Post-transplant lymphoproliferative disorderin children: Recent outcomes and response todual rituximab/low-dose chemotherapycombination

PTLD is a well-recognized complication follow-ing SOT, in part because of extrinsic immuno-suppression (1). PTLD encompasses a spectrumof lymphoid proliferative disorders ranging frombenign polyclonal hyperplasia to malignantmonoclonal neoplasms that resemble lymphomas(2). Historically, treatment options, which arenot standardized, included: RI, interferon-alpha,

or other antivirals, anti B-cell antibody (ritux-imab), various chemotherapy regimens, surgery,and radiotherapy. Usually these treatment strat-egies are employed sequentially, starting with RIand progressively escalating to chemotherapeutictherapy, if response to prior strategies is inade-quate.However, it is not clear if a sequential approach

results in the best outcome. The challengesinvolved in the treatment of PTLD, besidestumor response, are secondary infection, rejec-tion, and drug-related toxicity. RI response is lowin adults (3), though may be better in children (4).Responses to interferon-alfa and rituximab havebeen variable (5–9). Chemotherapy regimenshave generally been avoided as early therapy inthe view of significant associated morbidity andmortality in early series (10–12). Gross et al. then

Gupta S, Fricker FJ, Gonzalez-Peralta RP, Slayton WB, Schuler PM,Dharnidharka VR. Post-transplant lymphoproliferative disorder inchildren: Recent outcomes and response to dual rituximab/low-dosechemotherapy combination.PediatrTransplantation2010:14:896–902.�2010JohnWiley&SonsA/S.

Abstract: PTLD is a major complication after transplantation. Treat-ment options for PTLD are not standardized, usually sequential,starting with reduction in immunosuppression. Recently, we have useda dual combination of rituximab and reduced dose chemotherapy (R/C)directly after failed RI. We retrospectively identified 30 pediatric PTLDcases across four organ systems at our center from 1995 to 2008. Weassessed recent outcomes of PTLD in children, comparing the responsesto different regimens. Two-yr failure-free survival was best in renal andheart recipients (80–88%), followed by liver (57%) and lung (0%). Ofnote, two patients were Epstein–Barr peripheral blood viral load lowpositive but tumor EBER negative. Three patients had no detectableviral load but were EBER positive. The R/C regimen (n = 8) had thehighest CR rate (100%), low recurrence (12%) and lowest mortality(12%). Interferon (n = 4) had 75% CR, 33% recurrence and 25%mortality. Rituximab/prednisone (n = 5) had 80% CR, 50% recur-rence and 20% mortality. Other chemotherapy (n = 7, including all 4T-cell PTLDs) had 57% CR, 0% recurrence and 14% mortality. Directdual R/C combination therapy after failed RI is effective and offersanother treatment option for B-cell PTLD.

Sushil Gupta, Frederick J. Fricker,Regino P. Gonz�lez-Peralta, WilliamB. Slayton, Pamela M. Schuler andVikas R. DharnidharkaDepartment of Pediatrics, University of FloridaCollege of Medicine and Shands Children�s Hospital,Gainesville, FL, USA

Key words: children – Epstein–Barr virus – outcome– PTLD – rituximab – solid organ – transplantation

Vikas R. Dharnidharka, Division of Pediatric Nephrol-ogy, PO Box 100296/Room HD 214, University of FloridaHealth Science Center, 1600 SW Archer Road,Gainesville, FL 32610-0296, USATel.: +1 352 273 9180Fax: +1 352 392 7107E-mail: vikasmd@peds.ufl.edu

Accepted for publication 19 May 2010

Abbreviations: COG, Children�s Oncology Group; CP,cyclophosphamide + prednisone; CR, complete response;EBER, Epstein–Barr virus encoded RNA; EBV, Epstein–Barr virus; EFS, event-free survival; FFS, failure-freesurvival; IVIG, intravenous immune globulin; PD, pro-gressive disease; PTLD, post-transplant lymphoproliferativedisorder; R/C, rituximab/low-dose chemotherapy; RI,reduction in immunosuppression; SOT, solid organ trans-plantation.

Pediatr Transplantation 2010: 14: 896–902 � 2010 John Wiley & Sons A/S.

