New evidence underscores the importance of conducting follow-up biopsies in children after treatment for rejection in their transplanted kidney. The results suggest that only monitoring kidney function is not sufficient in assessing whether kidney rejection is resolved.
Kidney transplant is the best treatment for people who are experiencing kidney failure and meet transplant requirements, but there is a risk the patient’s immune system will attack the newly transplanted organ. When this occurs, it is referred to as rejection and the doctor will order a kidney biopsy. If rejection in the kidney tissues is confirmed, treatment with a potent medication is initiated to lower their immune system activity.
If an immune attack on the new organ isn’t adequately controlled in the short term, it could lead to kidney failure in the long term. “So it’s imperative to really ensure that rejection has been treated effectively,” emphasizes Dr. Tom Blydt-Hansen, a clinical pediatric nephrologist at BC Children's Hospital.
Traditionally, doctors have monitored their transplant patients’ overall kidney function to indirectly estimate whether the organ is being rejected and whether treatment for rejection is working. If kidney function drops, a kidney biopsy will be done to confirm if there is rejection. But Blydt-Hansen and his colleagues wanted to explore whether repeating a biopsy after immune-suppressing medication treatment – regardless of kidney function changes – offers a more accurate diagnosis of persistent, ongoing organ rejection.
In their study, published in Pediatric Transplantation, they analyzed data from two pediatric centres – BC Children’s Hospital and University of Alabama Birmingham in the United States – where follow-up kidney biopsies were done routinely on 58 children after treatment for acute kidney rejection.
The results show that more than half of the children (55%) had persistent kidney rejection, despite treatment with immune-suppressing medication. They also show the traditional kidney function tests did not catch all of these cases, and the biopsies were a much more effective means for identifying cases of ongoing organ rejection. These children needed further treatment to fully treat rejection, which would have been missed without the follow-up biopsy.
“The other thing we found is that the more severe rejections were less likely to resolve completely than the milder forms of rejection,” says Blydt-Hansen, noting this is important for identifying the patients who would most benefit from a follow-up biopsy. “Also, what was really clear was that looking at the change in kidney function after the biopsy told us nothing.”
Blydt-Hansen points out children are more likely to experience organ rejection after transplant than adults, and so monitoring their transplant effectively is especially important. He is currently teaming up with other researchers in Canada to explore new ways of identifying transplant rejection that would be less invasive than a biopsy, such as a urine test that identifies an inflammatory protein associated with the rejection. This work is underway in the early stages of a clinical trial.
