Clonal analysis of posttransplant lymphoproliferative disorders, using both episomal Epstein-Barr virus and immunoglobulin genes as markers

Post-transplant lymphoproliferative disorder after solid-organ transplant in children

The post-transplant lymphoproliferative disorders (PTLD) are a diverse group of potentially life-threatening conditions affecting organ transplant recipients. PTLD arises in the setting of an attenuated host immunologic system that is manipulated to allow a foreign graft but then fails to provide adequate immune surveillance of transformed malignant or premalignant lymphocytes. The diversity of biological behavior and clinical presentation makes for a challenging clinical situation for those involved in the care of children with PTLD occurring after solid-organ transplantation. This review details a large transplant center's multidisciplinary approach to monitoring for PTLD and systematic approach to intervention, which has been essential for early recognition and successful treatment.

Subcutaneous panniculitis-like T-cell lymphoma in a case of carcinoma cervix

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is an uncommon extra nodal non-Hodgkin lymphoma accounting for less than 1% of all NHLs known to have an aggressive course, with no well-defined treatment protocols. A 42-year-old lady, operated five months earlier for a squamous cell carcinoma of the cervix presented with pain and induration of the lower part of the anterior abdominal wall; 3 months after completing chemotherapy and radiotherapy. FNAC done, yielded scanty material and was inconclusive. The biopsy showed features of a subcutaneous panniculitis-like T-cell lymphoma. While on chemotherapy she developed a vault recurrence and extensive intra-abdominal spread of the squamous cell carcinoma and succumbed. SPTCL is a rare entity and has been reported in renal and cardiac allograft recipients and in one case of ovarian carcinoma. Its occurrence in the setting of carcinoma cervix is unusual, hence is being reported.

Using Epstein-Barr viral load assays to diagnose, monitor, and prevent posttransplant lymphoproliferative disorder

Epstein-Barr virus (EBV) DNA measurement is being incorporated into routine medical practice to help diagnose, monitor, and predict posttransplant lymphoproliferative disorder (PTLD) in immunocompromised graft recipients. PTLD is an aggressive neoplasm that almost always harbors EBV DNA within the neoplastic lymphocytes, and it is often fatal if not recognized and treated promptly. Validated protocols, commercial reagents, and automated instruments facilitate implementation of EBV load assays by real-time PCR. When applied to either whole blood or plasma, EBV DNA levels reflect clinical status with respect to EBV-related neoplasia. While many healthy transplant recipients have low viral loads, high EBV loads are strongly associated with current or impending PTLD. Complementary laboratory assays as well as histopathologic examination of lesional tissue help in interpreting modest elevations in viral load. Circulating EBV levels in serial samples reflect changes in tumor burden and represent an effective, noninvasive tool for monitoring the efficacy of therapy. In high-risk patients, serial testing permits early clinical intervention to prevent progression toward frank PTLD. Restoring T cell immunity against EBV is a major strategy for overcoming PTLD, and novel EBV-directed therapies are being explored to thwart virus-driven neoplasia.

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.

Genetic and phenotypic analysis of B-cell post-transplant lymphoproliferative disorders provides insights into disease biology

B-cell post-transplant lymphoproliferative disorders (PTLD) are classified as early lesions, polymorphic lymphomas (P-PTLD) and monomorphic lymphomas (M-PTLD). These morphologic categories are thought to reflect a biologic continuum, although supporting genetic data are lacking. To gain better insights into PTLD pathogenesis, we characterized the phenotypes, immunoglobulin (Ig) gene alterations and non-Ig gene (BCL6, RhoH/TTF, c-MYC, PAX5, CIITA, BCL7A, PIM1) mutations of 21 PTLD, including an IM-like lesion, 8 P-PTLD and 12 M-PTLD. Gene expression profile analysis was also performed in 12 cases. All PTLD with clonal Ig rearrangements showed evidence of germinal centre (GC) transit based on the analysis of Ig and BCL6 gene mutations, and 74% had a non-GC phenotype (BCL6 +/- MUM1+). Although surface Ig abnormalities were seen in 6/19 (32%) PTLD, only three showed 'crippling' Ig mutations indicating other etiologies for loss of the B-cell receptor. Aberrant somatic hypermutation (ASHM) was almost exclusively observed in M-PTLD (8/12 vs. 1/8 P-PTLD) and all three recurrent cases analysed showed additional mutations in genes targeted by ASHM. Gene expression analysis showed distinct clustering of PTLD compared to B-cell non-Hodgkin lymphomas (B-NHL) without segregation of P-PTLD from non-GC M-PTLD or EBV+ from EBV- PTLD. The gene expression pattern of PTLD appeared more related to that of memory and activated B-cells. Together, our results suggest that PTLD represent a distinct type of B-NHL deriving from an antigen experienced B-cell, whose evolution is associated with accrual of genetic lesions.

