B

L

AcltBbcbbbtnvedfmudrdcchiaTeb

©3

T

orderline Changes in the Banff Schema: Rejection or No Rejection?

.W. Gaber

ABSTRACT

The relationship between acute renal allograft rejection and histopathologic biopsyalterations recognized by the Banff Schema as “borderline changes” is not clear. Someevidence supports the contention that about one third of patients with borderlineinfiltrates and clinical evidence of graft dysfunction do indeed have acute rejection, which,if left untreated, progresses to a histologically more advanced stage of rejection. Severalinvestigators recognize that not all patients with mild tubulitis respond clinically toantirejection therapy; a significant number of these biopsy specimens display additionalhistological alterations. The most common concurrent lesions are chronic allograftnephropathy, arteriolar lesions consistent with calcineurin inhibitor toxicity, acute tubularnecrosis, and obstructive nephropathy. Management of patients with borderline changesmust tightly correlate the pathologic features and the clinical information.

dtwhbtiidTi

“tasutrtcrbt

H

P

CCORDING to the Banff 1997 working classificationof renal allograft pathology, the category “borderline

hanges” includes biopsy specimens with foci of mild tubu-itis in combination with at least mild interstitial inflamma-ion in the absence of intimal arteritis.1 At the time theanff schema was proposed, borderline changes were la-eled clinically as “suspicious for rejection.” Borderlinehanges were identified in 23% of 351 renal allograftiopsies performed for graft dysfunction.2 We observedorderline changes in 16% of reviewed renal allograftiopsy specimens, which were diagnosed with acute rejec-ion or suspicious for acute rejection before 1997. There areo recent data for the incidence of borderline changes usingarious new immunosuppressive protocols. In our experi-nce, there has been a steady decrease in the number ofiagnoses of borderline changes after 1997.3 The reasonsor the decrease are uncertain. We suspect that changes inaintenance immunosuppression protocols have led to the

se of more potent agents that resulted in a generalecrease in the incidence of early acute rejection, ie, acuteejection in the first year posttransplantation and thereby aecrease in the occurrence of the diagnosis of “borderlinehanges.” Our criteria to render such diagnosis have be-ome increasingly stringent to enhance the specificity of theistological diagnosis. For example, if moderate interstitial

nflammation is observed in the biopsy specimen (i2), allttempts are exhausted to obtain a specific diagnostic entity.hese attempts include, but are not limited to, meticulousvaluation of tubulitis in multiple serial sections in the

iopsy specimen, since upgrading the diagnosis from “bor- M

2004 by Elsevier Inc. All rights reserved.60 Park Avenue South, New York, NY 10010-1710

ransplantation Proceedings, 36, 755–757 (2004)

erline changes” to “mild acute rejection, IA” depends onhe grade of tubulitis, ie, the finding of moderate tubulitisith �4 mononuclear cells per tubular cross-section. Weave been using immunologic techniques to analyze renaliopsy specimens, including immunophenotyping of infil-rating cells, evaluating HLA-DR expression, and C4dmmunostaining. Moreover, tight correlations between clin-cal events and morphologic lesions are being establisheduring the evaluation of renal allograft biopsy specimens.hese factors have largely contributed to a decrease in the

ncidence of “borderline changes” in our institution.Mild acute rejection has been the primary suspect for

borderline changes” as reflected in the consensus report ofhe Banff 1997 conference. This view was later supported byfew clinical validation studies that demonstrated progres-

ion of “borderline changes” to acute rejection (if leftntreated) in a percentage of patients. In about one third ofhe cases with the diagnosis of borderline lesions, acuteejection appeared to be the direct cause of this mildubulitis.2 The transplant group at the University of Chi-ago reported that a subset of patients who had noteceived antirejection treatment following the diagnosis oforderline changes had a second biopsy within 40 days dueo failure of clinical improvement. Progression to acute

From the Department of Pathology, University of Tenneseeealth Science Center, Memphis, Tennesee.Address reprint requests to L.W. Gaber, MD, Department of

athology, University of Tennessee Health Science Center, 930

adison, Rm 521, Memphis TN 38103.

0041-1345/04/$–see front matterdoi:10.1016/j.transproceed.2004.03.042

755

roattsgtce

tdiohdfilvr

iqnspprirrpbbcWlRst

cCttarod(f7dNgt

cciehmtsmgbgipw

bitiwabilfiRcwagrgtlt“cspbltttsTo

nrnaume

756 GABER

ejection, proven based on the second biopsy specimen wasbserved in 28% of initial borderline cases.4 The sum ofcute scores (acute score index) was �2 in 89% of caseshat showed progression to acute rejection and in 62% ofhose without progression. This difference was statisticallyignificant. The presence of mild- to moderate-grade acutelomerulitis also correlated with later acute rejection pa-hology. Conversely, none of the clinical parameters, in-luding HLA mismatches, number of transplants, or recentpisodes of acute rejection, predicted progression.

