Molecular characterization of post-transplant lymphoproliferative disorders of donor origin occurring in liver transplant recipients

Post-transplant lymphoproliferative disorders (PTLD) in adolescents and young adults: A category in need of definition

Post-transplant lymphoproliferative disorders are a well-recognized complication of solid organ and stem cell transplantation. Much data has accumulated with respect to the pathobiology and clinical behavior of these lesions in the general post-transplant population as well as in the pediatric and adult age groups. However, information as to these lesions in the adolescent and young adult populations, which bridge the pediatric and adult groups, is limited. In this review, the focus is on this unique population of PTLD patients and their proliferations.

Donor-Transmitted Cancers in Transplanted Livers: Analysis of Clinical Outcomes

The risk of transmission of malignancy from donor to recipient is low. However, this occurrence has dramatic consequences. Many reports of donor-derived cancers in liver transplant recipients have been published, but they have not been systematically summarized into a lucid and unified analysis. The present study is an attempt to provide clarity to this unusual but clinically important problem. We systematically reviewed all patient reports, patient series, and registries published on cancer transmission events through the end of December 2019. We identified a total of 67 publications with 92 transmission events. The most frequently transmitted cancers were lymphomas (30; 32.6%), melanomas (8; 8.7%), and neuroendocrine tumors (8; 8.7%). Most of the melanomas were metastasizing, whereas most of the lymphomas were localized to the graft. The median time to cancer diagnosis after transplantation was 7 months, with 78.1% of diagnoses established in the first year. Melanoma carried the worst prognosis, with no recipients alive at 1 year after cancer diagnosis. Lymphoma recipients had a better outcome, with more than 75% surviving at 2 years. A metastatic cancer carries a worse prognosis for recipients, and recipients with localized cancer can benefit from the chance to undergo transplantation again. The findings confirm the need to pay attention to donors with a history of melanoma but also suggest the need for a more careful evaluation of groups of donors, such as those dying from cerebral hemorrhage. Finally, recipients of organs from donors with cancer should be carefully followed to detect potential transmission.

Comparative analysis of post-transplant lymphoproliferative disorders after solid organ and hematopoietic stem cell transplantation reveals differences in the tumor microenvironment

Post-transplant lymphoproliferative disorders (PTLD) occur after solid organ transplantation (SOT) or hematopoietic stem cell transplantation (HCT) and are frequently associated with Epstein-Barr virus (EBV). Because of the complex immune setup in PTLD patients, the tumor microenvironment (TME) is of particular interest to understand PTLD pathogenesis and elucidate predictive factors and possible treatment options. We present a comparative study of clinicopathological features of 48 PTLD after HCT (n = 26) or SOT (n = 22), including non-destructive (n = 6), polymorphic (n = 23), and monomorphic (n = 18) PTLD and classic Hodgkin lymphoma (n = 1). EBV was positive in 35 cases (73%). A detailed examination of the TME with image analysis-based quantification in 22 cases revealed an inflammatory TME despite underlying immunosuppression and significant differences in its density and composition depending on type of transplant, PTLD subtypes, and EBV status. Tumor-associated macrophages (TAMs) expressing CD163 (p = 0.0022) and Mannose (p = 0.0016) were enriched in PTLD after HCT. Double stains also showed differences in macrophage polarization, with more frequent M1 polarization after HCT (p = 0.0321). Higher counts for TAMs (CD163 (p = 0.0008) and cMaf (p = 0.0035)) as well as in the T cell compartment (Granzyme B (p = 0.0028), CD8 (p = 0.01), and for PD-L1 (p = 0.0305)) were observed depending on EBV status. In conclusion, despite the presence of immunosuppression, PTLD predominantly contains an inflammatory TME characterized by mostly M1-polarized macrophages and cytotoxic T cells. Status post HCT, EBV positivity, and polymorphic subtype are associated with an actively inflamed TME, indicating a specific response of the immune system. Further studies need to elucidate prognostic significance and potential therapeutic implications of the TME in PTLD.

Primary lung neoplasms presenting as multiple synchronous lung nodules

Multiple synchronous lung nodules are frequently encountered on computed tomography (CT) scanning of the chest and are most commonly either non-neoplastic or metastases from a known primary malignancy. The finding may initiate a search for primary malignancy elsewhere in the body. An exception to this rule, however, is a class of rare primary lung neoplasms that originate from epithelial (pneumocytes and neuroendocrine), mesenchymal (vascular and meningothelial) and lymphoid tissues of the lung. While these rare neoplasms also present as multiple synchronous unilateral or bilateral lung nodules on chest CT, they are often overlooked in favour of more common causes of multiple lung nodules. The correct diagnosis may be suggested by a multidisciplinary team and established on biopsy, performed either as part of routine diagnostic work-up or staging for malignancy. In this review, we discuss clinical presentations, imaging features, pathology findings and subsequent management of these rare primary neoplasms of the lung.