Cytogenetic analysis of B-cell posttransplant lymphoproliferations validates the World Health Organization classification and suggests inclusion of florid follicular hyperplasia as a precursor lesion

Cytogenetic abnormalities in B-cell posttransplant lymphoproliferative disorders (PTLD) have not been well characterized. We thus performed cytogenetic analysis of 28 cases of B-cell PTLD, 1 infectious mononucleosis (IM)-like lesion, 9 polymorphic PTLD, 17 monomorphic PTLD, and 1 classical Hodgkin lymphoma (HL), and correlated the karyotypic findings with the phenotype, Epstein-Barr virus infection status, and clinical outcome. Karyotypes of 19 cases of posttransplant florid follicular hyperplasia (FFH) were also analyzed. Informative karyotypes were obtained in 20 (71.4%) of 28 PTLDs and 18 (94.7%) of 19 FFHs. Clonal karyotypic abnormalities were detected in 13 (65%) of 20 PTLDs, including 9 (75%) of 12 monomorphic PTLDs, 2 (33.3%) of 6 polymorphic PTLDs, 1 IM-like lesion, and 1 HL, and 2 (11.1%) of 18 FFHs. Recurrent chromosome breaks at 1q11-21 (n = 6, including 1 FFH), 14q32 (n = 3, including 1 FFH), 16p13 (n = 3), 11q23-24 (n = 2), and 8q24 (c-MYC) (n = 2); gains of chromosome 7 (n = 4), X (n = 3), 2 (n = 3), 12 (n = 2); and loss of chromosome 22 (n = 2, including 1 IM-like lesion) were identified. The presence of cytogenetic abnormalities did not correlate with PTLD phenotype, Epstein-Barr virus infection, or clinical outcome. We describe novel karyotypic aberrations in PTLD and report clonal cytogenetic abnormalities in posttransplant FFH and an IM-like lesion for the first time. Our findings provide validation of the current World Health Organization classification of PTLD and also suggest incorporation of FFH as the earliest recognizable precursor of PTLD.

Diagnostic application of Epstein-Barr virus-encoded RNA in situ hybridisation

AIMS

Epstein-Barr virus (EBV) has been implicated in the pathogenesis of nasopharyngeal carcinoma and a range of proliferative lymphoid conditions. In situ hybridisation (ISH) looking for virus-encoded RNA (EBER) transcripts is performed simply using a commercially available probe. We aimed to examine the application of this test in a routine diagnostic setting.

METHODS

In total, 26 cases in which EBV ISH was requested for diagnostic purposes were examined. We looked at the indication for testing, the result and its implication for the final diagnosis.

RESULTS

Cases were classified into three categories: possible nasopharyngeal carcinoma; possible EBV-related lymphoma; and possible immunodeficiency-associated lymphoproliferative disorder. Six of nine cases of possible nasopharyngeal carcinoma were EBV ISH positive (3/3 primary and 3/6 secondary), confirming the diagnosis. Three of 14 possible lymphoma cases were EBV ISH positive which, along with appropriate ancillary tests, assisted in making the diagnoses of Burkitt's lymphoma, lymphomatoid granulomatosis and extranodal NK/T-cell lymphoma of nasal type. All of three immunodeficiency-associated cases were EBV ISH positive. Two of these were post-transplant lymphoproliferative disorders, monomorphic type. The third case was classified as HIV-related polymorphic lymphoproliferative disorder.

CONCLUSIONS

In our experience, EBV ISH is a straightforward and rapid procedure to perform, giving unequivocal results. Used in the appropriate clinicopathological setting it can be a highly useful ancillary diagnostic aid.

