Subclinical Rejection: a Universally Held Concept?

Purpose of Review The goal of this paper is to evaluate the published literature to assess the evidence for a pathogenic role for subclinical inflammation in the renal allograft. Recent Findings It has become apparent from a growing body of evidence that most of the inflammation observed in renal allografts is alloimmune in nature, and ultimately pathogenic, even if it is below the classic Banff threshold for rejection. There are recent data to indicate the subclinical inflammation that is usually detectable only by protocol biopsies is a risk factor for subsequent clinical T cell-mediated rejection, the development of de novo donor-specific antibody (DSA), and graft loss. The need and potential for novel non-invasive methods in the detection of subclinical inflammation in the renal allograft are discussed in the context of future research studies.