Signatures of B-cell receptor diversity in B lymphocytes following Epstein-Barr virus transformation

Epstein-Barr virus (EBV) is a widespread human virus that establishes latent infection, potentially leading to tumors, hematological disorders, and other severe diseases. EBV infections are associated with diverse symptoms and affect various organs; therefore, early diagnosis and treatment are crucial. B cell receptor (BCR) repertoires of B cell surface immunoglobulins have been widely studied for their association with various infectious diseases. However, the specific genetic changes that modulate the BCR repertoires after an EBV infection are still poorly understood. In this study, we employed high-throughput sequencing (HTS) to investigate the diversity of BCR repertoires in an EBV-transformed lymphoblastic cell line (LCL). Compared with the noninfected control B cell line, the LCL exhibited a decrease in overall BCR diversity but displayed an increase in the expansion of some dominant rearrangements such as IGHV4-31/IGHJ4, IGHV4-59/IGHJ4, IGHV5-51/IGHJ3, and IGHV3-74/IGHJ3. A higher frequency of occurrence of these rearrangement types was confirmed in patients with EBV infection. Interestingly, the IGHV3-74 rearrangement was only detected in EBV-infected children, suggesting that our experimental observations were not coincidental. In addition, we identified a highly dominant consensus motif, CAR(xRx)YGSG(xYx)FD, in complementarity-determining region 3 (CDR3) sequences of the heavy chain in the LCL. Our findings demonstrated the utility of HTS technology for studying the variations in signature motifs of the BCR repertoires after EBV infection. We propose that the analysis of BCR repertoire sequences represents a promising method for diagnosing early EBV infections and developing novel antibody- and vaccine-based therapies against such infections.

Impact of the posttransplant lymphoproliferative disorder subtype on survival

BACKGROUND

Posttransplant lymphoproliferative disorder (PTLD) is a life-threatening complication of solid organ transplantation. Histologic heterogeneity and a lack of treatment standards have made evaluating clinical outcomes in specific patient populations difficult. This systematic literature review investigated the impact of the PTLD histologic subtype on survival in a large data set.

METHODS

Case series were identified on PubMed with the search terms post-transplant lymphoproliferative disorder/disease, PTLD, and solid organ transplantation, with additional publications identified through reference lists. The patient characteristics, immunosuppressive regimen, treatment, survival, and follow-up time for 306 cases were extracted from 94 articles, and these cases were combined with 11 cases from Emory University Hospital. Patients with a recorded subtype were included in a Kaplan-Meier survival analysis (n = 234). Cox proportional hazards regression analyses identified predictors of overall survival (OS) for each subtype and B-cell subgroup.

RESULTS

OS differed significantly between monomorphic T-cell neoplasms (median, 9 months) and polymorphic, monomorphic B-cell, and Hodgkin-type neoplasms, for which the median OS was not reached (P = .0001). Significant differences in OS among B subgroups were not detected, but there was a trend toward decreased survival for patients with Burkitt-type PTLD. Kidney transplantation and a reduction of immunosuppression were associated with increased OS for patients with B-cell neoplasms in a multivariate analysis. Immunosuppression with azathioprine was associated with decreased OS for patients with T-cell neoplasms, whereas radiotherapy was associated with improved OS for patients with that subtype.

CONCLUSIONS

The histologic subtype represents an important prognostic factor in PTLD, with patients with T-cell neoplasms exhibiting very poor OS. Possibly lower survival for certain subsets of patients with B-cell PTLD should be explored further and suggests the need for subtype-specific therapies to improve outcomes. Cancer 2018;124:2327-36. © 2018 American Cancer Society.

Donor-derived infections in solid organ transplant patients: toward a holistic approach

PURPOSE OF REVIEW

Solid organ demand far exceeds organ supply. Strategies to increase the donor pool include the liberalization of selection criteria without increasing the risk of unexpected donor-derived infection (DDI), a rare complication of transplantation carrying high morbidity and mortality. We review the challenging aspects in the prevention of DDI, focusing on the complexities of data sharing and efficient communication and the role infectious diseases specialists play in the process.