Histogenetic phenotypes of B cells in posttransplant lymphoproliferative disorders by immunohistochemical analysis correlate with transplant type: solid organ vs hematopoietic stem cell transplantation

We immunohistochemically defined the histogenesis of posttransplantation lymphoproliferative disorders (PTLDs; B-cell phenotype) occurring after allogeneic T cell-depleted hematopoietic stem cell transplantation (HSCT; n = 15) or solid organ transplantation (SOT; n = 11) to determine whether transplantation type or morphologic subtype of PTLD affected the histogenetic subtype. Immunohistochemical stains using histogenetic markers for germinal center (GC) B cells, late GC and post-GC B cells, and post-GC B cells were performed on paraffin-embedded samples. Morphologically, 14 cases were polymorphic; 12 were monomorphic. Histogenetic marker expression was as follows: 1 monomorphic case (4%), GC phenotype expressing bcl-6 and CD10; 17 cases (65%; polymorphic, 9; monomorphic, 8), late GC-early post-GC phenotype expressing MUM1/IRF4; 8 cases (31%; polymorphic, 5; monomorphic, 3), post-GC phenotype expressing MUM1/IRF4 and CD138 but not bcl-6. PTLD cases after HSCT more frequently were post-GC phenotype than after SOT (7/15 vs 1/11, respectively; P = .040) and were independent of morphologic subclassification. Results suggest that most PTLDs are late GC-early post-GC phenotype with a minor group of post-GC phenotype and rare cases of GC phenotype. Findings also suggest a correlation between histogenetic phenotype of B-cell PTLD and type of transplantation.

T-cell Posttransplant Lymphoproliferative Disorder Occurring in a Pediatric Solid-organ Transplant Patient

Posttransplantation lymphoproliferative disorder (PTLD) is a serious complication seen in transplant patients as a consequence of immunosuppressant therapy. Most cases are of B-cell origin and are commonly associated with Epstein-Barr virus (EBV) infection. T-cell PTLDs are rare and only 13 pediatric T-cell PTLDs with clinicopathologic correlation have been reported previously. We present the histologic, immunophenotypic, and molecular features of a monomorphic PTLD (T-cell lymphoma) identified in a pediatric patient following orthotopic liver transplantation. The lymphoma was identified in the ileum, rectum, and mesenteric lymph nodes. In situ hybridization revealed numerous EBER-1-positive tumor cells. A current review of the literature is also discussed. Of the 14 cases of pediatric T-cell PTLD reported in the literature, only 3 (21.4%) are described as being EBV positive. Most of the reported PTLDs are monoclonal, with 9 of 11 cases (82%) showing a clonal T-cell population by gene rearrangement studies. T-cell PTLD cases appear to have a poor prognosis (11 of 14 patients died of the disease), although patients with involvement of specific anatomic sites may have a better outcome.

Post-transplant lymphoproliferative disorders: implications for acquired immunodeficiency syndrome-associated malignancies

Post-transplant lymphoproliferative disorders (PTLDs) comprise a histologic spectrum, ranging from hyperplastic-appearing lesions to frank non-Hodgkin's lymphoma or multiple myeloma histology. Multiple clones may coexist, each representing a discrete lymphomagenic event, a situation that is unique to immunodeficiency states. The incidence varies from 1% in renal recipients to 5% in heart recipients, but can be markedly increased by the use of anti-T-cell therapies or by T-cell depletion in bone marrow transplantation. PTLD continues to arise, even many years after transplantation, and late T-cell lymphomas have recently been recognized. Pretransplant Epstein-Barr virus (EBV) seronegativity increases risk to as high as 30%-50%. PTLD has a highly variable clinical picture; certain patterns are, however, seen. Reversibility of PTLD with reduction in immunosuppressives has long been recognized. Predicting reversibility has been difficult. The presence or absence of bcl-6 mutations has recently been identified as being of predictive value. Surgical resection can be curative. Cytotoxics, although problematic, can also be curative. Long-term remission has been achieved with anti CD21 and CD24 antibodies; efficacy has been reported for interferon alfa and for rituximab. In vitro expanded EBV-specific T cells have been effective as treatment and as prophylaxis in the setting of bone marrow transplantation. EBV viral load measured in blood appears to associate with the emergence of PTLD and may facilitate prophylactic studies. PTLD is a model of immunodeficiency-related EBV lymphomagenesis. Pathogenetic, therapeutic, and prophylactic insights gained from the study of PTLD are likely to be applicable to the acquired immunodeficiency syndrome setting.

Orbital presentation of posttransplantation lymphoproliferative disorder: a small case series

OBJECTIVE

To describe a small series of patients with orbital presentation of posttransplantation lymphoproliferative disorder (PTLD).

DESIGN

Retrospective, interventional case series.

PARTICIPANTS

Three patients with orbital presentation of histologically diagnosed PTLD.

METHODS

Review of medical records.

MAIN OUTCOME MEASURES

Measured parameters included vision, proptosis, and tumor extent.

