Urinary thromboxane B2 as an indicator of acute rejection in human liver transplantation.

Urinary thromboxane B2 (u-TXB2) was measured and analyzed after a human liver transplantation in 28 patients (30 transplantations) who underwent an orthotopic liver transplantation. Our results showed that the u-TXB2 levels exceeded 3.0 micrograms/mmol creatinine in only 2 of the 13 cases that had a favorable postoperative course. In 10 of the 11 episodes of acute rejection, the u-TXB2 levels exceeded 3.0 micrograms/mmol creatinine. In 6 episodes of acute rejection, the TXB2 levels were more than 5.0. In 4 out of 6 episodes of infection unassociated with rejection, the u-TXB2 values were between 3.0 and 4.9 micrograms/mmol creatinine. In 2 episodes of liver necrosis the TXB2 value reached 5.3 in one and 0.9 in the other. In conclusion, the u-TXB2 level was observed to be elevated in cases of acute rejection, infection, or necrosis. The diagnosis of acute rejection on the basis of u-TXB2 showed a sensitivity of 58.8%, a specificity of 93.3%, and an accuracy of 75.0% for a threshold level of 3.0 micrograms/mmol creatinine, and a sensitivity of 85.7%, a specificity of 79.2%, and an accuracy of 80.6% for a threshold level of TXB2 of 5.0 micrograms/mmol creatinine. These results indicate that the serial determination of u-TXB2 is a useful diagnostic means for predicting acute rejection after liver transplantation.