Epstein-Barr virus-induced posttransplant lymphoproliferative disorders. ASTS/ASTP EBV-PTLD Task Force and The Mayo Clinic Organized International Consensus Development Meeting

Posttransplant lymphoproliferative disorder following pancreas transplantation

The incidence, risk factors and impact on patient and graft survival were evaluated for posttransplant lymphoproliferative disorder (PTLD) among 212 pancreas transplant recipients. Thirteen (6.1%) developed PTLD during 71 +/- 27 months follow-up. Cumulative incidences of PTLD at 1, 3, 5 and 10 years posttransplant were 4.2%, 5.3%, 6.0% and 7.0%, respectively. Incidence of PTLD was lower for recipients of simultaneous pancreas kidney compared to pancreas after kidney transplant or pancreas transplant alone, though not significantly so. Recipient Epstein-Barr virus (EBV) seronegativity and number of doses of depleting antibody therapy administered at transplant were associated with increased risk of PTLD, while recipient age, gender, transplant type, cytomegalovirus mismatch maintenance immunosuppression type and treated acute rejection were not. All 13 cases underwent immunosuppression reduction, and 10 received anti-CD20 monoclonal antibody. During follow-up, 10/13 (77%) responded to treatment with complete remission, while 3 (23%) died as a result of PTLD. Patient and graft survivals did not differ for recipients with and without PTLD. The strong association of PTLD with EBV-seronegativity requires considering this risk factor when evaluating and monitoring pancreas transplant recipients. With reduction of immunosuppression and anti-CD20 therapy, survival for pancreas transplant recipients with PTLD was substantially better than previously reported.

Minimizing the risk of posttransplant malignancy

Recent improvements in immunosuppressive therapies have reduced the incidence of acute rejection and increased patient survival. These agents may however contribute to higher rates of mortality due to an increased risk of cardiovascular disease or malignancy. Transplant patients are immunocompromised with a reduced ability to combat the development of malignancy. The higher risk for the activity of oncoviruses may also contribute to the higher incidence and determine specific tumor types. Some immunosuppressants seem to have direct oncogenic effects. In vitro data have demonstrated that calcineurin inhibitors (CNIs) may show direct effects on tumor growth and the development of metastases. In contrast, mTOR inhibitors have demonstrated anti-tumoral properties in vitro and perhaps potent anti-angiogenic effects thereby. Recent studies and registry analyses have confirmed that mTOR inhibitors are associated with a reduced incidence of malignancies. UNOS data demonstrated that an mTOR inhibitor, with or without a CNI, is associated with a reduced incidence of tumors compared to regimens without mTOR inhibitors. The Rapamune Maintenance Regimen study demonstrated that patients receiving sirolimus-based, CNI-free therapy after CsA withdrawal at 3 months showed a reduced incidence of malignancy at 5 years posttransplant, compared with those who continued on a regimen that included CsA. In the CONVERT study, patients converted to sirolimus revealed a significantly lower malignancy rate at 24 months (3.1%) compared with those who continued CNI-based therapy (9.8%, P < .001). The elimination of CNIs and the introduction of sirolimus may, therefore, have a role to reduce the risk of cancer among posttransplant patients.

Hepatosplenic gammadelta T-cell lymphoma after liver transplantation: report of the first 2 cases and review of the literature

Hepatosplenic gammadelta T-cell lymphoma is a rare lymphoproliferative disorder originating from natural killer-like Vdelta1-lymphocytes. This subtype has been described after different types of solid organ transplants. In this article, we describe the first 2 cases after liver transplantation. Both patients had thrombocytopenia with (hepato)splenomegaly but without peripheral lymphadenopathies and sinusoidal infiltration of the liver and spleen by monomorphic gammadelta-lymphocytes on pathological examination. The clinical and pathological findings, immunophenotypical profile, prognosis, and treatment are highlighted. In order to make an early diagnosis, physicians who take care of liver transplant recipients should be aware of the characteristic features of this posttransplant lymphoproliferative disorder. Therefore, a diagnostic algorithm is proposed.

Epitope specificity and clonality of EBV-specific CTLs used to treat posttransplant lymphoproliferative disease

In a recent phase II clinical trial using banked allogeneic CTL lines to treat EBV-associated posttransplant lymphoproliferative disease, a response rate of 52% was recorded 6 mo posttreatment. Tumor response was associated with an increase in both CTL/recipient HLA matches and CD4(+) T cells within the infused CTL lines. The present study was undertaken to correlate tumor response with CTL specificity. The majority of CTL lines infused recognized EBV-encoded nuclear Ag-3 proteins, but CTL protein specificity itself did not correlate with tumor response. Specificity in conjunction with donor/recipient functional HLA matching as opposed to HLA matching alone, however, was important for tumor response. CTL receptor TCR beta-chain variable gene subfamilies were polyclonal, with no preferential use of a particular family. However, tumor response was improved in those receiving CTL lines with polyclonal vs clonal distribution for subfamilies 2, 3, and 9. Interestingly, in five of six tumors (five Hodgkin's-like and one Burkitt's-like posttransplant lymphoproliferative disease) with restricted viral gene expression a complete response was recorded, although in some cases the tumor cells did not express the proteins recognized by the infused CTL. Thus CTL were advantageous when functionally HLA matched but for certain tumor types complete responses occurred in the absence of detectable specific CTL/tumor recognition. We suggest that either the allogenic CTL contained small, undetectable, EBV-specific, HLA-matched T cell populations or perhaps they stimulated nonspecific inflammatory responses in vivo, which were beneficial for tumor regression. These observations should be considered when designing and implementing CTL therapies.

