The Banff 2019 Kidney Meeting Report (I): Updates on and clarification of criteria for T cell– and antibody-mediated rejection

Abstract

The XV. Banff conference for allograft pathology was held in conjunction with the annual meeting of the American Society for Histocompatibility and Immunogenetics in Pittsburgh, PA (USA) and focused on refining recent updates to the classification, advances from the Banff working groups, and standardization of molecular diagnostics. This report on kidney transplant pathology details clarifications and refinements to the criteria for chronic active (CA) T cell–mediated rejection (TCMR), borderline, and antibody‐mediated rejection (ABMR). The main focus of kidney sessions was on how to address biopsies meeting criteria for CA TCMR plus borderline or acute TCMR. Recent studies on the clinical impact of borderline infiltrates were also presented to clarify whether the threshold for interstitial inflammation in diagnosis of borderline should be i0 or i1. Sessions on ABMR focused on biopsies showing microvascular inflammation in the absence of C4d staining or detectable donor‐specific antibodies; the potential value of molecular diagnostics in such cases and recommendations for use of the latter in the setting of solid organ transplantation are presented in the accompanying meeting report. Finally, several speakers discussed the capabilities of artificial intelligence and the potential for use of machine learning algorithms in diagnosis and personalized therapeutics in solid organ transplantation.

Donor-derived Cell-free DNA Combined With Histology Improves Prediction of Estimated Glomerular Filtration Rate Over Time in Kidney Transplant Recipients Compared With Histology Alone

“… 4 , 12 More recently, the Banff working group has recommended revising the diagnostic classification for borderline CMR to establish a minimum threshold of interstitial inflammation involving 10%–25% of unscarred cortical parenchyma (i1 lesion) in the presence of tubulitis (at minimum t1 lesion). 8 This recommendation was based on 2 reports showing that isolated tubulitis without interstitial inflammation was associated with similar graft survival compared with biopsies without rejection. 13 , 14 …”

“…Biopsies were graded according to Banff 2019 criteria, which establish a minimum threshold for interstitial inflammation involving 10%–25% of unscarred cortical parenchyma (i1 lesion) in the presence of tubulitis as criteria for borderline cell-mediated rejection (CMR). 8 Because there was no difference in dd-cfDNA values between borderline CMR and CMR cases, histology meeting criteria for borderline CMR was classified as CMR for this study.…”

Herausforderungen in der Behandlung später antikörpermediierter Abstoßung

“…Seit ihrer Erstbeschreibung als eigene Entität wurde die Diagnose ABMR in vielfachen Neuauflagen und Konsensuspapieren der Banff-Klassifizierung verfeinert [8]. Die wesentlichen morphologischen diagnostischen Kriterien der ABMR sind zum einen die Mikrozirkulations-Inflammation der peritubulären Kapillaren (ptc) und Glomerula (g) sowie eine Transplantat-Glomerulopathie, welche eine chronische Inflammation in den Glomerula widerspiegelt, zum anderen das regelmäßige Auftauchen des Komplementspaltproduktes C4d in den peritubulären Kapillaren mittels Immunhistochemie oder Immunfluoreszenz als Zeichen der antikörpervermittelten Komplementaktivierung auf den Endothelzellen.…”

Banff klasifikacija patohistologije bubrežnih presadaka

“…Cilj je bio razjasniti dijagnostičke kriterije za ABMR i kronično aktivno TCMR radi usklađivanja patološke dijagnoze i posljedične terapijske strategije. Postignut je i dogovor za dijagnozu graničnog TCMR-a 18 . Ova klasifikacija detaljno je razradila kriterije za 5 kategorija promjena: -kategorija I: normalan nalaz; -kategorija II: antitijelima posredovano odbacivanje transplantata (aktivni ABMR, kronični aktivni ABMR, kronični inaktivni ABMR); -kategorija III: granično (sumnja na) odbacivanje posredovano stanicama (TCMR); -kategorija IV: odbacivanje posredovano stanicama (akutni i kronično aktivni TCMR); -kategorija V: polioma virusna nefropatija.…”

“…Klasifikacija Banff radne skupine za poliomavirus nefropatiju dijeli BK nefropatiju u 3 razreda, a za prognozu se oslanja prvenstveno na količinu virusa u tkivu bubrega i stupanj intersticijske fibroze ne uzimajući u obzir količinu upale 23 . Na Banff konferenciji 2019. raspravljalo se i o mogućnostima umjetne inteligencije i potencijalu za upotrebu algoritama strojnog učenja u dijagnozi i personaliziranoj terapiji u transplantatima solidnih organa, uključujući i bubreg 18 . Zaključno, najnoviji međunarodni konsenzus o Banff klasifikaciji je u tijeku.…”