Kidney Week

Abstract: TH-PO1056

Characterization of the Inflammatory Infiltrate in Biopsies with Borderline Changes and Their Association with Outcomes in Kidney Transplant Recipients

Session Information

• Transplantation: Clinical - Outcomes, Malignancy, and Pathology
  October 22, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Transplantation

• 2002 Transplantation: Clinical

Authors

• Fernandez-Camargo, Dheni Aide, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Dheni Aide Fernandez-Camargo, MD

• Marino-Vazquez, Lluvia A., Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Lluvia A. Marino-Vazquez, MD

• Aguilar-Leon, Diana Elodia, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Diana Elodia Aguilar-Leon, MMSc, ScD

• Furuzawa-Carballeda, Janette, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Janette Furuzawa-Carballeda, PhD

• Alberú, Josefina, Tecnologico de Monterrey, Monterrey, N.L., Mexico

Josefina Alberú

• Uribe-Uribe, Norma O., Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Norma O. Uribe-Uribe, MD

• Morales-Buenrostro, Luis E., Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Luis E. Morales-Buenrostro, MD, PhD

Background

Despite being a common finding in surveillance allograft biopsies, the clinical significance of diagnosing and treating subclinical borderline changes (SC-BL) remains inclear. The aim of this study was to characterize Treg and other inflammatory and regulatory cell subpopulations, and to evaluate their association with allograft outcomes.

Methods

Surveillance kidney allograft biopsies performed at 3 and 12 months post-transplant were classified into three groups: 1) BL (n=40), 2) Banff IA acute cellular rejection (ACR) (n=20, positive controls), and 3) normal biopsies (n=20, negative controls). BL biopsies were further categorized as focal (BL-F) or diffuse (BL-D) according to the extent of tubulitis, with BL-D defined by the presence of tubulitis in ≥5 tubules across 10 high-power fields. Regulatory (Treg, Breg, and plasmacytoid dendritic cells) and inflammatory (CD8, Th1, Th2, and Th17) cell subpopulations were identified by immunohistochemistry. Associations with renal function, subsequent rejection, and graft loss during the first year of follow-up were analyzed.

Results

The BL-F group exhibited higher Treg/CD8 and Treg/Th2 ratios compared with the ACR-D group; while the BL-D group showed a higher Breg/CD8, Breg/Th17, and Breg/Th2 ratios compared with the ACR-ND group. Biopsies with BL-F showed a lower percentage of Th2 cells compared with BL-D, which was also associated with a lower degree of interstitial fibrosis. The ACR-ND and ACR-D groups showed a trend toward a higher number of rejection episodes, as well as a shorter time to rejection compared with the BL-F group.

Conclusion

Biopsies with a lower degree of inflammation (BL-F) showed a more regulatory immunophenotype, with a trend toward a higher proportion of Treg cells. In contrast, biopsies with ACR exhibited a more inflammatory profile, which was associated with worse outcomes.

Fig. 1. a) Presence of rejection in subsequent biopsies during the first year of follow-up; b) Bubble plots showing characterization of the inflammatory infiltrate in each study group

Funding

• Government Support – Non-U.S.