[Infections in immunosuppressed patients]

Molecular biology techniques represent a major advance in the microbiologic diagnosis of infectious diseases, since these methods are able to detect etiological microorganisms with high sensitivity. Moreover, these procedures can also establish prognostic and therapeutic efficacy markers with a sufficiently short turnaround time for the results to have a real impact on the clinical management of immunosuppressed patients. However, these techniques still have substantial limitations that should be solved in the near future: lack of standardization, inter- and intra-assay variability, the difficulty of comparing results among different laboratories and low positive predictive value, due to their high sensitivity, leading to problems in the interpretation of results. The present article reviews the usefulness of molecular biology techniques in the diagnosis and clinical management of infectious diseases caused by human cytomegalovirus, Epstein-Barr virus, human herpes viruses 6 and 7, JC and BK viruses, Toxoplasma gondii and Pneumocystis jiroveci in immunosuppressed patients.

Increased Ig-null B lymphocytes in the peripheral blood of pediatric solid organ transplant recipients with elevated Epstein-Barr viral loads

In this study, the characteristics of Ig-null B cells in high viral load carriers were examined by four-color flow cytometry. The frequency of Ig-null B cells in patients with high, low or undetectable virus loads was found that while patients with a high load had more Ig-null cells, these cells were also present in the low and undetectable load groups. As Ig-null cells from patients with no viral load were EBV-negative, EBV infection was not absolutely required for the generation or survival of Ig-null cells. Ig-null cells were CD19(+), sIg(-), CD5(-), CD10(-), CD27(-), CD23(-), CD38(-), and CD69(-) with variable surface expression of CD20 and CD40. Ig-null cells did not have a proliferating cell phenotype (Ki67(-)) and a high proportion were HLA class I(-) and class II(-). Virus copy number in CD19(+) Ig-null cell populations may be much higher than in CD19(+) Ig(+) cell populations. EBV infected Ig-null cells were common in blood specimens from pediatric solid organ transplant recipients and infected Ig-null cells may pose potential problems for immunotherapies that target infected B cells directly.

EBV-related lymphoproliferative disease complicating therapy with the anti-CD2 monoclonal antibody, siplizumab, in patients with T-cell malignancies

PURPOSE

We report an increased incidence of EBV-induced B-cell lymphoproliferative disease (LPD) in patients treated with siplizumab, an anti-CD2 antibody. The development of EBV-LPD has been associated with the use of immunosuppressive agents used in solid organ, bone marrow, and stem cell transplantation and in certain congenital immunodeficiencies.

EXPERIMENTAL DESIGN

We conducted a single-institution phase I dose-escalation trial of siplizumab, a humanized monoclonal antibody to CD2, in 29 patients with T-cell malignancies.

RESULTS

Although initial responses were encouraging, 4 (13.7%) patients developed EBV-LPD and the trial was stopped. Reductions in CD4(+) and CD8(+) cell count numbers in response to therapy were seen in all patients, but in those patients developing EBV-LPD a significantly greater reduction in natural killer (NK) cell number and CD2 expression on T cells was seen. These findings highlight the importance of NK-cell depletion and CD2 expression in addition to T-cell depletion in the etiology of EBV-LPD.

CONCLUSIONS

The emergence of EBV-LPD may be associated with the ability of siplizumab to deplete both T and NK cells without affecting B cells. Agents that deplete T- and NK-cell populations without affecting B cell number should be screened for this potentially serious adverse event.

Seeking beyond rejection: an update on the differential diagnosis and a practical approach to liver allograft biopsy interpretation

Pathologic evaluation of liver allograft biopsies plays an integral role in the management of patients after liver transplantation. This review summarizes the clinical context and classical histology of different types of allograft rejection and also the common entities that enter the differential diagnosis of allograft rejection, and provides practical approaches to liver allograft biopsy interpretation. In addition, some of the new developments in the field of liver transplant pathology are updated. The purpose of this review is to provide guidance for pathologists interpreting liver allograft biopsies, particularly those interested in developing expertise in the field of liver transplant pathology.

Endobronchial Epstein-Barr Virus Associated Post-transplant Lymphoproliferative Disorder in Hematopoietic Stem Cell Transplantation

The Epstein-Barr virus (EBV) associated Post-Transplant Lymphoproliferative Disorders (PTLD) are increasingly recognized as a fatal complication of hematological stem cell transplantation (HSCT). Thoracic involvement, that may be isolated or part of a disseminated disease, usually encompasses pulmonary nodules or masses and mediastinal lymph node enlargement.

The current case study presents 2 patients who underwent HSCT, one allogenic and the other autologous, who developed an exceptional endobronchial EBV related PTLD. The first patient had a fleshy white endobronchial mass resulting in a right upper lobe atelectasis and the second had an extensive necrotising mucosa from trachea to both basal bronchi without any significant change of lung parenchyma on the CT scan. In both cases, the diagnosis was made by bronchial biopsies. Physicians should be aware of an endobronchial pattern of EBV associated PTLD after HSCT to permit quick diagnosis and therapeutic intervention.

