Correlation of histology to clinical rejection reversal: A Thymoglobulin Multicenter Trial report

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1 Kidney Interntionl, Vol. 55 (1999), pp CLINICAL NEPHROLOGY EPIDEMIOLOGY CLINICAL TRIALS Correltion of histology to clinicl rejection reversl: A Thymogloulin Multicenter Tril report LILLIAN W. GABER, LINDA W. MOORE, A. OSAMA GABER, RAYMOND J. TESI, JAYNE MEYER, nd TIMOTHY J. SCHROEDER, FOR THE U.S. MULTICENTER THYMOGLOBULIN STUDY GROUP The University of Tennessee-Memphis, Memphis, Tennessee; SngStt Medicl Corportion, Menlo Prk, Cliforni; nd University of Cincinnti, Cincinnti, Ohio, USA Correltion of histology to rejection reversl: A Thymogloulin Multicenter Tril report Bckground. Histology my provide link etween clinicl response to ntirejection therpy nd grft function. In suset of centers, renl iopsy ws secondry end point for the Thymogloulin Multicenter Tril. Methods. Thirty-eight ptients hd protocol iopsy one to two weeks following the end of therpy. Inclusion nd posttretment iopsies were grded nd scored ccording to Bnff criteri y centrl pthologist who ws linded to the type nd outcome of therpy nd the timing of the iopsy. Results. The mjority of ptients (31 of 38) hd moderte rejection on their inclusion iopsy. An improvement of t lest one Bnff grde occurred in 58% of the ptients. The tretment ws cliniclly successful in 33 ptients, ut two thirds of the ptients (25 out of 38) demonstrted residul inflmmtion in the grft. The degree of improvement of inflmmtion ws proportionte to rejection severity (P 0.006). Bnff scoring indicted tht residul inflmmtion ws less in Thymogloulin-treted ptients thn in those receiving Atgm (P 0.05) nd correlted with the incidence of recurrent rejection (P 0.015). Conclusions. These dt demonstrte discrepncy etween clinicl nd histologicl resolution of cute renl llogrft rejection. Residul infiltrtes in the grft following rejection therpy re common nd, despite clinicl improvement, my indicte n incresed risk for recurrent rejection. The success of ntirejection therpy is ssessed y clinicl nd iochemicl prmeters tht mesure im- provement in grft function, rther thn y histologicl evidence of resolution of grft inflmmtion [1 3]. Biopsies following rejection therpy hve trditionlly een dignostic iopsies, indicted y inpproprite recovery of grft function. In this event, llogrft iopsy is neces- Key words: kidney trnsplnt, iopsy, cute rejection, Bnff histology, Atgm, rejection therpy. Received for puliction Decemer 22, 1997 nd in revised form Octoer 1, 1998 Accepted for puliction Jnury 11, y the Interntionl Society of Nephrology sry to distinguish etween refrctory rejection nd other cuses of continued dysfunction such s the development of drug-induced nephrotoxicity. Previously, most trils ssessing the efficcy of rejection tretment hve used clinicl prmeters s primry end points [4 6]. Recently, however, more ojective criteri for quntittion of llogrft inflmmtion hve een devel- oped [7, 8]. The development of such schem hs stimu- lted interest in the use of histologicl informtion de- rived from the protocol iopsies s end points in rejection tril nlysis. The dvntge of histologicl end points in rejection trils my provide n explntion for inde- qute therpeutic response, which my e crucil in in- terpreting tril outcomes. Moreover, the histologicl schem provide wy to quntitte ojectively the chnges in grft inflmmtion in response to therpy nd to compre quntittively the histologicl improvement under vrious ntirejection protocols. Finlly, grft histology erly fter tretment my prove importnt in the correltion of the long-term grft survivl, crucil end point for therpeutic success of rejection therpy. Limittions for the use of post-tretment protocol iopsies s n efficcy end point re relted to the generl inexperience with postrejection grft chnges. First, the sequence nd timing of the resolution of the cellulr nd vsculr chnges of rejection re, t est, incompletely understood, nd thus, the question of the est time point to ssess for complete histologicl reversl of rejection is still unnswered. Second, the existence of tight corre- ltion etween clinicl nd histologicl resolution of re- jection is still doutful [9]. Third, the relevnce of cellulr inflmmtion in stle renl llogrfts is undefined [10, 11]. In fct, the few studies on postrejection tretment iopsies descrie discrepncy etween grft histology nd function (strct; Chvers, Am Soc Trnsplnt Physicins 12:261, 1993) [9]. Persistent grft inflmmtion despite clinicl reversl of cute rejection occurred with n unexpected, reltively high frequency in these reports. The incresing specultion linking silent grft cellulr 2415

