Abstract: TH-PO951

The Incidence of Chronic Changes in Protocol Biopsies in Asymptomatic Young Pediatric Renal Transplant Recipients

Session Information

Category: Transplantation

  • 1702 Transplantation: Clinical and Translational

Authors

  • Panombualert, Sunee, Mattel Children's Hospital at UCLA, Los Angeles, California, United States
  • Weng, Patricia L., Mattel Children's Hospital at UCLA, Los Angeles, California, United States
  • Ettenger, Robert B., Mattel Children's Hospital at UCLA, Los Angeles, California, United States
Background

Previous studies of protocol biopsies (Bx) in stable pediatric kidney transplant (KTx) patients have found a high incidence of interstitial fibrosis (ci) and tubular atrophy (ct), but the effect of recipient age as a continuous variable is unclear.

Methods

We examined the relationships between recipient age (1-10 yrs vs 11-20 yrs) at Bx and the results of protocol Bxs at 6 months, 1 and 2 years in stable pediatric KTx patients from 2005-2016. Bxs were evaluated for subclinical rejection and ci/ct by Banff 2013 criteria.

Results

A total of 506 protocol Bxs were performed. Subclinical rejection was found in 5.5%, 3.8%, and 2.5% at 6 months, 1 and 2 years, respectively of all Bxs and did not differ significantly by time post-Tx or by patient age. In all Bxs, ci ≥ 1 was detected in 15.1% and ct ≥ 1 was found in 16.3% at 6 months. There was no relationship between time after transplant or subclinical rejection and the incidence of ci or ct. However, in the 6 months Bxs, the frequency of ci score was 26.8% in patients 1-10 yrs and only greater than 9.5% those 10-20 yrs (p=0.003). Similarly, ct scores were 28.6% vs 10.3% (p=0.002) at 6 months. By 1 year, ci and ct had increased in both age groups but continued to be significantly higher in patients 1-10 yrs (Table).

Conclusion

Young age as a continuous variable is significantly associated with a higher incidence of chronic tubulointerstitial damage in early protocol biopsies, and this is unrelated to subclinical rejection.

Histology
scores
ci score ≥ 1ct score ≥ 1
6 mo Bx1 yr Bx2 yr Bx6 mo Bx1 yr Bx2 yr Bx
Age 1-1015(n=56)
26.8%
23(n=51)
45.1%
19(n=41)
46.3%
16(n=56)
28.6%
24(n=51)
47.1%
18(n=41)
43.9%
Age 11-2011(n=116)
9.5%
24(n=100)
24%
17(n=56)
30.4%
12(n=116)
10.3%
25(n=100)
25%
16(n=56)
28.6%
p-value0.0030.0080.1070.0020.0060.118