Viruses

Viral infections are an important and often unrecognized component of disease in immunocompromised patients. The diagnosis and management of viral infections have expanded largely because of new quantitative molecular diagnostic assays. Well-recognized pathogens such as herpes simplex virus (HSV), cytomegalovirus (CMV), and respiratory viruses have been joined by newly recognized pathogens such as BK virus, human herpesvirus-6 (HHV-6), and human metapneumovirus in this highly susceptible patient population. The role of Epstein-Barr virus (EBV) and Human herpesvirus-8 (HHV-8) in lymphoproliferative diseases also continue to be clarified. As a result, the management of viral infections in patients with hematologic malignancies continues to be a growing challenge for the clinician.

Neurologic complications after solid organ transplantation

Neurologic complications are common after solid organ transplantation and are associated with significant morbidity. Approximately one-third of transplant recipients experiences neurologic alterations with incidence ranging from 10% to 59%. The complications can be divided into such of those common to all types of transplant and others of those specific to transplanted organ. The most common complication seen with all types of transplanted organ is neurotoxicity attributable to immunosuppressive drugs, followed by seizures, opportunistic central nervous system (CNS) infections, cardiovascular events, encephalopathy and de novo CNS neoplasms. Amongst immunosuppressants, calcineurin inhibitors are the main drugs involved in neurotoxicity, leading to complications which ranges from mild symptoms, such as tremors and paresthesia to severe symptoms, such as disabling pain syndrome and leukoencephalopathy. Neurologic complications of liver transplantation are more common than that of other solid organ transplants (13-47%); encephalopathy is the most common CNS complication, followed by seizures; however, central pontine myelinolysis can appear in 1-8% of the patients leading to permanent disabilities or death. In kidney transplanted patients, stroke is the most common neurologic complication, whereas cerebral infarction and bleeding are more typical after heart transplantation. Metabolic, electrolyte and infectious anomalies represent common risk factors; however, identification of specific causes and early diagnosis are still difficult, because of patient's poor clinical status and concomitant systemic and metabolic disorders, which may obscure symptoms.

Abdominal involvement in pediatric heart and lung transplant recipients with posttransplant lymphoproliferative disease increases the risk of mortality

BACKGROUND

Posttransplant lymphoproliferative disease (PTLD) is a serious complication in transplant recipients. Abdominal PTLD has been reported, but the prognosis remains undefined. The purpose of this study was to identify the incidence, predisposing factors, and outcome of abdominal PTLD in pediatric cardiothoracic transplant patients.

METHODS

Retrospective chart review of 134 transplant patients (50 heart, 77 lung, 7 heart/lung) at our institution (1995-2005).

RESULTS

Posttransplant lymphoproliferative disease was diagnosed in 14 patients. Most were Epstein-Barr virus naive initially, but all had seroconverted when diagnosed with PTLD. Eight had abdominal involvement; 4 required surgical interventions-1 for intussusception and for bowel perforation, 2 for bowel perforation, and 1 for tumor debulking. All had lifelong follow-up, with an average follow-up of 3 years. Of 8 patients with abdominal PTLD, 4 died of complications related to PTLD, whereas 1 of 6 patients with extraabdominal PTLD died of PTLD.

CONCLUSIONS

Epstein-Barr virus infection after transplantation is a major risk factor for PTLD. Pediatric patients with PTLD who present with abdominal involvement are more likely to die of PTLD than those without abdominal disease. Delay in diagnosis may contribute to the high mortality. Therefore, prompt evaluation and surveillance for possible abdominal PTLD may decrease mortality associated with this devastating problem.

Immunotherapy targeting EBV-expressing lymphoproliferative diseases

Epstein-Barr virus (EBV) is associated with non-Hodgkin's lymphoma (NHL), occurring in immunocompetent individuals as well as those with immunodeficiency. In patients with immunodeficiency, the nature of EBV infection in the malignant cell determines the pattern of antigen expression and the associated presence of targets for cellular immunotherapy. EBV-expressing lymphoma cells in the setting of immunodeficiency express type III latency, characterized by expression of all nine latent-cycle EBV antigens, and strategies to restore EBV-specific immune responses have resulted in effective anti-tumour activity. In contrast, EBV-associated NHL in immunocompetent individuals is characterized by type II latency, where a more restricted array of EBV-associated antigens is expressed. In this setting, T-cell therapies are limited by inadequate persistence of transferred T cells and by tumour-evasion strategies. A number of strategies to genetically modify the infused T cells and modulate the host environment are under evaluation.

Clinical significance of peripheral blood Epstein-Barr viral load monitoring using polymerase chain reaction in renal transplant recipients

PTLD is a complication of EBV infection. We examined the efficacy of EBV-PCR monitoring to detect early replication in an attempt to prevent EBV-associated PTLD. Blood EBV levels in 156 renal transplant recipients (58 children) from three institutions over nine yr were retrospectively analyzed. Patients who were asymptomatic and at high risk for PTLD were monitored for EBV infection by PCR or serology followed by PCR at the time of EBV seropositivity. More children than adults had positive EBV-PCR (12/58 vs. 2/98, p < 0.001). Adults remained asymptomatic and viremia resolved post-therapy. 3/12 EBV-PCR positive children developed PTLD (3/12 children vs. 0/2 adults, p = NS). Two out of three with PTLD were initially monitored by serology, and later by PCR. PTLD resolved post-therapy in all three patients. The remaining 9/12 EBV-PCR positive children stayed asymptomatic. None of the children and adults with negative EBV-PCR developed PTLD. EBV-PCR monitoring in high-risk renal transplant recipients, especially in children, may allow early diagnosis and intervention, and therefore may help in preventing EBV-associated PTLD.

