URINARY MARKERS OF REJECTION

For ages physicians have appreciated the diagnostic value of examining the urinary sediment to detect renal disease because urine is a direc t product of the kidney, Because kidney transplant failure is usually caused by rejection processes, there is an urgent need to find a clini cally relevant marker that can provide an early warning that distingui shes allograft rejection from other forms of allograft insult and/or p roffers a reliable index to monitor antirejection therapy. The occurre nce of allograft rejection correlates inconsistently with the content of urinary electrolytes or cellular elements, such as lymphocytes, tub ular epithelial cells, or eosinophils, Although non-selective proteinu ria appears to be a useful indicator of allograft rejection, the measu rement of microproteins or urinary enzymes tends to be limited in its clinical application because it fails to distinguish alloimmune proces ses from ischemic injury or systemic infection, Improved accuracy and specificity has been obtained by the recent development of monoclonal antibodies that quantitatively detect distinctive epitopes on the surf ace of exfoliated cells in the sediment or cytokines released into the supernate of urine during the process of immune activation, Among the se non-invasive tests, urinary interleukin-2 receptor, intercellular a dhesion molecules, adenosine binding protein, or eosinophilic cationic protein are the most promising ne tv markers, Ongoing efforts to clar ify the events during cytokine signalling, induction, and interaction seek to discover even better markers to detect key steps in the reject ion cascade, including tumor necrosis factor-alpha and interferon-gamm a, These studies of urinary markers forecast the future discovery of a panel of immunoreactive antibodies to identify specific urine markers of acute allogaft rejection.