2 2416 Ger et l: Correltion of histology to rejection reversl infiltrtes to chronic grft dmge continues to stimulte these iopsies, ut results of their review were included interest in exmining the completeness of the resolution s secondry end point in the study nlysis. of histologicl grft inflmmtion in postrejection iopsies nd the possile reltionship etween post-tretment Biopsy mteril histology nd susequent clinicl outcome. Enrollment in the study nd the nlysis of entry strti- We were interested in testing the vlidity of using fiction were sed on the histologicl dignosis mde protocol postrejection iopsies s n end point of ther- t ech center. At the end of the clinicl tril, pretretpeutic response. A multicenter, doule-lind, phse III ment nd post-tretment iopsies from the prticipting clinicl tril ws conducted to compre the efficcy of centers were sent for centrl linded review. The results Thymogloulin to Atgm in the tretment of renl llo- of the centrl pthologist review were used in this report. grft rejection [12]. The study design encourged post- Centrlized pthology ws fvored to minimize interotretment protocol iopsies s mens to enhnce the server error or is in the interprettion of histologicl ssessment of rejection reversl y therpy. An nlysis chnges nd therey ensure more consistent grding nd of the postrejection iopsy findings, in correltion with scoring of the llogrft histology. Ech iopsy ws s therpeutic response nd with the initil rejection p- signed study numer tht did not distinguish pretretthology, is the suject of this report. ment from post-tretment iopsies. The centrl pthologist review ws not only linded to the sttus of the METHODS iopsy (tht is, inclusion iopsy vs. post-tretment protocol iopsy), ut lso to the trnsplnt center, ptient, Study design nd therpeutic rm. A minimum of two hemtoxylin This study ws designed s prt of the U.S. multicennd eosin nd period cid-schiff stined slides were reter phse III clinicl tril comprison of the efficcy nd viewed for ech iopsy. Grft histology ws recorded sfety of Thymogloulin versus Atgm in the tretment ccording to strict Bnff criteri, with four levels of rejecof cute renl llogrft rejection. The rndomized, protion entered: orderline chnge, grde I, grde II (A or spective, doule-linded tril ws conducted t 25 U.S. B specified), nd grde III. Biopsies were scored individcenters nd included 163 ptients rndomized sed on ully for the intensity of interstitil inflmmtion, glothe histologicl clssifiction of cute rejection. The merulitis, tuulitis, nd intiml rteritis. In ddition, study protocol required n inclusion iopsy tht ws nrrtive description of the pthology ws provided. grded ccording to the Bnff schem. Only ptients After linded pthology review of the study iopsies, with Bnff grde II or III cute rejections were recruited the iopsy codes were unmsked, nd ccordingly, preinto the study. Ptients with Bnff grde I rejections tretment nd post-tretment iopsies were grouped for were included if they demonstrted steroid resistnce. dt nlysis. Histologicl improvement in the post- All iopsies hd to e otined within 24 hours prior tretment protocol iopsies ws defined priori s n to the strt of the ntilymphocyte tretment. Stndrd improvement of t lest one grde in the Bnff clssificinclusion nd exclusion criteri were used nd hve een tion scle, from the rejection grde of the inclusion reported [12]. Ptients received either Thymogloulin (1.5 mg/kg/dy), rit immune gloulin (SngStt iopsy. Medicl Corportion, Menlo Prk, CA, USA), or Atnl llogrft iopsies were initilly identified. Six iopsy Forty-four pired pretretment nd post-tretment regm (15 mg/kg/dy), horse ntilymphocyte gloulin (Phrmci & Upjohn, Klmzoo, MI, USA), for 7 to pirs were excluded from this nlysis for the following 14 dys vi centrl line. The withdrwl of ptients for resons: () the iopsy mteril ville for review ws lck of efficcy ws llowed in this doule-linded considered indequte y Bnff criteri (N 4); nd study if fter five dys of therpy clinicl prmeters () there were mjor, unreconciled discrepncies e- indicted lck of reversl or iopsy confirmed worsening tween the locl nd centrl pthology dignoses (N 2). of rejection. Sttisticl nlysis The primry end point of therpy success ws decline in serum cretinine to or elow the seline cretinine Sttisticl nlysis ws performed using microcom- on two consecutive mesurements tken t lest two puter softwre progrm, JMP Version Softwre dys prt. Severl clinicl secondry end points were for Sttisticl Visuliztion on the Apple Mcintosh mesured, including grft survivl t dy 30, serum cretof (SAS Institute Inc., Cry, NC, USA). One-wy nlysis inine response t dy 30 (s percentge of seline), vrince ws used to determine the difference etween nd iopsy improvement t the end of therpy. Protocol groups s men comprisons for quntittive dt. The iopsies were encourged s prt of the study design chi-squre test ws used to compre ctegoricl dt. nd were specified to e otined within one week of Results were considered to e of sttisticl significnce the end of therpy. No clinicl decisions were mde on for P vlues of less thn 0.05.