RESULTS

Three cases of orbital PTLD are described. In two of the cases, the tumor initially demonstrated orbital signs and symptoms, whereas in the third case, orbital and systemic signs were synchronous. Two of three patients had disseminated disease discovered at the time of presentation. One adult patient had synchronous presentation of PTLD in the orbit and prostate. One pediatric patient had tumor dissemination to the liver at the time of presentation. The PTLD tumors were classified histologically as diffuse large cell lymphoma of monomorphic or immunoblastic type in all three cases. Treatment included local irradiation, decreased immunosuppression, and antilymphocyte monoclonal antibodies.

CONCLUSIONS

Orbital presentation is a rare manifestation of PTLD. However, ophthalmologists must consider this diagnosis carefully in organ transplant recipients with subtle orbital signs and symptoms at presentation. Early detection may alter prognosis. In each case presented, the diagnosis was established via lesion biopsy and subsequent histologic or flow cytometric evaluation, or both.

Posttransplant lymphoproliferative disorders in liver transplantation: a 20-year experience

OBJECTIVE

To evaluate the incidence of posttransplant lymphoproliferative disease (PTLD) and the risk factors and the impact of this complication on survival outcomes in a large cohort of liver transplant recipients at a single institution.

SUMMARY BACKGROUND DATA

Liver transplantation has been accepted as a therapeutic option for patients with end-stage liver disease since 1983, in large part due to the availability and reliance on the use of nonspecifically directed immunosuppression. However, as predicted and subsequently verified in 1968, an increased incidence of certain de novo malignancies has been observed, particularly with regards to lymphoid neoplasms. While many reports have confirmed and clarified the nature of PTLD, the literature is fraught with conflicting experience and outcomes with PTLD.

METHODS

Four thousand consecutive patients who underwent liver transplants between February 1981 and April 1998 were included in this analysis and were followed to November 2001. The effect of recipient age at the time of transplant, recipient gender, diagnosis, baseline immunosuppression, grading of PTLD, and association with Epstein-Barr virus were compared. The causes of death were also examined. Treatment for PTLD varied over the 20-year period, but all included massive reduction or elimination of baseline immunosuppression.

RESULTS

The 1-year patient survival for liver transplant patients with PTLD was 85%, while the overall patient survival for the entire cohort was 53%. The actuarial 20-year survival was estimated at 45%. The overall median time to PTLD presentation was 10 months, and children had an incidence of PTLD that was threefold higher than adults. Patient survival was better in children, in patients transplanted in the era of tacrolimus immunosuppression, in patients with polymorphic PTLD, and in those with limited disease. Interestingly, neither the presence or absence of Epstein-Barr virus nor the timing of PTLD presentation appeared to influence overall patient survival. Patients transplanted for alcohol-related liver disease had a similar incidence of PTLD but had a higher risk of mortality.

CONCLUSIONS

While PTLD continues to pose problems in patients receiving liver transplants, improvements in patient survival have been observed over time. While it is too early to assess the impact of new advances in prophylaxis, diagnosis, and treatment, such approaches are based on an increased knowledge of the pathophysiology of PTLD.

Posttransplant lymphoproliferative disorders in liver transplantation: a 20-year experience

OBJECTIVE

To evaluate the incidence of posttransplant lymphoproliferative disease (PTLD) and the risk factors and the impact of this complication on survival outcomes in a large cohort of liver transplant recipients at a single institution.

SUMMARY BACKGROUND DATA

Liver transplantation has been accepted as a therapeutic option for patients with end-stage liver disease since 1983, in large part due to the availability and reliance on the use of nonspecifically directed immunosuppression. However, as predicted and subsequently verified in 1968, an increased incidence of certain de novo malignancies has been observed, particularly with regards to lymphoid neoplasms. While many reports have confirmed and clarified the nature of PTLD, the literature is fraught with conflicting experience and outcomes with PTLD.

METHODS

Four thousand consecutive patients who underwent liver transplants between February 1981 and April 1998 were included in this analysis and were followed to November 2001. The effect of recipient age at the time of transplant, recipient gender, diagnosis, baseline immunosuppression, grading of PTLD, and association with Epstein-Barr virus were compared. The causes of death were also examined. Treatment for PTLD varied over the 20-year period, but all included massive reduction or elimination of baseline immunosuppression.

RESULTS

The 1-year patient survival for liver transplant patients with PTLD was 85%, while the overall patient survival for the entire cohort was 53%. The actuarial 20-year survival was estimated at 45%. The overall median time to PTLD presentation was 10 months, and children had an incidence of PTLD that was threefold higher than adults. Patient survival was better in children, in patients transplanted in the era of tacrolimus immunosuppression, in patients with polymorphic PTLD, and in those with limited disease. Interestingly, neither the presence or absence of Epstein-Barr virus nor the timing of PTLD presentation appeared to influence overall patient survival. Patients transplanted for alcohol-related liver disease had a similar incidence of PTLD but had a higher risk of mortality.

