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 CDS8+ T cells followed by effector memory CD4(+) T cells. The population of effector memory CDS8(+) T cells with low expression of interleukin-7 receptor alpha 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.