Comparison of regulatory T cells and FoxP3-positive T-cell subsets in the peripheral blood of renal transplant recipients with sirolimus versus cyclosporine: a preliminary study.

BACKGROUND

Sirolimus-based regimens have recently been introduced as nephron-sparing strategies to avoid the calcineurin inhibitors-induced nephrotoxicity.

METHODS

To investigate the different effects of these 2 immunosuppressants on CD4(+)CD25(hi)FoxP3(+) regulatory T cells (Tregs) and the newly defined subsets of FoxP3(+) T cells, including CD45RA(-)FoxP3(lo) cytokine-secreting T cells (csT cells), CD45RA(-)FoxP3(hi) activated Treg (aTregs), and CD45RA(+)FoxP3(+) resting Treg (rTregs), 52 cases of renal transplant recipients who have received a maintenance immunosuppressive regimen comprised either cyclosporine (n = 34) or sirolimus (n = 18) were collected and proportion of Tregs and each subset of FoxP3(+) T cells in peripheral blood was detected by flowcytometry.

RESULTS

Sirolimus significantly prompted the proportion of Tregs (5.92 ± 0.40 vs 2.19 ± 0.18; P < .001) and both of the CD45RA-negative subsets, including csT cells (4.92 ± 0.50 vs 1.83 ± 0.18; P < .001) and aTregs (1.04 ± 0.15 vs 0.23 ± 0.05; P < .05) when compared with cyclosporine. However, the rTregs were not remarkably affected (0.36 ± 0.09 vs 0.79 ± 0.28; P = .063).

CONCLUSION

Sirolimus plays its immune regulatory role in renal transplantation partly by increasing the proportion of Tregs. However, the increasing of both pro- and anti-inflammatory subsets of FoxP3(+) T cells also indicates the potential compromising of the effects of sirolimus on immune regulation.