Urinary polyamines are noninvasive markers of heart allograft rejection

Histologic evaluation of the heart allograft biopsy is currently the generally accepted method to monitor for rejection after transplantation. A noninvasive marker of host prerejection immunologic activation might be a useful clinical tool and provide the basis for a more continuous evaluation than is available with the biopsy technique. Urinary polyamine levels, in the context of immune activation, may fluctuate as an indicator of lymphocyte proliferation and organ rejection. To test this hypothesis cervical heterotopic heart transplantation was performed in six dogs that did not receive immunosuppression therapy. Daily percutaneous transmural biopsy of the transplanted heart and urine samples were collected. Urinary polyamines were measured by high-pressure liquid chromatography. Between 2 and 4 days after transplantation all allografts showed a histologic picture of mild to moderate rejection. The urinary excretion of total polyamines and putrescine fraction increased during the rejection process after transplantation, attaining a maximum from the first to the third day after operation. This early elevation suggests that urinary polyamines are markers of immune activation and unmodified heart allograft rejection. Further studies need to be done to define a potential clinical application of urinary polyamines as markers of cellular metabolic activity of the immune system and allograft rejection.