TFF3 as a Diagnostic Biomarker in Kidney Transplant Patients

Intestinal trefoil factor 3 (TFF3) is a protein secreted by many cell types, and its serum and urine levels vary in patients with kidney disease. Therefore, the present study aimed to determine the diagnostic value of TFF3 in allogeneic kidney transplant patients included in the one-year follow-up. To analyze the influence of the diagnostic method used, we studied the type of biological material and the time elapsed since renal transplantation on the parameter's value. The study also aimed to investigate the relationship between TFF3 levels and creatinine and estimated glomerular filtration rate (eGFR) values in the serum and urine of the patients studied. The study used blood and urine samples from adult patients (n = 19) 24-48 h, 6 months, and 12 months after kidney transplantation. We collected one-time blood and urine from healthy subjects (n = 5) without renal disease. We applied immunoenzymatic ELISA and xMap Luminex flow fluorimetry to determine TFF3 in serum and urine. There was a significant difference in TFF3 levels in the serum of patients collected on the first one or two days after kidney transplantation compared to the control group (determined by ELISA and Luminex) and six months and one year after kidney transplantation (ELISA). We observed a correlation between creatinine concentration and urinary TFF3 concentration (ELISA and Luminex) and a negative association between eGFR and urinary (ELISA) and serum (Luminex) TFF3 concentration in patients on the first and second days after kidney transplantation. We noted significant correlations between eGFR and TFF3 levels in the serum and urine of patients determined by the two methods six months and one year after transplantation. In women, we observed that urinary TFF3 concentration increased significantly with increasing creatinine and that with increasing eGFR, urinary TFF3 concentration determined by two methods decreased significantly. In the present study, the choice of diagnostic method for the determination of TFF3 in serum and urine significantly affected the concentration of this biomarker. The values of this parameter determined by ELISA were higher than those assessed using the Luminex assay. Based on the presented results, we can conclude that TFF3 has great potential to monitor renal transplant patients. Determination of this protein in parallel with creatinine and eGFR levels in serum and urine may provide helpful diagnostic information.