There is limited information about the role of protocol kidney biopsies for de novo donor-specific antibodies (dnDSA) in kidney transplant recipients, especially in those with stable graft function. We initiated a routine posttransplant DSA monitoring and surveillance biopsy program for dnDSA since 2014. We identified 45 kidney transplant recipients with dnDSA detected between January 2014 and February 2017 who underwent kidney biopsy within 60 days of detection of dnDSA. Twenty-nine (64%) had stable graft function and 16 (36%) had impaired graft function at the time of dnDSA detection. Even in the group with stable graft function, we found a high rate of rejection (53%) on biopsy. Eighty-eight percent of patients with impaired graft function had rejection. Those patients with impaired graft function had significantly lower estimated glomerular filtration rate at 12 months postbiopsy and at last follow-up. Those with impaired graft function had more graft failures; however, this result was not statistically significant. The high rate of asymptomatic rejection, and the fact that outcomes in asymptomatic patients are poor, is in support of the utility of surveillance biopsies in patients with dnDSA.

We surveyed US transplant programs to assess practices used to assess kidney health in living kidney donor candidates in 2017. Response rate was 31%. This manuscript focuses on the kidney, and a companion piece focuses on the metabolic and cardiovascular aspects of candidate evaluation. Compared to 2005, programs have become more stringent in accepting younger candidates, and less stringent in accepting older candidates. 24‐hour creatinine clearance remains the mainstay for kidney function assessment, with 74% continuing to use a value below 80 ml/min/1.73m² for exclusion, and 22% using age‐based criteria. ApoL1 genotyping is obtained routinely or selectively by 45%, half of which use the high‐risk genotype as an absolute exclusion criterion. For history of symptomatic stones, 49% accept if there is no current radiographic evidence of stones and urine profile is low risk. 80‐95% consider candidates with unilateral asymptomatic stones; but only 33‐48% consider if stones are bilateral. 14% use the risk assessment tool developed by Grams et al. routinely for decision‐making, and 42% use it sometimes. 57% reported not having yet determined a risk threshold for acceptable post‐donation risk above which candidates are excluded. Contemporary practice variation underscores the need for better evidence to guide the donor selection process.

It is commonly assumed that in simultaneous kidney and pancreas (SPK) recipients, rejection of the two organs is concordant. As a result, concurrent biopsies of both organs are rarely performed and there are limited histological data on how often rejection is in fact discordant. We reviewed all SPK recipients transplanted at the University of Wisconsin between 01/01/2001 and 12/31/2016 that underwent biopsy of both organs. We included all patients whose biopsies were within 30 days. If patients were treated for rejection between biopsies, they were excluded if the biopsies were more than 4 days apart. 91 simultaneous biopsies were performed within 30 days of each other, and 40 met our inclusion criteria. 25 (62.5%) patients had concordance of biopsy findings: 11 had rejection of both organs and 14 had no rejection of either organ. The other 15 (37.5%) were discordant for rejection, with 10 having pancreas-only rejection and 5 kidney-only rejection. It was striking to find that 4 of the 11 patients with concordance for rejection (36%) had different types (AMR, ACR or mixed) of rejection in the two organs. This large series of simultaneous kidney and pancreas biopsies demonstrates the continued utility of performing biopsies of both organs.