An Exosomal mRNA Urine Test for Detection and Risk Stratification of Human Kidney Transplant Rejection

Area of Science:

• Nephrology
• Molecular Diagnostics
• Transplant Medicine

Background:

• Kidney transplant rejection diagnosis relies on invasive biopsies.
• Urinary exosomal mRNA signatures offer a non-invasive diagnostic approach.
• Previous research identified potential mRNA signatures for rejection detection.

Purpose of the Study:

• To develop and clinically validate the Exosome Transplant Rejection Urine (ExoTRU) test for kidney transplant rejection.
• To assess the utility of a 4-gene urinary exosomal mRNA signature in a new patient cohort.
• To evaluate the prognostic value of the molecular signature in predicting adverse outcomes.

Main Methods:

• A 4-gene signature (IL32, B2M, CXCL11, PGK1) was developed and tested.
• 226 urine samples from 214 kidney transplant recipients were analyzed using standardized qPCR.
• The test was validated in an independent cohort and compared against biopsy results.

Main Results:

• The 4-gene signature achieved 94% sensitivity in detecting rejection or inflammation.
• The test demonstrated an AUC of 0.838 in an independent validation cohort.
• Positive test results correlated with a higher likelihood of adverse outcomes and subsequent rejection.

Conclusions:

• Urinary exosomal mRNA signatures provide a non-invasive tool for kidney transplant rejection detection and risk stratification.
• The ExoTRU test can aid in clinical decision-making, potentially reducing unnecessary biopsies.
• Molecular signatures offer prognostic insights beyond traditional biopsy assessment.