Korean J Transplant.  2022 Nov;36(Supple 1):S309. 10.4285/ATW2022.F-4494.

Urinary beta-2-microglobulin is associated with allograft function and rapid renal function decline in kidney transplant recipients

• Jeon HJ
• Shin DH
• Oh J
• Kee YK
• Park JY
• Ko K
• Lee S

• KMID: 2535536
• DOI: http://doi.org/10.4285/ATW2022.F-4494

Abstract

Background
Urinary beta-2-microglobulin (B2MG) has been known as a biomarker for chronic kidney disease. The aim of this study was to investigate the association of urinary B2MG with allograft function and renal function decline in kidney transplant recipients (KTRs).
Methods
Thirty KTRs whose estimated glomerular filtration rate (eGFR) were less than 60 mL/min/1.73 m ² (chronic allograft injury group) and 20 KTRs with normal allograft function group were included in this study. Though urinary proteomic analysis with liquid chromatography-tandem mass spectrometry, several urinary proteins including B2MG were identified and then vali-dated by enzyme-linked immunosorbent assay (ELISA). Rapid renal function decline was defined as eGFR decline of >3 mL/min/1.73 m ² /yr or initiation of dialysis, and 19 (38%) were included in rapid renal function decline group.
Results
Among protein profiles identified by proteomics, urinary B2MG levels were different between chronic allograft injury group and normal allograft function group (9,882.0 vs. 1,165.7, P<0.001). Urinary B2MG levels measured by ELISA were also higher in chronic allograft injury group (1,686.4±2,997.8 vs. 28.1±27.5 ng/mL, P=0.005). Urinary B2MG/creatinine levels had high association with chronic allograft injury group (the area under the receiver operating characteristic, 0.770 [0.641–0.899], P<0.001). Urinary B2MG levels were higher in rapid renal function decline group than stable renal function group (2,253.5±3,615.4 vs. 269.0±631.6 ng/mL, P=0.029). Higher urinary B2MG levels (>2,347 ng/mL) were associated with significantly lower graft survival compared to lower urinary B2MG levels (<2,347 ng/mL) (log-rank test, P=0.006).
Conclusions
Urinary B2MG levels might be a potential biomarker for detection of chronic allograft injury and could be used as predictor for rapid renal function decline in KTRs.