3 Ger et l: Correltion of histology to rejection reversl 2417 Tle 1. Demogrphic nd ptient chrcteristics of individuls vidul renl comprtments reveled tht interstitil, tureceiving post-tretment protocol iopsies fter therpy with either Thymogloulin or Atgm for cute rejection ulr, vsculr, glomerulr, nd totl sum scores were not different in inclusion iopsies of ptients rndomized Thymogloulin Atgm to either tretment rm. However, differences were seen Totl ptients, N for interstitil, tuulr, nd totl sum score in post-tret- Posttretment iopsy study ptients, N Rce (Cucsin), N (%) 11 (53) 10 (58) ment protocol iopsies, fvoring ptients receiving Thy- Gender (mle), N (%) 14 (71) 13 (74) mogloulin tretment for rejection (Tle 4). In ddi- Age, men sd tion, in the sugroup of 38 ptients receiving protocol CAD/LRD/LURD % 65/29/6 68/21/11 PRA%, men sd iopsies, significntly more recurrent rejection occurred Dys to rejection, medin (rnge) 48 (5 1457) 36 (5 2057) in the Atgm group (47%) thn in the Thymogloulin Donor ge, yers group (12%, P 0.02). There ws trend for n in- CMV positive, N (%) 13 (65) 9 (53) cresed incidence in grft loss in Atgm-treted ptients Arevitions re: CAD, cdver donor; LRD, living relted donor; LURD, living unrelted donor; PRA, pnel of rective ntiodies; CMV, cytomeglovirus. (21%) thn in ptients receiving Thymogloulin (0%, P NS). To determine whether the length of therpy hd n effect on the histologicl improvement in rejection grde, n nlysis ws performed to evlute differences if nti- RESULTS rejection therpy hd een received for seven dys or One hundred nd sixty-three ptients were rndom- less or more thn seven dys. The cretinine response ized to oth tretment rms (Thymogloulin, N 82; ws not different: 74% of seline serum cretinine level Atgm, N 81). Of the ptients rndomized to Thymo- for seven dys or less of therpy or 76% for more thn gloulin, 10 hd mild rejection (Bnff grde I) with ste- seven dys of therpy (P 0.84). Likewise, length of roid resistnce; 58 hd moderte cute rejection (grde therpy ws correlted to the Bnff grde t the post- II), nd 14 hd severe cute rejection (grde III). This tretment protocol iopsy, nd no difference ws found ws not different from the ptients rndomized to Atgm (P 0.70). If seven dys or less of therpy were received, (8, grde I; 59, grde II; 14, grde III). Rejection reversl 1 of 11 ptients (9%) hd orderline cute rejection on ws chieved more often in Thymogloulin-treted p- the post-tretment protocol iopsy. Two of 11 ptients tients (88%) compred with Atgm-treted ptients (18%) hd Bnff grde I cute rejection. Four of 11 (76%, P 0.027). The full results of efficcy nd sfety ptients (36%) hd Bnff grde II cute rejection. No comprisons of these ntilymphocytes hve een pre- ptients hd Bnff grde III, nd 4 of 11 ptients (36%) viously reported [12]. hd no rejection on the iopsy. Compred with those receiving more thn seven dys of therpy, 5 of 27 p- Reltionship of ntilymphocyte tretment rm to tients (19%) hd orderline cute rejection. Five of 27 postrejection protocol iopsies ptients (19%) hd Bnff grde I cute rejection. Six of Nine centers otined 38 protocol post-tretment 27 ptients (22%) hd Bnff grde II cute rejection. iopsies s specified y the study design. The demo- Two of 27 ptients (7%) hd Bnff grde III, nd 9 of grphics of the ptients hving the iopsy re displyed 27 ptients (33%) hd no rejection on the post-tretment in Tle 1 nd were not different from the demogrphics protocol iopsy. of the overll study prticipnts. As with the totl study popultion, the mjority of ptients undergoing protocol Clinicopthologicl correltes to histologicl iopsies hd moderte rejection on their inclusion iopsy improvement in post-tretment protocol iopsies (31 of 38) with few ptients with grde I (N 2) or grde A secondry nlysis ws conducted in n ttempt III (N 5) cute rejection. Histologicl improvement of to understnd the clinicopthologicl correltes to the t lest one Bnff grde, s defined in the study protocol, histologicl improvement in cute rejection chnges rews seen with equl frequency in ptients receiving ei- grdless of tretment type. All 38 ptients hving postther ntilymphocyte tretment (Tle 2). The tretment tretment protocol iopsy were grouped ccording to ws cliniclly successful in 94% of ptients receiving whether their post-tretment protocol iopsy indicted Thymogloulin nd in 79% of ptients receiving Atgm, n improvement y t lest one Bnff grde from the ut only 35 nd 33% of the respective iopsies demon- inclusion iopsy. An improvement in the Bnff grde strted totl resolution of the rejection on the repet ws inversely proportionl to the severity of rejection iopsy. The grde of the residul histologicl chnges on the inclusion iopsies (P 0.006; Tle 5). This y tretment group is shown in Tle 3. There ws inverse reltionship etween initil severity nd susetrend towrd milder residul histologicl chnges in the quent improvement ws lso pprent for individul hispost-tretment protocol iopsies of ptients receiving tologicl comprtment scores, interstitil (P 0.008), Thymogloulin. Scoring of histologicl chnges in indi- tuulr (P 0.055), nd vsculr (P 0.093; Fig. 1).