Pediatric TransplantationDOI: 10.1111/j.1399-3046.2010.01370.x

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developed a low-dose chemotherapy protocolthat was associated with lesser drug toxicity andbetter tolerance (13). The use of this chemother-apeutic regimen, directly after failure of RI,resulted in a two-yr FFS rate of 67% but didnot work in cases of fulminant PTLD (14). Thenext logical step was to assess whether a combi-nation of R/C would result in better responserates than either alone (15).Our center participated in the COG ANHL

0221 trial, a single-arm prospective multi-centerstudy of the R/C combination, directly afterfailure of RI, without intervening steps. Ourcenter continued using this combination evenafter enrollment in this NIH-sponsored trial wascomplete. In this analysis, we hypothesized thatthe dual R/C combination, directly after failedRI, would provide superior outcomes in the non-COG study patients compared to other sequentialtreatment options.

Methods

We retrospectively identified all PTLD cases at our centeracross four solid organ systems in children between January,1995 and July, 2008. Data collected included age at trans-plant, date of PTLD, pathological findings from the tumorbiopsy, and treatment regimen used. Pathological findingswere reported by our hematopathologist using the WHOcriteria in place at that time. All patients were initiallytreated with reduction in immunosuppression. The amountof RI was variable ranging from reduction in the dose todiscontinuation of one of the immunosuppressant medica-tion. Prior to the initiation of the R/C protocol, our usualapproach was sequential application of (i) RI; (ii) inter-feron-alpha or rituximab/prednisone or radiotherapy; (iii)other chemotherapy regimens. Once the R/C protocol wasstarted, patients with PTLD received (i) RI; then (ii) R/Cprotocol. Some of the patients with severe disease or withunfavorable histology (T-cell origin) received chemotherapyalong with RI to start with. We calculated FFS, defined asa period with no recurrence or persistence of PTLD, graftfailure or death, similar to Gross et al. (14), analogous toEFS for cancer but also including the parameter of allo-graft survival, an important transplant-specific outcome.Response was defined based on reduction in tumor massas complete (total resolution of the tumor mass, CR) or PDfor all others including those with partial response andprogressive disease.Data were analyzed with Graph Pad version 5.0 (La Jolla,

CA, USA). Descriptive statistics used to express the datainclude median with range or mean with standard error, asappropriate. Chi-square test for trend was used to compareproportions between groups and Mann–Whitney test tocompare continuous non-parametric variables. A p-value<0.05 was considered significant.

Results

A total of 30 pediatric patients (16 females and14 males) with PTLD were identified among fourdifferent solid organ transplants. Age at the time

of PTLD ranged from 2.2 yr to 18.7 yr (Table 1).Of these 30 patients, eight received a kidneytransplant, nine received a liver transplant, 10received a heart transplant, and three received alung transplant (Tables 1 and 2). The immuno-suppression protocol prior to PTLD varied withdifferent organ transplant and with time. Theincidence of PTLD was 4.6%, 4.7%, 7.5%, and5.5% in kidney, liver, heart, and lung transplant,respectively, at our center.The overall median time to develop PTLD was

33.7 months (range 3.8–155.8 months). Organ-related median time to PTLD is depicted inTable 2. The time to PTLD was more than twoyr (late onset) in 19/30 (63%) of cases. The meanage at transplant was three yr, lower in the groupof patients with late-onset PTLD compared tothe mean age (9.9 yr) in the group with earlyonset (<2yr of post-transplant). This differencewas significant (p value = 0.0037) by Mann-Whitney test. In heart transplant recipients, earlyonset PTLD was found in 50% of patients. Inkidney, liver, and lungs transplants recipients,early onset PTLD was seen in 25%, 33%, and33% of the patients, respectively. In the late-onset PTLD group, the tumor EBER stainingwas negative in 21% of patients compared to10% of patients in early onset.The organs involved with PTLD at presenta-

tion were lymph nodes, gastrointestinal tract,tongue, lungs, iris, bone marrow, central nervoussystem, or an allograft kidney. Lymph nodeswere the commonest site of involvement atpresentation (56%). Peripheral blood EBV loadat PTLD presentation was available in 18 of the30 patients. Of these, 15 patients had positiveperipheral blood PCR for EBV, with a viral loadranging from 20 to >5000 per 105 lymphocytes(Table 1).The organ-associated distribution of clinico-

pathological characteristics and the outcomes areshown in Table 2. Overall, histological examina-tion of the tumors revealed that 71% werepolyclonal, 75% polymorphic, 86% B-cell type,and 79% were EBER positive. Among 11patients who presented with early-onset PTLD,nine had positive EBER staining in tumor(Table 1). Two of the patients who had relativelylow peripheral blood viral PCR loads were foundto have tumor cells that lacked EBER expression(Table 1). In contrast, three patients had nodetectable EBV load by peripheral blood PCRbut were found to have a tumor mass thatexpressed EBER. Data on EBV serostatus of thedonor and recipient were incomplete and hencenot analyzed.