CONCLUSIONS

While PTLD continues to pose problems in patients receiving liver transplants, improvements in patient survival have been observed over time. While it is too early to assess the impact of new advances in prophylaxis, diagnosis, and treatment, such approaches are based on an increased knowledge of the pathophysiology of PTLD.

Anaplastic T large cell lymphoma diagnosed by exfoliative cytology in a post renal transplant patient

In the last two decades posttransplant lymphoproliferative disorders (PTLDs) have been recognized as a complication of organ transplantation with immunosuppression. The reported incidence of PTLDs in renal transplant patients ranges between 0.3-3% (Birkeland et al., Transplantation 1999;67:876-881). In contrast to the reported incidence of PTLDs in post bone marrow transplant, it is 1% in HLA-matched recipients and up to 20% in HLA mismatched T-cell depleted bone marrow recipients (Curtis et al., Blood 1996;94:2208-2216). In cardiac transplant recipients the reported incidence of PTLDs is between 1.8-9.8 (Mihalov et al., Clin Transplant 1996;10:248-255). PTLDs are predominately extranodal. They have varied morphologic patterns and clonality, but almost all are associated with Epstein-Barr virus (EBV). The vast majority are of B cell lineage; only about 10% are of T-cell origin. We report a T-cell anaplastic large cell lymphoma (ALCL) presenting with bilateral pleural effusion and liver involvement in a renal transplant recipient.

Post-transplantation lymphoproliferative disease in Chinese: the Queen Mary Hospital experience in Hong Kong

Post-transplantation lymphoproliferative disease (PTLD) is an unique iatrogenic complication after bone marrow transplantation (BMT) and solid organ transplantation (SOTx). The pattern of EBV related lymphoma in Chinese is different from Caucasians. We surveyed the incidence, clinical and pathological spectrum of PTLD among 541 cases of allogeneic BMT, 145 cases of renal transplant, 35 cases of heart/lung transplantation and 146 cases of orthotopic liver transplantation (OLT). From 1994 to 2001, 13 consecutive cases of PTLD were diagnosed, ranging from disseminated NK cell lymphoma to localized plasmacytoma. Both donor and recipient derived PTLD was documented. Disease was often heralded by cytomegaloviral disease and antithymocyte globulin (ATG) usage. Two cases were diagnosed post-mortem, and six patients died of PTLD at a median of 3 months. Complete and partial remission was only achieved in 3 and 2 cases, respectively, despite a range of treatment (reduced immunosuppression, explantation, radiotherapy, combination chemotherapy, donor lymphocytes, autologous marrow infusion and rituximab). Most responding patients died subsequently of rejection, infection and graft versus host disease (GVHD). The incidence of PTLD is not increased in Chinese patients. However, some patients may be at increased risk, especially mismatched allogeneic BMT, parental OLT (especially involving young infants) and heavy ATG exposure.

Posttransplant lymphoproliferative disorders in lung transplant patients: the Cleveland Clinic experience

PTLD is a well-recognized complication of organ transplantation. Large series of heart, renal, and liver transplants have been examined for the incidence and behavior of PTLD. However, reports of the incidence and characteristics of PTLDs in lung transplant (LTx) patients are few. We report our experience with PTLDs in a large series of LTx recipients at a single institution and compare them to other solid organ transplant recipient PTLDs seen at our institution. Twenty-eight patients were found to have PTLD, of whom 8 were lung transplant recipients. We evaluated nine PTLD specimens from these 8 patients for their histology, immunophenotype (CD20, CD3, EBV-LMP1), EBER status by in situ hybridization, and clinical features. The incidence of PTLD was 3.3% (8/244 patients). The time to development of PTLD, after transplant, was short (median time, 7 mo). All were of B-cell lineage. Overall, EBV was demonstrated in 77.7% (7 of 9 specimens) of PTLDs. All specimens tested for clonality were found to be monoclonal. Five patients died, with a median time to death of only 4.6 months. PTLDs in LTx patients are EBV-associated B-cell, predominantly monoclonal lymphoid lesions similar to other solid organ transplant PTLDs. Compared with other solid organ transplant recipients with PTLD at our institution, PTLDs in LTx patients have a propensity to involve the transplanted organ (P =.001, Fisher's exact test), occur earlier after transplant (P =.003, Wilcoxon test), and have a shorter survival (P =.002, log rank test). Reasons for this may include the relatively higher level of immunosuppression required in these patients and limited options in decreasing it. Although the incidence is low, careful early monitoring of lung transplantation patients is warranted because of the poor prognosis of patients developing this complication.