RECENT FINDINGS

Advances in donor screening, transmission recognition and reporting allow for a better estimation of the risk of DDI. However, there is great variability in the frequency and methods with which organ procurement organizations report transmission events.Moreover, the Scientific Registry of Transplant Recipients provides limited donor and recipient outcome infectious diseases related data. Infectious disease contribution to the allocation process has been found to improve organ donation efficiency and communication between involved parties. Although communication gaps are strongly associated with infection transmission (relative risk 2.36%, confidence interval 1.48-3.78), effective communication minimizes or prevents infection in transplant recipients (X(1) 13.13, P = 0.0003).

SUMMARY

Prospective research is still required to define optimal screening protocols and further prevent transmission of infection. A holistic approach is likely to result in enhanced transplantation safety. Toward this goal, development of standards of investigation; improvement in reporting and data sharing; and strategies ensuring coordinated and rapid communication among parties involved in the allocation process need to be pursued.

Identification of distinct subgroups of EBV-positive post-transplant diffuse large B-cell lymphoma

Post-transplantation lymphoproliferative disorder is an aggressive complication of transplantation, most frequently of diffuse large B-cell lymphoma morphology and associated with Epstein-Barr virus (EBV) infection/reactivation. In this study the microenvironment of EBV⁺ (n=23) and EBV^- (n=9) post-transplant non-germinal center B-cell diffuse large B-cell lymphoma was characterized. Of EBV⁺ cases somatic hypermutation analysis, gene expression profiling, and extensive phenotyping were performed. Our results demonstrated variable cytotoxic T-cell infiltration and significantly increased CD163⁺ M2 macrophage infiltration in EBV⁺ compared with EBV^- post-transplant diffuse large B-cell lymphoma. On the basis of IgM staining and hypermutation analysis, two EBV⁺ post-transplant diffuse large B-cell lymphoma subgroups were identified: IgM⁺ tumors lacking somatic hypermutations and IgM^- tumors harboring somatic hypermutations. IgM^- tumors arose late following transplantation (median interval: 16 months), mainly in kidney recipients. IgM⁺ tumors on the other hand arose early (median interval: 3 months, P-value=0.0032), almost exclusively following stem cell transplantation and were associated with worse outcome (median survival 1 month for IgM⁺ versus 41 months for IgM^- tumors, log-rank/Wilcoxon P-value 0.07/0.04). Notably, IgM⁺ tumors were characterized by plasma cell features (monotypic kappa/lambda expression, high MUM1 expression, and partial CD138 expression) and a high proliferation index. Consistent with the plasma cell phenotype, unfolded protein response signaling was upregulated. In contrast, IgM^- EBV⁺ post-transplant diffuse large B-cell lymphoma did not express kappa, lambda, IgD, or CD138 and expressed limited MUM1. In these tumors T-cell signaling was enhanced associated with increased T-cell infiltration compared with IgM⁺ cases. Overall, our results allow further molecular classification of EBV⁺ post-transplant diffuse large B-cell lymphoma and provide a rationale for the use of subtype-specific-targeted therapies (eg, bortezomib in IgM⁺ tumors). Our findings also provide a biological basis for the clinical differences between post-transplant lymphoproliferative disorder following solid organ and stem cell transplantation, which are regarded as different disorders.

EBV-negative monomorphic B-cell post-transplant lymphoproliferative disorders are pathologically distinct from EBV-positive cases and frequently contain TP53 mutations

Monomorphic post-transplant lymphoproliferative disorder commonly resembles diffuse large B-cell lymphoma or Burkitt lymphoma, and most are Epstein-Barr virus (EBV) positive. We retrospectively identified 32 cases of monomorphic post-transplant lymphoproliferative disorder from two institutions and evaluated EBV in situ hybridization; TP53 mutation status; p53, CD30, myc, and BCL2 expression by immunohistochemistry; proliferation index by Ki67; and germinal center vs non-germinal center immunophenotype by Hans criteria. Post-transplant lymphoproliferative disorder arose after hematopoietic stem cell transplant in five and solid organ transplant in 27 patients, a median of 4 and 96 months after transplant, respectively (overall median latency 71 months, range 2-295). The most common morphology was diffuse large B-cell lymphoma (28 cases), with three cases of Burkitt lymphoma, and one case of plasmablastic lymphoma. Ten cases (31%) were EBV negative. Of those with the morphology of diffuse large B-cell lymphoma, the EBV-negative cases were more frequently TP53-mutated (P<0.001), p53 positive by immunohistochemistry (P<0.001), CD30 negative (P<0.01), and of germinal center immunophenotype (P=0.01) compared with EBV-positive cases. No statistically significant difference in overall survival was identified based on EBV, TP53 mutation status, germinal center vs non-germinal center immunophenotype, or other immunohistochemical parameters evaluated. Patients who died of post-transplant lymphoproliferative disorder were older with a longer latency from time of transplant to diagnosis (P<0.05). Our study demonstrates that diffuse large B-cell lymphoma-related immunohistochemical prognostic markers have limited relevance in the post-transplant setting and underscores differences between EBV-positive and EBV-negative post-transplant lymphoproliferative disorder in terms of immunophenotype and TP53 mutation frequency, supporting an alternative pathogenesis for EBV-negative post-transplant lymphoproliferative disorder.

