Urine i-TXB2 in renal allograft rejection.

Immunoreactive thromboxane B2 (i-TXB2) was measured in daily urine samples from twelve patients after renal transplantation. In 21 of 30 rejection episodes, the increase in i-TXB2 preceded both the increase in serum beta 2-microglobulin (beta 2-MG) and the clinical diagnosis of rejection. In 26 of 30 rejection episodes, the increase in urine i-TXB2 preceded the increase in serum creatinine. The degree of change in i-TXB2 is greater than that of either serum beta 2-MG or creatinine. Urinary i-TXB2 was very high in one patient with deep venous thrombosis, but it did not rise in patients with urinary tract infection, pneumonia, or acute tubular necrosis. Thus, urinary i-TXB2 seems to be an early indicator of clinical renal allograft rejection.