The molecular characterization of fatal infectious mononucleosis

We describe a retrospective study of 4 cases of sporadic fatal infectious mononucleosis (IM), 1 case of fatal IM, and 1 case of sporadic severe IM. Patients were 26 months to 17 years old; 3 were male. Five died of complications of IM. All 5 of these patients had the Epstein-Barr virus (EBV) present in examined tissue specimens; EBV was monoclonal in 3 patients and biclonal in 1. EBV clonality studies were not performed in the remaining patient. All 5 patients also had monoclonal gene rearrangements. The sixth patient survived despite a life-threatening clinical course; EBV was oligoclonal, and gene rearrangements were not detected. EBV clonality and gene rearrangement studies may be usefulfor predicting which patients with clinically aggressive IM are at highest risk for fatal outcome. Patients in whom IM has a fatal outcome are more likely to have monoclonal or biclonal EBV and immunoglobulin heavy chain or T-cell receptor gene rearrangements. In contrast, patients with nonfatal IM may lack monoclonal EBV and monoclonal rearrangements of the aforementioned genes. The reasons EBV induces a monoclonal proliferation only in some patients remain to be elucidated.

Extranodal posttransplant plasmacytic hyperplasia with subsequent posttransplant plasmacytic malignancy: six-year interval case report and review of the literature

Posttransplant lymphoproliferative disorders (PTLDs) represent a morphologic, immunophenotypic, and genotypic spectrum of disease. Most recently, Knowles et al divided PTLDs into 3 distinct categories: (1) plasmacytic hyperplasia, (2) polymorphic B-cell hyperplasia and polymorphic B-cell lymphoma, and (3) immunoblastic lymphoma and multiple myeloma. Although one form of PTLD may progress to another form, only 1 previous case has been reported in which multiple myeloma developed 14 months after an original diagnosis of plasmacytic hyperplasia. The type of solid organ transplant was not specified in that case. We report a post--cardiac transplant plasmacytic hyperplasia developing 7 years posttransplant. Six years subsequent to the plasmacytic hyperplasia, the patient developed a posttransplant plasmacytic malignancy, supported by morphology, flow cytometric immunophenotyping, and genotypic studies. Since we have no data to support disseminated bony disease or an abnormal serum protein, we have not used the term "multiple myeloma" for this case.

Epstein--Barr virus post-transplant lymphoproliferative disease and virus-specific therapy: pharmacological re-activation of viral target genes with arginine butyrate

Lymphoproliferative disorders associated with the Epstein-Barr virus (EBV) include non-Hodgkin's lymphoma, Hodgkin's lymphoma, and "post-transplant lymphoproliferative disorders" (PTLD), which occur with immunosuppression after marrow and organ transplantation. PTLD is characterized by actively proliferating, latently infected EBV(+) B-lymphocytes, and often manifests a rapidly progressive fatal clinical course if the immunosuppression cannot be reversed. Lung transplant recipients are a subset of patients at special risk for developing PTLD. The incidence of PTLD development in these patients has been estimated at 5--10%. Whereas immunologic and antiviral therapy have been moderately effective for treating EBV-associated infections in the lytic phase, they have been less useful in the more common latent phase of the disease. One common treatment for herpesvirus infections has targeted the virus-specific enzyme thymidine kinase (TK). The lack of viral TK expression in EBV(+) tumor cells, due to viral latency, makes anti-viral therapy alone ineffective as an anti-neoplastic therapy, however. We have developed a strategy for the treatment of EBV-associated lymphomas/PTLD using pharmacologic induction of the latent viral TK gene and enzyme in the tumor cells, followed by treatment with ganciclovir. Arginine butyrate selectively activates the EBV TK gene in latently EBV-infected human lymphoid cells and tumor cells. A Phase I/II trial has been initiated, employing an intra-patient dose escalation of arginine butyrate combined with ganciclovir. In six patients with EBV-associated lymphomas or PTLD, all of which were resistant to conventional radiation and/or chemotherapy, this combination produced complete clinical responses in four of six patients, with a partial response occurring in a fifth patient. Pathologic examination in two of three patients demonstrated complete necrosis of the EBV lymphoma, with no residual disease, following a single three-week course of the combination therapy. Possible side-effects of the therapy included nausea and reversible lethargy at the highest doses. One patient suffered acute liver failure, thought to be secondary to release of FasL from the necrotic tumor. Analysis of patient-derived tumor cells in culture demonstrated that arginine butyrate produced selective induction of the EBV TK gene, which then conferred sensitivity to ganciclovir, resulting in tumor apoptosis. Additional patient accrual is sought for further evaluation of this therapy.

