Rabbit antithymocyte globulin dose and early subclinical and clinical rejections in kidney transplantation.

Abstract

Antithymocyte globulin (ATG) is a commonly used induction agent in kidney transplant recipients. However, the optimal dosing has not been well defined. Our protocol aims for a 5-6mg/kg cumulative dose. It is unclear if a dose lower than 5mg/kg is associated with more rejection. We performed a retrospective cohort study of patients who received a kidney transplant at our center between January 1, 2013 and December 31, 2016. Primary outcome was biopsy proven acute rejection (clinical and subclinical) in the first 6months after kidney transplant. CMV viremia in high risk (D+/R-) recipients and BK viremia was compared as a secondary endpoint. Of the 543 patients, the Low Dose (LD) group (n = 56) received <5mg/kg ATG and Regular Dose (RD) group (n = 487) received ≧5mg/kg. Patients in RD were more sensitized (higher PRA and CPRA). LD received a dose of 4 ± 1.1mg/kg ATG whereas RD received 5.6 ± .3mg/kg ATG (P < .001). TCMR (Banff 1A or greater) was present in 34% of patients in LD versus 22% in RD (P = .04) (OR 2.1; 95%CI 1.12-3.81; P = .019). There was no difference in the incidence of CMV or BK viremia. ATG doses lower than 5mg/kg may be associated with a heightened risk of rejection despite a low degree of sensitization.