Validation of a gene expression signature to measure immune quiescence in kidney transplant recipients in the CLIA setting.

Allograft rejection remains a major cause of graft failure in kidney transplantation. Here the authors report the validation of a non-invasive molecular diagnostic assay, AlloMap Kidney, using peripheral blood. The AlloMap Kidney test is a gene expression profile utilizing the RNA-seq platform to measure immune quiescence in kidney transplant patients. Analytical validation showed robust performance characteristics with an accuracy correlation coefficient of 0.997 and a precision coefficient of variation of 0.049 across testing. Clinical validation from the prospective, multi-center studies of 235 samples (66 rejection and 169 quiescence specimens) demonstrated the sensitivity of 70% and specificity of 66% for allograft rejection, while the negative predictive value was 95% to discriminate rejection from quiescence at 10% prevalence of rejection.