There is evidence that calcineurin inhibitors may poten-ially cause borderline changes. Two independent reportsescribed the presence of calcineurin inhibitor nephrotox-

city concurrently with borderline changes in as few as 18%r as many as 58% of biopsy specimens.2,5 More than onealf of the borderline change episodes that were clinicallyeemed not acute rejection and received no steroids bene-ted from lowering the cyclosporine dosage. This evidence

inks cyclosporine and mild tubulitis. This unconventionaliew of the histopathology of cyclosporine nephrotoxicityequires a larger study for validation.

Other less frequent conditions that have been identifiedn patients with borderline changes at a much lower fre-uency include urinary tract obstruction, chronic allograftephropathy, drug-induced hypersensitivity responses, sep-is, acute tubular necrosis, and renal artery stenosis. Theathology of drug-induced hypersensitivity—interstitial ne-hritis—may be difficult to distinguish from acute cellularejection. A large number of eosinophils in the interstitialnfiltrate, although not excluding the diagnosis of acuteejection, certainly suggest an allergic drug response. Aeport of 5 cases of borderline changes showed the uniqueresence of eosinophils not only in the interstitial infiltratesut also in the walls of the tubules.6 This lesion, describedy the authors as “eosinophilic tubulitis,” resulted from theoncomittant use of sulfa compounds and/or ranitidine.

ithout the use of an antirejection agent, serum creatinineevels returned to borderline levels after discontinuation.enal transplant recipients with urinary tract infection may

how neutrophilic tubulitis in tubules in addition to theraditional mononuclear cell tubulitis.7

We reviewed our renal allograft biopsy file to identifyases with the primary diagnosis of borderline changes.ases selected for this report excluded borderline changes

hat were superimposed on chronic allograft nephropathy,hose diagnosed based on a protocol surveillance renalllograft biopsy, and those following treatment for acuteejection. Twenty episodes of borderline changes werebserved in 20 renal transplant recipients, who were pre-ominately male (70%) of ages ranging from 12 to 65 yearsmean age, 42 � 13 years). Most biopsies had been per-ormed in the first 6 weeks after transplantation (range,–173 days). Four of the 20 patients had biopsies while onialysis for posttransplantation delayed graft function.one of the biopsy specimens showed concurrent acute

lomerulitis. Interstitial inflammation was mild in 18 pa-

ients and moderate in 2 patients. After reviewing the a

linical courses, the immediate- and long-term graft out-omes, and the clinical responses to immediate therapeuticnterventions, we classified the patients into suspectedtiologic diagnoses. Six patients (30%) were suspected toave acute rejection, due to the absence of other concurrentorphologic features, to a positive response to antirejec-

ion therapy, and to a subsequent clinical course thatupported continued immunologic graft injury that ulti-ately developed into chronic rejection or chronic allograft

lomerulopathy. Another 6 grafts showed the coexistence oforderline changes with hyaline arteriolopathy that sug-ested calcineurin inhibitor nephrotoxicity. Similar to othernvestigators, we identified urinary tract obstruction anderinephric inflammation in smaller numbers of patients, asell as acute tubular necrosis.The interpretation of borderline changes in protocol

iopsy specimens of stable renal allografts poses a challeng-ng problem. There is an ongoing debate about the impor-ance of protocol biopsies in clinical practice, about thenterpretation of the morphologic changes, and abouthether clinical interventions are appropriate. Rush et alnd Nickerson et al reported that up to 30% of protocoliopsies performed on cyclosporeine-treated patients dur-

ng the first 3 months posttransplantation displayed histo-ogical features of “subclinical rejection,” which they de-ned as moderate tubulitis with graft inflammation (i2, t2).8

ush and colleagues presented evidence that supports theirlaim that this morphology is an allogenic immune reaction,hich bears immunologic characteristics similar to clinicalcute rejection, and that if left untreated it leads to inferiorraft function and interstitial fibrosis.9,10 However, theelationship between “subclinical rejection” and long-termraft outcomes remains hypothetical, awaiting larger mul-icenter trials and long-term studies. If such controversyooms concerning subclinical rejection, it is not surprisinghat it is difficult to interpret the multifactorial entityborderline changes.” Gloor et al11 reported borderlinehanges (mild tubulitis) in 11% of 3-month protocol biop-ies performed on tacrolimus-treated patients. The trans-lant group at Pittsburgh reported a 21% incidence oforderline changes in protocol biopsies performed at ear-

ier points in time (mean, 8.2 � 2.6 days after transplanta-ion). The patients in the latter series also were treated withacrolimus and had normal or improving graft function athe time of their 1-week biopsy, and were treated withteroid pulses along with augmented tacrolimus doses.here are no data yet on the immediate- or long-termutcomes of these patients.Various markers have been used to differentiate immu-

ologic events in the renal allograft during episodes ofejection versus nonimmunologic dysfunction. Immunophe-otyping of the cells infiltrating the graft, the distributionnd upregulation of adhesion molecules in the kidney, thepregulation of HLA-DR expression along tubular base-ent membranes, the degree of apotosis, and the intragraft

xpression of chemokines and chemokine-receptors are

mong the many markers that have been tested during renal

timdRrTtttLtngrppmfitastom

rattitesnptsphdIame

alor

R

a

ib

a4

wp

b

s5

bp

fiT

cs

lp

r

m1

rD

bi

gK

rt

ml2

BORDERLINE CHANGES IN BANFF SCHEMA 757

ransplant rejection.12,13 Concurrently, there has been annterest in developing noninvasive diagnostic tests based on

