Influence of host-recipient origin on clinical aspects of posttransplantation lymphoproliferative disorders in kidney transplantation

Multimodality imaging findings of infection-induced tumors

Several infections can predispose to certain malignancies in different body parts. These infections include viral, bacterial, and fungal pathogens. Imaging plays a vital role in the diagnosis, staging, and management of these neoplastic conditions. Furthermore, it can help in differentiating infection-related non-neoplastic processes that can mimic malignancies. Both radiologists and clinicians should be familiar with these conditions. This review discusses the epidemiology, pathogenesis, and imaging features of infection-related tumors.

Treatment of Epstein-Barr Virus-Related Post-Renal Transplantation Development of Diffuse Large B Cell Lymphoma of the Distal Ureter: A Case Report

Posttransplant lymphoproliferative disorder with involvement of the donor urogenital tissue is a rare and serious complication of solid organ transplant. We report an adult kidney transplant recipient who developed the diffuse large B cell lymphoma of the distal ureter in the setting of new allograft nephropathy. Early intervention, reduction of immunosuppression, surgical reconstruction and chemotherapy salvaged the allograft kidney and averted a fatal outcome. The renal function recovered to the baseline with creatinine ranging between 1.3 and 1.5. The patient did not require dialysis at any point after ureteral stent placement and reconstructive surgery. In addition, the case highlights the importance of multidisciplinary management involving transplant nephrology, oncology, transplant surgery, and urology in such a complicated disease process.

Donor-Transmitted Cancer in Orthotopic Solid Organ Transplant Recipients: A Systematic Review

Donor-transmitted cancer (DTC) has major implications for the affected patient as well as other recipients of organs from the same donor. Unlike heterotopic transplant recipients, there may be limited treatment options for orthotopic transplant recipients with DTC. We systematically reviewed the evidence on DTC in orthotopic solid organ transplant recipients (SOTRs). We searched MEDLINE, EMBASE, PubMed, Scopus, and Web of Science in January 2020. We included cases where the outcome was reported and excluded donor-derived cancers. We assessed study quality using published checklists. Our domains of interest were presentation, time to diagnosis, cancer extent, management, and survival. There were 73 DTC cases in liver (n = 51), heart (n = 10), lung (n = 10) and multi-organ (n = 2) recipients from 58 publications. Study quality was variable. Median time to diagnosis was 8 months; 42% were widespread at diagnosis. Of 13 cases that underwent re-transplantation, three tumours recurred. Mortality was 75%; median survival 7 months. Survival was worst in transmitted melanoma and central nervous system tumours. The prognosis of DTC in orthotopic SOTRs is poor. Although re-transplantation offers the best chance of cure, some tumours still recur. Publication bias and clinical heterogeneity limit the available evidence. From our findings, we suggest refinements to clinical practice.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020165001, Prospero Registration Number: CRD42020165001.

Epstein-Barr Virus-Associated Post-Transplant Lymphoproliferative Disorders after Hematopoietic Stem Cell Transplantation: Pathogenesis, Risk Factors and Clinical Outcomes

Epstein-Barr virus (EBV) is a ubiquitous virus belonging to the human γ-herpes virus subfamily. After primary infection, EBV maintains a life-long latent infection. A major concern is that EBV can cause a diverse range of neoplasms and autoimmune diseases. In addition, patients undergoing hematopoietic stem cell transplantation or solid organ transplantation can experience post-transplant lymphoproliferative disorders (PTLDs) due to dysfunction or suppression of host’s immune system, or uncontrolled proliferation of EBV-infected cells. In recent years, the number of EBV-associated PTLD cases has increased. This review focuses on the current understandings of EBV-associated PTLD pathogenesis, as well as the risk factors and clinical outcomes for patients after allogeneic stem cell transplantation.