Dual PTLD treatment in children

897

Overall, four (13%) cases achieved remissionwith RI only (Fig. 1). Of these four, one patient�sdisease recurred. This patient did not respond to

interferon and died of progressive PTLD. Theremaining 26 patients did not respond to onlyRI. The distribution of treatment for these 26 is

Table 1. Clinical and pathological details of each patient with PTLD

No.TransplantOrgan

Age atTransplant (yr)

Time toPTLD(months)

Highest treatmenttype for PTLD Tumor pathology

Tumor EBERstatus

EBV load atpresentation(per 105 lymphocytes)

1 Kidney 5.9 50.9 R/C combination PMPC, B cell Positive 50002 Kidney 3.0 57.7 Other lymphoma�

chemotherapyPMPC, B cell Positive NA

3 Kidney 2.8 7.8 Interferon PMPC, B cell Positive NA4 Kidney 7.4 31.0 R/C combination PMPC, B cell Positive 405 Kidney 11.2 26.7 R/C combination PMPC, B cell Positive 406 Kidney 16.1 9.2 R/C combination PMPC, B cell Positive 207 Kidney 1.3 72.1 Other lymphoma�

chemotherapyPMMC, B cell Positive 0

8 Kidney 4.5 134.4 R/C combination PMPC, B cell Negative NA9 Liver 18.2 5.3 RI MC, B cell Positive NA10 Liver 0.6 155.8 R/C combination MMMC, B cell Positive 40011 Liver 5.5 47.2 Radiotherapy PMPC, B cell Positive NA12 Liver 0.5 90.4 R/C combination B cell Negative 60013 Liver 3.4 60.6 Other lymphoma

chemotherapyMMMC, T cell Positive NA

14 Liver 1.2 36.4 R/C combination PMPC, B cell Positive >500015 Liver 1.5 8.6 Rituximab/prednisone PMPC, B cell Positive 8016 Liver 4.0 35.2 R/C combination PMPC, B cell Burkitt�s Positive >500017 Liver 0.5 22.4 Interferon NA NA NA18 Heart 7.9 3.8 R/C combination PMPC, B cell Positive 10019 Heart 17.7 6.5 R/C combination PMPC, B cell Positive 020 Heart 15.4 16.8 RI PMPC, B cell Positive NA21 Heart 0.04 88.7 Rituximab/prednisone MMMC, B cell Positive NA22 Heart 0.23 68.6 Other lymphoma

chemotherapyB-cell Burkitt�s Positive 80

23 Heart 9.5 10.8 Other lymphomachemotherapy

T cell Negative NA

24 Heart 0.7 30.5 RI PMPC, B cell Positive NA25 Heart 7.71 99.60 Rituximab/prednisone PMPC, B cell Positive Positive*26 Heart 6.0 11.20 RI NA Positive 027 Heart 0.12 104.57 Other lymphoma

chemotherapyMMMC, T cell Negative 400

28 Lungs 0.32 32.23 Other lymphomachemotherapy

MMMC, T cell Negative NA

29 Lungs 14.07 6.13 R/C combination� MMMC, B cell Positive 2030 Lungs 0.16 93.27 Rituximab/prednisone PMPC, B cell Positive 5000

RI, reduced immunosuppression; NA, not available.R/C combination (rituximab+ cyclophosphamide+ prednisone), Other lymphoma chemotherapy (AALL0232 and CCG 5961 modified CHOP, Cytoxan) are all chemo-therapy protocols created by the COG or its predecessor Children�s Cancer Group (CCG). PMPC (Polymorphic polyclonal), MMMC (Monomorphic monoclonal), MC(Monoclonal), T cell (T-cell origin), B cell (B-cell origin).*Only qualitative EBV PCR test performed in this case; all other quantitative EBV PCR tests were performed at University of Pittsburgh.�Failed initial therapy with interferon.�Failed initial therapy with rituximab/prednisone.