Adoptive cell therapy against EBV-related malignancies: a survey of clinical results

BACKGROUND

Epstein-Barr Virus (EBV) infection is associated with a heterogeneous group of tumors, including lymphoproliferative disorders, Hodgkin's disease, nasopharyngeal carcinoma and Burkitt's lymphoma. As such neoplastic disorders express viral antigens, they can be treated by adoptive immunotherapy strategies relying mostly on in vitro generation and expansion of virus-specific cytotoxic T lymphocytes (CTL), which can be administered to patients for both prophylaxis and treatment.

OBJECTIVE

We reviewed results obtained in all clinical trials reported thus far employing anti-EBV adoptive immunotherapy for different virus-related malignancies.

METHODS

'PTLD after HSCT', 'PTLD after SOT', 'NPC', 'HD', 'SCAEBV' and 'extranodal NK/T cell lymphoma', in combination with 'Adoptive immunotherapy' and 'Adoptive transfer', were used as search keys for papers in PubMed.

CONCLUSIONS

Although the heterogeneity of different studies precludes their collection for a meta-analysis, it can be inferred that adoptive therapy with EBV-specific CTL is safe, well tolerated and particularly effective in the case of most immunogenic tumors, like post-transplant lymphoproliferative disease.

EBV-associated lymphoproliferative disorders: classification and treatment

Since its discovery as the first human tumor virus, Epstein-Barr virus (EBV) has been implicated in the development of a wide range of B-cell lymphoproliferative disorders, including Burkitt's lymphoma, classic Hodgkin's lymphoma, and lymphomas arising in immunocompromised individuals (post-transplant and HIV-associated lymphoproliferative disorders). T-cell lymphoproliferative disorders that have been reported to be EBV associated include a subset of peripheral T-cell lymphomas, angioimmunoblastic T-cell lymphoma, extranodal nasal type natural killer/T-cell lymphoma, and other rare histotypes. EBV encodes a series of products interacting with or exhibiting homology to a wide variety of antiapoptotic molecules, cytokines, and signal transducers, hence promoting EBV infection, immortalization, and transformation. However, the exact mechanism by which EBV promotes oncogenesis is an area of active debate. The focus of this review is on the pathology, diagnosis, classification, and pathogenesis of EBV-associated lymphomas. Recent advances in EBV cell-based immunotherapy, which is beginning to show promise in the treatment of EBV-related disorders, are discussed.

Poor outcome in post transplant lymphoproliferative disorder with pulmonary involvement after allogeneic hematopoietic SCT: 13 years' experience in a single institute

EBV-induced post transplant lymphoproliferative disorder (PTLD) continues to be a major complication after transplantation. Between January 1993 and April 2006, 12 cases of B-cell lymphoproliferative disorder were identified among 577 patients after allogeneic hematopoietic SCT (HSCT) with an overall incidence of 2.51% at 1 year. Grades II-IV acute GVHD, CMV antigenemia and the use of antithymocyte globulin (ATG) were independent risk factors for PTLD. At diagnosis, all of the tumors were CD20-positive and 11 (92%) were EBV-encoded RNA (EBER)-positive. Of the 12 patients with B-cell lymphoproliferative disorder, 8 had pulmonary involvement and 10 had extranodal involvement. Eleven patients received weekly rituximab therapy at a dose of 375 mg/m(2); the median interval between the onset of symptoms and rituximab therapy was 6 days. The overall mortality rate was 92% and seven (64%) of the deaths were directly attributable to disseminated PTLD within days or weeks of presentation. In our series, pulmonary PTLD followed an extremely aggressive course and poor response to current therapy, even though rituximab was included in the therapeutic regimens.

BCL6 expression correlates with monomorphic histology in children with posttransplantation lymphoproliferative disease

Posttransplantation lymphoproliferative disease (PTLD) is a complication of organ transplantation with high mortality. Predicting response to first-line therapy, reduction of immune suppression, is difficult because of the heterogeneity of lesions and disease behavior. We sought to determine if BCL6 protein expression in PTLD cells is associated with poor outcome. In a cohort of 25 children with PTLD, 9 of the patients' tumor specimens were positive for BCL6 protein expression. Eight of 13 monomorphic lesions were BCL6 positive, compared with 1 of 11 evaluable polymorphic lesions (P=0.01). Only 1 of the patients with BCL6 expression responded to reduced immune suppression (P=0.19). Recipients of heart transplants who developed PTLD had reduced overall survival rates compared with recipients of other organ transplants who developed PTLD (P=0.04).

EBV reactivation and post transplant lymphoproliferative disorders following allogeneic SCT

Fatal problems encountered in allogeneic stem cell transplantation include EBV reactivation and post transplant lymphoproliferative disorders (PTLDs) with high mortality rates. We performed a retrospective analysis in all consecutive adult and pediatric EBV reactivations and PTLD during a period of 8.5 years. There were 26 patients with EBV reactivation/PTLD out of a total of 854 transplantations giving an overall incidence of 3.0%. Specifically, the incidence of EBV-PTLD was 1.3%, whereas that of EBV reactivation was 1.8%. Median age was 46.0 and 11.0 years in the adult and pediatric patients, respectively. There were high rates (54%) of concomitant bacterial, viral, fungal and parasitic infections at the time of EBV manifestation. Variable treatment regimens were applied including in most cases an anti-CD20 regimen often in combination with virustatic compounds, polychemotherapy or donor lymphocytes. The mortality rates were 9 of 11 (82%) in patients with EBV-PTLD and 10 of 15 (67%) in patients with reactivation. Only 7 of 26 patients (27%) are alive after a median follow-up of 758 days (range 24-2751). The high mortality rates of EBV reactivation and of EBV-PTLD irrespective of multimodal treatment approaches emphasize standardization and optimization of post transplant surveillance and treatment strategies to improve control of these often fatal complications.