Donor Monoclonal Gammopathy May Cause Lymphoproliferative Disorders in Solid Organ Transplant Recipients

Prior research on donor monoclonal gammopathy of undetermined significance (MGUS) has been inadequate regarding the risk for lymphoproliferative disease in solid organ transplantation recipients. Seven organ recipients from two different donors developed lymphoproliferative disease. The origin of the malignancy was determined by use of microsatellite analysis, and the plasma of the two donors was analyzed with the use of electrophoresis. The clinical courses of the seven recipients were followed for 36-60 months. One donor transmitted lymphoplasmacytic lymphoma to two kidney recipients and MGUS to a liver recipient, all IgMκ. A second donor caused IgGλ myeloma in two kidney and one liver recipient, and IgGλ gammopathy in a heart recipient. Transplant nephrectomy was performed in three kidney recipients and remission was achieved. The fourth kidney recipient has kept the graft and the disease has progressed. The liver recipient died from myeloma. There were no clinical signs of lymphoproliferative disease in the donors, but retrospective serum analyses showed M-components, IgMκ (37 g/L) and IgGλ (8 g/L). Donors with MGUS may cause donor-transmitted malignancies via passenger lymphocytes/plasma cells in solid organ recipients. The results call for a large register study of the incidence of donor MGUS and lymphoproliferative disease in their recipients.

Epstein- Barr Virus: Clinical and Epidemiological Revisits and Genetic Basis of Oncogenesis

Epstein-Barr virus (EBV) is classified as a member in the order herpesvirales, family herpesviridae, subfamily gammaherpesvirinae and the genus lymphocytovirus. The virus is an exclusively human pathogen and thus also termed as human herpesvirus 4 (HHV4). It was the first oncogenic virus recognized and has been incriminated in the causation of tumors of both lymphatic and epithelial nature. It was reported in some previous studies that 95% of the population worldwide are serologically positive to the virus. Clinically, EBV primary infection is almost silent, persisting as a life-long asymptomatic latent infection in B cells although it may be responsible for a transient clinical syndrome called infectious mononucleosis. Following reactivation of the virus from latency due to immunocompromised status, EBV was found to be associated with several tumors. EBV linked to oncogenesis as detected in lymphoid tumors such as Burkitt's lymphoma (BL), Hodgkin's disease (HD), post-transplant lymphoproliferative disorders (PTLD) and T-cell lymphomas (e.g. Peripheral T-cell lymphomas; PTCL and Anaplastic large cell lymphomas; ALCL). It is also linked to epithelial tumors such as nasopharyngeal carcinoma (NPC), gastric carcinomas and oral hairy leukoplakia (OHL). In vitro, EBV many studies have demonstrated its ability to transform B cells into lymphoblastoid cell lines (LCLs). Despite these malignancies showing different clinical and epidemiological patterns when studied, genetic studies have suggested that these EBV- associated transformations were characterized generally by low level of virus gene expression with only the latent virus proteins (LVPs) upregulated in both tumors and LCLs. In this review, we summarize some clinical and epidemiological features of EBV- associated tumors. We also discuss how EBV latent genes may lead to oncogenesis in the different clinical malignancies

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.

