Comparison of Regulatory T Cells in Hemodialysis Patients and Healthy Controls

Abstract

SummaryBackground and objectives Cell-based therapy with natural (CD4 + CD25 hi CD127 lo ) regulatory T cells to induce transplant tolerance is now technically feasible. However, regulatory T cells from hemodialysis patients awaiting transplantation may be functionally/numerically defective. Human regulatory T cells are also heterogeneous, and some are able to convert to proinflammatory Th17 cells. This study addresses the suitability of regulatory T cells from hemodialysis patients for cell-based therapy in preparation for the first clinical trials in renal transplant recipients (the ONE Study).Design, setting, participants, & measurements Healthy controls and age-and sex-matched hemodialysis patients without recent illness/autoimmune disease on established, complication-free hemodialysis for a minimum of 6 months were recruited. Circulating regulatory T cells were studied by flow cytometry to compare the regulatory T cell subpopulations. Regulatory T cells from members of each group were compared for suppressive function and plasticity (IL-17-producing capacity) before and after in vitro expansion with and without Rapamycin, using standard assays.Results Both groups had similar total regulatory T cells and subpopulations I and III. In each subpopulation, regulatory T cells expressed similar levels of the function-associated markers CD27, CD39, HLA-DR, and FOXP3. Hemodialysis regulatory T cells were less suppressive, expanded poorly compared with healthy control regulatory T cells, and produced IL-17 in the absence of Rapamycin. However, Rapamycin efficiently expanded hemodialysis regulatory T cells to a functional and stable cell product.Conclusions Rapamycin-based expansion protocols should enable clinical trials of cell-based immunotherapy for the induction of tolerance to renal allografts using hemodialysis regulatory T cells.

Phenotypic Complexity of the Human Regulatory T Cell Compartment Revealed by Mass Cytometry

“…Using CD45RA and FOXP3 expression, Miyara et al (17) demonstrated a population of naive Tregs and two populations of memory Tregs that exhibited differential methylation of the TSDR region, a measure of FOXP3 constitutive expression and, as such, Treg stability. As expected, our data showed that the naive Treg compartment (CD45RA + ) did not express markers associated with Ag-experienced Tregs [CCR4 (12), CD39 (19,26,34), and HLA-DR (27,35)] and displayed reduced expression of a number of other markers (ICOS and CD147). However, the inclusion of multiple markers revealed that the CD45RA + population of Tregs is composed of a number of subpopulations itself.…”

Transient antibody targeting of CD45RC induces transplant tolerance and potent antigen-specific regulatory T cells

“…To date, there is no therapy with these properties in clinical organ transplantation (35). Clinical protocols applying polyclonal or antigen-specific CD4 + Treg cell therapy in transplantation are underway and hold promise, but results are not yet available (36). In the last years, we have investigated the properties of a population of CD8 + Tregs that arise in a model of cardiac allograft tolerance following blocking of CD40-CD40L interactions (18,20,21,23,24,(37)(38)(39) and are characterized by the low expression or absence of the CD45RC marker, which is one of the less known and studied alternative splice variants of the CD45 molecule.…”

Impact of immunosuppressive drugs on the therapeutic efficacy of ex vivo expanded human regulatory T cells

“…ISDs were used as previously described: 16-18 TAC 2 mg/Kg (Prograf, Astellas), MPA 100 mg/Kg (CellCept, Roche), mPr 20 mg/Kg (Solu-Medrone, Pharmacia) and RAPA 300 mg/Kg (LC-Laboratories). HLA-A2+Tregs (1x10 7 ) were introduced into this environment after one day of drug administration. Spleen and lymph nodes were harvested three days after Treg transfer.…”

“…29 Another group of mice received saline solution only. Twenty-four hours after the first injection of immunosuppressive drugs, human HLA-A2 + Tregs (1x10 7 ) were injected into the different groups of mice. After three additional days, mice were culled.…”

“…6 We have shown that the expansion of Tregs using rapamycin provides a new and refined approach for large-scale generation of functionally potent and phenotypically stable regulatory T cells, rendering them safe for clinical use in the settings of inflammatory diseases. 6,7 Our group is currently involved in a multi-center phase I/II study to investigate the safety of infusing ex vivo expanded Tregs in solid organ transplantation (the ONE Study, funded by the European Union FP7 program). In this trial, Tregs expanded in vitro are being injected in kidney transplant patients receiving concurrent immunosuppressive drugs (ISDs).…”