Table 2. Clinical–pathological characteristics and outcomes in each transplant organ system

Organ type NumberMedian time toPTLD months (range)

TumorEBER + n/total (%)

TumorCD20 + n/total (%)

B-cell typen/total (%) 2-yr FFS (%) R/C used %

Kidney 8 41 (7.7–72.0) 7/8 (87) 7/8 (87) 8/8 (100) 88 25Liver 9 36 (5.3–155.8) 7/8 (87) 8/8 (100) 7/8 (87) 57 44Heart 10 24 (3.8–104.5) 7/10 (70) 6/8 (75) 7/9 (78) 80 20Lungs 3 32 (6.1–93.2) 2/3 (67) 1/2 (50) 2/3 (67) 0 33

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depicted in Fig. 1, the total exceeding 30 as threepatients moved between groups. Four of the12 patients received dual R/C treatment as a partof the COG ANHL0221 study and were excludedfrom further outcome analysis as the primaryCOG study results have not been published. Allthe patients in the R/C group had PTLD ofB-cell origin. Of these, 82% of them werepolymorphic and polyclonal in morphology. Incontrast, four of seven patients in the group withother chemotherapy had PTLD that was T cell inorigin and three of these patients had monomor-phic monoclonal morphology (Table 1).In the R/C group, 100% had CR compared to

80% CR in the rituximab/prednisone treatedgroup and just 57% in other chemotherapygroup (Table 3). All the patients in the R/Cand rituximab/prednisone groups had at least apartial response, such that overall response rateswere 100% (Table 3). The overall response ratewas slightly lower in the group treated withinterferon (75%) and other chemotherapy(85%). None of the patients in the group treatedwith other chemotherapy had a recurrence ofPTLD (Fig. 1, Table 3). Patients treated with R/C combination had a lower recurrence rate(12%) compared to group of patients treatedwith interferon (33%) or rituximab/prednisone(50%). The lowest mortality rate (12%) was seen

in R/C combination group compared to inter-feron or rituximab/prednisone (20–25%). By chi-square test for trend, none of the trends werefound to be statistically significant (p valueslisted in Table 3 footnote).The two-yr FFS was 80% in the dual R/C

combination group and 40% in other chemo-therapy group. Two-yr FFS was also calculatedfor each transplant organ system with PTLD.The two-yr FFS appeared clinically better withkidney and heart transplant (88% and 80%,respectively) than liver and lung transplant(57% and 0%, respectively) patients, but thedifference did not reach statistical signifi-cance (chi-square test for trend p value = 0.08;Table 2).Of the 30 patients with PTLD, seven died.

Three of these patients died because of progres-sive PTLD (including the one death in the R/Ctreated group). Other deaths were attributed toinfection (n = 1) or transplant organ-relatedcomplications (n = 3). Fever with neutropeniawas the most common adverse effect of chemo-therapy seen in 71% of the patients in R/Ccombination group and 75% of patients in otherlymphoma chemotherapy group. One patient inthe lung transplant group who was treated withrituximab and prednisone died of aspergillosis.Data on the length of hospitalization for PTLD

treatment–related complication were availablefrom six patients in R/C group and 4 patientsin the other chemotherapy group. The meanhospital stay because of treatment-related com-plication was 12.17 d (s.e. 4.6) in R/C group whencompared to 26.5 d (s.e. 15.9) in the group withother chemotherapy. This difference was notstatistically significant (p value = 0.9) by Mann–Whitney test.In the R/C group, one of seven patients (data

were not available in 1 patient) had two episodesof acute rejections during the treatment ofPTLD. In the other chemotherapy group, no

4 Interferon

7 Other chemotherapy 4CR +3 PD

12 R/C

Combination(excluded 4) 8CR

(1RR)

1 Radiotherapy 1CR

4 Reduced immuno-

suppression 4 CR (1 RR)

Total 30 patientswith PTLD

5 Rituximab prednisone 4 CR + 1 PD

(2 RR)

3 CR + 1 PD (1 RR)

Fig. 1. Distribution of the patients in different treatmentgroups and their outcomes. CR, complete response; RR,recurrence; PD, persisting disease. The total number is morethan 30 as patients moved between the groups (more detailsof which are provided in Table 1).

