Non-invasive monitoring of renal transplant recipients: Urinary excretion of soluble adhesion molecules and of the complement-split product C4d

Background: The number of inducible adhesion molecules known to be
involved in cell-mediated allograft rejection is still increasing.
In addition, recent data describe complement activation during
acute humoral allograft rejection. The aim of this study was to
assess whether specific molecules from either pathway are excreted
into urine and whether they can provide useful diagnostic tools for
the monitoring of renal transplant recipients. Methods: Urinary
concentrations of soluble adhesion molecules (sICAM-1, sVCAM-1) and
of the complement degradation product C4d were determined by
standardized ELISA technique in 75 recipients of renal allografts
and 29 healthy controls. Patient samples were assigned to four
categories according to clinical criteria: group 1: acute
steroid-sensitive rejection (ASSR, n=14), group 2: acute
steroid-resistant rejection (ASRR, n=12), group 3: chronic
allograft dysfunction (CAD, n=20) and group 4: stable graft
function (SGF, n=29). Results: All patients with rejection episodes
(groups 1-3) had significantly higher values of urinary sC4d
compared with healthy controls and patients with stable graft
function (p