Posttransplant lymphoproliferative disorder in pediatric patients

Transplantation of solid organs and hematopoietic stem cells is accompanied by profound disturbance of immune function mediated by immunosuppressive drugs or delayed immune reconstitution. Disturbed T cell control of Epstein-Barr virus (EBV)-infected B cells leads to posttransplant lymphoproliferative disorder (PTLD) in up to 10% of patients. Children are at a higher risk because they are more often EBV-naïve before transplantation. Patients with PTLD often present with unspecific symptoms (pain and organ/graft dysfunction). Depending on the onset of PTLD, manifestations vary between mainly nodal (late PTLD) and extranodal sites (early PTLD). Histology, immunohistology, EBER in situ hybridization and molecular pathology are required for diagnosis and subclassification of PTLD. The three major types are early lesions (resembling reactive proliferations in immunocompetent patients), polymorphic PTLD (proliferation of B and T cells with effacement of histoarchitecture) and monomorphic PTLD (presenting as malignant lymphomas, mainly high-grade B cell lymphomas). In a subfraction of cases, including monomorphic PTLD, reduction of immunosuppressive medication alone is sufficient to induce remission. Surgical debulking of tumor mass and anti-CD20-antibody treatment with or without chemotherapy (usually at lower dosages than in immunocompetent patients) constitute the basis of additional therapy.

Molecular pathogenesis of B-cell posttransplant lymphoproliferative disorder: what do we know so far?

Posttransplant lymphoproliferative disorder (PTLD) is a potentially fatal disease that arises in 2%-10% of solid organ and hematopoietic stem cell transplants and is most frequently of B-cell origin. This very heterogeneous disorder ranges from benign lymphoproliferations to malignant lymphomas, and despite the clear association with Epstein-Barr Virus (EBV) infection, its etiology is still obscure. Although a number of risk factors have been identified (EBV serostatus, graft type, and immunosuppressive regimen), it is currently not possible to predict which transplant patient will eventually develop PTLD. Genetic studies have linked translocations (involving C-MYC, IGH, BCL-2), various copy number variations, DNA mutations (PIM1, PAX5, C-MYC, RhoH/TTF), and polymorphisms in both the host (IFN-gamma, IL-10, TGF-beta, HLA) and the EBV genome to B-cell PTLD development. Furthermore, the tumor microenvironment seems to play an important role in the course of disease representing a local niche that can allow antitumor immune responses even in an immunocompromised host. Taken together, B-cell PTLD pathogenesis is very complex due to the interplay of many different (patient-dependent) factors and requires thorough molecular analysis for the development of novel tailored therapies. This review aims at giving a global overview of the currently known parameters that contribute to the development of B-cell PTLD.

Characteristics of early and late PTLD development in pediatric solid organ transplant recipients

BACKGROUND

Posttransplantation lymphoproliferative disorders (PTLD) present a major cause of mortality and morbidity after solid organ transplantation. The purpose of this study was to identify the factors associated with the development of early- and late-onset PTLD in pediatric solid organ transplant recipients.

METHODS

We examined the medical history, laboratory parameters, and pathology of 127 children with PTLD who were registered in the German multicenter pediatric PTLD registry. Data were collected retrospectively from 1991 to 2003 and prospectively from 2004 onward. We compared early (<1 year) and late (>1 year) PTLD using survival analysis.

RESULTS

The median time to PTLD was 3.00 (95% confidence interval, 2.12-3.26) years. Forty-two patients developed PTLD within the first year after transplantation (early PTLD) and 85 patients developed PTLD after 1 year (late PTLD). Early PTLD development was associated with younger age (P=0.0016), extranodal disease (P=0.019), graft organ involvement (P=0.0065), and immunosuppressive regimens including tacrolimus (P=0.001) or mycophenolate (P=0.0025). Most early PTLD patients experienced graft rejection before PTLD diagnosis (P=0.0081). Early PTLD was often of B-cell lymphoma histology (P=0.024) and tended to be Epstein-Barr virus positive (P=0.052). In contrast, Burkitt's lymphoma (P=0.0047) and Hodgkin's disease (P=0.016) were only observed in late PTLDs, which are more likely to present with nodal disease (P=0.019). Overall survival and event-free survival were not significantly different between early and late PTLD.

CONCLUSION

Early and late childhood PTLD have distinct characteristics. Whereas early PTLD appears mainly as an Epstein-Barr virus-driven disease especially favored by insufficient immunosurveillance, late PTLD often resembles tumors with distinct pathogenetic alterations and nodal appearance.