4 2418 Ger et l: Correltion of histology to rejection reversl Tle 2. Improvement in Bnff grde fter tretment with either Thymogloulin or Atgm for cute rejection Thymogloulin Atgm Inclusion iopsy rejection severity Improved Not improved Improved Not improved Grde I, N (%) 1 (100%) (100%) Grde II, N (%) 10 (59%) 7 (41%) 8 (58%) 6 (42%) Grde III, N (%) 2 (199%) 0 1 (34%) 2 (66%) Totl 13 (65%) 7 (35%) 9 (50%) 9 (50%) P NS. Defined y study protocol s one Bnff grde level improvement on post-tretment protocol iopsy from the inclusion iopsy Tle 3. Bnff grde of residul inflmmtion fter therpy with Tle 4. Histologic renl comprtment scores in inclusion iopsies either Thymogloulin or Atgm for cute rejection nd post-tretment protocol iopsies of ptients receiving either Thymogloulin or Atgm for cute rejection Bnff Grde Thymogloulin (%) Agrm (%) Post-tretment protocol Borderline 4 (23) 1 (6) Inclusion iopsy iopsy Grde I 5 (24) 2 (11) Grde II 4 (18) 7 (39) Thymogloulin Atgm Thymogloulin Atgm Grde III 0 2 (11) No rejection 7 (35) 6 (33) Interstitil Tuulr Clinicl success 19 (94) 14 (79) Vsculr P 0.14, chi-squre Glomerulr Defined s decline in serum cretinine to or elow serum cretinine on Sum score c two successive mesurements otined t lest two dys prt P 0.025, P 0.096, c P 0.044, one-wy nlysis of vrince, difference etween Thymogloulin nd Atgm on post-tretment protocol iopsy Interestingly, none of the clinicl prmeters monitored s prt of the study protocol (neither primry end point, groups, nd four were from the Atgm group. An nlysecondry end points, dys to protocol iopsy, nor creti- sis of iopsy improvement etween study groups, when nine level t the time of protocol iopsy) correlted with the second reding ws considered, continued to indicte histologicl improvement in rejection grde (Tle 6). no difference etween the two therpies (Thymoglo- Additionlly, fter the centrl pthologist ws un- ulin, Bnff grde improvement, 80%; Atgm, Bnff linded s to the timing of the iopsy (tht is, inclusion grde improvement, 72%). vs. post-tretment iopsy), second review of the posttretment iopsy ws performed. When numericl scores Reltionship etween recurrent rejection nd nd intensity of histologicl lesions were compred etween the inclusion nd post-tretment protocol iop- protocol iopsies histologicl chnges on post-tretment sies, seven post-tretment protocol iopsy cses showed In the 38 ptients receiving post-tretment protocol discrepncy from the linded reding. In five cses, iopsy, 11 developed recurrent rejection (31%), of which the intensity of the inflmmtion nd the scoring for 4 hd experienced successful response to the initil interstitil inflmmtion ws reduced from scores of 2 therpy. Demogrphic nd clinicl criteri did not differor 3 to scores of 0, 1, or 2. Also, tuulitis in these cses entite ptients with recurrent rejection (Tle 7). Histows reduced y the numer of tuules with inflmmtion. logicl grding indicted equivlent sum scores from the However, ccording to the strict definition of the Bnff inclusion iopsy for ptients with nd without recurrent criteri, if ny tuule hs high score, the Bnff grde rejection. Importntly, the only prmeter ssocited is higher, thus resulting in perceived lck of improve- with the occurrence of recurrent rejection ws the histoment y Bnff grde. In two post-tretment protocol logicl grding of the post-tretment protocol iopsy s iopsy specimens, the vsculr lesions were present in expressed y the Bnff sum score. The sum score on the the form of firinoid chnges, which resulted in n ssess- post-tretment protocol iopsy in ptients who susement of no improvement from the inclusion iopsy. quently developed recurrent rejection ws , However, the vessel wll nd the prenchym exhiited which ws significntly higher thn those without recurless inflmmtion when the numericl scores were re- rent rejection ( , P 0.015). viewed. In oth of these situtions, the linded posttretment protocol iopsy reding ws ssessed s no improvement in Bnff grde over the inclusion iopsy DISCUSSION reding when inflmmtion ws ctully improved. Of Renl llogrft hlf-life is dependent on multitude these seven cses, three were from the Thymogloulin of immunologicl nd nonimmunologicl fctors tht in-

