Multiple abnormal peripheral blood gene expression assay results are correlated with subsequent graft loss after kidney transplantation.

Abstract

The aim of this study was to correlate peripheral blood gene expression profile (GEP) results during the first post-transplant year with outcomes after kidney transplantation. We conducted a prospective, multicenter observational study of obtaining peripheral blood at five timepoints during the first post-transplant year to perform a GEP assay. The cohort was stratified based on the pattern of the peripheral blood GEP results: Tx-all GEP results normal, 1 Not-TX had one GEP result abnormal and >1 Not-TX two or more abnormal GEP results. We correlated the GEP results with outcomes after transplantation. We enrolled 240 kidney transplant recipients. The cohort was stratified into the three groups: TX n=117 (47%), 1 Not-TX n=59 (25%) and >1 Not-TX n=64 (27%). Compared to the TX group, the >1 Not-TX group had lower eGFR (p<.001) and more chronic changes on 1-year surveillance biopsy (p=.007). Death censored graft survival showed inferior graft survival in the >1 Not-TX group (p<.001) but not in the 1 Not-TX group. All graft losses in the >1 Not-TX group occurred after 1-year post-transplant. We conclude that a pattern of persistently Not-TX GEP assay correlates with inferior graft survival.