Table 3. Outcomes in each treatment regimen group

Type of therapy

Overall responserate %* (CR/partialresponse)

Recurrencerate n (%)

Mortalityrate n (%)

Interferon (n = 4) 75 (75/0) 1 (33) 1 (25)Rituximab/prednisone (n = 5) 100 (80/20) 2 (50) 1 (20)R/C combination (n = 8) 100 (100/0) 1 (12) 1 (12)Other Chemotherapy (n = 7) 85 (57/28) 0 (0) 1 (14)

*Includes complete response and partial response with some persisting dis-ease.CR, complete response.P values by chi-square test for trend: 0.2946 (CR), 0.1146 (recurrence), 0.6022(mortality), all not significant.

Dual PTLD treatment in children

899

episode of rejection was observed during thetreatment for PTLD in five patients (limitedinformation was available on other two patients).The graft function was stable in all seven patientswith data available in the R/C group and five ofsix patients with data available in the otherchemotherapy group.

Discussion

PTLD remains a major complication followingtransplantation. Patient and graft survival out-comes after PTLD remain suboptimal, moreso inthose with late-onset disease more than two- yrpost-transplant (16). In addition, survival afterPTLD differs by recipient age and allograft type(16). Outcomes in children after PTLD are muchbetter than in adults (1). For instance, pediatrickidney transplant recipients with PTLD from arecent trial had an 89% survival (4). Thisoutcome has improved from a near 50% mor-tality in a mid-1990s survey (17). PTLD present-ing in children who received other allograft typestends to have worse patient survival. The rangeof survival is from 36% in a mixed group (18),43% in heart (19, 20), 54% in lung (20) to 60% inliver recipients (21). More recent studies suggestimproved survival of 80–82% (22, 23). In a seriesof 56 PTLD cases in pediatric heart transplantrecipients, the probability of survival was 75% atone yr, 68% at three yr, and 67% at five yr afterdiagnosis (24). Kidney transplant recipients maydo better than other allograft types as greaterdegrees of immunosuppression reduction arepossible, and the fear of allograft loss is lessbecause of the ability to dialyze patients whoreject their transplanted kidneys.The historical paradigm for the management

of most PTLD cases has involved a stepwiseapproach, going from least to most toxic treat-ments. The initial step typically has been someform of RI, though the amount of reduction andfor which agent is not standardized. Subsequentsteps, in the past, have involved alpha-interferon,IVIG, anti-viral agents, radiotherapy or chemo-therapy. Further, the overall success rate for mildto moderate PTLD cases seemed similar acrossthe various treatment options (3). The reportedresponse to RI has ranged from no remission inan adult population (3) to high remission rate of79% in a recent pediatric population (4). Somestudies in adults have reported relatively lowcomplete remission rate of 28–53% with theuse of rituximab after failed RI in the treatmentof CD 20–positive B-cell PTLD (5, 6, 8, 9),also associated with one-yr survival of <50%because of progressive disease, infection, or

rejection (25). In contrast, when rituximab wasused early, concomitant to RI in adults, Evenset al. reported a high overall survival rate of>70% (26). Early data on multi-drug chemo-therapy regimens revealed that graft rejectionrates were reduced and complete remission rateswere high but the survival remained <50%because of drug toxicity and infection (10–12).Chosen chemotherapy regimens were lymphomaregimens, given the close histological relationshipbetween PTLD and lymphoma. Short-term suc-cess rates (complete or partial response) were inthe range of 40–70% whether patients receivedRI or alpha-interferon or with chemotherapy(27–30).Gross et al. therefore devised the CP regimen

