ß2 as Marker of Kidney Function in Patients with Delayed Graft Function

Kidney transplant recipients with delayed graft function face worse short- and long-term outcomes than those without delayed graft function. According to A. Perez-Gutierrez and colleagues at the University of Chicago, Chicago, Illinois, there are no biomarkers to predict outcomes in patients with delayed graft function.

Serum ß2 microglobulin is a low-molecular-weight protein that strongly correlates with serum cystatin C and creatinine and is a predictor of cardiovascular events, overall mortality, and graft failure in kidney transplant recipients. There are few data on the role of the ß2 microglobulin trend in patients with delayed graft function.

During a virtual session at the 2021 American Transplant Congress, the researchers reported results of a retrospective study examining the role of the ß2 microglobulin trend in kidney transplant recipients. The presentation was titled The Role of the ß2 Microglobulin Trend in Patients with Delayed Graft Function after Kidney Transplant.

The study population included all kidney transplants from deceased donors performed at the center from 2014 to 2017. Exclusions were pediatric and multiple organ transplants. Inclusion criteria were measurements of serum levels of ß2 microglobulin from postoperative day 1 to day 5; ß2 microglobulin trend was defined as the difference between ß2 on postoperative day 4 and ß2 on postoperative day 1. The researchers used univariate and multivariate logistic regression.

The analysis included 150 kidney transplant recipients. Of those, 45% (n=68) had delayed graft function (median 7.5 days, range 1-51 days). Fifty percent of the patients with delayed graft function received dialysis for 1 week only. Three patients had primary nonfunction.

With the exception of the cause of kidney failure, baseline characteristics of the two groups (with and without delayed graft function) were similar. There was a strong correlation between ß2 microglobulin and delayed graft function (P<.001), and there was a significant correlation between ß2 microglobulin and estimated glomerular filtration rate at 1, 6, and 12 months in all patients (P<.05).

In the delayed graft function group, there was correlation between ß2 microglobulin trend and the duration of delayed graft function (P=.05). The correlation was independent of donors after circulatory death and type of kidney storage. There was no association between ß2 microglobulin and mortality or rejection.

In conclusion, the researchers said, “The ß2 microglobulin trend is a marker of kidney function useful particularly in patients with delayed graft function, because it measures the residual kidney function in the setting of dialysis. Following the trend of ß2 microglobulin in patients with delayed graft function is informative about the duration of the delayed graft function and may help make clinical decisions. Validation of this marker in a larger population of patients with delayed graft function is needed.”

Source: Perez-Gutierrez A, Bachul P.J., Juengel B, et al. The role of the  ß2 microglobulin trend in patients with delayed graft function after kidney transplant. Abstract of a presentation at the virtual American Transplant Congress 2021 (abstract #664), June 6, 2021.