Screening for PTLD in lung and heart-lung transplant recipients by measuring EBV DNA load in bronchoalveolar lavage fluid using real time PCR

Pediatric L-HLTx recipients are at risk for developing PTLD with the lung being a primary site of disease. We hypothesized that BALF is a better sample than peripheral blood for measuring EBV DNA load in this high-risk population. Archived BALF specimens from pediatric L-HLTx recipients with and without PTLD were assayed for EBV DNA load using a quantitative real time TaqMan PCR assay. These values were compared with values determined in peripheral blood by a competitive PCR assay. Fifty-five BALF specimens from 16 L-HLTx patients were evaluated. Three patients with PTLD had mean BALF EBV DNA load values almost 50-fold higher than subjects without PTLD (4.6 x 10(5) copies/mL vs. 1.0 x 10(4) copies/mL). Patients who were EBV seronegative pretransplantation (i.e., high risk for PTLD) had elevated EBV DNA load values vs. patients who were EBV seropositive pretransplantation, regardless of the diagnosis of PTLD (mean values of 3.2 x 10(5) copies/mL vs. 1.1 x 10(4) copies/mL). Lastly, BALF analysis identified all subjects with PTLD, whereas peripheral blood analysis identified only one of these cases. Therefore, it can be concluded that monitoring EBV DNA load in BALF following L-HLTx facilitates detection of PTLD in high-risk patients and may be superior to peripheral blood assays.

Monitoring of Epstein-Barr virus load after hematopoietic stem cell transplantation for early intervention in post-transplant lymphoproliferative disease

Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disease is a life-threatening complication following hematopoietic stem cell transplantation. A quantitative polymerase chain reaction to evaluate EBV-genome copy numbers based on a nested polymerase chain reaction and an end-point dilution was used. Applying this assay EBV load was prospectively screened weekly in 123 patients after transplantation. The results demonstrate that EBV reactivations with more than 1,000 EBV-genome copies measured in 10(5) peripheral blood mononuclear cells were observed in 31 patients (25.2%). Three patients developed lymphoproliferative disease with extremely high EBV-genome copies in peripheral blood mononuclear cells (>100,000 copies/10(5) cells) and plasma. After combined antiviral and immune therapy two of three patients showed a dramatic decrease of EBV load and survived, while the third patient died of lymphoma. A subclinical EBV reactivation was observed in 24 cases (19.5%) with EBV-genome copies in 10(5) peripheral blood mononuclear cells ranging between 2,500 and mostly 10,000. After reduction of immunosuppression the EBV levels normalized. In four patients, the high copy number of > or =80,000 copies/10(5) peripheral blood mononuclear cells and plasma positivity prompted us to start pre-emptive therapy with rituximab and cidofovir for prevention of lymphoproliferative disease. After drug administration the high EBV load was reduced remarkably. Ninety-two patients (74.8%) who had < or =1,000 copies/10(5) peripheral blood mononuclear cells did not develop EBV-associated lymphoproliferative disease. In conclusion, monitoring of EBV load is a sensitive and useful parameter in the surveillance of EBV reactivation for early intervention in EBV-associated lymphoproliferative disease as well as for follow-up of the efficacy of therapy.

Diffuse large B-cell lymphoma in a renal allograft associated with Epstein-Barr virus in the recipient: a case report and a review of lymphomas presenting in a transplanted kidney

The purpose of this review was to evaluate the case reports with lymphoproliferative disorders exclusively localized in the allograft transplanted kidney. We also report a rare case of diffuse large B-cell lymphoma originated from the lymphocytes of the recipient with exclusive localization in the kidney allograft. We searched the medical literature for case reports of this condition. We found only 16 cases of lymphoma presenting in the kidney allograft without systemic affectation. The most frequent clinical manifestations were graft dysfunction and fever. In the majority of patients included in this review, the diagnosis was established from the tissue of explanted allograft. Seven patients were diagnosed with B-cell lymphoma, and the relationship with Epstein-Barr virus could only be demonstrated in four patients. However, the outcome was satisfactory in all cases, except in one case in which death was not related with the lymphoma etiology. Health care providers should be aware of this clinical entity and heightened index of suspicion should be used so as not to delay diagnosis and not to lose the allograft.

Primary cutaneous Epstein-Barr virus–related lymphoproliferative disorders in 4 immunosuppressed children

Primary cutaneous Epstein-Barr virus-related lymphoproliferative disorders are rare. We describe 4 cases in children: two with acquired immunodeficiencies (HIV infection, heart transplantation) and two with congenital immunodeficiencies (ataxia-telangiectasia and an undetermined disease affecting the T lymphocytes). Two of the lymphoproliferative disorders were T-cell types and two were B-cell types. The two T-cell types were also Epstein-Barr virus positive, which is extremely rare. Three of the patients developed extracutaneous disease with poor outcome, resulting in death.

