Measurement of serum amyloid A protein concentrations as test of renal allograft rejection in patients with initially non-functioning grafts.

Serum amyloid A protein concentrations were monitored in 10 renal transplant recipients who required dialysis after transplantation because of an initially non-functioning graft. Fifteen rejection episodes were identified by repeated fine needle aspiration biopsies of the grafts. All rejections were characterised by pronounced increases in serum amyloid A concentrations, the mean peak value being 363 (SE 57) mg/1 as compared with a mean preoperative concentration of 14 (5) mg/1. The rise in concentrations preceded the start of anti-rejection treatment by an average of 2.5 days in eight of the rejection episodes, in five episodes it occurred the same day, and in two episodes it occurred the next day. With exclusion of the predictable surgery induced rise in values, which peaked on the second postoperative day, there were 17 increases in amyloid A concentrations peaking at greater than or equal to 100 mg/1; in two cases they were not related to documented rejection. These findings show that measurements of serum amyloid A concentration provide a valuable non-invasive aid in identifying acute renal allograft rejection, including that in patients whose graft does not function initially.