Cells expressing the Epstein-Barr virus growth program are present in and restricted to the naive B-cell subset of healthy tonsils

In this paper we demonstrate, for the first time, that Epstein-Barr virus (EBV)-infected cells expressing the lymphoblastoid growth program are present in healthy carriers of the virus. Previously we observed that latently infected naive B cells are present in tonsils only when viral replication is detected, suggesting that these may represent newly infected B cells. We have tested this idea by performing a reverse transcription-PCR analysis for the expression of latent genes (EBNA2 and the EBNA3s) that are characteristically expressed only by newly infected cells expressing the growth latency program. EBNA2 expression is regularly detected in purified naive (IgD(+)) tonsillar B cells (13 of 16 tonsils tested) but was never found in the IgD(-) population (0 of 16). More detailed analysis revealed that the mRNAs for the latent genes EBNA1 (3 of 3 tonsils tested), EBNA3a (3 of 5), EBNA3b (3 of 5), EBNA3c (3 of 5), LMP1 (6 of 6), and LMP2 (5 of 6) were also present in the IgD(+) population, but the EBNA1Q-K transcript, characteristic of nonlymphoblastoid forms of latency, was never detected (0 of 6). Finally, we demonstrate that the latently infected naive (IgD(+)) cells express CD80 (B7.1), a marker characteristically expressed on activated naive lymphoblasts but absent from resting naive B cells. The infected naive (IgD(+)) population in the tonsil therefore has the viral and cellular phenotype of a B-cell directly infected with EBV-an activated lymphoblast expressing the growth program.

Posttransplantation lymphoproliferative disorder in children: clinical, histopathologic, and imaging features

Posttransplantation lymphoproliferative disorder (PTLD) is a condition in patients who receive transplants in which chronic immunosuppression leads to an unregulated expansion of lymphoid cells; the condition ranges from hyperplasia to malignant lymphoid proliferation. Risk factors affecting the incidence of PTLD include allograft type, Epstein-Barr virus infection, and immunosuppression. In this article, we review the clinical, histopathologic, and imaging features of PTLD in children. Because PTLD can affect nearly any organ system, a wide variety of clinical manifestations is possible. The heterogeneous nature of the disease is also reflected on imaging studies. The goals of imaging in patients with PTLD are to detect disease, guide biopsy, and direct appropriate follow-up imaging rather than to establish a specific diagnosis. Because the clinical and imaging manifestations of PTLD are nonspecific and are not reliably predictive of histopathologic subtype, tissue biopsy is necessary for final diagnosis.

Post-transplantation lymphoproliferative disease of natural killer cell lineage: a clinicopathological and molecular analysis

Post-transplantation lymphoproliferative disorders (PTLD) occur after solid organ and bone marrow transplantation. They are predominantly of B-cell and occasionally of T-cell lineage. We report a case of PTLD of natural killer (NK) cell lineage. A renal allograft recipient developed progressive pancytopenia 1 year after transplantation. Serial bone marrow biopsies showed an increasing infiltration by large granular lymphoid cells. A subsequent leukaemic phase also developed with systemic infiltration of other organs. Immunophenotyping showed that these cells were CD2+, CD3-, CD3epsilon+, CD56+, CD94+, CD158a- and CD158b-. In situ hybridization showed Epstein-Barr virus (EBV) infection of the neoplastic cells. Genotypical analysis showed the T-cell receptor gene in germline configuration and clonal EBV episomal integration. The overall features were consistent with NK cell lymphoma/leukaemia. The patient did not respond to cessation of immunosuppression or anti-EBV treatment. Combination chemotherapy was given, but the patient died ultimately of disseminated fungal infection. In conclusion, we have demonstrated that NK cell lymphoma is another rare type of PTLD that appears to be highly aggressive and therefore may require early chemotherapy to improve treatment outcome.