5 Ger et l: Correltion of histology to rejection reversl 2419 Tle 5. Reltionship etween the oserved improvement in posttretment protocol iopsies nd Bnff grde of inclusion iopsy Post-tretment protocol iopsy Inclusion iopsy rejection grde Improved Not improved Grde I, N (%) 3 (30) 7 (70) Grde II, N (%) 15 (63) 9 (37) Grde III, N (%) 4 (100) 0 c Biopsy tken t the time of rejection, prior to ntirejection therpy Defined y study protocol s one Bnff grde level improvement on posttretment protocol iopsy from the inclusion iopsy c P 0.006, chi-squre Fig. 1. Histologicl renl comprtment score improvement (defined s one Bnff grde level of improvement) from inclusion iopsy to posttretment protocol iopsy following ntilymphocyte ntiody therpy for cute rejection. Symols re ( ) Bnff score 1; ( ) Bnff score 2; ( ) Bnff score 3; *P 0.008; **P 0.055; #P fluence the progression to chronic rejection. Of these fctors, cute rejection hs een strongly linked to the development of chronic rejection, prticulrly cute rejection ssocited with recurrent rejection, cute rejec- tions of lte onset, nd severe cute rejection [13 18]. Although the exct mechnism y which cute rejection influences the long-term grft survivl is specultive, it is presumed tht persistent, suclinicl rejection could progress to cliniclly pprent chronic injury. Defining whether persistence of grft infiltrtes following rejec- tion tretment could e correlted to ny clinicl prmeters could help in identifying ptients t risk for long-term llogrft dysfunction. Thus, the link etween complete histologicl resolution of cute rejection nd clinicl prmeters of rejection reversl ws the purpose of this nlysis. Our dt demonstrte tht within the time frme chosen for the post-tretment protocol iopsy, there ws lck of correltion etween clinicl rejection reversl nd histologicl resolution of rejection. Our most common finding ws persistence of some histologicl inflmmtion despite functionl improvement. These histologicl chnges crried prognostic significnce in suset of cses in which the inflmmtion severity hd Bnff sum score of 4.0 or more. In those cses, inflmmtion ws ssocited with recurrent rejection, indicting tht relying solely on renl function improvement my led to indequte tretment of rejection episodes. Whether this discrepncy in functionl improvement nd histologicl outcomes cn explin the correltion etween cute rejection episodes nd chronic llogrft deteriortion is unknown. The results of the rndomized study demonstrted significnt differences in the rte of rejection reversl in ptients treted with Thymogloulin versus Atgm [12]. A similr trend ws oserved in the suset of ptients included in this report who received post-tretment protocol iopsy (94% for Thymogloulin vs. 79% for Atgm, P 0.17), lthough significnce ws not chieved in the smll numer of ptients. The incresed potency of Thymogloulin s rejection reversl gent cn e explined y the multiplicity of its trget epitopes nd the more complete nd sustined depletion of T-cell susets seen during tretment (strct; Woodle, Am Soc Trnsplnt Physicins 16:260, 1997) [12]. The incresed efficcy of Thymogloulin ws lso demon- strted in this suset of ptients y the trend towrd higher rte of histologicl improvement of one or more Bnff grde levels in the post-tretment protocol iopsy; 65% of Thymogloulin-treted ptients improved, wheres only 50% of ptients receiving Atgm im- proved. However, only one third of the ptients demon- strted complete resolution of rejection histology in oth tretment rms. Residul rejection histology s mesured y Bnff scoring of vrious renl comprtments ws worse in At- gm-treted ptients, wheres Thymogloulin-treted ptients hd significntly lower interstitil, tuulr, nd totl sum scores. The lck of difference in vsculr nd glomerulr scores ws likely due to the fct tht men vsculr nd glomerulr scores on inclusion iopsy were less thn one in oth tretment rms. The ility to demonstrte significnt differences in residul rejection histology etween tretment rms my indicte tht comprtment nd totl sum scoring is more sensitive mesure thn the prmeter chosen prospectively in the study protocol (tht is, improvement y one Bnff grde level), which did not demonstrte difference etween tretment rms. Thus, comprtment scoring y Bnff schem my e more relevnt for future immunosup- pressive trils thn grding of rejection. In ddition, when using the Bnff schem in protocols with post- tretment protocol iopsies, the pthologist should not e linded s to whether the iopsy ws tken s n inclusion iopsy or following therpy. Becuse the nu- mericl scores my e more sensitive for indicting im- provement, linding to only the study therpy rm would e more pproprite for the pthology reding. Possily two lyers of reding should occur: first, reding in which the timing of the iopsy is known, nd second, reding in which the inclusion iopsy is compred directly with the post-tretment protocol iopsy.

