SWOT Analysis of Banff: Strengths, Weaknesses, Opportunities and Threats of the International Banff Consensus Process and Classification System for Renal Allograft Pathology

Abstract

The Banff process defined the diagnostic histologic lesions for renal allograft rejection and created a standardized classification system where none had existed. By correcting this deficit the process had universal impact on clinical practice and clinical and basic research. All trials of new drugs since the early 1990s benefited, because the Banff classification of lesions permitted the end point of biopsy-proven rejection. The Banff process has strengths, weaknesses, opportunities and threats (SWOT). The strength is its self-organizing group structure to create consensus. Consensus does not mean correctness: defining consensus is essential if a widely held view is to be proved wrong. The weaknesses of the Banff process are the absence of an independent external standard to test the classification; and its almost exclusive reliance on histopathology, which has inherent limitations in intraand interobserver reproducibility, particularly at the interface between borderline and rejection, is exactly where clinicians demand precision. The opportunity lies in the new technology such as transcriptomics, which can form an external standard and can be incorporated into a new classification combining the elegance of histopathology and the objectivity of transcriptomics. The threat is the degree to which the renal transplant community will participate in and support this process.

Fibrosis with Inflammation at One Year Predicts Transplant Functional Decline

“…5,9,40 This study, however, demonstrates that IF alone on T12 surveillance biopsies is typically associated with stable graft function up to 5 years after transplantation. In contrast, we found that when IF was accompanied by an interstitial cellular infiltrate (termed "inflammation" by the Banff schema [41][42][43] ), a progressive decline in GFR commonly occurred. Importantly, the histologic severity of inflammation on T12 biopsies in the IFϩi group studied was generally mild (mean i score was 1.4) and below the threshold for diagnosis of acute cellular rejection.…”

“…17,18,20,23 We also propose, however, that selection of specific histologic and clinical scenarios for the application of molecular techniques represents a viable model for the eventual clinical translation of these emerging analysis tools. Although it has been suggested that gene expression assays could eventually supplant conventional graft histology for the purpose of making therapeutic decisions, 10,21,22,43 we believe it more likely that pathologic classification of graft abnormalities will remain the initial step toward diagnosing injurious processes. Furthermore, for overt complications (e.g., BK nephropathy, recurrent primary disease, severe acute rejection), the diagnostic and prognostic information provided by histology may prove not to be greatly enhanced by gene expression analysis.…”

“…for Banff '97 scores and for "total inflammation" (total i) to include information regarding cellular infiltrates contained within areas of cortical fibrosis. 41,43 As we described previously, 8 T12 biopsies with i Ͼ0 and ci ϭ 0 ("interstitial cellular infiltrates alone") were very infrequent (2% of cases screened) and, as a result, were not included in the study. Clinical data were abstracted from patient medical records using a dedicated transplant database as described previously.…”

Potential Impact of Microarray Diagnosis of T Cell–Mediated Rejection in Kidney Transplants: The INTERCOM Study

“…The lesions (interstitial infiltrate, tubulitis, intimal arteritis) were selected at the 1991 meeting based on opinions derived from the case mix at the time: relatively young donor kidneys with early severe TCMR, the prevalent disease phenotype. It was known that the interstitial inflammation and tubulitis lesions were nonspecific and found in other conditions, for example, acute kidney injury (AKI) and progressive renal diseases, creating the potential for false positives (3)(4)(5)(6)(7)(8)(9), and difficult to assess in scarred tissue, creating false negatives (10). Many biopsies are assigned the ambiguous ''borderline'' designation: In our recent study of 403 biopsies, 35 biopsies were diagnosed TCMR but 40 were called borderline (11).…”

An Economic Analysis of the Cost Effectiveness of Blood Gene Expression Profiling in Kidney Transplant Recipients

“…Drug levels may indicate potential toxicity, but are poor predictors of kidney damage. Biopsies are expensive, invasive, risking infection and bleeding and even graft loss, such that they are unsuited for frequent monitoring; moreover, significant intra-observer variation in interpretation of biopsy results exists [5]. As a consequence, using modern innovations in genomics tied to appropriate responses with immunosuppressive regimens has become a highpriority objective of transplant medicine to prevent transplant failure.…”