Posttransplant Malignancy

Posttransplant malignancy is a leading cause of death after solid organ transplantation (SOT). Recipients of SOT are at significantly higher risk of multiple cancers compared with the general population, most notably nonmelanoma skin cancer and posttransplant lymphoproliferative disorders. Risk factors for posttransplant malignancy include history of malignancy, immunosuppression, oncogenic viral infections, sun exposure, and disease-specific associations. Early detection and treatment of malignancies can improve survival.

Epstein-Barr virus and renal transplantation

Epstein-Barr virus (EBV) is a gamma herpesvirus associated with diseases ranging from asymptomatic viremia to post-transplant malignancies in kidney transplant recipients. EBV specifically is associated with post-transplantation lymphoproliferative disorder (PTLD), in kidney transplant recipients, with increased risk in EBV seronegative patients with EBV seropositive donors on intensified immunosuppression. The diagnosis of PTLD relies on clinical suspicion plus tissue biopsy with polymerase chain reaction (PCR) testing of blood currently used for risk determination in high-risk recipients. Therapeutic strategies for PTLD include reduction of immunosuppression, chemotherapy and rituximab, and consideration of sirolimus-based immunosuppression. Antivirals such as ganciclovir are used to prevent reactivation of cytomegalovirus and other herpes viruses but are not onco-therapeutic. Radiation therapy or surgery is indicated for bulky, disseminated or recalcitrant disease. Prognosis varies depending on the type of malignancy identified and stage of disease.

Early Post-transplant Lymphoproliferative Disease in the Donor Ureter Without Systemic Involvement: A Case Report

BACKGROUND

Post-transplant lymphoproliferative disease is a serious complication of renal transplantation. Major risk factors include Epstein-Barr virus (EBV) seronegativity and induction immunosuppression with lymphocyte-depleting agents.

RESULTS

We present a case of a 50-year year-old woman with very early onset PTLD confined to the donor ureter. Phenotypic studies on the tumor material reveal that the lymphoma was most likely of donor origin. A complete staging workup including the kidney allograft was negative for any other sites of involvement.

CONCLUSIONS

This case, which had a fatal outcome, emphasizes the risk of renal transplantation in BV-negative individuals when given induction with lymphocyte-depleting drugs.

Donor or recipient origin of posttransplant lymphoproliferative disorders following solid organ transplantation

Previous studies of donor or recipient origin of posttransplant lymphoproliferative disorders (PTLDs) following solid organ transplantation (SOT) have either been small or with selected patient groups. We studied tumor origin in a population-based cohort of 93 patients with PTLD following SOT. Tumor origin of PTLD tissue was analyzed by fluorescence in situ hybridization of the sex chromosomes in cases of sex mismatch between donor and recipient (n = 41), or HLA genotyping in cases of identical sex but different HLA type (n = 52). Tumor origin of PTLD could be determined in 67 of the 93 cases. All 67 PTLDs were of recipient origin. They were found in recipients of kidney (n = 38), liver (n = 12), heart (n = 10) and lung (n = 7). The most common recipient-derived lymphomas were monomorphic B-cell PTLDs (n = 45), monomorphic T cell PTLDs (n = 9), indolent lymphomas (n = 6), and polymorphic PTLD (n = 4). Half of the recipient-derived PTLDs were Epstein-Barr virus-positive. Twelve of the recipient-derived PTLDs were located in the grafts: in four cases exclusively and in eight cases in combination with disseminated disease outside the graft. Tumor origin was indeterminable in 26 cases, probably due to low DNA quality. We conclude that the vast majority of PTLDs after SOT was of recipient origin.