apping the immune profile of the patients during graftysfunction. These noninvasive tests measure messengerNA levels cytotoxic granules (perforin, granzyme B), their

espective ligands/receptors, fibrinogenic molecules, eg,GF-�, or HLA-DR in the blood or urine.14–16 Interpre-

ation of this data is still in an evolutionary state. Althoughhere are now emerging patterns of immune activation,heir use in routine clinical practice is far from standard.ast but not least, ongoing research seeks to map the genes

hat are activated during rejection. We presented prelimi-ary data to show that the coexpression of HLA-DR andranzyme B, measured using real-time polymerase chaineaction assays for target genes, resulted in a 100% positiveredictive value for acute rejection and an 83% negativeredictive value.17 We do not know the specificity of thesearkers if used in cases of borderline changes, but data

rom Rush et al suggest that the immune activation profilen blood samples from patients with borderline changesends to show activity levels that are intermediate betweencute rejection and no rejection. Cost, test standardization,pecimen collection and preparation, availability of theechniques, and assimilation of large data sets are only a fewf the handicaps that impede the spread and effective use ofolecular diagnostic techniques beyond research projects.In conclusion, we believe that borderline infiltrates in

enal allografts are, in many cases, the earliest evidence ofllogenic immunologic activity that is amenable to steroidherapy. A similar inflammatory pattern may result fromhe adverse effects of some medications; calcineurin inhib-tors may eventually prove to be a common cause of mildubulitis, second only to acute rejection. Based on thetiology of the borderline changes, the management isubstantially different. A majority (72%) of the patients willot progress into rejection. It is crucial that an experiencedathologist who is knowledgeable in the field of transplan-ation evaluates an adequate appropriately stained biopsypecimen with borderline infiltrates. Attention should beaid to identifying coexistent histological lesions; immuno-istochemical techniques may enhance the specificity of theiagnosis and help to characterize the graft infiltrates.mmunologic and molecular diagnostic techniques, whenvailable, are potentially quite useful to understand theechanisms involved but at this time are still considered

xperimental. There is no substitute for meticulous evalu-

tion of the clinical circumstances as well as the standardaboratory and radiologic tests to determining the etiologyf “borderline changes” in the individual kidney transplantecipient.

EFERENCES

1. Racusen LC, et al: The Banff 97 working classification of renalllograft pathology. Kidney Int 55:713, 1999

2. Meehan SM, et al: The relationship of untreated borderlinenfiltrates by the Banff criteria to acute rejection in renal allograftiopsies. J Am Soc Nephrol 10:1806, 19993. Gaber LW, et al: Correlation between Banff classification,

cute renal rejection scores and reversal of rejection. Kidney Int9:481, 19964. Saad R, et al: Clinical significance of renal allograft biopsies

ith “borderline changes,” as defined in the Banff Schema. Trans-lantation 64:992, 19975. Schweitzer EJ, et al: Significance of the Banff borderline

iopsy. Am J Kidney Dis 28:585, 19966. Emovon OE, et al: Clinical significance of eosinophils in

uspicious or borderline renal allograft biopsies. Clin Nephrol9:367, 20037. Shapiro R, et al: An analysis of early renal transplant protocol

iopsies—the high incidence of subclinical tubulitis. Am J Trans-lant 1:47, 20018. Rush DN, Jeffery JR, Schroeder TJ, et al: Histollogical

ndings in early routine biopsies of stable renal allograft recipients.ransplantation 57:208, 19949. Lipman ML, et al: Immune-activation gene expression in

linically stable renal allograft biopsies: molecular evidence forubclinical rejection. Transplantation 66:1673, 1998

10. Nickerson P, et al: Identification of clinical and histopatho-ogic risk factors for diminished renal function 2 years posttrans-lant. J Am Soc Nephrol 9:482, 199811. Gloor JM, et al: Subclinical rejection in tacrolimus-treated

enal transplant recipients. Transplantation 73:1965, 200212. Briscoe DM, et al: Expression of vascular cell adhesionolecule-1 in human renal allografts. J Am Soc Nephrol 3:1180,

99213. Segerer S, et al: Expression of chemokines and chemokine

eceptors during human renal transplant rejection. Am J Kidneyis 37:518, 200114. Li B, et al: Noninvasive diagnosis of renal-allograft rejection

y measurement of messenger RNA for perforin and granzyme Bn urine. N Engl J Med 344:947, 2001

15. Suthanthiran M: Molecular analyses of human renal allo-rafts: differential intragraft gene expression during rejection.idney Int 58(suppl):S15, 199716. Strehlau J, et al: The intragraft gene activation of markers

eflecting T-cell- activation and -cytotoxicity analyzed by quantita-ive RT-PCR in renal transplantation. Clin Nephrol 46:30, 1996

17. Sabek O, et al: Quantitative detection of T-cell activationarkers by real-time PCR in renal transplant rejection and corre-

ation with histopathologic evaluation. Transplantation 74:701,002