Interleukin 6 in bile as an indicator of liver function after hepatectomy in patients with biliary tract carcinoma

Background: Interleukin (IL) 6 is one of the important components of the early signalling pathways leading to liver regeneration, and has been detected in the bile after liver transplantation. IL‐6 concentrations in the bile were studied in an attempt to predict liver function after major hepatectomy for biliary tract carcinoma. Methods: This study involved 24 patients without cirrhosis who underwent major hepatectomy for biliary tract carcinoma. The bile was sampled regularly through external biliary drainage tubes. IL‐6 concentrations in bile and serum were measured using an enzyme‐linked immunosorbent assay. Results: Bile IL‐6 concentrations increased 37‐fold (from mean(s.e.) 56(13) pg/ml before hepatectomy to 2071(398) pg/ml on day 1 after operation) in patients without liver failure after hepatectomy ( n = 18) and increased sevenfold (from 71(24) to 530(76) pg/ml) in patients with liver failure after hepatectomy ( n = 6). The values were significantly lower in patients with liver failure than in those without liver failure ( P < 0·05). The bile IL‐6 concentration on day 1 after operation exhibited a significant negative correlation with the maximum serum total bilirubin concentration after hepatectomy. Although serum IL‐6 concentrations were also increased in both groups after hepatectomy, there was no significant correlation with postoperative liver function. Conclusion: Increased bile IL‐6 concentrations after hepatectomy may reflect liver regenerative capacity. Measurement of bile IL‐6 concentrations may be clinically useful for the early identification of liver failure after hepatectomy. © 1999 British Journal of Surgery Society Ltd