The management of posttransplant lymphoproliferative disorder

Posttransplant lymphoproliferative disorder (PTLD) is a life-threatening complication of allogeneic hematopoietic stem cell and solid organ transplantation. Most cases are EBV-positive B-cell neoplasms, which occur in the setting of pharmacologically impaired cellular immunity. Several different treatment strategies including cytotoxic antitumor therapy, anti-B-cell monoclonal antibody therapy, antiviral therapy, and modalities aimed at restoration of EBV-specific cellular immunity have been employed. In addition, efforts to identify patients at high risk for PTLD have resulted in attempts at prophylactic and preemptive therapies. In this review we discuss the available literature on differing approaches to PTLD management, identify areas in need of further investigation, and, when possible, make general recommendations. Reduction of immunosuppression remains the mainstay of first-line treatment. Accumulating evidence supports the role of rituximab as second-line therapy with cytotoxic chemotherapy reserved for specific circumstances. Further investigations are needed to better define the role of more novel and less widely available therapies such as the adoptive transfer of EBV-specific T cells and optimization of antiviral therapies.

Monomorphic post-transplant lymphoproliferative disorder of the tongue: case report and review of literature

Background

Post-transplant lymphoproliferative disorder (PTLD) is a spectrum of hematological diseases arising in context of immunosuppression after organ transplantation. PTLD can involve any organ; however, it is extremely rare in oral cavity.

Methods

Using morphologic and immunophenotypic approaches we have studied a case of monomorphic PTLD of the tongue that developed in a patient following unilateral kidney and pancreas transplantation on immunosuppressive therapy. Additionally, cases of PTLD in the oral cavity were reviewed in the English literature.

Results

The neoplasm showed large cell morphology and B-cell phenotype. In situ hybridization for Epstein-Barr virus was positive. Complete remission was obtained after decreasing immunosuppressive therapy. The patient remained in remission at 790 days' follow up.

Conclusion

This rare case increased our awareness of PTLD in the oral cavity of patients following solid organ transplantation and immunosuppressive therapy.

25 years of live related renal transplantation in children: The Buenos Aires experience

The number of pediatric patients with end stage renal disease (ESRD) has been steadily growing during the last 10 years all over the world, because of the improvement of medical and surgical treatment of severe urologic malformations and congenital and acquired nephrological disorders. Kidney transplantation (Tx) with a live related donor continues to be the gold standard therapy to treat ESRD in children because of the best final results, the chronic lack of cadaveric donors and the frequent possibility of young patients to have parents or relatives as a source of a potential graft donor.Nowadays almost every pediatric patient can be dialyzed and transplanted, even early in life, if he or she has the possibility of a live related donor. Improvements in pediatric anesthesiology and intensive care have also been very important, in reducing the morbidity and mortality related to Tx procedures.Here we report our experience with Tx for the last 25 years, specially our long experience of live related donor transplantation in children and adolescents with emphasis on technical issues in small children and pediatric patients with severe urologic malformations and bladder dysfunction. We'll make special considerations on the improvement in short and long follow-up with the actual prevention and treatment of graft rejection, due to the new immunosuppressive agents and protocols.

Immunosuppression of the elderly kidney transplant recipient

The growing number of elderly patients with end-stage kidney disease awaiting transplantation has resulted in a corresponding rise in the number of elderly transplant recipients. In this paper, we review existing literature on age-related changes, transplant outcomes, and complications in the elderly in an attempt to propose a tailored approach to immunosuppression management in this group of patients. Despite the fact that the benefit of transplantation in the elderly is well established, clinical trials evaluating the safety and efficacy of immunosuppression regimens are lacking. Until such data exists, immunosuppression of the elderly transplant recipient should be based on the traditional principles which guide all transplant protocols and consideration of factors that are unique to the elderly. There are limited data regarding age-related changes in immune function and metabolism of immunosuppression agents in this population. Results of registry data analyses suggest that the risk of acute rejection decreases with age; however, the impact of acute rejection on long-term allograft function is greater in this population. There is also an increased risk of infection and adverse events posttransplantation among these patients. Elderly patients are more likely to receive organs from extended criteria donors and the impact of donor factors on transplant outcomes must therefore be considered. Taking these factors into consideration, we propose an approach to immunosuppression in the elderly based on individual risk stratification of treatment failure and the potential for adverse events.

Infection in renal transplant recipients

Renal transplant recipients are susceptible to infection by a wide array of pathogens. Impaired inflammatory responses due to immunosuppressive therapies suppress clinical and radiologic findings engendered by microbial invasion. As a result, patients are often minimally symptomatic and evaluation and diagnosis are delayed. Specific microbiologic diagnosis is essential both for the optimization of antimicrobial therapy and to avoid unnecessary drug toxicities. Differential diagnosis is guided by knowledge of organisms commonly involved in infection in immunocompromised hosts and understanding of the limitations of prophylactic strategies. The risk of infection in the organ transplant recipient is determined by the interaction between the individual's epidemiologic exposures and net state of immunosuppression. Epidemiology includes environmental exposures in the community and hospital, organisms derived from donor tissues and latent infections activated in the host during immune suppression. The net state of immune suppression is determined by the interaction of all factors contributing to infectious risk. Routine antimicrobial prophylaxis is aimed at common infections and unique risk factors in individual patient groups. This includes trimethoprim-sulfamethoxazole (for Pneumocystis, Toxoplasma, most Nocardia and Listeria, common urinary pathogens), perioperative (eg, anti-fungal prophylaxis for pancreas transplants), or antiviral (for herpesviruses in high risk recipients).