for treating PTLD, eliminating the vincristineand daunorubicin components of the CHOPregimen (13). This group reported a two-yr FFSrate of 67% after PTLD diagnosis with the use ofCP regimen in single-arm uncontrolled multi-center trial, though fulminant PTLD cases faredpoorly. Recently, Gallego et al. in a single-centerstudy were able to achieve a two-yr EFS (notFFS) rate of 57% with a combination of ritux-imab and a milder chemotherapy regimen (31).Orjuela et al., in a pilot multi-center study,suggested that rituximab in combination withlow-dose chemotherapy (R/C) is well toleratedand may be more efficacious in patient withPTLD after SOT (32). In their study, six patientswere treated with the R/C combination. Theyhad an overall response rate of 100% (CR 85%),and only one of six patients in this study hadrecurrent disease. Similarly, the overall responserate in our series was 100% in the patientstreated with R/C combination with a recurrencerate of only 12%. The two-yr FFS was 80% indual R/C combination group and 40% in otherchemotherapy group. Of note, these two groupsdid not have similar patient populations. In theother chemotherapy group, 56% of cases hadT-cell origin PTLD when compared to R/Cgroup with no T-cell origin PTLD. Given theknown worse outcomes of T-cell PTLD, a directKaplan–Meier survival analysis of R/C to otherchemotherapy regimens was not performed in thepresent study. Trappe et al. have shown thatrituximab may still lead to response in patientswho fail chemotherapy and vice versa (33, 34).Further, the combination of RI, rituximab, andchemotherapy prevented deterioration in renalallograft function (35). The results from the largemulti-center single-arm prospective trial of R/Ccombination in PTLD (COG ANHL 0221 trial)are expected shortly.

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There were some unique features within ourseries. Only 37% of cases had early onset PTLD(defined as occurring within two-yr post-trans-plant) and 63% were late-onset PTLD (>2 yr).This is an unusual distribution in a pediatricPTLD series, where most cases are early PTLD.Peripheral blood EBV measurements are nowmore closely followed at many transplant centerssuch as ours, with potential intervention forpositive results. Although others have reportedthat such serial viral load monitoring leads toearlier detection of early stage PTLD (36), wespeculate that preemptive interventions mightalso delay the presentation of a later-stage andfully symptomatic PTLD disease. Another unu-sual feature was that three cases in our study(case numbers 7, 19, and 26 in Table 1) hadundetectable EBV DNA in peripheral blood butexpressed EBER in the tumor mass, of whomone case has been reported previously (37). As wehave pointed out in that report (37), monitoringwith only peripheral blood EBV load may notalways lead to early PTLD detection. In contrast,two cases (numbers 12 and 27 from Table 1) hadtumor tissue that did not express EBER but hadlow EBV DNA copies in peripheral blood byPCR. We speculate that, similar to the immuno-competent population, transplant recipients pre-viously exposed to EBV may also transiently andrepetitively show low-level EBV replication inblood (38–40).The main limitations of this study include its

retrospective nature, heterogeneous PTLD pre-sentation, and the small sample size of enrollees,which likely precluded the detection of a signif-icant difference in outcomes between R/C versusother regimens. Nevertheless, our data are valu-able as no prospective randomized controlledtrials of PTLD treatment have ever been con-ducted. Direct R/C treatment after failed RIappears effective and offers an additional treat-ment option for B-cell PTLD.

Acknowledgments

This study was presented as a poster at the AmericanTransplant Congress, the joint annual meeting of theAmerican Society of Transplantation and American Soci-ety of Transplant Surgeons, in May 2009. The authorsthank Ms. Stacia Hayes, ARNP, for assistance in dataabstraction.

References

1. Dharnidharka VR, Araya CE. Post-transplant lymphopro-

liferative disease. Pediatr Nephrol 2009: 24: 731–736.

2. Swerdlow SH. Classification of the posttransplant lympho-

proliferative disorders: From the past to the present. Semin

Diagn Pathol 1997: 14: 2–7.

3. Swinnen LJ, Leblanc M, Grogan TM, et al. Prospective study

of sequential reduction in immunosuppression, interferon

alpha-2B, and chemotherapy for posttransplantation lympho-

proliferative disorder. Transplantation 2008: 86: 215–222.

4. Mcdonald RA, Smith JM, Ho M, et al. Incidence of PTLD in

pediatric renal transplant recipients receiving basiliximab,

calcineurin inhibitor, sirolimus and steroids. Am J Transplant

2008: 8: 984–989.

5. Choquet S, Leblond V, Herbrecht R, et al. Efficacy and

safety of rituximab in B-cell post-transplantation lymphopro-

liferative disorders: Results of a prospective multicenter phase

2 study. Blood 2006: 107: 3053–3057.

