Standardization in Renal Allograft Biopsy Interpretation: The Banff Classification Kim Solez, M.D.

Slide 2 Two future phases in the relationship between renal biopsies and management of the renal allograft recipient: In the short term the rigorous quantitation and internationally-agreed-upon evaluation of renal biopsies via the Banff Classification which has proven itself quite useful in the early post- transplant period will be extended to apply fully to late graft biopsies. In the short term the rigorous quantitation and internationally-agreed-upon evaluation of renal biopsies via the Banff Classification which has proven itself quite useful in the early post- transplant period will be extended to apply fully to late graft biopsies. In the long term – perhaps decades away – the processes of acute and chronic rejection will be so well understood mechanistically that a test for specific markers in blood or urine will completely replace the percutaneous biopsy as a means of diagnosing these conditions. In the long term – perhaps decades away – the processes of acute and chronic rejection will be so well understood mechanistically that a test for specific markers in blood or urine will completely replace the percutaneous biopsy as a means of diagnosing these conditions.

Slide 3Introduction: Acute renal failure in the transplant kidney is a high stakes situation. Many different entities present the same clinically – ATN, acute rejection, CsA toxicity – and misdiagnosis can rapidly lead to loss of the graft or sometimes the patient. Acute renal failure in the transplant kidney is a high stakes situation. Many different entities present the same clinically – ATN, acute rejection, CsA toxicity – and misdiagnosis can rapidly lead to loss of the graft or sometimes the patient.

Slide 4Introduction: In 1990 all standard textbooks were incorrect in interpretation of kidney transplant biopsies, suggesting for example that arteritis meant that the kidney was doomed and antirejection treatment should be abandoned. It became imperative for the field to correct this and standardize interpretation. In 1990 all standard textbooks were incorrect in interpretation of kidney transplant biopsies, suggesting for example that arteritis meant that the kidney was doomed and antirejection treatment should be abandoned. It became imperative for the field to correct this and standardize interpretation.

Slide 5

Slide 6

Slide 7

Slide 8 Banff Classification Milestones 1991 First Conference 1991 First Conference 1993 First Kidney International paper First Kidney International paper Integration with CADI - identical scoring 1995 Integration with CADI - identical scoring 1997 Integration with CCTT classification Integration with CCTT classification Second KI paper. Clinical practice guidelines. Implantation biopsies, microwave Second KI paper. Clinical practice guidelines. Implantation biopsies, microwave Classification of antibody-mediated rejection. Regulatory agencies participating Classification of antibody-mediated rejection. Regulatory agencies participating.

Slide 9 Banff Classification - Subjects in Aberdeen mtg June Updates of Schemas for Diagnosis and Treatment of Allograft Rejection Updates of Schemas for Diagnosis and Treatment of Allograft Rejection Chronic transplant nephropathy Chronic transplant nephropathy Genomics of Rejection Genomics of Rejection Antibody-mediated rejection/C4d Antibody-mediated rejection/C4d Monocyte/Macrophages Monocyte/Macrophages Tolerance/Accomodation/Immunodepletion Tolerance/Accomodation/Immunodepletion Continued Development/Consensus Generation via Internet Communication Continued Development/Consensus Generation via Internet Communication

Slide 10

Slide 11

Slide 12

Slide 13

Slide 14

Slide 15

Slide 16

Slide 17

Slide 18

Slide 19 Table 11: Quantitative Criteria for Arteriolar Hyaline Thickening 0 = No PAS-positive hyaline thickening. 1 =Mild-to-moderate PAS-positive hyaline thickening in at least one arteriole. 2 = Moderate-to-severe PAS-positive hyaline thickening in more than one arteriole. 3 = Severe PAS-positive hyaline thickening in many arterioles.

Slide 20

Slide 21 Changes not considered to be due to rejection: Post-transplant lymphoproliferative disorder Post-transplant lymphoproliferative disorder Non-specific changes Non-specific changes  Focal interstitial inflammation without tubulitis: Nodular infiltrates, parivasular infiltrates.  Vascular changes: endothelial reactive changes, vacuolization, venulitis. Acute tubular injury Acute tubular injury Acute Interstitial nephritis Acute Interstitial nephritis Cyclosporine-associated changes, acute or chronic Cyclosporine-associated changes, acute or chronic Subcapsular injury Subcapsular injury Pre-transplant acute endothelial injury Pre-transplant acute endothelial injury Papillary necrosis Papillary necrosis De novo glomerulonephritis De novo glomerulonephritis Recurrent disease Recurrent disease Pre-existing disease Pre-existing disease Other-viral infection (CMV), obstruction and reflux Other-viral infection (CMV), obstruction and reflux

