguing findings on individual or group-specific dosing requirements. Rapid computing allows for processing of data and discovering otherwise undetected clinical patterns. Genetic polymorphisms of CYP3A5 and ABCB1 have yielded results to suggest varying dose requirements correlated with race and sex. Newly proposed biomarkers offer precise and noninvasive ways to monitor patient's status. Cell-free DNA quantitation is increasingly explored as an indicator of allograft injury and rejection, which can help avoid unneeded biopsies and more frequently monitor graft function.

Recent Progress in Treg Biology and Transplant Therapeutics

Purpose of Review

Regulatory T cell (Treg) biology continues to evolve at a rapid pace. The role of Tregs in solid organ transplantation offers a unique window into Treg ontogeny and function as well as limitless possibilities for clinical application. Here we review recent significant discoveries and key translational work.

Recent Findings

Advances in transplantation deepen understanding of Treg differentiation, expansion, transcription, co-stimulation, and signaling. T cell receptor (TCR) sequencing and single-cell analytics allow unprecedented insight into Treg repertoire diversity and phenotypic heterogeneity. Efforts to replace conventional immunosuppression with Treg adoptive immunotherapy are underway and coalescing around strategies to increase efficiency through development of donor-reactive Tregs.

Summary

Adoptive immunotherapy with Tregs is a leading tolerogenic strategy. Early clinical trials suggest that Treg infusion is safe and reports on efficacy will soon follow.