Objectives: We evaluated posttransplant lympho-proliferative disorder after solid-organ transplant.

Materials and Methods: All 2224 solid-organ transplant recipients who underwent transplant between 1985 and 2013 were included. Clinicopathological findings were examined, and all patients with posttransplant lymphoproliferative disorder were reclassified to World Health Organization 2008 lymphoma classification.

Results: Only 27 of 2224 patients developed posttransplant lymphoproliferative disorder. The incidence of posttransplant lymphoproliferative disorder was 3.3-fold higher in children than in adults. The mean interval between transplant and diagnosis of posttransplant lymphoproliferative disorder was 65 months. Patients with tacrolimus were associated with a shorter posttransplant lymphoproliferative disorder development time compared with cyclosporine patients. Epstein-Barr virus-encoded small RNA positive showed shorter time for development of posttransplant lymphoproliferative disorder compared with Epstein-Barr virus-encoded small RNA negative patients. The risk of developing posttransplant lymphoproliferative disorder within the first year of transplant was higher in patients under tacrolimus protocol compared with patients under cyclosporine. Of 27 patients, 4 showed early lesion and 23 patients showed monomorphic posttransplant lymphoproliferative disorder. The development of T-cell monomorphic posttransplant lymphoproliferative disorder was significantly late compared with patients with B-cell monomorphic posttransplant lymphoproliferative disorder. Eight patients died at 38 ± 50 months after posttransplant lymphoproliferative disorder diagnosis. Four patients with early type posttransplant lymphoproliferative disorder were alive, and 3 of 4 patients with T-cell monomorphic posttransplant lymphoproliferative disorder died shortly after diagnosis. Five of 19 patients with B-cell monomorphic posttransplant lymphoproliferative disorder died at a mean 29 ± 18 months. A significant difference was found between the histologic types regarding patient survival. A significant difference was found between the Epstein-Barr virus-encoded small RNA positive and Epstein-Barr virus-encoded small RNA negative patients regarding mean survival time.

Conclusions: To decrease the incidence of posttransplant lymphoproliferative disorder, risk factors should be evaluated and new approaches must be derived for prophylaxis, diagnosis, and treatment.

Key words : Liver transplant, Kidney transplant recipient, Posttransplant lymphoproliferative disorder, Epstein-Barr virus

Introduction

Posttransplant lymphoproliferative disorder (PTLD) is a disease with lymphoid or plasmacytic proliferation that may occur in solid-organ, bone marrow, or stem cell transplant recipients.^1,2 This disease may include early polyclonal proliferation that resembles nonspecific plasma cell hyperplasia, infectious mononucleosis, or clonal proliferations of B cells, T cells, or natural killer (NK) cells. Many PTLDs occur within 1 year after transplant, are associated with Epstein-Barr virus infection, and originate from B cells. The disease may have aggressive behavior, a predilection for extranodal sites, and higher incidence in children than adults.³

The incidence of PTLDs (1% to 4.6%) may depend on the type and number of organs transplanted and the intensity and type of immunosuppressive drugs.² In adult transplant recipients, PTLD is second to skin cancer as the most common malignancy, and PTLD is the most common posttransplant malignancy in children.⁴ The risk of developing PTLD may be high after kidney transplant because the kidney is the most frequently transplanted solid organ. However, the intensity of immunosuppression may vary between organ graft types. Recipients of heart, lung, and intestinal transplant may be at high risk for the development of PTLD because they may require the most intense immunosuppression of all transplants. In addition, children are at a higher risk ( ≥ 4-fold) than adults because of frequent primary infection with Epstein-Barr virus after transplant in children, especially when the donor tests positive for Epstein-Barr virus. In some patients, PTLD may regress partially or completely after reduction or withdrawal of immunosuppressive therapy.⁵ Nevertheless, PTLDs include life-threatening cancers including non-Hodgkin and Hodgkin lymphoma.⁶ The risk of developing lymphoproliferative diseases is 3-fold to 21-fold higher in transplant recipients and 120-fold higher in children transplant recipients than the general population. The risk of developing non-Hodgkin lymphoma is highest in the first year, decreased from 2 to 5 years, and increased at ≥ 5 years after transplant.⁶

We performed a clinicopathologic study of PTLD and Epstein-Barr virus status in Turkish patients who had PTLD after solid-organ transplant.

