#818 Correlation between proteinuria and soluble IL-33 receptor levels in kidney transplant recipients

Abstract Background and Aims Kidney transplantation is a curative procedure for end-stage kidney disease with improving short-term outcomes over the past two decades. However, long-term outcomes including both graft and patient survival seem to lag behind. Intensive biomarker research is underway to identify additional clinical targets in an attempt to break this conundrum. We investigated the relationship between proteinuria, a known predictor of graft outcomes and several cardiac biomarkers in a subset of kidney transplant patients with congestive heart failure. Method The study included 16 kidney transplant patients with congestive heart failure and 37 gender and age-matched controls with kidney transplant and without heart failure. All subjects received post-transplant care between November 2023 and June 2024 in the Division of Nephrology at the University of Debrecen. Exclusion criteria included anti-rejection treatment within 6 months, acute bacterial or viral infection, malignant disease requiring hospitalization, active oncological treatment and pregnancy. Routine laboratory parameters used for correlation analysis included complete blood count, liver and kidney function tests, lipid panel, C-reactive protein, total protein and albumin, Il-6, PCT, ntProBNP, cardiac troponin T, troponin I and soluble IL-33 receptor levels. Results A total of 45 male patients and 8 female patients were selected for analysis. In the heart failure group, there was a close correlation between urinary protein excretion (mg/mmol) and soluble Il 33 receptor levels (pg/ml) (Pearson r = 0.666, 95% CI: 0.1112–0.9047, P = 0.0251). A significant correlation was also found between NT-proBNP (ng/L) and soluble Il-33 receptor levels (pg/ml) (Pearson:r = 0.6691, 95% CI:0.1156–0.9055, P = 0.0244). Also in the heart failure group, hemoglobin (g/L) concentration and NT-proBNP (ng/L) showed a significant correlation (P = 0.0360, 95% CI: −0.839 to −0.0479, r = 0.6173). Conclusion In our population of heart failure patients after kidney transplantation, we found a close correlation between proteinuria and soluble Il-33 receptor levels. Further studies are needed to clarify the significance of the Il33/sT2 signaling process in the pathomechanism of graft failure in this subset of kidney transplant recipients.