Kidney transplants that show a combination of fibrosis (scarring) and inflammation after one year are at higher risk of long-term transplant failure, according to a study appearing in an upcoming issue of the Journal of the American Society of Nephrology (JASN).
To identify these abnormalities, doctors would need to perform routine biopsies on apparently normal kidney transplants—rather than waiting for problems to occur. "Even for some transplants that would be expected to have a very long graft survival, protocol biopsies performed in the first year may indicate the kidney is undergoing damaging inflammation, which is associated with increased risk for reduced function and graft survival," comments Mark D. Stegall, MD (Mayo Clinic, Rochester, MN).
As part of a project to explore the reasons for long-term kidney transplant failure, the Mayo Clinic transplant program has been performing routine biopsies at regular intervals after transplantation. The Mayo Clinic program was among the first to incorporate such "protocol" biopsies into the routine care of clinically stable transplants.
The researchers analyzed factors related to transplant survival in 151 patients who had no apparent problems after living-donor kidney transplantation. One-year biopsies showed no abnormalities in 57 percent of kidneys; another 30 percent had fibrosis (scarring) but no inflammation. In these two groups, the transplanted kidney continued to function normally from one to five years' follow-up.
However, in the remaining 13 percent of transplants, the biopsies showed fibrosis plus inflammation. These transplants had declining kidney function and a reduced long-term survival rate. Kidneys showing fibrosis plus inflammation also had increased numbers of immune cells as well as a "rejection-like" gene expression signature.