Beyond the Biopsy: Monitoring Immune Status in Kidney Recipients

Abstract

Improved long-term kidney allograft survival is largely related to better outcomes at 12 months, in association with declining acute rejection rates and more efficacious immunosuppression. Finding the right balance between under- and overimmunosuppression or rejection versus immunosuppression toxicity remains one of transplant's holy grails. In the absence of precise measures of immunosuppression burden, transplant clinicians rely on nonspecific, noninvasive tests and kidney allograft biopsy generally performed for cause. This review appraises recent advances of conventional monitoring strategies and critically examines the plethora of emerging tests utilizing tissue, urine, and blood samples to improve upon the diagnostic precision of allograft surveillance.

Keywords: biopsy; immunosuppression; kidney transplantation series; molecular genetics; transplant outcomes; transplantation.

Figure 1.

Schematic depicting potential time frames for using conventional and emerging transplant biomarkers. Conventional testing is shown below the timeline with pretransplant (grey) and post-transplant (tan) testing. Novel and experimental tests are shown above the timeline with pretransplant (blue) and post-transplant (light red) testing. DSA, donor-specific antibody; ELISPOT, enzyme-linked immune absorbent spot; MMDX, microarray-based molecular diagnostic system.