Urinary Liver-Type Fatty Acid-Binding Protein Linked with Increased Risk of Acute Kidney Injury after Allogeneic Stem Cell Transplantation

• This study showed the utility of urinary biomarker in allogeneic stem cell transplantation.
• Antecedent subclinical kidney injury may contribute to acute kidney injury after allogeneic stem cell transplantation.
• Urinary liver-type fatty acid-binding protein is a biomarker to detect subclinical kidney injury.
• Increased urinary liver-type fatty acid-binding protein before transplantation is linked with acute kidney injury after allogeneic stem cell transpslantation.
• Urinary liver-type fatty acid-binding protein is a noninvasive and easy measurement to predict acute kidney injury after allogeneic stem cell transplantation.

Stem cell transplantation (SCT) involves a great risk of acute kidney injury (AKI). Urinary liver-type fatty acid-binding protein (uL-FABP) is a sensitive biomarker to detect kidney damage before an increase in serum creatinine (Cr); however, the utility of uL-FABP is not fully understood in the platform of SCT. A prospective study was conducted in 84 allogeneic SCT recipients to ascertain a link between the uL-FABP level before preparative procedures and AKI incidence after SCT. The association between them was analyzed using Gray's method and a multivariate Fine-Gray proportional hazards regression model. The recipients were stratified into high and low uL-FABP groups, according to the reference value for healthy subjects (8.4 μg/g Cr). AKI developed more frequently in the high (n = 20) than low (n = 64) group (55.0% versus 26.6% at day 30, P = .005), and high uL-FABP was an independent risk for the emergence of AKI (hazard ratio, 2.78; 95% confidence interval, 1.24 to 6.22, P = .01). In conclusion, increased baseline uL-FABP, which may indicate previous incipient kidney injury, is linked with a high risk of AKI after allogeneic SCT.