The molecular genetics of post-transplantation lymphoproliferative disorders

The post-transplantation lymphoproliferative disorders represent a significant clinical and diagnostic problem. However, these disorders also represent an important biological model for studying the development and progression of lymphoid neoplasia in immune deficiency. Accurate diagnosis and classification of these disorders requires correlative multiparametric analysis of the clinical behavior of the patient with the histopathological features, immunophenotype, clonal composition, and genetic alterations of the lymphoproliferative disorder. Such analyses should also assist in furthering our understanding of the pathogenesis of these disorders.

Arginine butyrate-induced susceptibility to ganciclovir in an Epstein-Barr-virus-associated lymphoma

Lymphoproliferative disorders associated with Epstein-Barr virus (EBV) infections can occur in the setting of immunosuppression. In some patients, the lymphoproliferative disorder can resemble an aggressive monoclonal non-Hodgkins lymphoma (NHL). These NHL are poorly responsive to conventional therapy. Similarly, antiviral therapy with synthetic nucleosides such as ganciclovir are ineffective because the genes that render the virus susceptible to therapy are not expressed in EBV+ lymphomas. Using a cell line derived from a lung transplant recipient with an EBV+ immunoblastic NHL, we studied the ability of arginine butyrate to induce the expression of EBV thymidine kinase. Arginine butyrate was not only effective in inducing EBV thymidine kinase transcription, but also acted synergistically with the antiviral agent ganciclovir to inhibit cell proliferation and decrease cell viability. Based on these findings, the patient from whom the cell line was derived was treated with arginine butyrate/ganciclovir as well as conventional cytotoxic chemotherapy. No additional toxicity was observed with the arginine butyrate/ganciclovir therapy. Histologic examination of the tumor showed substantial necrosis. These observations suggest the feasibility of arginine butyrate induction of ganciclovir susceptibility in patients with EBV-associated lymphomas.

Polyclonal B cell chronic lymphoproliferative disease with hairy cell morphology: a case report and clonal studies

We describe a patient who has a chronic polyclonal B lymphocyte proliferation with a hairy-cell appearance. A 48-year-old Japanese woman with marked splenomegaly, systemic lymphadenopathy, and leukocytosis was referred to out hospital. Laboratory examination revealed marked polyclonal IgG hypergammaglobulinemia. Morphologic examination of the patient's peripheral blood, including May-Giemsa staining and scanning electron microscopy, showed a monotonous proliferation of hairy-appearing mature lymphocytes. An immunophenotypic study revealed an expansion of cells with mature B cell antigens positive for CD11c; however, light-chain restriction was not seen. The lack of both immuno-globulin heavy-chain and T cell receptor gene rearrangements by Southern blot analysis indicated the polyclonal nature of the proliferating B cells. This was confirmed further by a clonal analysis of the patient's lymphocytes using an X-chromosome-linked restriction fragment polymorphism within the X-linked phosphoglycerate kinase (PGK) gene. Since chronic B cell lymphoproliferation with a hairy cell appearance has not been described previously, this case might be extremely rare, and has important implication for the pathogenesis of mature B cell lymphoproliferative diseases, including hairy cell leukemia.

Molecular genetic analysis demonstrates that multiple posttransplantation lymphoproliferative disorders occurring in one anatomic site in a single patient represent distinct primary lymphoid neoplasms

BACKGROUND

Posttransplantation lymphoproliferative disorders (PT-LPDs) are a clinicopathologically heterogeneous group of lymphoid proliferations of varied clonal composition, the majority of which are associated with Epstein-Barr virus (EBV) infection. The clonal content and clonal relatedness of 24 separate PT-LPD lesions occurring synchronously in one organ in a single patient were investigated.

METHODS

Twenty-four separate PT-LPD lesions from the colon and mesentery of a 15-year-old male, developing 4 months after cardiac transplantation, were studied for clonality based on immunoglobulin heavy chain (IgH) gene rearrangements for the presence, clonality, and type of EBV infection and for the presence of c-myc, ras, and p53 gene alterations. Southern blot hybridization, polymerase chain reaction, and single strand conformation polymorphism assays were employed.

RESULTS

All 24 lesions were histologically similar (polymorphic B-cell lymphomas) but exhibited varied clonality and were clonally distinct with respect to both IgH gene rearrangements and EBV infection. All lesions were infected with EBV type A. Structural alterations of oncogenes or tumor suppressor genes were not identified.

CONCLUSIONS

Separate PT-LPD lesions occurring synchronously in a single organ or patient may be clonally distinct, suggesting that they represent multiple distinct primary lymphoid proliferations rather than metastatic disease as in conventional malignant lymphomas. This may explain partially the rapid development in some patients of a large PT-LPD tumor burden that may regress rapidly after reduction of immunosuppression.