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Significance of the total i-score

Michael MengelAlberta Transplant Applied Genomics Centre

University of Alberta, Edmonton, Canada

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10% 25%0%

The Banff-ConsensusLorraine Racusen & Kim Solez

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Cellular rejection

Granzyme B

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Do not consider for i-score:- subcapsular infiltrates- perivascular infiltrates- fibrotic areas- areas of tubular atrophy

?nodular infiltrates

Do not consider for t-score:- moderately to severe atrophic tubules

?mild atrophic tubules in areas of tubular atrophy and fibrosis

?tubules in areas with minor inflammation

Table 4 - Quantitative Criteria for Mononuclear Cell Interstitial Inflammation ("i") Scores

i0 - No or trivial interstitial inflammation (<10% of unscarred parenchyma) i1 - 10 to 25% of parenchyma inflamedi2 - 26 to 50% of parenchyma inflamed i3 - >50% of parenchyma inflamed

Table 2 - Quantitative Criteria for Tubulitis ("t") Score (applies to tubules no more than mildly atrophic)

t0 - No mononuclear cells in tubules t1 - Foci with 1 to 4 cells/tubular cross section or 10 tubular cells t2 - Foci with 5 to 10 cells/tubular cross section t3 - Foci with >10 cells/tubular cross section, or the presence of at least two areas of tubular basement membrane destruction accompanied by i2/i3 inflammation and t2 tubulitis elsewhere in the biopsy.

Banff i- and t-score

Racusen L. et al., Kidney Int. 1999 Feb;55(2):713-23.

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subcapsular perivascular

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Infiltrates in areas of fibrosis and tubular atrophy

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nodular Infiltrates

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How do people score?(Poll at the 2007 Banff meeting)

Inflammation in IF/TA

24

16 17

10

0

5

10

15

20

25

30

ignore consider depends scoring changed

nodular infiltrates

17

22

17

7

0

5

10

15

20

25

ignore consider depends scoring changed

perivascular infiltrates

26

1714

3

0

5

10

15

20

25

30

ignore consider depends scoring changed

subcapsular Infiltrates

44

310

3 1.505

101520253035404550

ignore consider depends scoring changed

averagedistance in

mm

(0.1 - 6 mm)

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0102030405060708090

100

%

protocol bx

indication bx

Infiltrate type

p 0.05

Mengel et al. Am J Transplant. 2007 Feb;7(2):356-65.

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Infiltrates and allograft function

p 0.05

Mengel et al. Am J Transplant. 2007 Feb;7(2):356-65.

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Infiltrates and outcome

Mengel et al. Am J Transplant. 2007 Feb;7(2):356-65.

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A relationship between inflammation and

progression of IF/TA?

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Inflammation as risk factor for progression of IFTA

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Progression of ci-score and Inflammation

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How much graft inflammation is significant?

Months post-transplant

6048362412

Gra

ft S

urvi

val

1.0

.9

.8

.7

.6

.5

.4

.3

normal

fibrosis

fibrosis+ i=1

fibrosis+ i >1

p<0.001

Cosio FG et al AJT, 5:2464, 2005

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Scoring inflammation in renal allograft biopsies

60% IFTA compartment40% non-scarred compartment

100% Cortex

relative scoringaccording to current Banff

rules

25% = Banff i-score 1 “67% i-IFTA”

5% 3% 3% 5%

absolute scoring40% i-IFTA10% i-Banff

nodularperivascular

subc

apsu

lar

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Infiltrates and time in BFC

0

5

10

15

20

25

30

<6 months post TX, n=42 >6 months post TX, n=87

mea

n %

cor

tex

invo

lved

nodular

perivascular

i-Banff

i-IFTA

IFTA

p<0.0001

p<0.0001

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Relationship of total i-score to other Banff lesions

v g

ptc

cgmm

ah

cv

cict

i

t

vPRA I

PRA IIptc

cgmm

ah

cict

ptcml

i

t

Time post-transplantg

cvC4d

ti

ti

Sis B. 2009 AJT, in press

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Relationship of total i-score to other Banff lesions

v g

ptc

cgmm

ah

cv

cict

i

t

vPRA I

PRA IIptc

cgmm

ah

cict

ptcml

i

t

Time post-transplantg

cvC4d

ti

ti

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i-score total i-score

% c

orte

x w

ith in

filtra

te

*p<0.05

*

*

*

*

*

*

Banff i- and total i-score and diagnosis: interstitial infiltrates are not disease specific