Post-transplant lymphoproliferative disorders: determination of donor/recipient origin in a large cohort of kidney recipients

Although in previous studies most post-transplant lymphoproliferative disorders (PTLD) were reported to derive from recipient cells, some cases derived from donor lymphocytes have been reported. To provide a better description of the features and outcome of PTLD according to the origin of the lymphoma, we performed histologic and molecular studies of PTLD in kidney recipients. Forty-three specimens were analyzed by histochemistry, fluorescent hybridization of the Y chromosome and analysis of multiple short tandem repeat microsatellite loci. Sixteen tumors were shown to be of donor origin and 27 of recipient origin. Time to PTLD was shorter in donor-derived PTLDs (20 ± 27 vs. 69 ± 67 months, p = 0.013). Ten-year patient survival was similar among patients with recipient- and donor-derived PTLD, but when PTLD-related mortality was analyzed, there was a trend to better survival in patients with donor lymphomas. Among the 21 PTLDs localized in the allograft, 14 lymphomas were of donor origin and seven of recipient origin. No difference was found between the two groups. Our analysis of the origin of PTLDs in the largest cohort studied to date with a description of the clinical and histological characteristics of donor and recipient PTLDs should lead to a better understanding of lymphomagenesis.

Management of posttransplant lymphoproliferative disorders following solid organ transplant: an update

Development of secondary malignancies is a well-known complication of solid organ transplant, with skin cancer and lymphoproliferative disorders being most frequently observed. Posttransplant lymphoproliferative disorders, caused by diminished immune surveillance, represent a broad spectrum of pathological and clinical disorders, ranging from benign conditions to very aggressive lymphomas. Here we review treatment options for adult patients experiencing posttransplant lymphoproliferative disorders following solid organ transplant.

Posttransplant lymphoproliferative diseases

The risk of developing cancer after solid organ transplantation (SOT) is about 5- to 10-fold greater than that of the general population. The cumulative risk of cancer rises to more than 50% at 20 years after transplant and increases with age, and so children receiving transplants are at high risk of developing a malignancy. Posttransplant lymphoproliferative disease (PTLD) is the most common cancer observed in children following SOT, accounting for half of all such malignancies. PTLD is a heterogeneous group of disorders with a wide spectrum of pathologic and clinical manifestations and is a major contributor to long-term morbidity and mortality in this population. Among children, most cases are associated with Epstein-Barr virus infection. This article reviews the pathology, immunobiology, epidemiology, and clinical aspects of PTLD, underscoring the need for ongoing systematic study of complex biologic and therapeutic questions.

EBV-positive B cell cerebral lymphoma 12 years after sex-mismatched kidney transplantation: post-transplant lymphoproliferative disorder or donor-derived lymphoma?

We present a follow-up case report of possible transmission of lymphoma 12 years after deceased-donor renal transplantation from a male donor who was found at autopsy to have had an occult lymphoma. The female recipient underwent prompt transplant nephrectomy. However, 12 years later, she presented with cerebral B cell lymphoma. A donor origin for the cerebral lymphoma was supported by in situ hybridization demonstration of a Y chromosome in the lymphoma. There was a dramatic resolution of the cerebral lesions with tapering of immunosuppression and introduction of rituximab treatment. The finding of a Y chromosome in the cerebral lymphoma does not exclude a host contribution to lymphoma development.

Complete Regression of Cutaneous B-Cell Lymphoma in a Renal Transplant Patient After Conversion From Cyclosporin to Sirolimus

Posttransplant lymphoproliferative disease remains a serious morbidity. Herein we have reported a case of complete regression of a biopsy-proven B-cell lymphoma that occurred in the posttransplant period. A 48-year-old man received a living donor renal transplant for end-stage renal disease due to undetermined etiology. His initial immunosuppression consisted of corticosteroid, mycophenolate mofetil, and cyclosporin. The patient developed severe pneumonia within the first 2 months after transplantation due to Acineotobacter, fungus, and cytomegalovirus infections. He experienced a complete recovery and was discharged for regional follow-up. Four months after discharge, he was referred again because of presence of two nodules on his trunk. A biopsy of the nodules revealed B-cell lymphoma. Cyclosporin was stopped and he was converted to sirolimus. The lesions regressed progressively and completely within 7 weeks. The patient remains well without clinical relapses at 19 months after conversion. Renal functions remained stable. We postulated that the antincoplastic properties of sirolimus may have played an active part in the positive outcome.

