Cf-DNA Assay During Treatment of Acute Rejection

The objective of this study is to determine whether cell-free DNA (cf-DNA) measurement can be used as a biomarker for successful treatment of an acute rejection (AR) episode after kidney transplantation. A fall in donor cf-DNA level may be a biomarker for successful AR treatment. The goal is to do an exploratory study to determine, in recipients with biopsy-proven AR, whether persistence or elevated levels of donor cf-DNA are associated with ongoing inflammation at the time of exit biopsy; and whether fall in donor cf-DNA level is associated with successful AR treatment. Measurement of cf-DNA has recently been started for kidney transplant recipients. There will be two groups of patients eligible for this study: 1. those who have had sequential measurement of cf-DNA prior to graft dysfunction leading to a biopsy, and 2. those who have not had previous measurement of cf-DNA