485 - Risk Factors for Early Acute Rejection in Pediatric Kidney Transplant Recipients.

Publication Number: 2472.485

Carlos C. Becerril Romero, Ann & Robert H. Lurie Children's Hospital of Chicago, Shorewood, IL, United States; Stella Kilduff, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, United States; Debora Matossian, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, United States; Priya S. Verghese, Northwestern University The Feinberg School of Medicine, Chicago, IL, United States

Background: Early acute rejection is associated with worse graft and patient outcomes.

Objective: The goal of this study is to identify transplant risk factors associated with kidney transplant rejection within the first ninety days post-transplantation.

Design/Methods: A retrospective cohort study of all biopsies within the first 90 days post-pediatric kidney transplant at Lurie Children's Hospital between September 1st, 2022, and September 30th, 2025. Patient characteristics and transplant factors were analyzed using descriptive statistics and stratified by rejection type: borderline, Banff 1A, or 1B cellular rejection.

Results: Of the 99 biopsies within the study period, 23% (23/99) were positive for acute rejection: 35% (8/23) occurred < 90 days and 65% (15/23) at the 90-day post-transplant protocol biopsy. The most common type of rejection was borderline (53%), followed by 1A (34%) and 1B (13%) cellular rejection. Mixed cellular and antibody-mediated rejection occurred in 2 recipients (9%).

Borderline rejection was most often identified in the 90-day post-transplant protocol biopsy (83%), and 1A cellular rejection in for-cause biopsies < 90 days post-transplant (75%). Recipients with borderline rejection had no associated differences by induction, donor type, gender, or age at time of transplant; however, 1A cellular rejection was associated with basiliximab induction (75%). Of all living donor pediatric recipients, 80% (8/10) received basiliximab induction, and 50% (4/8) had rejection within the first thirty days post-transplant.

Conclusion(s): Among living donor kidney transplant recipients, the use of basiliximab appears to be associated with an increased incidence of early Banff 1A cellular rejection. Early severe rejection and acute antibody-mediated rejection are rare. Borderline rejection had no associated risk factors, but protocol kidney biopsies are valuable for their detection. The use of basiliximab in presumed living donor recipients may attenuate the presumed advantages of living donor kidney transplant,

Table 1.
Demographics of patients with acute rejection within the first 90 days post-kidney transplant.