B lymphocytes and Epstein-Barr virus: the lesson of post-transplant lymphoproliferative disorders

Applying Rituximab During the Conditioning Regimen Prevents Epstein-Barr Virus Infection Following Allogeneic Hematopoietic Stem Cell Transplant in a Children's Cohort: A Retrospective Case-Control Study

INTRODUCTION

Since hematopoietic stem cell transplant (HSCT) is an important therapy for malignant and non-malignant pediatric diseases, improving transplant-related mortality remains a challenge. Currently, rituximab, a monoclonal antibody of anti-CD20, is widely used for several post-HSCT complications. However, few studies have focused on the application of rituximab before HSCT.

METHODS

We conducted a retrospective case-control study from January 2019 to July 2021 to determine this effect in a single center. Forty-eight patients were included in the rituximab group, with a one-to-one ratio matched to the control group.

RESULTS

Both the occurrence rate and cumulative incidence rate of Epstein-Barr virus (EBV) infection were significantly lower in the rituximab group than in the without-rituximab group (10.4% vs. 33.3%, p = 0.014 and 12.2% vs. 39.3% p = 0.0026, respectively). Furthermore, without the application of rituximab was identified as a risk factor for post-HSCT EBV infection via both univariate [hazard ratio (HR) = 4.17, 95%CI (1.52-11.43), p = 0.005] and multivariate analyses [HR = 4.65, 95%CI (1.66-13.0), p = 0.003]. Although the overall survival (OS) probability of the rituximab group was comparable to the without-rituximab group, a markedly improved OS of the rituximab group was found in the malignant disease subgroup (78.9% vs. 42.1%, p = 0.032). The outcomes of graft-versus-host disease, neutrophil and platelet engraftment, other viral infections, and the reconstitution of lymphocytes showed no significant differences between the two groups.

CONCLUSIONS

The administration of rituximab before HSCT may prevent EBV infection following HSCT.

Treatment Advances in EBV Related Lymphoproliferative Diseases

Epstein Barr virus (EBV) can affect 90% of the human population. It can invade B lymphocytes, T lymphocytes and natural killer cells of the host and remain in the host for life. The long latency and reactivation of EBV can cause malignant transformation, leading to various lymphoproliferative diseases (LPDs), including EBV-related B-cell lymphoproliferative diseases (EBV-B-LPDs) (for example, Burkitt lymphoma (BL), classic Hodgkin's lymphoma (cHL), and posttransplantation and HIV-related lymphoproliferative diseases) and EBV-related T-cell lymphoproliferative diseases (EBV-T/NK-LPDs) (for example, extranodal nasal type natural killer/T-cell lymphoma (ENKTCL), aggressive NK cell leukaemia (ANKL), and peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS). EBV-LPDs are heterogeneous with different clinical features and prognoses. The treatment of EBV-LPDs is usually similar to that of EBV-negative lymphoma with the same histology and can include chemotherapy, radiotherapy, and hematopoietic stem cell transplant (HSCT). However, problems such as serious toxicity and drug resistance worsen the survival prognosis of patients. EBV expresses a variety of viral and lytic proteins that regulate cell cycle and death processes and promote the survival of tumour cells. Based on these characteristics, a series of treatment strategies for EBV in related malignant tumours have been developed, such as monoclonal antibodies, immune checkpoint inhibitors, cytotoxic T lymphocytes (CTLs) and epigenetic therapy. These new individualized therapies can produce highly specific killing effects on tumour cells, and nontumour cells can be protected from toxicity. This paper will focus on the latest progress in the treatment of EBV-LPDs based on pathological mechanisms.

