Urine flow cytometry as a tool to differentiate acute allograft rejection from other causes of acute renal graft dysfunction

Recently, urine flow cytometry (UFC) was introduced as a useful noninvasive tool for the immunological monitoring of renal allograft recipients. The presence of an active urine sediment as determined by UFC was found to be associated with acute rejection (AR) episodes. In the present study we assess the value of UFC in the setting of acute graft dysfunction. UFC was performed in 30 patients (32 events) at the time of admission to the hospital for the evaluation of rising creatinine (serum creatinine increment > or =0.6 mg/dl above baseline). UFC analysis was done blinded to the clinical diagnosis, and results were compared with the discharge diagnosis: AR, n=15; chronic rejection (CR), n=8; drug toxicity, n=4; urinary leak, n=2; recurrence of primary disease, n=1; lymphocele, n=1; and unknown, n=1. The presence of at least 5% of HLA-DR-positive cells and intercellular adhesion molecule-1-positive cells was detected in 100% and 53%, respectively, of the samples associated with AR (P