*Purpose: Patients aged ≥65 years are a growing segment of kidney transplant recipients (KTRs). Consensus on induction immunosuppression in this population is unclear given higher rates of infection and decreased immunogenicity. This study evaluated the safety and effectiveness of low-dose rabbit antithymocyte globulin (rATG) among elderly KTRs at higher immunologic risk.

*Methods: A single-center, retrospective analysis of 133 KTRs >65 years from January 1, 2012 to November 1, 2018 was performed. Per institution protocol and provider discretion, patients >65 years at perceived higher immunologic risk were given low-dose rATG compared to patients who received primarily steroid-only induction. Infectious episodes per patient, infection-related hospital length of stay, and incidence of clinical acute rejection within 1 year post-transplant were compared among KTRs who did and did not receive rATG induction.

*Results: Patients who received rATG (mean total dose 3.4 mg/kg) were younger and had a higher frequency of elevated cPRA, pre-transplant DSA, and delayed graft function (Table 1). Of patients who did not receive rATG induction, 90.2% received steroid-only induction. At discharge, 92% of KTRs received maintenance immunosuppression consisting of tacrolimus, mycophenolate, and prednisone. rATG induction was associated with similar number of infectious episodes per patient (2.89 vs 2.54, p=0.51) and infection-related hospital length of stay (7.37 vs 7.22, p=0.65). The major source of infection was genitourinary, with a higher proportion in the rATG induction group (Figure 1). Patients who received rATG induction had a numerically lower incidence of rejection at one year (5.9% vs 15.9%, p=0.15) but a similar incidence of BPAR (3.9% vs 4.9%, p>0.99).

*Conclusions: Low-dose rATG in elderly KTRs at higher immunologic risk may mitigate early clinical acute rejection without excess infectious morbidity. This investigation highlights the demand for a tailored approach to immunosuppression among elderly KTRs with potential future exploration regarding use of alternative markers for immunosenescence.

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