URINE FLOW-CYTOMETRY AS A PREDICTOR OF RENAL-ALLOGRAFT FUNCTION

The value of urine flow cytometry (UFC) in diagnosing acute renal allo graft rejection (AR) was recently established in a prospective double- blind study. In this study, we report the 1-year follow-up of three gr oups of patients identified during the previous study: group 1--stable patients (no ARs) with persistently negative UFCs (n=7); group II--pa tients who had early ARs (<3 months after transplantation), with posit ive UFCs that completely normalized with antirejection therapy (n=8); group HI-stable patients (no ARs) with positive UFCs (n=7). By definit ion, group III consists of patients previously considered to have ''fa lse positive'' UFCs. All patients received standard immunosuppressive therapy, with regimens that included cyclosporine at doses adjusted to maintain target levels. Serum creatinine (SCr) levels (mg/dl) were si milar in all three groups at 1 month after transplantation. However, a t 1 year after transplantation, SCr was 1.4+/-0.2 in group I, 2.0+/-0. 9 in group II, and 1.9+/-0.3 in group III (P=0.004 group I vs. group I II). There were no ARs clinically diagnosed during this follow-up peri od in any of the three groups of patients, but there were significantl y higher SCr increments among group III patients after the 1 year of f ollow-up. The detection of an active urine sediment by flow cytometry in ''clinically stable'' allograft recipients may indicate ongoing, su bclinical acute rejection activity, which in this study was found to b e associated with worse renal function at the end of the first posttra nsplant year as compared with patients with persistently negative UFCs . Increased immunosuppression may be indicated for these patients with persistently positive UFCs.