Quantitative real-time polymerase chain reaction for evaluating DNAemia due to cytomegalovirus, Epstein-Barr virus, and BK virus in solid-organ transplant recipients

Testing for cytomegalovirus-, Epstein-Barr virus-, and BK virus-specific gene targets in specimens from solid-organ transplant recipients for DNA by quantitative real-time polymerase chain reaction has been implemented in many diagnostic facilities. This technology provides rapid, accurate, and reproducible results for early detection, monitoring, and medical management of patients with these infections. Because these assays are becoming commonly used in clinical practice, the technical variables associated with specimen processing (e.g., nucleic acid extraction, gene target, and result reporting), amplification, and unique patient characteristics (e.g., age, sex, underlying diseases, immune status, and immunosuppressive regimens received) are factors that may influence the understanding and interpretation of test results. We emphasize the need for standardization of existing variables through parallel comparative and proficiency testing, uniform units for expressing results, to provide for clinical correlation with the results of these molecular assays.

Risk Assessment of Immunosuppressive Therapy in Facial Transplantation

BACKGROUND

Immunosuppression-related risks are foremost among ethical concerns regarding facial transplantation. However, previous risk estimates are inaccurate and misleading, because they are based on data from studies using different immunosuppression regimens, health status of the transplant recipients, tissue composition, and antigenicity. This review provides a comprehensive risk assessment for facial transplantation based on comparable data of immunosuppression, recipient health status, and composition and antigenicity of the transplanted tissue.

METHODS

The risk estimates for face transplantation presented here are based on data reported in clinical kidney (10-year experience) and hand transplantation (5-year experience) studies using tacrolimus/mycophenolate mofetil/corticosteroid therapy. Mitigating factors including ease of rejection diagnosis, rejection reversibility, infection prophylaxis, patient selection, and viral serologic status are taken into account.

RESULTS

Estimated risks include acute rejection (10 to 70 percent incidence), acute rejection reversibility (approximating 100 percent with corticosteroid therapy alone), chronic rejection (<10 percent over 5 years), cytomegalovirus disease (1 to 15 percent), diabetes (5 to 15 percent), hypertension (5 to 10 percent), and renal failure (<5 percent).

CONCLUSIONS

A review of these data indicates that previously reported estimates of immunosuppression-related risks are outdated and therefore should no longer be used. These updated risk estimates should be used by facial transplant teams, institutional review boards, and potential recipients when considering the immunologic risks associated with facial transplantation.

Immunosuppressive therapy and malignancy in organ transplant recipients: a systematic review

Post-transplant malignancy is recognised as being a major limitation to the success of solid organ transplantation and it is currently considered one of the unavoidable costs of long-term immunosuppressive therapy. However, the continual introduction of new immunosuppressive drugs and the growing knowledge about their different oncogenic profiles, requires a continuous evaluation of the available evidence on this topic. The incidence and risk of malignancy is elevated in solid organ transplant recipients compared with the general population. As proof of the relationship between immunosuppressive therapy and post-transplant malignancy, epidemiological data reveal that the length of exposure to immunosuppressive therapy and the intensity of therapy are clearly related to the post-transplant risk of malignancy, and that once cancer has developed, more intense immunosuppression can translate into more aggressive tumour progression in terms of accelerated growth and metastasis and lower patient survival. The association between malignancy and immunosuppressive therapy is mediated through several pathogenic factors. Indirectly, immunosuppressive drugs greatly increase the post-transplant risk of malignancy by impairing cancer surveillance and facilitating the action of oncogenic viruses. However, the direct pro- and anti-oncogenic actions of immunosuppressants also play an important role. The cancer-promoting effect of calcineurin inhibitors, independently of depressed immunosurveillance, has been demonstrated in recent years, and currently only mammalian target of rapamycin (mTOR) inhibitors have shown simultaneous immunosuppressive and antitumour properties. Reports of the initial results of the reduced incidence of cancer in organ transplant recipients receiving mTOR inhibitor therapy strongly indicate separate pathways for pharmacological immunosuppression and oncogenesis. The role of mTOR inhibitors has been firmly established for the treatment of post-transplant Kaposi's sarcoma and its role in the management of patients with other post-transplant malignancies should be clarified as soon as possible. Prevention of morbidity and mortality resulting from post-transplant malignancy should become a main endpoint in solid organ transplant programmes, and the choice and management of immunosuppressive therapy in each phase of transplantation plays a central role in this objective. Although comprehensive and rigorous information about the management of immunosuppressive therapy in transplant recipients at risk of or affected by cancer is still lacking, new experimental and clinical data about mTOR inhibitors offers novel approaches to this problem.

Ex vivo generation of cytokine-induced killer cells (CD3+ CD56+) from post-stem cell transplant pediatric patients against autologous-Epstein-Barr virus-transformed lymphoblastoid cell lines

EBV-PTLDs affect as high as 20% of SCT recipients especially those with T-cell depleted grafts while high mortality rates were also noted. Adoptive allogeneic and autologous CTLs have a therapeutic potential in this setting. However, the process of expansion of these cells is tedious and time consuming in both allogeneic and autologous CTL generation. For the allogeneic SCT, another major obstacle is unavailability of donors especially in an unrelated SCT setting. The aim of the present study was therefore to investigate the efficacy of autologous CIK cells (CD3+ CD56+) against autologous EBV-LCLs from post-SCT pediatric patients. We could demonstrate that CIK cells can be generated within two wk and did show the significant cytotoxicity against autologous EBV-LCLs. CIK cells may provide a potent tool for use in post-transplantation adoptive immunotherapy.