EBV-Driven Lymphoproliferative Disorders and Lymphomas of the Gastrointestinal Tract: A Spectrum of Entities with a Common Denominator (Part 3)

EBV is the first known oncogenic virus involved in the development of several tumors. The majority of the global population are infected with the virus early in life and the virus persists throughout life, in a latent stage, and usually within B lymphocytes. Despite the worldwide diffusion of EBV infection, EBV-associated diseases develop in only in a small subset of individuals often when conditions of immunosuppression disrupt the balance between the infection and host immune system. EBV-driven lymphoid proliferations are either of B-cell or T/NK-cell origin, and range from disorders with an indolent behavior to aggressive lymphomas. In this review, which is divided in three parts, we provide an update of EBV-associated lymphoid disorders developing in the gastrointestinal tract, often representing a challenging diagnostic and therapeutic issue. Our aim is to provide a practical diagnostic approach to clinicians and pathologists who face this complex spectrum of disorders in their daily practice. In this part of the review, the chronic active EBV infection of T-cell and NK-cell type, its systemic form; extranodal NK/T-cell lymphoma, nasal type and post-transplant lymphoproliferative disorders are discussed.

[The diagnostic value of whole blood Epstein-Barr virus DNA load in lymphoproliferative diseases after allogeneic hematopoietic stem cell transplantation]

Objectives: To investigate the diagnostic value of whole blood quantitative PCR for DNA load of Epstein-Barr virus (EBV) in post-transplant lymphoproliferative disease (PTLD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) . Methods: A total of 694 patients with hematologic diseases who underwent allo-HSCT at the Hematology Department of Peking University First Hospital from April 2004 to April 2019 were included, and their data were retrospectively analyzed. Results: ①Among the 694 cases, 29 cases (22 males and 7 females, with a median age of 22 (1-52) years) developed PTLD after allo-HSCT with a cumulative incidence of 4.2% and a median onset time of 2.1 (0.8-20.6) months. ② Univariate analysis showed that age<30 years, diagnosis with aplastic anemia, human leukocyte antigen (HLA) mismatch, use of antithymocyte globulin (ATG) in preconditioning regimens, and EBV reactivation were the risk factors for the occurrence of PTLD. Multivariate analysis showed that EBV reactivation was an independent risk factor for the occurrence of PTLD. ③Further analysis of EBV reactivation cases showed that the peak value of EBV-DNA load was significantly higher in the PTLD group than that in the non-PTLD group (P<0.001) and the incidence of PTLD increased with the increase of EBV-DNA load. Receiver operating characteristic (ROC) curve analysis indicated that PTLD was more likely to be diagnosed when the EBV-DNA load was >1.19×10(6) copies/ml (sensitivity 0.800 and specificity 0.768) . ④All patients with PTLD received rituximab-based treatment, with an overall response rate of 86.2% and an overall survival rate of 54.3%. Conclusion: The PTLD occurrence after allo-HSCT is highly correlated with EBV reactivation, and the higher the EBV-DNA load, the greater the risk of PTLD occurrence. The dynamic monitoring of EBV-DNA load plays an important role in predicting PTLD occurrence.

Exosomes derived from Vδ2-T cells control Epstein-Barr virus-associated tumors and induce T cell antitumor immunity

Treatment of life-threatening Epstein-Barr virus (EBV)-associated tumors remains a great challenge, especially for patients with relapsed or refractory disease. Here, we found that exosomes derived from phosphoantigen-expanded Vδ2-T cells (Vδ2-T-Exos) contained death-inducing ligands (FasL and TRAIL), an activating receptor for natural killer (NK) cells (NKG2D), immunostimulatory ligands (CD80 and CD86), and antigen-presenting molecules (MHC class I and II). Vδ2-T-Exos targeted and efficiently killed EBV-associated tumor cells through FasL and TRAIL pathways and promoted EBV antigen-specific CD4 and CD8 T cell expansion. Administration of Vδ2-T-Exos effectively controlled EBV-associated tumors in Rag2^-/-γc^-/- and humanized mice. Because expanding Vδ2-T cells and preparing autologous Vδ2-T-Exos from cancer patients ex vivo in large scale is challenging, we explored the antitumor activity of allogeneic Vδ2-T-Exos in humanized mouse cancer models. Here, we found that allogeneic Vδ2-T-Exos had more effective antitumor activity than autologous Vδ2-T-Exos in humanized mice; the allogeneic Vδ2-T-Exos increased the infiltration of T cells into tumor tissues and induced more robust CD4 and CD8 T cell-mediated antitumor immunity. Compared with exosomes derived from NK cells (NK-Exos) with direct cytotoxic antitumor activity or dendritic cells (DC-Exos) that induced T cell antitumor responses, Vδ2-T-Exos directly killed tumor cells and induced T cell-mediated antitumor response, thus resulting in more effective control of EBV-associated tumors. This study provided proof of concept for the strategy of using Vδ2-T-Exos, especially allogeneic Vδ2-T-Exos, to treat EBV-associated tumors.

