Abstract: FR-PO1177
Significance of Borderline Rejection in Protocol Biopsies in Kidney Transplantation
Session Information
- Transplantation: Clinical - Rejection, Biomarkers, and Pharmacology
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Transplantation
- 2002 Transplantation: Clinical
Authors
- Tsuchimoto, Akihiro, Kyushu Daigaku, Fukuoka, Fukuoka Prefecture, Japan
- Matsukuma, Yuta, Kyushu Daigaku, Fukuoka, Fukuoka Prefecture, Japan
- Ueki, Kenji, Kyushu Daigaku, Fukuoka, Fukuoka Prefecture, Japan
- Okamoto, Hirofumi, Kyushu Daigaku, Fukuoka, Fukuoka Prefecture, Japan
- Kaku, Keizo, Kyushu Daigaku, Fukuoka, Fukuoka Prefecture, Japan
- Yamada, Shunsuke, Kyushu Daigaku, Fukuoka, Fukuoka Prefecture, Japan
- Masutani, Kosuke, Fukuoka Daigaku, Fukuoka, Fukuoka Prefecture, Japan
- Nakano, Toshiaki, Kyushu Daigaku, Fukuoka, Fukuoka Prefecture, Japan
Background
In kidney transplantation, subclinical T-cell-mediated rejection (TCMR) detected on protocol biopsies is associated with impaired graft survival, particularly in its chronic-active form. However, the clinical significance of borderline rejection (BC), a mild, early-stage form of TCMR, detected on protocol biopsy remains unclear.
Methods
Among adult kidney transplant recipients at our institution between 2009 and 2022, 497 patients with absent or mild interstitial fibrosis on 3-month protocol biopsy (3mBx) and without other concurrent pathologies were included. Patients were classified into three groups based on 3mBx findings: no acute rejection (NoAR; n=389, 78%), borderline rejection (BC; n=79, 16%), and TCMR (n=29, 6%). We investigated the prevalence of histological rejection and moderate-to-severe interstitial fibrosis (Mod-ci) on 12-month protocol biopsy (12mBx).
Results
The median age was 47 years (IQR 36–58), and 460 patients (92%) received living donor kidneys. Intensified immunosuppressive therapy based on 3mBx findings was administered in 10%, 28%, and 72% of patients in the NoAR, BC, and TCMR groups, respectively. At 12mBx, rejection was diagnosed in 7% (NoAR), 25% (BC), and 24% (TCMR) of patients. Mod-ci was observed in 11% (NoAR), 20% (BC), and 31% (TCMR). On multivariate logistic regression analysis, compared with the NoAR group, the odds ratios (95% CI) for rejection at 12mBx were 4.4 (2.3–8.7) for BC and 4.4 (1.7–11.5) for TCMR, and for Mod-ci were 1.9 (0.94–3.7) for BC and 3.5 (1.5–8.6) for TCMR. Both TCMR and BC were independently associated with significantly higher rates of subsequent rejection. Furthermore, greater severity of rejection at 3mBx showed a trend towards increased risk subsequent Mod-ci at 12mBx.
Conclusion
Borderline rejection on early post-transplant protocol biopsy is independently associated with subsequent histological deterioration, at a magnitude largely comparable to that of TCMR. These findings support the consideration of treatment interventions for BC similar to those applied for TCMR.