Novel transcriptomic signatures associated with premature kidney allograft failure

Prediction power of kidney allograft outcomes based on non-invasive assays is limited. Assessments of operational tolerance (OT) patients allow to identify transcriptomic signatures of true non-responders for construction of predictive models. In the discovery cohort, RNA sequencing was used to identify protective set of transcripts by comparison of 15 OT patients from TOMOGRAM Study (NCT05124444) with 14 chronic active antibody-mediated rejection (CABMR) and 23 stable graft function =15 years (STA). Archetypal analysis and classifier performance of RNA sequencing data showed that OT is clearly distinguishable from CABMR, but similar to STA. Selected differentially expressed transcripts between OT and CABMR were used in validation cohort (n=396) to predict 3-year kidney allograft loss at 3 time-points using RT-qPCR. Based on significant transcripts in univariable analysis, 2 multivariable Cox models were created. 3-transcripts (ADGRG3, ATG2A and GNLY) model from POD 7 predicted graft loss with C C-statistics (C) 0.727 (95% CI, 0.638-0.820). Another 3-transcript (IGHM, CD5, GNLY) model from M3 predicted graft loss with C 0.786 (95% CI, 0.785-0.865). Combining 3-transcript model with eGFR at month 3 improved C-statistics to 0.860 (95% CI, 0.778-0.944) and 0.868 (95% CI, 0.790-0.944), respectively. The model based on DGF, acute rejection, HLA mismatch and eGFR reached similar performance (C 0.846). In conclusion, identification of transcripts distinguishing OT from CABMR allowed to construct models predicting premature graft loss. Predictive statistics of these models reach same performance as well known-clinical models. Identified transcripts reflect mechanisms of injury/repair and alloimmune response when assessed at day 7 or with a loss of protective phenotype when assessed at month 3. Overall design: To identify protective set of peripheral blood transcripts by expression profiling (RNAseq) of operationally tolerant patients (OT) with chronic active antibody-mediated rejection (CABMR) as “high-responders” and stable graft function =15 years (STA) as “low responders”. Other controls involved CNI-treated patients with primary glomerulopathies and healthy people.