6 2420 Ger et l: Correltion of histology to rejection reversl Tle 6. Comprison of clinicl prmeters nd oserved histologic improvement on post-tretment protocol iopsy specimens fter therpy for cute rejection Biopsy Biopsy Prmeter improved not improved P vlue Clinicl rejection reversl, N (%) 17 (81) 14 (93) Dys to post-tretment iopsy, men sd Serum cretinine prmeters, men sd At rejection, mg/dl At post-tretment iopsy, % of rejection cretinine At post-tretment iopsy, mg/dl At 30 dys, % of rejection cretinine At 30 dys, mg/dl Defined s one Bnff grde level improvement on post-tretment protocol iopsy from the inclusion (seline, rejection) iopsy Defined s decline in serum cretinine to or elow seline serum cretinine on two successive mesurements otined t lest two dys prt Tle 7. Correltion of Bnff sum score nd clinicl prmeters of rejection to occurrence of recurrent rejection Prmeter Recurrent rejection No recurrent rejection Rejection cretinine, mg/dl Cretinine response, % of seline cretinine Primry success, N (%) 13 (55) 25 (65) Post-tretment protocol iopsy cretinine, mg/dl Serum Cretinine t 30 dys, mg/dl Inclusion iopsy sum score Post-tretment protocol iopsy sum score All vlues re men sd P 0.015, one-wy nlysis of vrince, difference etween recurrent rejection nd no recurrent rejection ment. They did demonstrte, however, tht improvement in serum cretinine ws not ssocited with histologicl resolution in one third of their ptients, indicting lck of correltion etween clinicl improvement nd histologicl resolution. Additionl support of this oservtion hs een descried recently in ptients re- ceiving steroid tretment for rejection (strct; Mzzuchi, Am Soc Trnsplnt Physicins 16:135, 1997). It is recognized tht some of this residul rejection histology could e explined y lck of homogeneity of infiltrtes nd the potentil vriility of needle iopsies. However, sed on the results of this study nd the ville liter- ture, it seems to follow ptients longitudinlly fter ntirejection tretment to determine the fte nd progres- sion of these residul histologicl chnges. As prt of the design of this prospective rndomized study, histologicl criteri were used for the first time for strtifiction of ptients into tretment rms. In n ttempt to include ojective histologicl criteri s end points for tretment success, n improvement in one Bnff grde level ws chosen s n end point. In ddition, we collected dt using Bnff criteri for scoring the chnges in renl comprtments (interstitil, glomerulr, tuulr, nd vsculr) of oth the inclusion iopsy nd the post-tretment protocol iopsy. Improvement in Bnff grding nd in interstitil, tuulr, nd vsculr scoring ws inversely relted to the severity of rejection scores. Severe rejection, prticulrly tht with vsculr The lck of correltion etween clinicl mesures of renl function nd histology ws suggested y Kerr nd Atkins, who demonstrted lck of correltion etween the clinicl outcome nd histology in OKT3-treted ptients. In their ptients, some improvement in post-tretment iopsies t dy 5 ws noted in ll ptients, despite the fct tht three grfts were lost to irreversile rejection [19]. Similrly, Chvers et l demonstrted in pilot study tht 8 of 13 ptients treted successfully for cute rejection hd histologicl fetures consistent with cute rejection on iopsies otined six weeks following tretment (strct; Chvers et l, Am Soc Trnsplnt Physicins 12:261, 1993). They postulted tht the histologicl evidence of cute rejection my persist in some ptients nd tht this smoldering suclinicl cute rejection my e fctor in the development of chronic rejection, despite seemingly successful response to therpy. Recently, Woodle et l reported series of post-tretment protocol iopsies otined during Tcrolimus therpy for refrctory renl rejection [9]. Biopsies were otined t time of inclusion in the Tcrolimus tretment protocol, one week fter initition of therpy nd weekly therefter if there ws lck of clinicl response. Their results demonstrted tht 40% hd persistence of the rejection histology on the post-tretment protocol iopsy. The dt from Woodle s report were somewht different from our findings in tht histologicl resolution of rejection more commonly preceded iochemicl improve-