Presentation and early detection of post-transplant lymphoproliferative disorder after solid organ transplantation

Post-transplant lymphoproliferative disorder (PTLD) is a serious and still frequently observed complication of solid organ transplantation. Despite the recent introduction of anti B-cell monoclonal antibody therapy (rituximab) for treatment of PTLD, mortality rates remain high. Because PTLD often presents in a nonspecific way in clinically unsuspected patients, it is a major challenge to diagnose PTLD at an early stage. Epstein-Barr virus (EBV)-DNA load monitoring is a promising tool for the identification of patients at risk for PTLD development. However, there are some limitations of this method, and not all patients at risk for PTLD can be identified by EBV-DNA measurements alone. Therefore, it is of major importance to recognize early clinical signs and symptoms of PTLD. In this review, risk factors for PTLD development, disease presentation, and methods for early detection will be discussed. Special attention is given to allograft and digestive tract localization and the relation with time of onset of PTLD. The value and pitfalls of EBV-DNA load monitoring are discussed. In addition, because fluorodeoxyglucose (FDG)-positron emission tomography (PET) has shown to be a powerful tool for staging and response evaluation of malignant lymphoma, the role of FDG-PET for early diagnosis and staging of PTLD is addressed.

Epstein-barr virus-associated posttransplant lymphoproliferative disorder of donor origin after simultaneous pancreas-kidney transplantation limited to pancreas allograft: A case report

A 45-year-old man was admitted with fever and elevated pancreas enzymes 6 months after simultaneous pancreas-kidney transplantation (SPKT). Function of the allografts was normal. Bacterial and fungal infections were excluded, while Epstein-Barr virus (EBV)-polymerase chain reaction (PCR) was positive. However, screening for EBV-associated lymphoma was negative. EBV infection did not respond to antiviral therapy. After an 18F-Fluorodeoxyglucose positron emission tomography positive signal and an abnormal computed tomography scan of the pancreas transplant, a biopsy revealed a diffuse large monomorphic B-cell lymphoma, which was confined to the grafted organ. Its origin was assigned to the donor by microsatellite analysis. Reduction of immunosuppression and immunotherapy with rituximab was unsuccessful. After 10 weeks, the patient developed an acute hemolytic uremic syndrome which required explantation of the allografts. Subsequent to the intervention, fever disappeared, EBV DNA became undetectable and lymphoma screening remained negative. In posttransplant lymphoproliferative disorder of donor origin after SPKT, transplantectomy may be a curative therapy.

Malignancy in pediatric transplant recipients

Malignancy is a well defined complication of chronic immunosuppression. Post transplant malignancies appear to be related to cumulative doses of immunosuppression, and in pediatric patients, acute infection of previously naive patients. The most commonly encountered malignancy in this age population is Post Transplant Lymphoproliferative Disorder (PTLD). PTLD is not a single entity but rather represents a continuum of disease. Treatment of PTLD should be initiated with immunosuppression reduction. Standard dose chemotherapy leads to significant morbidity. With the introduction of anti-CD20 antibody treatment with rituximab, chemotherapy has become second line therapy. The occurrence of solid malignancy appears to be associated with chronic immunosuppression. These cancers include those of skin, gynecologic organs, and the rectum, all of which appear to have the strongest association with viral mediators. Several strategies have been postulated to minimize the occurrence of malignancy. These include ganciclovir prophylaxis for the prevention of PTLD and the use of mychophenolic acid and TOR inhibitor maintenance to diminish the incidence of PTLD and solid malignancies. This leaves transplant physicians with several new and novel immunosuppressive agents with uncertain oncologic potentials that will need to be examined over the next decade.