Materials and Methods

Patients
From 1985 to 2013, there were 2224 organ transplants (1 transplant per patient) (1334 men [60%]) performed at Baskent University, including 1740 kidney (78%), 408 liver (18%), and 76 heart transplants (3%). In these patients, there were 27 patients (1.2%) who had biopsy-confirmed PTLD identified and treated at the same center. Clinical and pathologic data were reviewed from the medical records of patients who had PTLD. Follow-up information was obtained from medical records or by direct communication with patients or families. Data collected included age, sex, Epstein-Barr virus status before and after transplant, immuno-suppressive therapy, time from transplant to diagnosis of PTLD, B symptoms (fever, weight loss, and night sweats), number of extranodal sites, and involvement of different organs. The study was approved by the Ethical Review Committee of the institute. All protocols conformed with the ethical guidelines of the 1975 Helsinki Declaration. Informed consent was obtained from all subjects.

Pathologic examination
Paraffin sections that were stained with hematoxylin-eosin and immunohistochemical slides of all patients were reviewed according to the 2008 World Health Organization classification.² In situ hybridization for detection of Epstein-Barr virus genome was performed in most patients diagnosed after 2000 using specific probes for Epstein-Barr virus-encoded small RNA 1. All slides were reviewed by the study pathologists who were experts in transplant pathology and hematopathology.

Statistical analyses
Data analysis was performed with statistical software (SPSS for Windows, Version 16.0, SPSS Inc., Chicago, IL, USA). Average data were reported as mean ± SD. Comparisons between groups were made with Mann-Whitney and Kruskal-Wallis tests. Categorical data were compared with Fisher exact test and chi-square test. Statistical significance was defined by P ≤ .05.

Results

Patient characteristics
Most patients who had PTLD were male (Table 1). The frequency of PTLD was greater after liver (12 of 408 patients [2.9%]) than kidney transplant (15 of 1740 patients [0.9%]).

The mean age at diagnosis of PTLD was 26 ± 18 years (range, 1-52 years), and 9 patients (33%) were aged < 19 years at diagnosis of PTLD. The frequency of PTLD was 3.3-fold greater in children (9 of 289 children [3.1%]) than adults (18 of 1935 adults [0.93%]) (P ≤ .001). The frequency of PTLD was similar between patients who received cyclosporine and tacrolimus. The frequency of PTLD in the 9 children was higher when taking tacrolimus (8 children [89%]) than cyclosporine (1 child [11%]) (P ≤ .001). In the 18 adults, the frequency of PTLD was higher when taking cyclosporine (89%) than tacrolimus (11%) (P ≤ .001). There were 23 patients (85%) who had living-related-donor transplant and 4 patients (15%) who had deceased-donor transplant.

In patients who developed PTLD, the most common indications for liver transplant were cryptogenic cirrhosis, progressive familial intra­hepatic cholestasis, and biliary atresia; the most common indications for kidney transplant were end-stage renal disease and polycystic kidney disease (Table 2). The most common immunosuppressive drugs included corticosteroids (all patients), tacrolimus (liver transplant), and cyclosporine (kidney transplant) (Table 1). There were 15 patients (56%) who received triple immunosuppressive therapy (calcineurin inhibitor, antimetabolite, and corticosteroids).

Acute cellular rejection was observed before the diagnosis of PTLD in 9 patients (33%) (mean, 2 ± 1 rejection episodes/patient) and chronic rejection in 3 patients (11%) (Table 1). During the first year after transplant, acute T-cell rejection episodes were observed in 8 patients, and all 8 patients were treated with steroid pulse therapy (methylprednisolone daily for 2 days and tapered from days 5 to 7). Steroid-resistant acute cellular rejection that was confirmed by biopsy was treated with antithymocyte globulin. There was no relation between occurrence or mean number of episodes of acute cellular rejection and parameters of PTLD (time to development or histopathologic type).

