Bile cytology versus serum sIL-2R for monitoring of acute liver allograft rejections

Rejection is a major cause of allograft loss after liver transplantation and is often difficult to diagnose in its early stages. Various tests have been suggested to supplant or supplement liver biopsies in the differential diagnosis of acute rejection (AR) from other causes of impaired organ function. This study was undertaken to evaluate the usefulness of two non-invasive tests for the monitoring of hepatic allograft recipients. We compared serial testing of serum sIL-2R levels with results of bile cytology (BC) analysis in their ability to differentiate AR from other causes of graft damage. Bile (from an externally draining T-tube) and blood samples from 12 liver transplant recipients were collected simultaneously at scheduled intervals during the first 3 months post-operatively in a prospective study. The assignment of clinical diagnosis and the description of BC were performed by blinded investigators. A total of 42 paired samples randomly chosen from each of the established clinical categories were analyzed: 12 from stable grafts, 10 during the ischemic injury period, 13 during AR and 7 during systemic infections. Serum levels of sIL-2R(U/ml) were significantly higher during AR (9847±6958) and infections (18437±11991) as compared to stable grafts (2457±1852); p<0.05. Cytological findings in stable grafts were unremarkable and consisted of occasional epithelial (ductal) cells. Inflammatory cells (ICs) were not seen in stable grafts. However, ICs (mostly PMNs) were noted in 70% (7/10) of infections and in 92% (12/13) of AR (p<0.001 compared with stable grafts). Sensitivity and specificity for each test for the diagnosis of AR was calculated. In conclusion, BC analysis was found to be both more sensitive (92.3% vs 58.3%) and specific (73.7% vs 68.2%) than serum sIL-2R levels in diagnosing AR after liver transplantation.