Analysis of Immune Cell Repopulation After Anti-thymocyte Globulin Administration for Steroid-Resistant T-cell-mediated Rejection

Abstract

Background: Anti-thymocyte globulin (ATG) is a treatment option for steroid-resistant T-cell-mediated rejection after kidney transplantation. However, the extent to which immune-cell subsets can repopulate the peripheral blood is unknown.

Methods: Six patients with steroid-resistant T-cell-mediated rejection were recruited and underwent analysis of their immune cells for 1 year after ATG administration. Multicolor flow cytometric analysis was used to evaluate the proportions of T cells, B cells, natural killer cells, and monocytes.

Results: T-cell repopulation from 24% to 75% occurred in the treatment group. The major repopulated cells were effector memory CD8⁺ T cells followed by effector memory CD4⁺ T cells. The population of effector memory CD8⁺ T cells with low expression of interleukin-7 receptor α increased over time. The population of regulatory T cells (eg, CD8⁺CD28^-CD56⁺ T cells and CD4⁺CD25^bright T cells) increased after ATG administration. However, the populations of other immune-cell subsets, including B cells, natural killer cells, and monocytes, were not significantly altered by ATG.

Conclusions: Our findings on immune cell repopulation after ATG administration will enable future studies aiming to unravel the steroid-resistance mechanism underlying T-cell-mediated rejection.