O049 Interleukin-16 in flush effluent fluid as a biomarker for kidney viability prior to transplantation

Abstract Background Kidney transplantation is limited by the number of transplantable organs. Biomarkers that can predict organ viability will reduce the number of organs currently discarded (13% UK, 2021-22, NHSBT). The kidney microcirculation can be flushed, prior to transplantation, with preservation solution as part of the back-table preparation. The effluent fluid is usually discarded, but we propose this as a source of potential biomarkers. Interleukin-16 (IL-16) is a pro-inflammatory cytokine previously shown to predict viability in liver grafts. Here we examine IL-16 in the context of kidney viability. Methods IL-16 concentration was measured, in the flush effluent, using an electrochemiluminescent multiplex assay. The total protein content of each sample was concurrently measured to normalise the concentration. IL-16 concentrations were then compared to donor characteristics and early transplant outcomes. Results Samples were collected from 30 transplanted kidneys (10 DCD, 10 DBD, 10 live donor) and 5 declined kidneys (4 DCD, 1 DBD). IL-16 concentration was significantly higher in DCD kidneys (mean 81.8+/-38 (SD)) compared to live donor kidneys (17.7+/-18 pg/ml) (p=0.0001). CIT did not affect IL-16 concentration (β=-0.014, p=0.4), nor was IL-16 able to predict delayed graft function. However, IL-16 was significantly higher in kidneys declined for transplantation (transplanted: 54.7+/-30 vs non-transplanted: 98+/-43, p=0.03). Conclusion Flush effluent is a rich source of potential biomarkers. IL-16 concentration in flush effluent fluid correlates with organ quality. With real-time assessment, it will be possible to identify kidneys currently discarded; that are either transplantable directly or would benefit from advanced therapy prior to transplantation.