Posttransplant lymphoproliferative disorder
The most common presenting symptoms of PTLD were abdominal symptoms (abdominal pain, diarrhea, constipation, nausea, or emesis) in 11 patients (41%) and fever in 7 patients (26%). In 5 of the 7 febrile patients, weight loss and weakness were noted. There were 2 patients who had skin lesions (erythematous plaques and skin bumps), and 1 patient presented with syncope.

Plasma Epstein-Barr virus DNA was present at diagnosis of PTLD in only 16 of 27 patients, and 15 patients had detectable Epstein-Barr viral load in plasma (9 of 9 children and 6 of 7 adults). Most children (8 of 9 children) were seronegative for Epstein-Barr virus before transplant, but all 9 of 9 children who had PTLD had detectable Epstein-Barr viral load in plasma at diagnosis.

Most patients had only 1 site involved with PTLD (Table 3). The most common site of PTLD was large bowel and lymph nodes (Table 3). The transplant graft was involved with PTLD in 4 patients (15%) (2 liver and 2 kidney grafts) (Table 3).

The mean time from transplant to diagnosis of PTLD was shorter after liver than kidney transplant (Table 1). The time to diagnosis of PTLD after transplant was significantly shorter in children (26 ± 18 mo) than adults (65 ± 28 mo; P ≤ .01). In all patients, time from transplant to diagnosis of PTLD was shorter in patients who had tacrolimus (22 ± 16 mo) than cyclosporine (78 ± 38; P ≤ .01) and shorter in patients who tested positive (32 ± 28 mo) than negative (88 ± 50 mo; P ≤ .01) for Epstein-Barr virus-encoded small RNA.

Only 8 patients (30%) developed PTLD within 1 year after transplant. The risk of developing PTLD within 1 year after transplant was significantly greater in patients who had the tacrolimus (6 patients [67%]) than cyclosporine protocol (4 patients [33%]; P ≤ .05). Age, Epstein-Barr virus-encoded small RNA, transplanted organ type, and acute rejection episodes did not have a significant effect on the development of PTLD within 1 year after transplant.

Pathologic findings
Histopathologic type was monomorphic B-cell PTLD in most patients (19 patients), most commonly diffuse large B-cell lymphoma (17 patients) (Table 1). The mean time from transplant to diagnosis of PTLD was longer for T-cell monomorphic (69 ± 42 mo) than B-cell monomorphic (48 ± 18 mo) or early PTLD (41 ± 25 mo) (P ≤ .05).

Epstein-Barr virus-encoded small RNA was negative in all patients who had T-cell monomorphic PTLD. In 3 of 4 patients who had T-cell PTLD, death occurred because of complications of PTLD (1 patient, 2 mo after diagnosis of PTLD; 1 patient, 16 mo after diagnosis of PTLD) or sepsis (1 patient, 131 mo after diagnosis of PTLD).

All 4 patients who had early PTLD were alive at the most recent follow-up with good response to therapy and no recurrence of PTLD. Epstein-Barr virus-encoded small RNA was positive in 2 patients and negative in 2 patients who had early PTLD.

In the 19 patients who had B-cell monomorphic PTLD (Table 1), 1 patient who had Burkitt lymphoma was alive at 90 months and 1 patient who had mucosa-associated lymphoid tissue lymphoma was alive at 129 months after the diagnosis of PTLD. Death occurred in 5 patients who had diffuse large B-cell lymphoma. In all patients who had B-cell monomorphic PTLD, mean survival time was shorter after diagnosis of diffuse large B-cell lymphoma (29 ± 18 mo) than the other B-cell monomorphic PTLDs (61 ± 27 mo; P ≤ .05). Epstein-Barr virus-encoded small RNA was positive in patients who had Burkitt and mucosa-associated lymphoid tissue lymphoma and was positive in 11 patients who had monomorphic B-cell PTLD.