Slide 22

Slide 23 Table 1 - Specimen Adequacy – (Banff ’97) – Minimum Sampling Unsatisfactory – No glomeruli or arteries Unsatisfactory – No glomeruli or arteries Marginal – 7 glomeruli with an artery Marginal – 7 glomeruli with an artery Adequate – 10 or more glomeruli with at least two arteries Adequate – 10 or more glomeruli with at least two arteries Minimum Sampling: 7 slides – 3 H&E, 3 PAS or silver stains, and 1 trichrome Minimum Sampling: 7 slides – 3 H&E, 3 PAS or silver stains, and 1 trichrome

We are victims of our own success: Rigid application of “possible clinical approach”: In Table 5 of original paper, “The Banff Schema Simplified”. We are victims of our own success: Rigid application of “possible clinical approach”: In Table 5 of original paper, “The Banff Schema Simplified”.

Slide 25 Standardization of tx biopsy interpretation.Banff Classification Classification begun at 1991 Banff meeting has become the worldwide standard, and the consensus process has now extended to all solid organs. Meetings continue every two years. Next meeting in Banff, Scotland (Aberdeen) June 14-18, 2003! Classification begun at 1991 Banff meeting has become the worldwide standard, and the consensus process has now extended to all solid organs. Meetings continue every two years. Next meeting in Banff, Scotland (Aberdeen) June 14-18, 2003! Future meetings planned every two years through Future meetings planned every two years through Standardization principles now being extended from biopsy reporting to tissue typing, imaging, all the other elements in transplant care. Standardization principles now being extended from biopsy reporting to tissue typing, imaging, all the other elements in transplant care.

Slide 26 Standardization of tx biopsy interpretation.Banff Classification Lesion quantitation. Lesion quantitation. Reproducibility and clinical validation studies. Reproducibility and clinical validation studies. Involvement of pathologists, clinicians, surgeons, scientists, registries, and regulatory agencies in consensus generation. Involvement of pathologists, clinicians, surgeons, scientists, registries, and regulatory agencies in consensus generation. Meetings have large amount of unstructured time for deliberation and consensus generation. Meetings have large amount of unstructured time for deliberation and consensus generation. Most content online at Most content online at Linked from Linked from

Slide 27 Hansen and Olsen, 1997 Actuarial Graft Survival (%) According to Most Severe Banff Grade Max. Banff GradeN1y2y5y Bo

Slide 28 Banff Standardization of tx biopsy interpretation. - Recent Comments Hass et al. Kidney International 61:2002, 2002 “The distinction between types 2A and 2B in the Banff ‘97 classification has significant prognostic value with regard to both short term and long term clinical outcomes.” Hass et al. Kidney International 61:2002, 2002 “The distinction between types 2A and 2B in the Banff ‘97 classification has significant prognostic value with regard to both short term and long term clinical outcomes.” Palomar et al. Trans. Proc. 34:349, 2002 “The 1997 Banff classification is an excellent tool to graduate acute rejection severity and to predict short- and mid-term graft survival.” Palomar et al. Trans. Proc. 34:349, 2002 “The 1997 Banff classification is an excellent tool to graduate acute rejection severity and to predict short- and mid-term graft survival.” McCarthy and Roberts: Transplantation 73:1518, 2002 “There is likely to be significant under-diagnosis and under-grading of acute rejection if the Banff ‘97 guidelines for slide preparation are not implemented.” McCarthy and Roberts: Transplantation 73:1518, 2002 “There is likely to be significant under-diagnosis and under-grading of acute rejection if the Banff ‘97 guidelines for slide preparation are not implemented.”

Slide 29 Banff Standardization of tx biopsy interpretation. - Recent Comments Quiroga et al. Trans. Proc. 35:1154, “The Banff 97 classification has had an unforeseen and significant impact on clinical practice.” Quiroga et al. Trans. Proc. 35:1154, “The Banff 97 classification has had an unforeseen and significant impact on clinical practice.” Howie AJ: The Problems with BANFF, Transplantation 73:1383, 2002 “…other approaches should be tried such as morphometry” Howie AJ: The Problems with BANFF, Transplantation 73:1383, 2002 “…other approaches should be tried such as morphometry” Financially and technically impractical for most centers. Financially and technically impractical for most centers. Banff classification is based on semiquantitative assessment. Quantitative assessment would ultimately be better, just as the molecular biology/genomics alternative would be. But they much be made practical! Banff classification is based on semiquantitative assessment. Quantitative assessment would ultimately be better, just as the molecular biology/genomics alternative would be. But they much be made practical!

