*4.2. Patient Study Cohort*

A total of 47 patients were enrolled in a cross-sectional, observational, single center study. All patients were transplanted between 2006 and 2012 in the Leiden University Medical Center (LUMC) in Leiden, The Netherlands. The cohort consisted of 2 groups, namely renal transplant recipients with AR (*n* = 15) and a control group consisting of renal recipients 12 months after transplantation without rejection and with a stable kidney transplant function (*n* = 32). In addition, recipients from the rejection group were followed longitudinally. Plasma samples were obtained at 6 and 12 months after rejection.

The cohort has been described earlier where analysis of circulating Ang-2 and sTM in plasma was performed [13].

All subjects gave their informed consent for inclusion before they participated in the study. The study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the Ethics Committee of The Leiden University Medical Center (P09.141).