Early-Onset EBV-Positive Post-transplant Plasmablastic Lymphoma Arising in a Liver Allograft

We report a case of a 51-year-old man who received a cadaveric liver allograft for autoimmune and hepatopulmonary syndrome. The patient was admitted with symptoms of progressive vomiting and diarrhea 16 months after transplantation. Laboratory studies showed abnormal liver functions, and abdominal magnetic resonance imaging (MRI) showed a 76-mm heterogeneous mass in the liver. Histological examination showed a malignant lymphoid neoplasm with plasmablastic features. Plasmablastic lymphoma (PL) is rare in the post-transplantation period. To the best of our knowledge, only 25 well-documented cases of posttransplant PL, including ours, have been described.

Molecular and clinicopathological analysis of Epstein-Barr virus-associated posttransplant smooth muscle tumors

Epstein-Barr virus (EBV)-associated posttransplant smooth muscle tumors (PTSMT) are very rare complications. We aimed to provide a clinicopathological characterization which is based on our own case series (n = 5) as well as previously reported PTSMT cases (n = 63). Meta-analysis of PTSMT and molecular analysis of tumor cells from our cohort was performed. Most PTSMT developed in kidney-transplanted patients (n = 41/68, 60%). Liver/transplant liver was the main site of manifestation (n = 38/68, 56%). Tumors occurred after a median interval of 48 months (range 5-348) and developed earlier in children than in adults. Most tumors showed no marked cellular atypia, low mitosis rate and no tumor necrosis. Gene expression analysis of 20 EBV-related genes, including two microRNAs, revealed overexpression of MYC (p = 0.0357). Therapy was mainly based on surgical resection or reduced immunosuppression but no significant differences in overall survival were evident. Lower overall survival was associated with multiorgan involvement (n = 33/68, 48.5%) and particularly with intracranial PTSMT manifestation (n = 7/68, 10%; p < 0.02), but not transplant involvement (n = 11/68, 16%). In summary, PTSMT differ from conventional leiomyosarcomas by their lack of marked atypia, unusual sites of involvement and defining EBV association. Surgery and reduced immunosuppression show comparable clinical results and prognosis is associated with intracranial manifestation.

Alterations of negative regulators of cytokine signalling in immunodeficiency-related non-Hodgkin lymphoma

We investigated immunodeficiency-related non-Hodgkin lymphoma for the presence of molecular alterations affecting negative regulators of the Janus family protein tyrosine kinase/signal transducer and activator of transcription pathway. Protein tyrosine phosphatase, non-receptor type 6/Src homology 2-containing tyrosine phosphatase-1 epigenetic silencing was recurrent in primary effusion lymphoma (100%), and diffuse large B-cell lymphoma (63%), with a higher prevalence in the non-germinal centre subtype, and was associated with the activation of the Janus family protein tyrosine kinase/signal transducer and activator of transcription 3 pathway. Suppressor of cytokine signalling (SOCS)1 and SOCS3 epigenetic silencing were occasionally detected, whereas SOCS1 was frequently mutated in diffuse large B-cell lymphoma and polymorphic post-transplant lymphoproliferative disorders, possibly as a cause of aberrant somatic hypermutation. However, the mutation profile of the coding region of the gene was different from that expected from the aberrant somatic hypermutation process, suggesting that, at least in some cases, SOCS1 mutations may have been selected for their functional activity.

[Transplant-associated lymphoproliferation]

Transplantation of solid organs and haematopoietic stem cells requires immunosuppressive drug therapy in order to prevent rejection or graft-versus-host disease. Depending on dosage and type of drug, the risk of developing an Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disease (PTLD) is increased. The lesion spectrum ranges from hyperplastic lesions to manifest lymphomas, the latter being classified as monomorphic PTLD. Hyperplastic changes, which are not distinguishable from viral reactions, comprise early or mononucleosis-like lesions. Those with effaced lymph node architecture or extranodal manifestation without a lymphoma-like phenotype are designated polymorphic PTLD. Monomorphic PTLD are either high grade B cell lymphomas, plasma cell neoplasms or Hodgkin lymphomas and only very rarely T cell lymphomas. Low grade B cell lymphomas do not occur. In a subfraction of cases, including even monomorphic PTLD, reduction of immunosuppression alone is sufficient to induce remission of the pathological process.

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.

Post-transplant lymphoproliferative disorders following solid-organ transplantation

A post-transplant lymphoproliferative disorder (PTLD) is an uncommon but serious complication following solid-organ transplantation. The incidence varies, depending on the type of organ transplanted, the degree of immunosuppression, the number of episodes of acute rejection and a patient's immune status to Epstein-Barr virus. The incidence of PTLD is thought to be bimodal; cases in the first year after solid-organ transplantation are typically related to Epstein-Barr virus. A second incidence occurs more than 1 year following transplantation and is typically not related to Epstein-Barr virus. A variety of therapeutic approaches has been used for these patients, with more recent strategies including the use of rituximab, with or without combination chemotherapy. Efforts continue to be made to improve the outcome of patients with PTLD.

