TR3-56 and Treg Regulatory T Cell Subsets as Potential Indicators of Graft Tolerance Control in Kidney Transplant Recipients

Identification of early signatures of immune rejection represents a key challenge in the clinical management of kidney transplant. To address such an issue, we enrolled 53 kidney transplant recipients without signs of graft rejection, no infectious episodes and no change in the immunosuppressive regimen in the last 6 months. An extensive immune profile revealed increased activation of the T cells, a decreased amount and growth ability of the Treg and a higher level of the T_R3-56 regulatory T cell subset, described by us as involved in the preferential control of cytotoxic T lymphocytes. In renal transplant recipients, the high level of the T_R3-56 cells associates with a reduction in both the amount and the growth ability of the Treg. Moreover, when the transplanted subjects were categorised according to their stable or unstable disease status, as defined by changes in serum creatinine ≥0.2 mg/dL in two consecutive detections, a higher T_R3-56 level and defective Treg growth ability were observed to characterise patients with unstable graft control. Further studies are required to substantiate the hypothesis that immune profiling, including T_R3-56 evaluation, might represent a valuable diagnostic tool to identify patients at risk of developing significant anti-donor allo-immune responses.