Treatment and follow-up
Initial treatment for PTLD varied between patients and included withdrawal of immunosuppressive drugs (3 patients), chemotherapy, radiation therapy, and/or surgical resection (Table 3). At mean follow-up 54 ± 50 months (range, 1-180 mo) after diagnosis of PTLD, most patients were alive but frequency of death was greater in patients after kidney than liver transplant (Table 1). There were 8 patients who died at mean 38 ± 50 months after the diagnosis of PTLD (range, 0.6-131 mo) (Table 1) because of multiple organ failure (5 patients), sepsis (5 patients), liver failure (2 patients), and gastrointestinal bleeding (1 patient) (> 1 cause of death per patient). There were 3 patients who could not have chemotherapy and died soon after the diagnosis of PTLD. In 2 of the 8 patients who died, recurrence of PTLD was noted (1 patient: primary was polymorphic PTLD at the liver and recurrence was monomorphic, T-cell PTLD at the liver; 1 patient: primary was primary cutaneous CD30 positive T-cell lymphoproliferative disorders at the lower extremities and recurrence had same histologic type at the skin and lungs PTCL, NOS = peripheral T-cell lymphoma, not otherwise specified (relapse developed).

Mean survival time was shorter for patients who tested Epstein-Barr virus-encoded small RNA positive (46 ± 32 mo) than negative (70 ± 52 mo; P ≤ .05). There was no relation between the mean survival time and other risk factors including extranodal involvement or number of disease sites.

Discussion

The present study included 27 patients who had PTLD during a 28-year experience at a single transplant center. The incidence of PTLD increased during the previous decade (9 patients from 1996 to 2004; 18 patients from 2005 to 2013), perhaps because of expansion of transplant activities, higher recipient age, increased clinical awareness, improved diagnostic techniques, and longer survival after solid-organ transplant.

The frequency of PTLD after liver transplant is higher in children (5% to 15%) than adults (2% to 5%), possibly because of more frequent seronegativity for Epstein-Barr virus before transplant in children than adults.⁷ Children are at a higher risk of developing PTLD than adults (≥ 4-fold) because of frequent postoperative primary infection with Epstein-Barr virus in children caused by organ grafts from donors seropositive for Epstein-Barr virus.⁵ The present study showed similar results, with a significantly higher frequency of PTLD in children than adults, and most children were seronegative for Epstein-Barr virus before transplant. The high male:female ratio (1.7:1) in the present study may have occurred, in part, because of the higher number of transplants in male recipients (60%).

Immunosuppression may cause PTLD, but there is no consensus about the effect of specific immunosuppressive drugs. There may be a higher risk of developing PTLD with tacrolimus than cyclosporine, but some studies (mostly retrospective) show no difference between the drugs.⁸ In the present study, the frequency of PTLD was similar between patients who received tacrolimus or cyclosporine, but the frequency of PTLD was higher in children who received tacrolimus and adults who received cyclosporine. The transplant organ type may indirectly affect the risk of developing PTLD because the intensity of immunosuppression may differ between organ graft types; recipients of heart, lung, and intestinal grafts may require the most intensive immunosuppression and may be at higher risk for development of PTLD than recipients of other organ types.⁵ The frequency of PTLD is greater after lung (5% to 20%) than kidney (1% to 3%) transplant.⁹ In the present study, the frequency of developing PTLD was greater after liver (2.9%) than kidney transplant (0.9%).

The diagnosis of PTLD typically is made at median 36 to 40 months after transplant.¹⁰ In the present study, the mean time from transplant to diagnosis of PTLD was 65 months, shorter for patients after liver than kidney transplant, possibly because of the greater frequency in children than adults who had liver than kidney transplant (Table 1). The time from transplant to diagnosis of PTLD typically was < 1 year in early reports and longer in more recent studies.¹¹ In the present study, most patients were diagnosed with PTLD > 1 year after transplant.

Early-onset PTLD may be associated with seropositive Epstein-Barr virus status and younger age. The lymphoproliferative disorders that develop later after transplant in older patients may be PTLD or lymphoproliferative disorders not related to transplant. In the present study, children who had early-onset PTLD (within 1 year after transplant) were seropositive for Epstein-Barr virus, consistent with previous reports. T-cell monomorphic PTLD was diagnosed later than B-cell monomorphic PTLD or early PTLD, and patients who had late PTLD (onset > 1 year after transplant) frequently were seronegative for Epstein-Barr virus. Very late diagnosis of PTLD (> 10 y) may occur in 15% patients who develop PTLD.¹⁰ In the present study, very late diagnosis was noted in 22% patients, and the longest time from transplant to diagnosis of PTLD was 16 years.

