Background.

Antibody-mediated rejection (AMR) is a leading cause of morbidity and mortality after kidney transplantation. Early diagnosis and treatment of subclinical AMR based on the donor-specific antibody (DSA) testing may result in better outcomes.

Methods.

We tested this hypothesis in 220 kidney transplant recipients who underwent an indication or DSA-based surveillance protocol biopsies between March 1, 2013 and December 31, 2016. Patients were divided into 3 groups: clinical AMR (n= 118), subclinical AMR (n= 25), or no rejection on protocol biopsy (controls; n= 77).

Results.

Both clinical and subclinical AMR groups underwent similar treatment including plasmapheresis, pulse steroids, IVIG, and rituximab (P= ns). Mean follow-up after AMR was 29.5±16.8 months. There were 2 (3%), 2 (8%), and 54 (46%) death-censored graft failures in the control, subclinical, and clinical AMR groups, respectively (P< 0.001). Graft outcomes were similar in the subclinical rejection and control groups. In adjusted Cox regression analysis, only clinical rejection (hazards ratio [HR], 4.31; 95% confidence interval [CI], 1.01-18.94; P= 0.05) and sum chronicity scores (HR, 1.16; 95% CI, 1.01-1.35; P= 0.03) were associated with increased risk of graft failure, while estimated glomerular filtration rate at time of biopsy (HR, 0.98; 95% CI, 0.96-0.99; P= 0.01) was associated with decreased risk of graft failure.

Conclusions.

Our study suggests that early diagnosis and treatment of subclinical AMR using DSA monitoring may improve outcomes after kidney transplantation.