Peng W et al. (2008) Urinary fractalkine is a marker of acute rejection. Kidney Int 74: 1454–1460

Chemokines and their receptors are involved in the development of allograft rejection. Researchers in China recently investigated whether urinary excretion of fractalkine and other chemokines could be used to detect acute rejection after kidney transplantation.

Urine samples taken from 215 renal transplant recipients every 2 weeks for 2 months after the procedure were assayed for possible markers of acute rejection (fractalkine, monokine induced by interferon γ, interferon-γ-inducible protein 10, macrophage inflammatory protein-3α, granzyme B and perforin). Urine samples from 80 healthy controls were also examined.

Urinary excretion of fractalkine was significantly higher in patients with acute rejection (n = 67) than in patients with acute tubular necrosis (ATN) (n = 15), those with chronic allograft nephropathy (n = 14), those with no abnormal histological findings (n = 119), and healthy controls (P≤0.002 for all). Fractalkine excretion had the capacity to differentiate acute rejection from ATN (area under the receiver operating characteristic curve 0.734). By contrast, despite being excreted at higher levels in patients with acute rejection, the other potential markers of acute rejection did not differentiate acute rejection from ATN. Fractalkine was also the best marker for differentiating steroid-resistant (n = 39) from steroid-sensitive (n = 28) acute rejection (area under the receiver operating characteristic curve 0.771).

The authors conclude that monitoring urinary fractalkine might be a useful noninvasive approach for detecting and determining the therapeutic responsiveness of acute rejection in kidney transplant recipients.