Banff Classification for Renal Allograft Pathology, 2022
The Banff Classification of Allograft Pathology is the international consensus classification for pathology reporting of biopsies from solid organ transplants. Since its initial conception in 1991 for renal transplants, it has undergone constant refinement. This reference document supersedes all previous Banff meeting reports and provides definitions, Banff Lesion Scores, Additional Diagnostic Parameters and Banff Diagnostic Categories.
Original source
Banff Foundation for Allograft Pathology — banfffoundation.org
No rejection. Findings within normal limits or showing non-specific pathological changes not meeting criteria for other categories.
2
Antibody-mediated changes (AMR)
Active, chronic-active, or chronic AMR. Requires DSA evidence and specific morphologic or molecular features including microvascular inflammation.
3
Borderline / Suspicious for TCMR
Foci of tubulitis (t1, t2, or t3) with minor interstitial infiltration (i0 or i1) or interstitial infiltration (i2 or i3) with mild tubulitis (t1).
4
T-cell mediated rejection (TCMR)
Acute or chronic-active TCMR. Classified by grade (IA, IB, IIA, IIB, III) based on degree of interstitial inflammation and tubulitis.
5
Interstitial fibrosis and tubular atrophy (IFTA)
IFTA without evidence of specific etiology (previously 'chronic allograft nephropathy'). Graded I–III by extent of cortical involvement.
6
Other changes not due to rejection
Recurrent or de novo disease, drug toxicity (CNI), polyoma virus nephropathy, post-transplant lymphoproliferative disorder, and other diagnoses.
Key Banff Lesion Scores
Semiquantitative scoring system (0–3)
Each lesion scored 0 (absent) to 3 (severe). Scores determine diagnostic category and rejection grade.
t
Tubulitis
Mononuclear cells within tubular epithelium; t0–t3 by cell count per tubular cross-section.
i
Inflammation
Interstitial infiltrate; scored as % of unscarred cortex involved (i0 <10%, i3 >50%).
g
Glomerulitis
Mononuclear cells in glomerular capillaries; key feature of microvascular inflammation in AMR.
ptc
Peritubular capillaritis
Mononuclear cells in peritubular capillaries; combined with g score for AMR MVI criteria.
v
Intimal arteritis
Mononuclear cells beneath the endothelium of arteries; v1–v3 defines TCMR grade IIA–III.
ci
Interstitial fibrosis
Fibrous replacement of cortical interstitium; scored by percentage of cortex affected.
ct
Tubular atrophy
Tubular simplification or loss; scored in parallel with ci; together define IFTA grade.
cg
Glomerulopathy
Double contours of GBM on EM or light microscopy; chronic AMR lesion scored 0–3.
This page provides a structured overview of the Banff Classification for educational purposes. The complete reference guide — including all lesion score definitions, diagnostic algorithms, illustrative histological figures and full scoring tables — is published by the
Banff Foundation for Allograft Pathology.
All original content and intellectual property belong to the respective authors. SOTAI references this material solely for clinical education and decision support.