Slide 30 Promising New Developments: Sirius red quantitiation of interstitial fibrosis. Sirius red quantitiation of interstitial fibrosis. Immunostaining for C4d as a marker for antibody mediated rejection and chronic rejection. Immunostaining for C4d as a marker for antibody mediated rejection and chronic rejection. Protocol (routine biopsy) prediction of chronic rejection. Protocol (routine biopsy) prediction of chronic rejection. Implantation biopsy (hyaline arteriolar change, fibrous intimal thickening, glomerulosclerosis, glomerular size) prediction of graft loss. Implantation biopsy (hyaline arteriolar change, fibrous intimal thickening, glomerulosclerosis, glomerular size) prediction of graft loss.

Slide 31

Slide 32

Slide 33

Slide 34

Slide 35

Slide 36 Agreed upon clinical practice guidelines that need buy in generally. Implantation biopsies. Implantation biopsies. Rapid paraffin (microwave) processing for rapid reading rather than frozen sections. Rapid paraffin (microwave) processing for rapid reading rather than frozen sections. Routine (“protocol”) biopsies. Routine (“protocol”) biopsies. H&E, PAS (+/o silver), and trichrome or Sirius red stains. H&E, PAS (+/o silver), and trichrome or Sirius red stains.

Slide 37 Perioperative (Implantation) Biopsy Core vs wedge Adequacy of sample Preimplantation vs. postimplantation Consensus: Perioperative biopsy (? core, ? wedge) is sufficiently safe to be recommended for any reasonable defined objective. STANDARD OF CARE!

Slide 38 Protocol (routine biopsies). Early and intermediate post-transplant protocol biopsies. Early and intermediate post-transplant protocol biopsies. Consensus: These biopsies, generally done under ultrasound guidance, have very low morbidity. They are safe enough to be requested of consenting patients for research purposes when the objectives are clearly formulated and stated. Consensus: These biopsies, generally done under ultrasound guidance, have very low morbidity. They are safe enough to be requested of consenting patients for research purposes when the objectives are clearly formulated and stated. STANDARD OF SCIENCE!

Slide 39 Routine biopsies to detect “subclinical rejection”! Kidney Value is not unequivocally proven, but many felt the evidence to be sufficient to justify at least a biopsy at 6 months (or earlier), with treatment of subclinical rejection if detected. Further studies are required to confirm the value of this approach in a wider setting. FUTURE STANDARD OF CARE!

Pathology Expertise Renal Pathology Society includes all pathologists with mentored training in renal pathology and who considered themselves primarily renal pathologists. Only 163 RPS members in USA. 70% of renal biopsies in the US are read by individuals self taught and/or lacking a primary interest in renal pathology. In other countries situation is even worse.

Slide 411Brazil 1 South America 3Australia 2Turkey 1Korea 4Japan 7Asia 13Canada 6 The Netherlands 1Sweden 2Spain 3Norway 1Italy 1Iceland 1Greece 2Germany 2France 2England 1Denmark 1Austria 23 23Europe 163USA211 RPS Membership (total)

Pathology Expertise cont. Furness et al. International variation in the interpretation of renal transplant biopsies. Kidney International 60:1998, Lack of reproducibility of local readings in Europe and have recommended central reading of biopsies from clinical trials, already the standard via the Banff classification. Concluded: “It is obvious that evaluation of biopsies in multicenter studies must be done in one center.”

Slide 43 To join Renal Pathology Society

Slide 44 Future Banff Meetings: Edmonton, Alberta, CANADA Edmonton, Alberta, CANADA Edinburgh, Scotland Edinburgh, Scotland. SEE YOU THERE!!

Slide 45Close: Banff ’97 Classification is the new universal classification of kidney transplant pathology. Banff ’97 Classification is the new universal classification of kidney transplant pathology. Future improvements involve participation in Banff meetings via physical presence or contributions via Internet. Future improvements involve participation in Banff meetings via physical presence or contributions via Internet.

Slide 46 To subscribe to Nephrol (it’s free): Send an message to with the message “subscribe Nephrol” (or Nephrol-digest) Or contact or