Delta and conjugated bilirubin as complementary markers of early rejection in liver-transplant recipients.

For 51 liver allograft recipients, we evaluated whether serum profiles of delta (Bd) and conjugated bilirubins (Bc) could be used to diagnose rejection during the first 30-50 postoperative days, in comparison with histology as the "gold standard." Daily measurements of aspartate aminotransferase, alkaline phosphatase, total bilirubin, Bd, and Bc were made, the last two by liquid chromatography. In 34 patients without any biochemical or histological evidence of rejection, within seven to 10 postoperative days Bd increased to greater than 40-50% of total bilirubin, while Bc decreased to less than 10%. In patients with severe rejections resulting in death, Bc increased rapidly to greater than 50%, while Bd remained less than 30%. In 24 histologically proven episodes of rejection in 17 patients there was either a rapid decrease in Bd or its persistence at 30%, plus either a steep increase in Bc, or its remaining at greater than 50% total bilirubin. Treatment of rejection resulted in a prompt reversal of these trends. Individually promising as prognostic adjuncts to existing liver-function markers, Bd and Bc also complemented each other, rendering the diagnosis of liver rejection much more incisive.