6. Oertel SH, Verschuuren E, Reinke P, et al. Effect of anti-

CD 20 antibody rituximab in patients with post-transplant

lymphoproliferative disorder (PTLD). Am J Transplant 2005:

5: 2901–2906.

7. Shapiro RS, Chauvenet A, Mcguire W, et al. Treatment of

B-cell lymphoproliferative disorders with interferon alfa and

intravenous gamma globulin. N Engl J Med 1988: 318: 1334.

8. Svoboda J, Kotloff R, Tsai DE. Management of patients

with post-transplant lymphoproliferative disorder: The role of

rituximab. Transpl Int 2006: 19: 259–269.

9. Webber SA, Harmon WE, Faro A. Anti-CD20 monoclonal

antibody (rituximab) for refractory PTLD after pediatric solid

organ transplantation: Multicenter experience from a registry

and from a prospective clinical trial. Blood 2004: 104: 213a.

10. Cohen JI. Epstein-Barr virus lymphoproliferative disease

associated with acquired immunodeficiency. Medicine (Balti-

more) 1991: 70: 137–160.

11. Morrison VA, Dunn DL, Manivel JC, Gajl-Peczalska KJ,

Peterson BA. Clinical characteristics of post-transplant lym-

phoproliferative disorders. Am J Med 1994: 97: 14–24.

12. Swinnen LJ, Mullen GM, Carr TJ, Costanzo MR, Fisher

RI. Aggressive treatment for postcardiac transplant lympho-

proliferation. Blood 1995: 86: 3333–3340.

13. Gross TG, Hinrichs SH, Winner J, et al. Treatment of post-

transplant lymphoproliferative disease (PTLD) following solid

organ transplantation with low-dose chemotherapy. Ann

Oncol 1998: 9: 339–340.

14. Gross TG, Bucuvalas JC, Park JR, et al. Low-dose chemo-

therapy for Epstein-Barr virus-positive post-transplantation

lymphoproliferative disease in children after solid organ

transplantation. J Clin Oncol 2005: 23: 6481–6488.

15. Choquet S, Trappe R, Leblond V, Jager U, Davi F, Oertel

S. CHOP-21 for the treatment of post-transplant lymphopro-

liferative disorders (PTLD) following solid organ transplanta-

tion. Haematologica 2007: 92: 273–274.

16. Dharnidharka VR. Epidemiology of PTLD. In: Dharnidh-

arka VR, Green M, Webber SA, eds. Post-Transplant

Lymphoproliferative Disorders. Berlin: Springer-Verlag, 2009:

pp. 17–28.

17. Hebert D, Sullivan EK. Malignancy and post transplant

lymphoproliferative disorder (PTLD) in pediatric renal trans-

plant recipients: A report of the North American Pediatric

Renal Transplant Cooperative Study (NAPRTCS). Pediatr

Transplant 1998: 1: 107.

18. Allen UD, Farkas G, Hebert D, et al. Risk factors for post-

transplant lymphoproliferative disorder in pediatric patients: A

case-control study. Pediatr Transplant 2005: 9: 450–455.

19. Boyle GJ, Michaels MG, Webber SA, et al. Posttransplan-

tation lymphoproliferative disorders in pediatric thoracic organ

recipients. J Pediatr 1997: 131: 309–313.

20. Cohen AH, Sweet SC, Mendeloff E, et al. High incidence of

posttransplant lymphoproliferative disease in pediatric patients

with cystic fibrosis. Am J Respir Crit Care Med 2000: 1 (4 Pt 1):

1252–1255.

Dual PTLD treatment in children

901

21. Newell KA, Alonso EM, Whitington PF, et al. Post-

transplant lymphoproliferative disease in pediatric liver

transplantation. Interplay between primary Epstein-Barr virus

infection and immunosuppression. Transplantation 1996: 62:

370–375.

22. Fernandez MC, Bes D, De Davila M, et al. Post-transplant

lymphoproliferative disorder after pediatric liver transplanta-

tion: Characteristics and outcome. Pediatr Transplant 2009: 13:

307–310.

23. Younes BS, Mcdiarmid SV, Martin MG, et al. The effect of

immunosuppression on posttransplant lymphoproliferative

disease in pediatric liver transplant patients. Transplantation

2000: 70: 94–99.