The clinical features differ between PTLD and lymphomas observed in the general population. Symptoms and signs may be mild or severe and may include fever, mononucleosislike syndrome, lymphadenopathy, recurrent infection, and severe organ dysfunction. At PTLD diagnosis, B symptoms (fever, weight loss, and night sweats) were present in 5 patients (19%). The most common presenting symptoms of PTLD were abdominal complaints and fever.

Serial monitoring of Epstein-Barr viral load is common practice in many transplant centers. This may enable preemptive therapy including reduction of immunosuppression or anti-CD20 immuno-therapy, especially in children. Plasma Epstein-Barr virus DNA loads were measured at diagnosis of PTLD in all children and detectable Epstein-Barr viral load was present in 77% children, and this correlated well with positive tissue Epstein-Barr virus-encoded small RNA detected with in situ hybridization. Epstein-Barr virus serology and virus-encoded small RNA results were consistent for 75% patients at diagnosis of PTLD.

In contrast with the heterogeneous presentation of typical lymphomas, PTLD frequently is advanced and has extranodal involvement. Extranodal involvement was noted in most patients in this study, most frequently at the gastrointestinal tract (Table 3). Compared with other studies, the frequency of central nervous system disease was low (only 1 patient had primary central nervous system lymphoma) (Table 3).

Kidney transplant recipients who have PTLD involving the liver are carefully evaluated for multiorgan involvement.¹² In these patients, bone marrow biopsy is considered, and evaluation includes assessment of the kidney allograft, heart, and spleen for PTLD involvement. In the present study, 1 kidney transplant recipient had PTLD that involved the liver, spleen, and multiple lymph nodes (Table 3).

In the present patients, the most frequent histologic type of PTLD was monomorphic diffuse large B-cell lymphoma (Table 1). The varied types of PTLD are heterogeneous in clinical and epidemi-ologic characteristics. In 2 previous studies that evaluated the risk of non-Hodgkin lymphoma in transplant recipients, there was an increased risk of diffuse large B-cell lymphoma compared with the general population but no increase in follicular lymphoma.^13,14 The risk of lymphoma subtypes may differ by the type of organ transplanted. The risk of developing diffuse large B-cell lymphoma and anaplastic large-cell lymphoma may be greatest in pancreas and in combined kidney and pancreas recipients, but the risk of developing Burkitt lymphoma may be greatest in liver and thoracic organ recipients. In patients who developed hepatosplenic T-cell lymphoma in a previous study, none had received a liver transplant but 4 patients received a kidney transplant.⁶ The relation between the frequency of PTLD and age, organ type, and time after transplant is similar for non-Hodgkin lymphoma and diffuse large B-cell lymphoma.⁶

Therapy for PTLD is not standardized, and the present patients had diverse treatment (Table 3). Treatment frequently is customized for specific clinical factors such as type of solid-organ transplant graft, risk of rejection, comorbidities, tumor burden, and disease presentation.

Previous studies showed that seronegative testing for Epstein-Barr virus and late PTLD were associated with decreased survival.⁸ Additional factors such as extranodal disease, stage, and number of disease sites may correlate with clinical outcome. In the present patients, mean survival time was shorter for patients who tested positive than negative for Epstein-Barr virus-encoded small RNA, but there was no relation between survival and other risk factors such as extranodal involvement or number of disease sites. The type and number of sites involved with PTLD could not be assessed accurately because complete systemic evaluation was not performed in many patients during the earlier part of the study. Prognostic factors for survival with PTLD may vary between studies because most studies were performed in single institutions during several decades, and changes may have occurred in diagnostic techniques, treatment regimens, and supportive care during the studies. Furthermore, studies of PTLD frequently include heterogeneous patient groups. Children may have better outcomes than adults who develop PTLD. In addition, studies may vary in treatment approaches and factors that are included in prognostic analysis.

