Late Antibody-Mediated Rejection in Kidney Transplant Recipients: Outcomes after Intravenous Immunoglobulin Therapy.

Development of acute antibody-mediated rejection (AMR) is associated with graft loss and can occur both early (<3 months) and late (>3 months) post-transplant. Treatment and prognosis differ in early and late AMR. Herein, we present a single-center experience using high-dose intravenous immunoglobulin (IVIg) (2g/kg) for the treatment of late AMR. All kidney recipients with negative T- and B-cell flow crossmatch at transplant and biopsy-proven late AMR were included (2009-2013, n=126). All patients were treated with IVIg at 2g/kg over divided doses and high-dose intravenous methylprednisolone. Variables collected included demographics, Banff 2007 renal allograft biopsy scoring criteria, and laboratory values. Multivariable Cox proportional hazard regression was used to identify factors predictive of graft loss. Median age was 46 years, with 60% male and 47.6% African American. Median time from transplant to rejection was 3.8 years. Baseline serum creatinine was 1.6 mg/dl and median serum creatinine at diagnosis was 2.6 mg/dl. Fifty-eight patients (46%) eventually lost their grafts at a median of 12 months (interquartile range: 4-21) from diagnosis. Serum creatinine >5.3 mg/dl at time of diagnosis was associated with a 94% probability of graft loss, and after controlling for multiple recipient and donor factors, only serum creatinine and urine protein creatinine ratio at diagnosis were predictive of graft loss. Late AMR has a poor prognosis, with 46% graft loss at a median follow-up of 12 months. Serum creatinine was a better predictor of subsequent graft failure than histological characteristics in late AMR. These findings help inform treatment plans as well as prognosis.