24. Webber SA, Naftel DC, Fricker FJ, et al. Lymphoprolifer-

ative disorders after paediatric heart transplantation: A multi-

institutional study. Lancet 2006: 367: 233–239.

25. Fischer A, Blanche S, Le Bidois J, et al. Anti-B-cell mono-

clonal antibodies in the treatment of severe B-cell lymphopro-

liferative syndrome following bone marrow and organ

transplantation. N Engl J Med 1991: 324: 1451–1456.

26. Evens AM, David KA, Helenowski I, et al. Multicenter

analysis of 80 solid organ transplantation recipients with post-

transplantation lymphoproliferative disease: Outcomes and

prognostic factors in the modern era. J Clin Oncol 2010: 28:

1038–1046.

27. Aull MJ, Buell JF, Trofe J, et al. Experience with 274

cardiac transplant recipients with posttransplant lymphopro-

liferative disorder: A report from the Israel Penn International

Transplant Tumor Registry. Transplantation 2004: 78: 1676–

1682.

28. Davis CL, Wood BL, Sabath DE, Joseph JS, Stehman-Breen

C, Broudy VC. Interferon-alpha treatment of posttransplant

lymphoproliferative disorder in recipients of solid organ

transplants. Transplantation 1998: 66: 1770–1779.

29. Hayashi RJ, Kraus MD, Patel AL, et al. Posttransplant

lymphoproliferative disease in children: Correlation of histol-

ogy to clinical behavior. J Pediatr Hematol Oncol 2001: 23:

14–18.

30. Tsai DE, Hardy CL, Tomaszewski JE, et al. Reduction in

immunosuppression as initial therapy for posttransplant

lymphoproliferative disorder: Analysis of prognostic variables

and long-term follow-up of 42 adult patients. Transplantation

2001: 71: 1076–1088.

31. Gallego S, Llort A, Gros L, et al. Post-transplant lympho-

proliferative disorders (PTLD) in children: The role of che-

motherapy in the era of rituximab. Pediatr Transplant 2010: 14:

61–66.

32. Orjuela M, Gross TG, Cheung YK, Alobeid B, Morris E,

Cairo MS. A pilot study of chemoimmunotherapy (cyclophos-

phamide, prednisone, and rituximab) in patients with post-

transplant lymphoproliferative disorder following solid organ

transplantation. Clin Cancer Res 2003;9(10 Pt 2):3945S–3952S.

33. Trappe R, Riess H, Babel N, et al. Salvage chemotherapy for

refractory and relapsed posttransplant lymphoproliferative

disorders (PTLD) after treatment with single-agent rituximab.

Transplantation 2007: 83: 912–918.

34. Trappe RU, Choquet S, Reinke P, et al. Salvage therapy for

relapsed posttransplant lymphoproliferative disorders (PTLD)

with a second progression of PTLD after upfront chemother-

apy: The role of single-agent rituximab. Transplantation 2007:

84: 1708–1712.

35. Trappe R, Hinrichs C, Appel U, et al. Treatment of PTLD

with rituximab and CHOP reduces the risk of renal graft

impairment after reduction of immunosuppression. Am J

Transplant 2009: 9: 2331–2337.

36. Kerkar N, Morotti RA, Madan RP, et al. The changing face

of post-transplant lymphoproliferative disease in the era of

molecular EBV monitoring. Pediatr Transplant 2010: 14: 504–

511.

37. Henry DD, Hunger SP, Braylan RC, Dharnidharka VR.

Low viral load post-transplant lymphoproliferative disease

localizedwithin the tongue.Transpl InfectDis 2008: 10: 426–430.

38. Miyashita EM, Yang B, Lam KM, Crawford DH, Thor-

ley-Lawson DA. A novel form of Epstein-Barr virus latency in

normal B cells in vivo. Cell 1995: 80: 593–601.

39. Wagner HJ, Bein G, Bitsch A, Kirchner H. Detection and

quantification of latently infected B lymphocytes in Epstein-

Barr virus-seropositive, healthy individuals by polymerase

chain reaction. J Clin Microbiol 1992: 30: 2826–2829.

40. Walling DM, Brown AL, Etienne W, Keitel WA, Ling PD.

Multiple Epstein-Barr virus infections in healthy individuals. J

Virol 2003: 77: 6546–6550.

Gupta et al.

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