Prospective evaluation of epstein-barr virus reactivation after stem cell transplantation: association with monoclonal gammopathy

Epstein-Barr Virus (EBV) reactivation and EBV-related post-transplant lymphoproliferative disease (PTLD) have emerged as a severe complication after stem cell transplantation (SCT). We prospectively evaluated 104 consecutive patients receiving SCT either autologous or allogeneic. Fifty-two patients (50%) presented EBV DNA-emia and five of them developed PTLD proven or probable. PTLD rate was 9.6% among patients with EBV DNA-emia. One patient developed PTLD without EBV DNA-emia (0.96%). Overall PTLD incidence was 5.7%. No PTLD developed after autologous SCT. EBV DNA-emia was significantly more frequent after allogeneic than autologous SCT (60.7% vs 17.4%, p = 0.0002). At EBV reactivation, serum protein electrophoresis and immunofixation were assessed. Global incidence of γ-peak after allogeneic SCT with EBV reactivation was 65.3% (32/49 patients) and monoclonal gammopathy (MG) was identified in 23/28 evaluable patients (82%). All patients with PTLD developed γ-peak and in five of them MG was identified. MG is consistently associated with EBV DNA-emia and may help identification of progression to PTLD after allogeneic SCT.

Donor cell leukemia in umbilical cord blood transplant patients: a case study and literature review highlighting the importance of molecular engraftment analysis

Donor cell neoplasms are rare complications of treatment regimens that involve stem cell transplantation for hematological malignancies, myelodysplastic processes, or certain genetic or metabolic disorders. We report a case of donor cell leukemia in a pediatric patient with a history of acute myeloid leukemia that manifested as recurrent AML FAB type M5 fourteen months after umbilical cord blood transplantation. Although there was some immunophenotypic drift from the patient's original AML and their posttransplant presentation, the initial pathological impression was of recurrent disease. Bone marrow engraftment analysis by multiplex PCR of short tandem repeat markers performed on the patient's diagnostic specimen showed complete engraftment by donor cells, with a loss of heterozygosity in the donor alleles on chromosome 7. This led to the reinterpretation of this patient's disease as donor-derived leukemia. This interpretation was supported by a routine karyotype and fluorescence in situ hybridization analysis showing loss of chromosome 7 and a male (donor) chromosome complement in this female patient. Also noted was a loss of the patient's presenting chromosomal abnormality, t(11;19)(q23;p13). This case highlights the need for close coordination between all aspects of clinical testing for the transplant patient, including molecular engraftment studies, when distinguishing the very common complication of recurrent disease from the exceedingly rare complication of donor cell leukemia.

Increased risk for lymphoid and myeloid neoplasms in elderly solid-organ transplant recipients

BACKGROUND

By assessing the spectrum of hematologic malignancies associated with solid-organ transplantation in the elderly, we provide information on the pathogenesis of lymphoid and myeloid neoplasms and the clinical manifestations of immunosuppression.

METHODS

Using data from the U.S. Surveillance, Epidemiology, and End Results Medicare database, we identified 83,016 cases with a hematologic malignancy (age 66-99 years) and 166,057 population-based controls matched to cases by age, sex, and calendar year. Medicare claims were used to identify a history of solid-organ transplantation. We used polytomous logistic regression to calculate odds ratios (OR) comparing transplantation history among cases with various hematologic malignancy subtypes and controls, adjusting for the matching factors and race.

RESULTS

A prior solid-organ transplant was identified in 216 (0.26%) cases and 204 (0.12%) controls. Transplantation was associated with increased risk for non-Hodgkin lymphomas [OR, 2.13; 95% confidence interval (95% CI), 1.67-2.72], especially diffuse large B-cell lymphoma (OR, 3.29; 95% CI, 2.28-4.76), marginal zone lymphoma (OR, 2.48; 95% CI, 1.17-5.22), lymphoplasmacytic lymphoma (OR, 3.32; 95% CI, 1.41-7.81), and T-cell lymphoma (OR, 3.07; 95% CI, 1.56-6.06). Transplantation was also associated with elevated risk of Hodgkin lymphoma (OR, 2.53; 95% CI, 1.01-6.35) and plasma cell neoplasms (OR, 1.91; 95% CI, 1.24-2.93). Risks for myeloid neoplasms were also elevated (OR, 1.99; 95% CI, 1.41-2.81).