Hodgkin disease-like posttransplantation lymphoproliferative disorder of donor origin in a renal allograft recipient

Posttransplantation lymphoproliferative disorder (PTLD) develops in 1.6% of renal allograft recipients. More than 90% are of recipient origin. There are only a few reports of Hodgkin disease-like PTLD in allograft patients. We report the case of a Hodgkin disease-like PTLD of donor origin in a 16-year-old renal allograft recipient. Fourteen months after transplantation, an increasing inhomogeneous structure in the hilar region of the transplanted kidney became apparent and was excised. Histological examination showed Hodgkin- and Sternberg-Reed-like cells. Immunostaining showed CD20-positive and CD15-negative cells and Epstein-Barr virus (EBV) involvement (EBV-encoded small nonpolyadenylated RNA and EBV-determined nuclear antigen 2). DNA fingerprinting analysis proved the lymphoma to be of donor origin. Treatment consisted of nephrectomy, discontinuation of immunosuppression therapy, and local radiation. Three years after lymphoma removal, the patient was still without relapse and underwent retransplantation with stable function of the second allograft for more than 2 years now.

Epstein-Barr Virus–Associated Posttransplantation Lymphoproliferative Disorder Following Lung Transplantation Is More Commonly of Host Origin

Context.—Posttransplantation lymphoproliferative disorder (PTLD) in patients who have undergone solid organ transplantation is thought to be mostly of host (ie, transplant recipient) origin, as opposed to being predominantly of donor origin, which is observed in patients who have undergone bone marrow transplantation. Donor-origin PTLDs reportedly follow a more indolent course than host-origin PTLDs.

Objective.—To determine the origin of PTLD and its clinical implications in patients who have undergone lung transplantation.

Design.—Patients' medical records were reviewed for clinical data. We performed a molecular study to determine the origin of abnormal lymphoid cells in 4 PTLD cases identified from our autopsy files. Each case underwent restriction fragment length polymorphism analysis using polymerase chain reaction–based genotyping for CYP2D6. Epstein-Barr virus (latent membrane protein 1) immunostaining and polymerase chain reaction analysis were performed on PTLD-involved tissues.

Results.—Three of 4 PTLD cases were of host origin, and the remaining case was of donor origin. Epstein-Barr virus was detected by immunohistochemical and polymerase chain reaction methods in all PTLD-involved tissues that were examined. There was no apparent difference in clinical manifestations between host-origin and donor-origin PTLD cases in our study.

Conclusions.—The PTLDs in our patients who had undergone lung transplantation were Epstein-Barr virus–positive and mostly of host origin, without any notable clinical difference from donor-origin PTLD.

HLA antigens and post renal transplant lymphoproliferative disease: HLA-B matching is critical

Although several risk factors for posttransplant lymphoproliferative disease (PTLD) after solid organ transplantation have been identified, the immunosuppressive regimen probably as most important one, their exact pathogenic role and relevance is still unclear. In hematopoietic stem cell transplantation, HLA mismatching also is a risk factor. We analyzed factors possibly associated with development of PTLD in patients receiving a kidney transplant at our hospital between 1985 and 2002. PTLD was observed in 20 out of 1,013 patients (2.0%). Mismatches at the HLA-B locus, but not at the HLA-A or HLA-DR loci, and anti T-cell antibody therapy were both independently associated with development of PTLD. Hazard ratios increased from 1.4 (0.5-4.1) with one mismatch to 5.1 (1.4-19.0) in case of two HLA-B mismatches. Decreased surveillance by T-cells with dual specificity for Epstein-Barr virus (EBV) as well as for allo HLA antigens on the allograft might facilitate clonal expansion of B-cells latently infected with EBV.

Prognostic analysis for survival in adult solid organ transplant recipients with post-transplantation lymphoproliferative disorders

PURPOSE

The objective of this study was to determine prognostic factors for overall survival in patients with post-transplantation lymphoproliferative disorders (PTLDs).

PATIENTS AND METHODS

This study focused on the 107 adult solid organ transplantation patients who were diagnosed with PTLDs at Mayo Clinic (Rochester, MN) between December 1970 and May 2003.