Hemophagocytic lymphohistiocytosis is a sign of poor outcome in pediatric Epstein-Barr virus-associated post-transplant lymphoproliferative disease after allogeneic hematopoietic stem cell transplantation

EBV-related PTLD developing after HSCT is a potentially life-threatening disease. HLH is uncommon after allogeneic HSCT. Data on outcome of patients with PTLD and concomitant HLH after allogeneic HSCT are limited. In this retrospective study, we collected demographic, clinical, laboratory, and outcome data for 408 patients who underwent allogeneic HSCT from 2006 to 2015. Graft source included CB (n = 135; 33.1%), PBSCs (n = 34; 8.3%), and BM (n = 239; 58.6%). Eight out of 408 patients (2%) developed EBV-PTLD with a median age at HSCT of 5.9 years (range: 2.3-17.3). All eight patients received ATG as part of the conditioning regimen. Graft source was PBSC in three patients (37.5%), BM in four patients (50%), and CB in one patient (12.5%). Donors were matched unrelated in five patients (62.5%) and matched sibling in three patients (37.5%). Seven out of eight patients developed EBV-PTLD within the first 100-day post-HSCT. Lymph node biopsy revealed early lesions in three patients, polymorphic in three patients, and monomorphic PTLD in two patients. Three patients (37.5%) died within 1 month of EBV-PTLD diagnosis. All deceased patients developed HLH manifestations with two of them meeting HLH diagnostic criteria and one having an incomplete workup. PTLD after allogeneic HSCT with manifestations of HLH is associated with high mortality. Early identification and treatment of EBV-PTLD seems imperative to control the disease, especially if signs of HLH are evolving.

Immunologic effects of chronic administration of tofacitinib, a Janus kinase inhibitor, in cynomolgus monkeys and rats - Comparison of juvenile and adult responses

Tofacitinib, an oral Janus kinase (JAK) inhibitor for treatment of rheumatoid arthritis, targets JAK1, JAK3, and to a lesser extent JAK2 and TYK2. JAK1/3 inhibition impairs gamma common chain cytokine receptor signaling, important in lymphocyte development, homeostasis and function. Adult and juvenile cynomolgus monkey and rat studies were conducted and the impact of tofacitinib on immune parameters (lymphoid tissues and lymphocyte subsets) and function (T-dependent antibody response (TDAR), mitogen-induced T cell proliferation) assessed. Tofacitinib administration decreased circulating T cells and NK cells in juvenile and adult animals of both species. B cell decreases were observed only in rats. These changes and decreased lymphoid tissue cellularity are consistent with the expected pharmacology of tofacitinib. No differences were observed between juvenile and adult animals, either in terms of doses at which effects were observed or differential effects on immune endpoints. Lymphomas were observed in three adult monkeys. Tofacitinib impaired the primary TDAR in juvenile monkeys, although a recall response was generated. Complete or partial reversal of the effects on the immune system was observed.

Clinical Utility of Epstein-Barr Virus Viral Load Monitoring and Risk Factors for Posttransplant Lymphoproliferative Disorders After Kidney Transplantation: A Single-Center, 10-Year Observational Cohort Study

Background

Posttransplant lymphoproliferative disease (PTLD) is an important cause of morbidity and mortality in solid organ transplants. Epstein Barr virus (EBV) plays a major role in PTLD development. Guidelines recommend EBV viral load (VL) monitoring in high-risk populations in the first year.