CONCLUSION

Solid-organ transplantation is associated with a wide spectrum of hematologic malignancies in the elderly. Risk was increased for four specific non-Hodgkin lymphoma subtypes for which a viral agent has been implicated, supporting an added role for immunosuppression.

IMPACT

Our results support monitoring for a wide spectrum of hematologic malignancies following solid-organ transplant.

Diagnosis of post-transplant lymphoproliferative disorder in solid organ transplant recipients - BCSH and BTS Guidelines

A joint working group established by the Haemato-oncology subgroup of the British Committee for Standards in Haematology (BCSH) and the British Transplantation Society (BTS) has reviewed the available literature and made recommendations for the diagnosis and management of post-transplant lymphoproliferative disorder (PTLD) in adult recipients of solid organ transplants. This review details the risk factors predisposing to development, initial features and diagnosis. It is important that the risk of developing PTLD is considered when using post transplant immunosuppression and that the appropriate investigations are carried out when there are suspicions of the diagnosis. These must include tissue for histology and computed tomography scan to assess the extent of disease. These recommendations have been made primarily for adult patients, there have been some comments made with regard to paediatric practice.

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.

Epstein-barr virus related lymphoproliferations after stem cell transplantation

Epstein-Barr virus related lymphoproliferative disorders are a rare but potentially fatal complication of allogeneic stem cell transplantation with an incidence of 1–3% and occurring within 6 months after transplantation. The most relevant risk factors include the use of in vivo T-cell depletion with antithymocyte globulin, HLA disparities between donor and recipient, donor type, splenectomy etc. The higher the numbers of risk factors the higher the risk of developing Epstein-Barr virus related lymphoproliferative disorders. Monitoring EBV viremia after transplantation is of value and it should be applied to high risk patients since it allows pre-emptive therapy initiation at specified threshold values and early treatment. This strategy might reduce mortality which was >80% prior to the implementation of anti-EBV therapy. Treatment of EBV-LPD after allogeneic SCT may consist of anti-B-cell therapy (rituximab), adoptive T-cell immunotherapy or both. Rituximab treatment should be considered the first treatment option, preferably guided by intensive monitoring of EBV DNA while reduction of immunosuppression should be carefully evaluated for the risk of graft versus host disease.

Post-transplant lymphoproliferative disorders: role of viral infection, genetic lesions and antigen stimulation in the pathogenesis of the disease

Post-transplant lymphoproliferative disorders (PTLD) are a life-threatening complication of solid organ transplantation or, more rarely, hematopoietic stem cell transplantation. The majority of PTLD is of B-cell origin and associated with Epstein–Barr virus (EBV) infection. PTLD generally display involvement of extranodal sites, aggressive histology and aggressive clinical behavior. The molecular pathogenesis of PTLD involves infection by oncogenic viruses, namely EBV, as well as genetic or epigenetic alterations of several cellular genes. At variance with lymphoma arising in immunocompetent hosts, whose genome is relatively stable, a fraction of PTLD are characterized by microsatellite instability as a consequence of defects in the DNA mismatch repair mechanism. Apart from microsatellite instability, molecular alterations of cellular genes recognized in PTLD include alterations of cMYC, BCL6, TP53, DNA hypermethylation, and aberrant somatic hypermutation of protooncogenes. The occurrence of IGV mutations in the overwhelming majority of PTLD documents that malignant transformation targets germinal centre (GC) B-cells and their descendants both in EBV–positive and EBV–negative cases. Analysis of phenotypic markers of B-cell histogenesis, namely BCL6, MUM1 and CD138, allows further distinction of PTLD histogenetic categories. PTLD expressing the BCL6+/MUM1+/-/CD138− profile reflect B-cells actively experiencing the GC reaction, and comprise diffuse large B-cell lymphoma (DLBCL) centroblastic and Burkitt lymphoma. PTLD expressing the BCL6−/MUM1+/CD138− phenotype putatively derive from B-cells that have concluded the GC reaction, and comprise the majority of polymorphic PTLD and a fraction of DLBCL immunoblastic. A third group of PTLD is reminiscent of post-GC and preterminally differentiated B-cells that show the BCL6−/MUM1+/CD138+ phenotype, and are morphologically represented by either polymorphic PTLD or DLBCL immunoblastic.