Abstract: FR-PO1180
A Banff Antibody-Mediated Rejection Gray Zone: Peritubular Capillaritis with C4d Positivity and T-Cell-Mediated Rejection
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
- Balakrishnan, Suryanarayanan, Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Arriola Montenegro, Jose J., Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Zahran, Somaya, Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Dziubas, Jakob, Charite - Universitatsmedizin Berlin, Berlin, BE, Germany
- Jarmi, Tambi, Mayo Clinic in Florida, Jacksonville, Florida, United States
- Alasfar, Sami, Mayo Clinic Arizona, Scottsdale, Arizona, United States
- Alexander, Mariam P., Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Schinstock, Carrie A., Mayo Clinic Minnesota, Rochester, Minnesota, United States
Background
Antibody mediated rejection (ABMR) needs microvascular inflammation (MVI) consisting of glomerulitis (g) and peritubular capillaritis (ptc) with a score of 2 or more along with donor-specific antibodies (DSA) and/or C4d positivity. In T-cell mediated rejection (TCMR), isolated ptc without g does not meet criteria, despite concurrent C4d positivity for ABMR. We evaluated their clinical significance through analysis of follow-up biopsies for evolving or unrecognized ABMR
Methods
We performed a multicenter retrospective cohort study (Mayo AZ, FL, and MN) of ABO compatible consecutive kidney transplant recipients with TCMR (Banff 2022), ptc and C4d positivity without g; DSA positivity defined as Mean fluorescent intensity >1500. Preformed DSA (preDSA) was present at transplant/ <30 days post-transplant; Denovo DSA (dnDSA) was detected >30 days post-transplant. Indication/follow up biopsies combined with annual HLA DSA screening and lab monitoring was obtained to determine MVI/ABMR incidence
Results
From 2010-'24, 8998 patients underwent ABO compatible solitary kidney transplant with biopsy data; 83 met inclusion criteria. Living donor transplantation occurred in 51%. PreDSA was present in 12.3% (10/81); dnDSA in 49.3% (40/81) and noDSA in 38.2% (31/81). Follow up biopsy was performed in 83% (67/81) at a median of 38.5 days (27.25, 98.75). MVI present in 33% (22/67); 50% (11/22) had DnDSA, 32% (7/22) had no DSA, and 18% (4/22) had preDSA. 2/67 had probable AMR. Persistent c4d positivity in 34% (23/67) and half had features of ABMR (12/23). Follow up biopsies showed higher mean glomerulitis compared with index biopsy(0.39 ± 0.67 v. 0, p<0.001)
Conclusion
Isolated ptc with C4d and TCMR is an uncommon histologic pattern that may mask evolving ABMR. We suggest follow-up biopsies after treatment of TCMR to look for evolving ABMR. Rates of MVI/ABMR in follow up biopsy were numerically higher among dnDSA but did not significantly differ across DSA groups (p=0.43). Further study is needed to determine long term outcomes.