Post-transplant lymphoproliferative disease and other Epstein-Barr virus diseases in allogeneic haematopoietic stem cell transplantation after introduction of monitoring of viral load by polymerase chain reaction

The clinical value of monitoring of Epstein-Barr virus (EBV) viraemia by quantitative polymerase chain reaction during 1 y was evaluated. 39 recipients of allogeneic hematopoietic stem cell transplantation (SCT) were followed. More than 100 EBV genome equivalents (gEq)/ml in blood or plasma were found in 16/39 patients (41%) at 34 d (range 1-139) post-transplant. Seven of these 16 patients developed EBV disease; 3 post-transplant lymphoproliferative disease (PTLD), 1 myelitis, 1 encephalitis and 2 reactivations with fever. EBV diseases were only found in the high-risk group among recipients of mismatched related or unrelated donor grafts or in patients who underwent reduced-intensity conditioning. In this group, 3/20 (15%) developed PTLD. Conditioning with antithymocyte globulin was significantly associated with EBV disease (p<0.01). EBV load in plasma was more strongly associated with EBV disease than viral load in blood. A cut-off level of 1000 gEq/ml plasma distinguished EBV disease from asymptomatic viraemia, but not PTLD from other EBV diseases. Weekly monitoring of EBV load in plasma in high-risk patients in the first 3 months following SCT seems to be of value for prediction of EBV disease. Therapy for PTLD including rituximab was evaluated during 2 y and showed response in 4/6 cases.

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.

Epstein–Barr virus infection as a complication of transplantation of a nerve allograft from a living related donor

✓Reconstruction of extensive nerve defects is hampered by the amount of autogenous nerve tissue available for transplantation and by donor site morbidity. Nerve allografts, being of foreign origin and potentially unlimited in supply, provide a solution to these problems. Studies have shown that nerve allotransplants require immunosuppression only until end-organ connections are made and that immunosuppressant therapy may be subsequently discontinued with no negative effect on functional outcome. Also, recent experimental and clinical focus has been on shorter periods of immunosuppression in order to reduce risk, even stopping immunosuppression after regeneration has reached the distal suture line rather than before recovery of end-organ connections. In the pediatric population, the increased disease burden and increased potential for nerve regeneration as well as the frequent availability of a living related donor make allografts all the more attractive as solutions to nerve reconstructive problems. Nevertheless, the risks of immunosuppression must not be underemphasized, and they deserve more attention in the current nerve transplantation literature.

The authors report on a child who, at the age of 1 year, received a nerve allograft from a living related donor who was positive for Epstein–Barr virus (EBV). The child quickly developed a symptomatic EBV infection concurrent with immunosuppressant drug therapy. The immunosuppression regimen was stopped prematurely, and the patient suffered only a short illness, but the EBV infection could have developed into a life-threatening posttransplant lymphoproliferative disorder (PTLD). The patient is consequently predisposed to develop PTLD and will have to be monitored for the rest of his life. This case highlights the importance of considering the potentially fatal risks associated with this elective procedure. Future studies are needed to quantify and minimize this complication. Nevertheless, it should be weighed against the potential functional benefit from using nerve allografts.

Epstein-Barr virus-associated lymphoproliferative disease in oral cavity in a renal transplant recipient: a case report

A 10-yr-old child on long-term cyclosporin immunosuppression for a renal transplant presented with gingival swelling enlargement, in a background of gingival hyperplasia. It is tempting to assume that it is a drug-related lesion; perhaps, an area of plaque-related inflammation. An incisional biopsy revealed a monomorphic B-cell post-transplant lymphoproliferative disease (PTLD). At this stage, high Epstein-Barrr virus (EBV) titres supported a diagnosis of EBV-driven PTLD. Despite discontinuation of cyclosporin and reduction of EBV viral load to undetectable levels, there was considerable enlargement of the tumour. The patient underwent six courses of cyclophosphamide, vincristine and prednisolone chemotherapy. This resulted in a dramatic reduction in the size of the right mandibular mass with complete mucosal healing intra-orally. Her renal transplant still has good function and there is no evidence of PTLD recurrence 23 months after initial diagnosis. This case illustrates that PTLD can manifest in unusual sites and in transplant recipients on cyclosporin immunosuppression it is easy to assume that any gingival hyperplasia is drug induced; however, the differential diagnosis of gingival hyperplasia should include PTLD.

EBV-specific CD8+ T cell reactivation in transplant patients results in expansion of CD8+ type-1 regulatory T cells

Posttransplantation lymphoproliferative disorders (PTLD) are life-threatening complications of solid organ transplantation, triggered by EBV infection in chronically immunosuppressed (IS) patients. Our goal is to establish DC-based protocols for adoptive immunotherapy of refractory PTLD, while understanding how the immunosuppressive drug environment may subvert DC-EBV-specific T cell interactions. Type-1 CD8(+) T cells are critical for efficient immune surveillance and control of EBV infection, whereas type-2 or Treg/type-3 responses may provide an environment conductive to disease progression. We have recently reported that chronic IS inhibits DC function in transplant patients. Here, we have analyzed the comparative ability of mature, type-1 polarized DCs (i.e. DC1) generated from quiescent transplant patients or healthy controls, to boost type-1 EBV-specific CD8(+) T cells in vitro. Our results show that unlike healthy controls, where DC1 loaded with MHC class I EBV peptides preferentially reactivate specific type-1 CD8(+) T cells, DC1 generated from transplant patients reactivate EBV-specific CD8(+) T cells that produce both IFN-gamma and IL-10, up-regulate FOXP3 mRNA, and suppress noncognate CD4(+) T-cell proliferation via cell-cell contact. These data support a novel regulatory pathway for anti-EBV T-cell-mediated responses in IS transplant patients, with implications for the design of adoptive immunotherapies in this setting.