Soluble interleukin-2 receptor monitoring during bacterial and viral infections in liver transplant recipients: a comparative evaluation.

We evaluated the significance of serial sIL-2R serum levels as a differential marker of immune activation during bacterial versus viral infections in liver transplant recipients. A comparative evaluation of sIL-2R levels was performed in 76 liver transplant recipients (51 pediatric and 27 adult) during bacterial versus viral infections at 7 days prior to infection diagnosis (DAY-7), the day of diagnosis (DAY 0), peak sIL-2R level and at the end of therapy (END). There were no significant elevations at any time point during bacterial infections in either adult or pediatric transplant recipients. However, adult recipients demonstrated significant elevations during viral infections when comparing DAY-7 to PEAK (3840 +/- 830 vs 7225 +/- 2814 p = 0.03), with PEAK levels significantly higher during viral versus bacterial infections in this population (7225 +/- 2814 vs 4195 +/- 1819). Pediatric recipients demonstrated similar increases in sIL-2R serum levels during viral infections from DAY-7 to PEAK (4932 +/- 887 vs 11323 +/- 2794 p = 0.0012). Significant decreases from PEAK to END were noted during viral infections in both adult and pediatric recipients (7225 +/- 2814 vs 2911 +/- 1376 p = 0.01 and 11323 +/- 2794 vs 5214 +/- 2403 p = 0.006). Pediatric recipients had higher mean sIL-2R levels than adult recipients at all time points during viral infections. In conclusion, significant elevations in mean sIL-2R serum levels were observed during viral but not bacterial infections in pediatric and adult liver transplant recipients. This suggests that serial sIL-2R monitoring is a valuable immunologic marker of viral pathogenesis and may be useful in monitoring the progression of viral infections as well as response to antiviral therapy.