7 Ger et l: Correltion of histology to rejection reversl 2421 portionl to the severity of the initil histologicl scoring. The scoring of infiltrtes using Bnff clssifiction did not correlte with clinicl prmeters of rejection reversl, ut hd prognostic significnce in ptients for whom the residul infiltrte score ws greter thn 4.0. The long-term significnce of the persistent infiltrtes is un- cler t this time. More prospective studies should proly include longitudinl protocol iopsy surveillnce to determine the histologicl nd functionl outcomes of ptients with residul rejection histology following suc- cessful therpy for cute rejection. chnges, hs een demonstrted in other studies to hve poor outcome (40% were clssified s irreversile) nd to e responsive to tretment with ntilymphocyte gents [20]. Clinicl response to ntirejection therpy ws not ssocited, however, with the selected histologicl outcome, tht is, n improvement of one Bnff grde level. In the cses in which clinicl rejection reversl occurred, there were n equl numer of post-tretment protocol iopsies with or without improvement over the inclusion iopsy, with two thirds of the iopsies demonstrting vrious degrees of residul rejection. In ddition, none of the routine clinicl prmeters used to judge the severity or response of rejection were relted to the one Bnff grde level of improvement in histologicl criteri or to iopsy scores (dt not shown). As mentioned previously, however, differences etween tret- ments nd correltion to recurrent rejection were seen when comprtment scores nd totl sum scores were nlyzed, indicting the possile utility of comprtmentl scoring s n end point for rejection tretment. The persistence of mild inflmmtory infiltrtes in the llogrfts hs een descried in stle llogrfts oth in the erly postopertive period s well s in long-term follow-up (strct; Argento, Am Society Trnsplnt Physicins 16:125, 1997) [10, 21]. The degree to which these infiltrtes persist fter cliniclly successful tretment of rejection is underscored y the findings in this nd other studies (strct; Chvers, Am Soc Trnsplnt Physicins 12:261, 1993; strct; Mzzucchi, Am Soc Trnsplnt Physicins 16:135, 1997) [9]. The significnce of persistent infiltrtes in stle llogrfts nd their reltionship to susequent rejection, chronic deteriortion, or ultimte grft loss is eing investigted in longitudinl studies [22]. Erly dt from Rush, Jeffrey, nd Gough indicte tht these infiltrtes my predict poor outcomes [23]. On the other hnd, the significnce of persistent infiltrtes following rejection tretment re only now eginning to e studied ut hve een presumed, ecuse of their proximity to the rejection episode, to indicte n incomplete rejection reversl nd to predict p- tients t high risk for filure [24]. Exmintion of the post-tretment protocol iopsies in this study revels tht, t lest in the short term, the degree of inflmmtion my e more significnt thn its persistence ecuse p- tients with milder degrees of persistent inflmmtion (tht is, sum scores of 2.5 or less) were not dignosed with recurrent rejection. The ultimte significnce, however, of persistent infiltrte cn only e determined on longer term follow-up of these llogrfts. In summry, our dt demonstrte the prevlence of residul infiltrtes in protocol iopsies otined two weeks following rejection tretment with ntilympho- cytes. Only one third of ll ptients treted hd totl resolution of infiltrtes in the post-tretment protocol iopsy. The degree of histologicl improvement ws pro- ACKNOWLEDGMENTS This study ws funded y n eductionl grnt from SngStt Medicl Corportion, Menlo Prk CA, USA. This informtion ws presented t the 16th Annul Meeting of the Americn Society of Trnsplnt Physicins, Chicgo, IL, USA, in My The following is n lphetic listing of the U.S. Multicenter Thymogloulin Study Group: Gicomo Bsdonn (Yle University); Dniel C. Brennn (Wshing- ton University); Lurence Chn (University of Colordo); M. Roy First (University of Cincinnti); A. Osm Ger (The University of Tennessee-Memphis); Roert S. Gston (University of Alm- Birminghm); John M. Hm (Medicl College of Virgini); Ernest E. Hodge (Clevelnd Clinic Foundtion); Brry D. Khn (University of Texs); Lwrence Khn (Tmp Generl Hospitl); Sturt Knechtle (University of Wisconsin); Jimmy A. Light (Wshington Hospitl Center); Roert Mendez (Ntionl Institute of Trnsplnttion); Lur L. Mulloy (Medicl College of Georgi); John F. Neyln (Emory University); Dougls J. Normn (Oregon Helth Science Center); Fud Shih (University of Uth); Elizeth Squiers (SUNY Helth Science Center- Syrcuse); Steven Steinerg (Shrp Memoril Hospitl); Roert W. Steiner (University of Cliforni-Sn Diego); Roert J. Strtt (Uni- versity of Nersk); Rodney J. Tylor (Bishop Clrkson Hospitl); Rymond J. Tesi (Tulne University); Erik Whlstrom (Lom Lind