Table 1.

Scope, preliminary results and activity status of current Banff Working Groups

Banff Working Group (BWG)	Scope	Preliminary results	Current activity status	Lead and contact person
C4d – Banff initiative for quality assurance in transplantation (BIFQUIT)	Assessment of interlaboratory and interobserver reproducibility of C4d immunohistochemistry in paraffin-embedded kidney allograft specimens	A fair to moderate reproducibility between laboratories and observers was observed. Also data regarding the optimal staining protocol were collected	Trial and data analysis completed. Manuscript in preparation	Michael Mengel, University of Alberta, Edmonton, Canada Parmjeet Randhawa, University of Pittsburgh, Pittsburgh, USA
BK – Banff initiative for quality assurance in transplantation (BIFQUIT)	Assessment of interlaboratory and interobserver reproducibility of polyomavirus immunohistochemistry in paraffin-embedded kidney specimens	This multicenter trial revealed that the proposed scoring system for BK stains shows a substantial interobserver reproducibility, while the interlaboratory reproducibility is quite limited. Also data regarding the optimal staining protocol were collected	Trial and data analysis completed. Manuscript in preparation	Parmjeet Randhawa, University of Pittsburgh, Pittsburgh, USA. Michael Mengel, University of Alberta, Edmonton, Canada
Glomerular lesion BWG	Assessment of interobserver reproducibility and diagnostic significance of established and alternative glomerulitis and TG scoring approaches	A limited reproducibility of glomerulitis and acceptable reproducibility of TG scoring was observed	First trial and data analysis completed. Follow-up trial in preparation with the aim to define reproducible diagnostic thresholds for glomerulitis and transplant glomerulopathy	Mark Haas, Cedars Sinai Hospital, Los Angeles, USA Banu Sis, University of Alberta, Edmonton, Canada
Isolated v-lesion BWG	Conduction of a retrospective multicenter study analyzing the clinical significance of isolated v-lesions	Isolated v-lesion were found to be associated with either ABMR, or TCMR, or delayed graft function, indicating that a more differentiated diagnostic and tailored therapeutic approach toward isolated v-lesion cases is warranted	Trial and data analysis completed. Manuscript in preparation	Banu Sis, University of Alberta, Edmonton, Canada Edward Kraus, Johns Hopkins University, Baltimore, USA
Implantation biopsies BWG	Conduction of a retrospective muticenter study analyzing the reproducibility (including frozen versus paraffin) and predictive value of lesions in implantation biopsies	The generated preliminary trial data as well as those available in the literature do not justify discarding a procured kidney solely based on histological findings. The sample size for the trial was small and thus a follow-up trial will be conducted	First trial and data analysis completed. Follow-up trial in preparation	Helen Liapis, Gerge Washington University, St. Louis, USA Parmjeet Randhawa, University of Pittsburgh, Pittsburgh, USA
Polyomavirus BWG	Conduction of a retrospective muticenter study analyzing the reproducibility and clinical significance of a provisional PVN scoring schema proposed at the 2009 Banff meeting	Acceptable reproducibility of the in 2009 proposed grading schema was seen. Group discussion of the clinical significance did not generated consensus and thus the proposal was not integrated into the classification at the 2011 Banff meeting	First trial completed. Further data analysis underway. Potential follow-up trial under consideration	Volker Nickeleit, University of North Carolina, Chapel Hill, USA
Fibrosis BWG	Assessment of interobserver reproducibility and clinical significance of different stains and methods for the evaluation of interstitial fibrosis in kidney biopsies (allografts and native)	A good correlation between visual fibrosis assessment using the trichrome stain with computer and immunohistochemistry-based image analysis was observed	First trial and data analysis completed. Follow-up trial for testing refined criteria for the assessment of interstitial fibrosis is in preparation	Alton B Farris, Emory University, Atlanta, USA Robert Colvin, Massachusetts General Hospital, Boston, USA
C4d-negative ABMR BWG	Established at the 2011 Banff meeting with the aim to define diagnostic criteria for C4d-negative ABMR	None yet	During an online discussion after the 2011 meeting available data were reviewed and currently efforts are underway for designing respective multicenter studies with the aim to define evidence-based diagnostic criteria for C4d-negative ABMR	Mark Haas, Cedars Sinai Hospital, Los Angeles, USA Banu Sis, University of Alberta, Edmonton, Canada Alexandre Loupy, Hôpital Européen Georges Pompidou, Paris, France