Methods

Retrospective observational study in all adult patients who had at least 1 EBV-VL performed in the postkidney transplant (KT) period from January 2005 to December 2014 at the Policlinico Modena Hospital. We compared patients with negative EBV-DNA to patients with positive EBV-DNA and we described PTLD developed in the study period.

Results

One hundred ninety (36.3%) KT patients of 523 were screened for EBV-DNA with 796 samples. One hundred twenty-eight (67.4%) of 190 tested patients presented at least 1 positive sample for EBV. Older age, the use of sirolimus, everolimus, and steroids were associated with EBV-DNA positivity in the univariate analysis. Nine (1.7%) of 523 patients had PTLD. Incidence rate of PTLD in the KT cohort was 0.19/100 person year follow-up (95% confidence interval, 0.09-0.37). One of 9 patients developed early PTLD and was a high-risk patient. Only this PTLD case was positive for EBV. No PTLD case had an EBV-VL superior to 4000 copies/mL.

Conclusions

Our results suggest that the keystone of PTLD diagnosis is the clinical suspicion. Our study suggests that, in line with guidelines, EBV-VL assays may be avoided in low-risk patients in the absence of a strong clinical PTLD suspicion without increasing patients' risk of developing PTLD. This represents a safe and cost-saving clinical strategy for our center.

Post-transplant lymphoproliferative disorders: from epidemiology to pathogenesis-driven treatment

Post-transplant lymphoproliferative disorders (PTLDs) represent the most severe complication of both solid organ and hematopoietic stem cell transplantation. The Epstein-Barr Virus (EBV) is the main driver of PTLD, particularly those occurring early after transplantation. EBV-driven malignancies are associated with selective expression of latent viral proteins, but uncontrolled lytic replication may favor early phases of cell transformation. Besides immunodepression, persistent immune activation and chronic inflammation play an important role in both virus reactivation and expansion of EBV-infected B cells. EBV-induced immortalization requires the expression of telomerase. TERT, the rate-limiting component of the telomerase complex, is central in the switch from the lytic to the latent viral program, and TERT inhibition induces the EBV lytic cycle and cell death. Immunotherapy and combination of EBV lytic cycle inducers with antiviral drugs are promising strategies to improve the treatment of PTLD patients. This review is aimed at providing an update on the intriguing association between EBV and PTLD, mainly focusing on cases arising after kidney and liver transplantation, which account for the vast majority of transplants.

High incidence of Epstein-Barr virus (EBV)-positive Hodgkin lymphoma and Hodgkin lymphoma-like B-cell lymphoproliferations with EBV latency profile 2 in children with interleukin-2-inducible T-cell kinase deficiency

AIMS

Interleukin-2-inducible T-cell kinase (ITK) deficiency is an inherited T-cell deficiency characterized by the development of Epstein-Barr virus (EBV)-associated lymphoproliferations. We aimed to describe the histopathological features of lymphoproliferative processes arising in ITK deficiency, and to compare them with lymphoproliferations in otherwise immunocompromised patients.

METHODS AND RESULTS

We revised the histopathological diagnoses of 12 biopsies of lymphoproliferations from seven ITK-deficient children according to the World Health Organization criteria, and determined the EBV latency types and lytic activity by staining for EBV-encoded small RNA, latent membrane protein 1, EBV nuclear antigen 2, and ZEBRA. We found polymorphic and borderline polymorphic to monomorphic B-cell lymphoproliferations with variable contents in large cells (five cases), a Hodgkin-like B-cell proliferation (one case), and classic mixed-cellularity Hodgkin lymphoma (six cases). All cases (12/12) were EBV-positive. The Hodgkin lymphoma-like and Hodgkin lymphoma, and all but one polymorphic B-cell lymphoproliferation, showed EBV latency type 2, as observed in classic EBV-positive Hodgkin lymphoma.