RESULTS

The median age at the time of diagnosis was 48 years (range, 15 to 75 years). Extranodal disease including grafted organ involvement was present in 85 patients (80%). The graft organ was involved in 30 patients (28%). At the time of these analyses, 62 patients (58%) had died. The median survival for the entire cohort was 31.5 months (95% CI, 10.7 to 72.5 months). The median follow-up of living patients was 51.8 months (range, 5.6 to 202.6 months). In univariate analyses for overall survival from the time of PTLD diagnosis, the following poor prognostic factors were identified: poor performance status with Eastern Cooperative Oncology Group levels 3 and 4 (P < .0001), grafted organ involvement (P = .0005), the presence of one or more extranodal sites (P = .005), both nodal and extranodal disease (P = .002), high International Prognostic Index (P = .006), advanced stage (P = .001), and elevated lactate dehydrogenase (P = .03). A final multivariable model for survival was constructed using three factors: poor performance status (3 to 4), monomorphic disease, and graft organ involvement.

CONCLUSION

A prognostic model has been developed for PTLD patients using one center's 30 years of experience. We propose additional confirmation and validation of these prognostic factors in larger prospective studies.

Simultaneous Development of Lymphoma in Recipients of Renal Transplants from a Single Donor: Donor Origin Confirmed by Human Leukocyte Antigen Staining and Microsatellite Analysis

BACKGROUND

Posttransplant lymphoproliferative disorders (PTLD) occur in 0.5% to 2.5% of cases in renal-transplant recipients. Epstein-Barr virus (EBV) is usually detected in the tumor cells, suggesting a role for this virus as an agent of B-cell proliferation. It is unusual for patients receiving allografts from the same donor to develop PTLD simultaneously.

METHODS

we describe two patients who received renal allografts from the same donor and developed PTLD simultaneously. The presence of EBV in both tumors was confirmed. In this report, the origin of tumor cells was determined by immunohistochemical human leukocyte antigen (HLA) typing and microsatellite analysis. Clonality was studied by immunoglobulin gene rearrangement analysis.

RESULTS

Our results suggest that the tumor originated from donor cells in both patients but, because immunoglobulin gene rearrangements were different, this could mean that lymphoid cells proliferate independently in each recipient.

CONCLUSIONS

We propose the following pathogenesis: immortalization of passenger B lymphocytes by EBV, proliferation of these cells, and development of PTLD by means of immunosuppression, antigenic stimulation, and HLA mismatch.

Successful renal retransplantation after post-transplant lymphoproliferative disease

Post-transplant lymphoproliferative disease (PTLD) is a rare but severe complication of renal transplantation. Reduction of immunosuppression is essential for controlling PTLD but may induce graft loss. Retransplantation after PTLD is considered dangerous, because immunosuppressive treatment resumption may trigger hematological relapse. We retrospectively report six patients (five adults, one child) who underwent a second renal transplantation after successfully treated PTLD. Epstein-Barr virus (EBV) serology was positive before the first transplantation in all patients except the child. Post-transplant lymphoproliferative disease was detected 6.6 months (range 4.5-9.4) after transplantation. Lymphoproliferation was always monomorphic, B-cell, and EBV-related. Post-transplant lymphoproliferative disease was confined to the renal allograft (n = 4), multilocular (n = 1) or cerebral (n = 1). Immunosuppression tapering (6/6) and transplantectomy (5/6) led to hematological remission in all patients. Retransplantation was performed 77 months (range 50-128) after PTLD diagnosis. Immunosuppression included steroids (n = 6), ATG (n = 2), anti-CD25 (n = 2), cyclosporine (n = 4), tacrolimus (n = 2), mycophenolate mofetil (n = 4) and azathioprine (n = 1). After a median follow up of 30 months (range 24-47) patient survival was 100%, with no recurrence of PTLD. In conclusion, renal retransplantation can be considered in patients with monomorphic PTLD history, without major risk of hematological recurrence.

