Rabbit antithymocyte globulin (rATG) is approved for the treatment of acute rejection following kidney transplantation and is routinely administered as a series of 5-7 consecutive daily doses via central intravenous catheter. This prolonged course is not consistent with the Medicare diagnosis-related group (DRG) for acute rejection which limits rejection admission to 3 days. The prolonged hospitalization results in increased medical costs and uniform financial loss to the hospital for patients admitted under this DRG. In addition there is a patient related toll of the prolonged hospitalization and a potential for additional hospital acquired complications. Single large-doses of rATG have been shown to have equivalent safety and efficacy profile compared to the standard daily protocol when used as an induction agent but there are no reported experiences of its use for rejection treatment. The investigators hypothesize that single-dose rATG infusion will be as safe and efficacious as standard rATG administration when used for rejection treatment and would result in significant reduction in the length of hospital stay (LOS) and hospital costs for rejection treatment.