CONCLUSIONS

The 100% EBV association, the high percentage of EBV-positive classic Hodgkin lymphoma and Hodgkin-like B-cell proliferations and the predominance of EBV latency type 2 even in polymorphic lesions are the main features of lymphoproliferations in patients with ITK deficiency, and suggest a unique pathomechanism of lymphomagenesis in this T-cell immunodeficiency.

In vivo intratumoral Epstein-Barr virus replication is associated with XBP1 activation and early-onset post-transplant lymphoproliferative disorders with prognostic implications

Post-transplant lymphoproliferative disorders are life-threatening complications following hematopoietic or solid organ transplantation. They represent a spectrum of mostly EBV-driven lymphoplasmacytic proliferations. While the oncogenic effect of EBV is related to latent infection, lytic infection also has a role in lymphomagenesis. In vitro, EBV replication is linked to plasma cell differentiation and XBP1 activation, although this phenomenon has never been addressed in vivo. We analyzed for the first time latent and lytic intratumoral EBV infection in a series of 35 adult patients with a diagnosis of post-transplant lymphoproliferative disorder (26M/9F, median age 54 years). A complete EBV study was performed including the analysis of the latent EBER, latent membrane protein-11, and EBV nuclear antigens as well as the immediate-early BZLF1/ZEBRA and early BMRF1/EADE31 lytic genes. XBP1 activation was assessed by nuclear protein expression. EBV infection was observed in 28 (80%) cases being latency II and III the most frequently observed 22 (79%). Intratumoral EBV replication was detected in 17 (60%) cases. Among these, XBP1 activation was observed in 11/12 evaluable cases associated with strong cytoplasmic immunoglobulin expression consistent with plasma cell differentiation. Intriguingly, the combination of latency III infection and EBV replication identified a high-risk subgroup of patients with significantly shorter survival (overall survival at 1 year 18% vs 48%) and early-onset (median of 7 vs 26 months) post-transplant lymphoproliferative disorder. Moreover, these patients appear to be more heavily immunosuppressed, so they exhibit lower rates of rejection and graft vs host disease but higher rates of cytomegalovirus reactivation. In conclusion, EBV replication is associated with plasma cell differentiation and XBP1 activation with prognostic implications. Both latency III and lytic EBV infection are related to aggressive and early-onset post-transplant lymphoproliferative disorder. These results suggest that immunohistochemical study of latent and lytic EBV genes in the clinical practice may help to select higher-risk patients to new therapies including antiviral treatments.

Very late relapse of PTLD 10 yr after allogeneic HSCT and nine yr after stopping immunosuppressive therapy

We present a very late onset relapse of PTLD 10 yr after allogeneic HSCT in a patient in third remission for ALL, nine yr after the first episode of PTLD. The recipient was conditioned with fractionated TBI 12 Gy, cyclophosphamide, and horse ATG. The first episode of PTLD with a large retroperitoneal tumor occurred one yr after transplantation; a residual tumor infiltrating spleen and colon was resected one yr later. Due to continual pathological signals in liver and lungs, persistent fever, and an M-component in peripheral blood, a new course of four rituximab doses was given, after which the fever settled, the PET scan normalized, and the M-component disappeared. Without any ongoing immunosuppressive therapy, PTLD relapsed nine yr later with large intra-abdominal lymph node masses causing ureteric obstruction with bilateral hydronephrosis. Pathological features were identical to the primary PTLD tumor: EBV related, of donor origin, positive for CD138 and CD79 alpha, but negative for CD20 and CD19. The transcription factor PAX5 was negative but BOB1 and OCT2 were positive, consistent with plasmablastic lymphoma. The relapse was successfully treated with a combination of low dose chemotherapy and rituximab. Five yr after end of treatment, the girl has moderately reduced renal function but otherwise remains well without evidence of disease.

