Use of radioactive fibrinogen for detecting rejection of human renal transplants.

Radioactive (125)I-labelled human fibrinogen was given to 11 recipients of cadaveric renal transplants and the radioactivity of the transplant was measured with a scintillation counter. In the six patients with no increase in radioactivity over the transplants there was no evidence of rejection. The five patients with an increased transplant radioactivity all had other evidence of rejection at that time. In one patient the test detected rejection in the absence of any other signs, and this result was afterwards confirmed by renal biopsy. The test in one patient was invalidated by haemorrhage occurring from the site of a renal biopsy, and other possible errors in the test may arise.It is suggested that the technique may have particular value in recipients with delayed function of their transplants, but may also be useful in patients with functioning transplants in helping to confirm the diagnosis of rejection suspected on other grounds.