Limitations of the present study included factors inherent with a retrospective cohort study from a single center, including missing data, heterogeneity of treatment, and variation in timing of staging. Data about Epstein-Barr virus status at transplant and peripheral blood Epstein-Barr viral load were missing because this test was introduced routinely only 10 years ago. In addition, the present results represented daily clinical practice in a large university transplant center. Nevertheless, the study provided an assessment of the utility of prognostic factors that were studied previously. The present patient cohort was not randomized or prospective, but it was representative of the population of patients who have PTLD and provided realistic data about the incidence, clinicopathologic features, changes in therapy, and outcomes of patients who were diagnosed with PTLD.

References:

1. Penn I, Hammond W, Brettschneider L, Starzl TE. Malignant lymphomas in transplantation patients. Transplant Proc. 1969;1(1):106-112.
   PubMed
2. Swerdlow SH, Campo E, Harris NL, et al. WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues (WHO Classification of Tumours, Volume 2). 4th ed. Lyon, France: International Agency for Research on Cancer; 2008.
3. Jaffe ES, Harris NL, Vardiman JW, Campo E, Arber DA, ed. Hematopathology. St Louis, MO: Sounders Elsevier; 2011.
4. Parker A, Bowles K, Bradley JA, et al. Diagnosis of post-transplant lymphoproliferative disorder in solid-organ transplant recipients - BCSH and BTS Guidelines. Br J Haematol. 2010;149(5):675-692.
   CrossRef - PubMed
5. Hussein K, Tiede C, Maecker-Kolhoff B, Kreipe H. Posttransplant lymphoproliferative disorder in pediatric patients. Pathobiology. 2013;80(6):289-296.
   CrossRef - PubMed
6. Clarke CA, Morton LM, Lynch C, et al. Risk of lymphoma subtypes after solid-organ transplantation in the United States. Br J Cancer. 2013;109(1):280-288.
   CrossRef - PubMed
7. Lo RC, Chan SC, Chan KL, Chiang AK, Lo CM, Ng IO. Post-transplant lymphoproliferative disorders in liver transplant recipients: a clinicopathological study. J Clin Pathol. 2013;66(5):392-398.
   CrossRef - PubMed
8. Mynarek M, Schober T, Behrends U, Maecker-Kolhoff B. Posttransplant lymphoproliferative disease after pediatric solid-organ transplantation. Clin Dev Immunol. 2013;2013:814973. doi: 10.1155/2013/814973. Epub 2013 Sep 24.
   CrossRef - PubMed
9. Chen DB, Song QJ, Chen YX, Chen YH, Shen DH. Clinicopathologic spectrum and Epstein-Barr virus status of post-transplant lymphoproliferative disorders after allogeneic hematopoietic stem cell transplantation. Int J Hematol. 2013;97(1):117-124.
   CrossRef - PubMed
10. 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(6):1038-1046.
    CrossRef - PubMed
11. Dierickx D, Tousseyn T, Sagaert X, et al. Single-center analysis of biopsy-confirmed posttransplant lymphoproliferative disorder: incidence, clinicopathological characteristics and prognostic factors. Leuk Lymphoma. 2013;54(11):2433-2440.
    CrossRef - PubMed
12. Khedmat H, Taheri S. Hepatic lymphomas post renal transplantation may signify worse disease behavior: analysis of data from 26 international studies. Arab J Nephrol Transplant. 2011;4(3):109-116.
    CrossRef - PubMed
13. Quinlan SC, Morton LM, Pfeiffer RM, et al. Increased risk for lymphoid and myeloid neoplasms in elderly solid-organ transplant recipients. Cancer Epidemiol Biomarkers Prev. 2010;19(5);1229-1237.
    CrossRef - PubMed
14. Vajdic CM, van Leeuwen MT, Turner JJ, et al. No excess risk of follicular lymphoma in kidney transplant and HIV-related immunodeficiency. Int J Cancer. 2010;127(11):2732-2735.
    CrossRef - PubMed