Screening of novel biomarkers for acute kidney transplant rejection using DIA‐MS based proteomics

Abstract Background Kidney transplantation is the preferred treatment for patients with end‐stage renal disease. However, acute rejection poses a threat to the graft long‐term survival. The aim of this study was to identify novel biomarkers to detect acute kidney transplant rejection. Methods The serum proteomic profiling of kidney transplant patients with T cell‐mediated acute rejection (TCMR) and stable allograft function (STA) was analyzed using data‐independent acquisition mass spectrometry (DIA‐MS). The differentially expressed proteins (DEPs) of interest were further verified by enzyme‐linked immunosorbent assay (ELISA). Results A total of 131 DEPs were identified between STA and TCMR patients, 114 DEPs were identified between mild and severe TCMR patients. The verification results showed that remarkable higher concentrations of serum amyloid A protein 1 (SAA1) and insulin like growth factor binding protein 2 (IGFBP2), and lower fetuin‐A (AHSG) concentration were found in TCMR patients when compared with STA patients. We also found higher SAA1 concentration in severe TCMR group when compared with mild TCMR group. The receiver operating characteristics (ROC) analysis further confirmed that combination of SAA1, AHSG, and IGFBP2 had excellent performance in the acute rejection diagnosis. Conclusions Our data demonstrated that serum SAA1, AHSG, and IGFBP2 could be effective biomarkers for diagnosing acute rejection after kidney transplantation. DIA‐MS has great potential in biomarker screening of kidney transplantation.