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Gene sets (Spearman correlation, p<0.001) Banff-i-score t-score total-i-score

T-cell associated 0.534 0.484 0.741

γ-Interferon induced 0.532 0.441 0.703

Kidney parenchyma associated -0.296 -0.303 -0.536

Injury and repair associated 0.379 0.355 0.645

B-cell associated 0.281 0.279 0.660

correlations between gene expression and Banff scores

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Correlation with PBTs is independent of time post transplant

Biopsies taken ≤6 months post Tx i-score t-score total i-score

T cell associated transcripts 0.633 0.608 0.726gamma-interferon inducible transcripts 0.587 0.493 0.68Kidney parenchymal transcripts -0.217 -0.185 -0.322Injury inducible transcripts 0.023 -0.018 0.191Immunoglobulin transcripts 0.259 0.36 0.276B-cell associated transcripts 0.336 0.428 0.516

Biopsies taken ≤1 year post Txi-score t-score total i-score

T cell associated transcripts 0.699 0.635 0.771gamma-interferon inducible transcripts 0.652 0.529 0.719Kidney parenchymal transcripts -0.323 -0.240 -0.383Injury inducible transcripts 0.066 -0.048 0.207Immunoglobulin transcripts 0.437 0.495 0.457B-cell associated transcripts 0.475 0.501 0.611

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Defining a molecular threshold for pathological inflammation

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A B

C D

AUCtotal i-score 0.85i-score 0.73

p=0.012

AUCtotal i-score 0.82i-score 0.58

p=0.001

AUCtotal i-score 0.86i-score 0.86

p=0.9

AUCtotal i-score 0.97i-score 0.91

p=0.7

The total i-score is superior in reflecting the molecular inflammatory burden

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*p<0.05

t0-cases with high total inflammatory burden have also significantly higher other Banff scores

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ABMR

TG TCMR,GN

Borderline

CNIT

ATNOther

IFTA NOS

total i-scoreAUC = 0.81

i-scoreAUC = 0.65

← increasing ti/i-scores

total vs. i-scorep=0.012

Prognostic value of Banff i- and total i-score versus diagnosis

ATAGC TSIall allografts (n=104)

p=0.058

A

i-score <25%

i-score >25%

Btotal i-score <25%

total i-score >25%

p<0.0001

allografts with ≥IFTA grade I (n=88)

C

D

i-score <25%

i-score >25%

p=0.599

p=0.002

total i-score <25%

total i-score >25%

i-sco

reto

tal i

-sco

reBanff i- and total i-score and allograft survival

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Conclusions about new total-i-score

• Comprises primarily two major inflammatory compartments:– i-Banff (non-scarred) – i-IFTA (scarred)

• reflects better the molecular burden of inflammation and tissue injury

• more robust predictor of allograft survival

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Proposal for total i-score

• Test reproducibility for i-Banff, i-IFTA, and total i-score: – if feasible, reporting of the different

inflammatory compartments might allow to design new clinical trials

• Incorporate into the Banff-classification as a prognostic lesion–either as ti-score alone or together with

i-Banff and i-IFTA

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Kara Allanach

Dina Badr

Sakarn Bunnag

Patricia Campbell

Jessica Chang

Gunilla Einecke

Konrad Famulski

Luis Hidalgo

Anna Hutton

Zija Jacaj

Deborah James

Bruce Kaplan

Bert Kasiske

Stromedix, AstellasRoche Molecular Systems, Roche Canada

Alberta Health ServicesUniversity Hospital Foundation

Roche Organ Transplant Research FoundationGenome Canada/Genome Alberta

University of AlbertaAlberta Ministry of Advanced Education and Technology

Canada Foundation for InnovationCanadian Institutes of Health Research

Kidney Foundation of CanadaAlberta Heritage Foundation for Medical Research

Muttart Chair in Clinical Immunology, Canada Research Chair in Life Sciences

Special thanks to our clinical collaborators

Special thanks to our patients

AcknowledgementsNathalie Kayser

Daniel Kayser

Daniel Kim

Rob Leduc

Arthur Matas

Vido Ramassar

Jeff Reeve

Gui Renesto

Joana Sellares

Banu Sis

Lin-Fu Zhu