Reconstitution of T-Cell Subsets Following Thymoglobulin-Induced Depletion in High Immunologic Risk and Donation After Cardiac Death Renal Transplant Recipients.

INTRODUCTION:Depletion therapy in high immunologic risk (HR) patients by antithymocyte globulin (rATG) induces lymphopenia and subsequent compartmental repopulation of T-cell subsets. rATG is also given to patients receiving kidneys from donations after cardiac death (DCDs) to mitigate innate immune activation associated with the DCD process. METHODS:We compared the T-cell response with rATG in both HR and DCD kidney recipients. We examined the reconstitution of T-cell subsets after rATG treatment in HR and DCD recipients (n = 19 per group) by multicolor flow cytometry. RESULTS:Following treatment, there was a rapid drop in the frequency of T cells in both groups, which persisted over 28 days. HR patients had an early surge in the frequency of CD4+ naïve, effector-memory, and regulatory T cells. Although we found a significant proliferation of the T cells in both groups, the DCD cohort had a blunted response as well as reduced CD4+ T-cell immune-reactivity compare with the HR group. CONCLUSIONS:Our data suggest that there is a lack of significant homeostatic proliferative response in DCD recipients following rATG, and CD4+ T cells may be less reactive in the DCD group than previously thought, indicating that rATG treatment may not have to be considered a first-line induction therapy in DCD recipients.