Biopsy-based transcript diagnostics may identify molecular antibody-mediated rejection (AMR) when microvascular inflammation (MVI) is absent. In this single-center cohort, biopsy-based transcript diagnostics were validated in 326 kidney allograft biopsies. A total of 71 histological AMR and 35 T cell-mediated rejection (TCMR) cases were identified as molecular AMR and TCMR in 55% and 63%, respectively. Among 121 cases without MVI (glomerulitis + peritubular capillaritis = 0), 45 (37%) donor-specific antibody (DSA)-positive and 76 (63%) DSA-negative cases were analyzed. Twenty-one out of the 121 (17%) cases showed borderline changes, or TCMR, while BK nephropathy was excluded. None of the 45 DSA-positive patients showed molecular AMR. Among 76 DSA-negative patients, 2 had mixed molecular AMR/TCMR. All-AMR phenotype scores (sum of R4-R6) exhibited median values of 0.13 and 0.12 for DSA-positive and DSA-negative patients, respectively (P = .84). A total of 13% (6/45) DSA-positive and 11% (8/76) DSA-negative patients showed an all-AMR phenotype score > 0.30 (P = .77). Patients with a higher all-AMR phenotype score showed 33% more histologic TCMR (P = .005). The median all-AMR phenotype scores of glomerular basement membrane double contours = 0 and glomerular basement membrane double contours > 0 biopsies were 0.12 and 0.10, respectively (P = .35). Biopsy-based transcript diagnostics did not identify molecular AMR in cases without MVI. Follow-up biopsies and outcome data should evaluate the clinical relevance of subthreshold molecular alterations.
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http://dx.doi.org/10.1016/j.ajt.2024.03.034 | DOI Listing |
Transplant Direct
January 2025
Transplant Laboratory, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
Background: Presensitized patients with circulating donor-specific antibodies (DSAs) before transplantation are at risk for antibody-mediated rejection (AMR). Peritransplant desensitization mitigates but does not eliminate the alloimmune response. We examined the possibility that subthreshold AMR activity undetected by histology could be operating in some early biopsies.
View Article and Find Full Text PDFDiagnostics (Basel)
November 2024
Department of Nephrology, University Medical Centre Ljubljana, Zaloška 7, 1000 Ljubljana, Slovenia.
Kidney allograft rejection is one of the main limitations to long-term kidney transplant survival. The diagnostic gold standard for detecting rejection is a kidney biopsy, an invasive procedure that can often give imprecise results due to complex diagnostic criteria and high interobserver variability. In recent years, several additional diagnostic approaches to rejection have been investigated, some of them with the aid of machine learning (ML).
View Article and Find Full Text PDFAm J Transplant
October 2023
Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Canada.
The XVI-th Banff Meeting for Allograft Pathology was held in Banff, Alberta, Canada, from 19th-23rd September 2022, as a joint meeting with the Canadian Society of Transplantation. To mark the 30 anniversary of the first Banff Classification, pre-meeting discussions were held on the past, present, and future of the Banff Classification. This report is a summary of the meeting highlights that were most important in terms of their effect on the Classification, including discussions around microvascular inflammation and biopsy-based transcript analysis for diagnosis.
View Article and Find Full Text PDFLab Invest
October 2024
Department of Urology, University Hospital Muenster, Münster, Germany. Electronic address:
Nephrol Dial Transplant
June 2024
University Hospital Zurich, Department of Nephrology; Zurich, Switzerland.
Background And Hypothesis: Isolated Tubulitis, Borderline Changes, and Isolated Arteritis suspicious for histologic T cell-mediated rejection (hTCMR) remain findings of uncertain significance. Although the Molecular Microscope Diagnostics System (MMDx) has not been trained on those lesions, it was suggested that MMDx might reclassify a subgroup to molecular TCMR (mTCMR).
Methods: In this single-center cohort of 326 consecutive, unselected kidney allograft biopsies assessed by histology and MMDx, we analyzed 249 cases with Isolated Tubulitis (i0, t1-3, v0; n=101), Borderline Changes (according to Banff 2022, v0; n=9), Isolated Arteritis (no borderline, v1; n=37), No Inflammation (i0, t0, v0; n=67) and a Positive Control Cohort (hTCMR, n=27; Mixed histologic Rejection, n=8; both according to Banff 2022; total n=35).
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