University); nd E. Steve Woodle (University of Chicgo). Reprint requests to Lillin W. Ger, M.D., Deprtment of Pthol- ogy, The University of Tennessee-Memphis, 800 Mdison Avenue, Memphis, Tennessee 38103, USA. E-mil: lger@utmem1.utmem.edu REFERENCES 1. Ger AO, Moore LW, Schroeder TJ: Oservtions on recovery of renl function following tretment for cute rejection. Am J Kidney Dis 31(Suppl):S47 S59, Guttmnn RD, Soulillou JP, Moore LW, First MR, Ger AO, Pouletty PO, Schroeder TJ: Proposed consensus for definitions nd endpoints for clinicl trils of cute kidney trnsplnt rejection. Am J Kidney Dis 31(Suppl):S40 S46, Ger LW, Moore LW, Allowy RR, Flx SD, Shokouh-Amiri MH, Schroeder TJ, Ger AO: Correltion etween Bnff clssi- fiction, cute renl rejection scores nd reversl of rejection. 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8 2422 Ger et l: Correltion of histology to rejection reversl PF, Häyry P, Jennette JC, Keown PA, Mrcussen N, Mihtsch rejection in renl llogrft recipients. Trnsplnttion 55: , MJ, Morozumi K, Myers BD, Nst CC, Olsen S, Rcusen LC, 1993 Rmos EL, Rosen S, Schs DH, Slomon DR, Snfilippo F, 14. Flechner SM, Modlin CS, Serrno DP, Goldfr DA, Ppjcik Verni R, von Willernd E, Ymguchi Y: Interntionl stndrdiztion D, Mstroinni B, Goormstic M, Novick AC: Determinnts of of criteri for the histologic dignosis of renl llogrft chronic renl llogrft rejection in cyclosporine-treted recipients. rejection: The Bnff working clssifiction of kidney trnsplnt Trnsplnttion 62: , 1996 pthology. Kidney Int 44: , Mts AJ, Gillinghm KJ, Pyne WD, Njrin JS: The impct 8. Colvin RB, Cohen AH, Siontz C, Bonsi S, Buick M, Burke of n cute rejection episode on long-term renl llogrft survivl B, Crter S, Cvllo T, Hs M, Lindld A, Mnivel JC, (t1/2). Trnsplnttion 57: , 1994 Nst CC, Slomon D, Wever C, Weiss M: Evlution of pthologic 16. Ceck JM: Erly rejection determining the fte of renl trnssensitivity, criteri for cute renl llogrft rejection: Reproduciility, plnts. Trnsplnt Proc 23: , 1991 nd clinicl correltion. J Am Soc Nephrol 8: , 17. Tesi RJ, Elkhmms EA, Henry M, Ferguson RM: Acute rejec tion episodes: Best predictor of long-term primry cdveric renl 9. Woodle ES, Cronin D, Newell KA, Millis JM, Bruce DS, Piper trnsplnt survivl. Trnsplnt Proc 25: , 1993 JB, Hs M, Josephson MA, Thistlethwite JR: Tcrolimus ther- 18. Bsdonn GP, Mts AJ, Gillinghm KJ, Pyne WD, Dunn py for refrctory cute renl llogrft rejection: Definition of the DL, Sutherlnd DE, Gores PF, Gruessnor RW, Njrin JS: histologic response y protocol iopsies. Trnsplnttion 62:906 Erly versus lte cute renl llogrft rejection: Impct on chronic 910, 1996 rejection. Trnsplnttion 55: , Burdick JF, Beschorner WE, Smith WJ, Mcgrw D, Bender 19. Kerr PG, Atkins RC: The effects of OKT3 therpy on infiltrting WL, Willims GM, Solez K: Chrcteristics of erly routine renl lymphocytes in rejecting renl llogrfts. Trnsplnttion 48:33 36, llogrft iopsies. Trnsplnttion 38: , Rush DN, Henry SF, Jeffrey JR, Schroeder TJ, Gough J: Histologicl 20. Ger LW, Moore LW, Allowy RR, Flx S, Ger AO: Correrecipients. findings in erly routine iopsies of stle renl llogrft ltion etween Bnff clssifiction, cute renl rejection scores Trnsplnttion 57: , 1994 nd reversl of rejection. Kidney Int 49: , Ger AO, First MR, Tesi RJ, Gston RS, Mendez R, Mulloy 21. Isoniemi HM, Krogerus L, von Willernd E, Tskinen E, Ahonen LL, Light JA, Ger LW, Squiers E, Tylor RJ, Neyln JF, J, Hyry P: Histopthologicl findings in well-functioning, Steiner RW, Knechtle S, Normn DJ, Shih F, Bsdonn G, long-term llogrfts. Kidney Int 41: , 1992 Brennn DC, Hodge EE, Khn BD, Khn L, Steinerg S, 22. Rush D, Jeffrey J, Trpkov K, Solez K, Gough J: Effect of suclini- Woodle ES, Chn L, Hm JM, Strtt RJ, Whlstrom E, Lm- cl rejection on renl llogrft histology nd function t 6 months. orn KR, Horn HR, Berger Morn H, Pouletty P, Schroeder Trnsplnt Proc 28: , 1996 TJ: Results of the doule-lind, rndomized, multicenter, phse 23. Rush DN, Jeffrey JR, Gough J: Sequentil protocol iopsies in III clinicl tril of Thymogloulin versus Atgm in the tretment renl trnsplnt ptients. Trnsplnttion 59: , 1995 of cute grft rejection episodes following renl trnsplnttion. 24. Serón D, Moreso F, Bover J, Condom E, Gil-Vernet S, Cñs Trnsplnttion 66:29 37, 1998 C, Fulldos X, Torrs J, Crrer M, Grinyó JM, Alsin J: 13. Almond PS, Mts A, Gillinghm K, Dunn DL, Pyne WD, Erly protocol renl llogrft iopsies nd grft outcome. Kidney Gores P, Gruessner R, Njrin JS: Risk fctors for chronic Int 51: , 1997