A case of plasmacytic hyperplasia arising in a kidney allograft salvaged with immunosuppression reduction alone

Post-transplant lymphoproliferative disorder (PTLD) is a well-known complication of organ transplantation. Plasmacytic hyperplasia (PH) is thought of as the mildest form of PTLD; however, a graftectomy is necessary in most situations. We experienced an interesting case of PH arising in a kidney allograft, which could be relieved with a reduction in immunosuppression. A 27-year-old female underwent a living-related kidney transplantation. A 3-month non-episode protocol biopsy unexpectedly showed the devastating appearance of polymorphic plasma cell infiltration into the graft intersitium, compatible with PH. The PH was located in the graft by radiographic examinations. The infiltration of plasma cell disappeared completely on the 6-month graft biopsy specimen following immunosuppression reduction and the graft is functioning, although it was damaged by a subsequent acute rejection. Our present case indicates that some PTLD can be completely cured with a reduction in immunosuppression alone. The diagnostic modality for the evaluation of PTLD cell extinction is necessary to maintain graft function with adequate immunosuppression thereafter.

Posttransplant lymphoproliferative disorder following nonmyeloablative allogeneic stem cell transplantation

Posttransplantation lymphoproliferative disorder (PTLD) is a well-recognized complication of conventional bone marrow/stem cell and solid organ transplantation. However, not much is known about PTLD following the more recently introduced nonmyeloablative allogeneic stem cell transplantation (NMST). This study reports the findings from two cases of PTLD following NMST and compares them to the one previously reported case. The donor origin of the PTLD was determined using short tandem repeat analysis, and B- and T-cell clonalities were evaluated by polymerase chain reaction. Two cases of PTLD evolved in a total of 70 patients who have undergone NMST at our institution from 1999 to 2003. Both patients received conditioning with Fludarabine/Cytoxan/Campath 1H (alemtuzumab, anti-CD52 antibody) and T-cell-depleted donor cells with Campath-1H. Both PTLDs were EBV positive (by immunohistochemistry and in situ hybridization) with diffuse large B-cell lymphoma morphology. Our findings indicate the incidence of PTLD following NMST is 3% (2 of 70 patients from our institution and 1 of 30 from the previously reported case). All three PTLDs arose 6 to 7 months after NMST and were rapidly fatal. The pathology of the PTLD in all cases was donor origin, EBV positive, diffuse large B-cell lymphoma.

Tumor origin and CD20 expression in posttransplant lymphoproliferative disorder occurring in solid organ transplant recipients: implications for immune-based therapy.1

BACKGROUND

Posttransplant lymphoproliferative disorder (PTLD) is a potentially fatal complication of transplantation for which new therapies are being explored, including cytotoxic T-cell infusion and anti-CD20 antibody. Whether the PTLD is of donor cell or recipient cell origin influences the type of cytotoxic T-cell therapy, in view of the MHC-restricted nature of the immune response. The efficacy of anti-CD20 therapy, on the other hand, depends on CD20 expression by neoplastic cells. Only limited prior data exist regarding either of these parameters.

METHODS

Materials for this study were obtained in part from a Southwest Oncology Group clinical trial of solid organ transplant patients with PTLD. Tumor tissue from 21 patients (15 heart, 4 lung, and 2 kidney recipients) was evaluated for donor versus recipient origin by analyzing DNA at multiple polymorphic microsatellites.

RESULTS

Twenty tumors (95%) were of recipient origin. Anatomically separate tumors from a given patient had the same origin. A single PTLD of donor origin arose in donor lung. Epstein-Barr virus (EBV), as assessed by EBER and LMP1 histochemical stains, was present in 16 of 17 tumors. CD20, evaluated immunohistochemically, was expressed diffusely in 12 of 17 tumors and focally in 3 and was undetectable in 2 tumors.

CONCLUSIONS

PTLD after solid organ transplantation is frequently EBV-related and of recipient origin, implying that therapeutic EBV-specific T cells must be matched to the HLA type of the recipient, not that of the donor, in most cases of PTLD. Variable CD20 expression among tumors suggests that in some patients anti-CD20 therapy might be more effective in combination with other therapies.