Impact of EBV essential nuclear protein EBNA-3C on B-cell proliferation and apoptosis

For over 40 years, EBV infection has been implicated in the etiology of a variety of lymphoid malignancies with the exceptional ability to drive resting B cells to continuously proliferate by successfully overriding cellular apoptotic stimuli. EBV utilizes the normal physiology of B-cell differentiation to persist within the memory B-cell pool of the immunocompetent host and subsequently establishes a life-long latent infection. During latency, out of a subset of viral genes expressed, EBNA-3C is one of the essential antigens required for in vitro primary B-cell transformation. EBNA-3C acts as a transcriptional coregulator by interacting with various cellular and viral factors. For the last 10 years, we have been actively engaged in discerning the biological significance of these interactions and revealed that EBNA-3C primarily targets two important cellular pathways - cell cycle and apoptosis. This review aims to summarize our current knowledge on EBNA-3C-mediated functions and describe how EBNA-3C seizes these cellular pathways that eventually promote B-cell lymphomagenesis. A scrupulous understanding of the critical relationship between EBNA-3C and these cellular machineries will not only aid in elucidating EBV pathogenesis, but also largely facilitate the development of novel diagnostic, as well as therapeutic, strategies against a vast range of EBV-associated B-cell lymphomas.

Epstein Barr virus DNA analysis in blood predicts disease progression in a rare case of plasmablastic lymphoma with effusion

Background

In HIV-1-infected patients a long lasting CD4+ cell decline influences the host-EBV balance and thereby increases the risk for EBV related malignancies. In spite of a world-wide access to combination antiretroviral therapy (cART) there are still a considerable number of HIV-1-infected patients who will develop severe immunodeficiency. These undiagnosed HIV-1 infected patients, so called late testers, demonstrate an increased lymphoma risk, compared to patients diagnosed early. Consecutive individual screening for EBV DNA-load in late testers might be a useful predictor of emerging EBV-malignancy.

Methods

Patient biopsies and ascites were analyzed morphologically, by immuncyto-histochemistry and in-situ hybridization. Viral DNA and RNA load were quantified by PCR. Cell lines from primary tumor and from ascites, were established in vitro and further analyzed.

Result

We here report on a case of EBV-positive lymphoma in an AIDS patient, first presenting with pleural effusion and ascites and was thus initially considered a primary effusion lymphoma (PEL) but was later diagnosed as a plasmablastic lymphoma (PBL). The patient had responded to cART with undetectable HIV-RNA and increased CD4 cell count one year prior to lymphoma presentation. At the time of lymphoma diagnosis the HIV-RNA values were <50 RNA-copies per mL blood (undetectable) and the CD4-positive cell count 170 ×10⁶/L. The lymphoma was CD45-negative and weakly CD22- and CD30-positive. The patient had a history of Kaposi sarcoma and HHV-8 seropositivity. The lymphoma biopsies, and three cell lines derived on different occasions from the tumor cell effusion, were all EBV-positive but HHV-8 negative.

A noticeable EBV-DNA load decline was observed during the remission of the lymphoma following CHOP-therapy. The EBV-DNA load increased dramatically at the time of recurrence.

Conclusion

EBV DNA load might be useful in monitoring the effect of lymphoma treatment as well as in estimating the risk of EBV-associated lymphoma in HIV-1 infected patients with pronounced immunosuppression.

Epidemiology of posttransplantation lymphoproliferative disorder in adult renal transplant recipients

BACKGROUND

There is little information in the literature describing the relationship between posttransplantation lymphoproliferative disorder (PTLD) incidence and presentation with both recipient Epstein-Barr virus (EBV) serostatus and EBV status of PTLD histology, particularly in the late posttransplantation period.

METHODS

This study reports the largest UK single-center, single-organ analysis of PTLD to date in a retrospective cohort study of 80 cases occurring in 4189 adult renal transplant recipients.

RESULTS

The incidence rate was 2.6 cases per 1000 patient-years (95% confidence interval [95% CI], 2.1-3.2) for PTLD, 1.8 (95% CI, 1.4-2.4) for non-Hodgkin's lymphoma, and 0.2 (95% CI, 0.07-4.2) for Hodgkin's lymphoma. Non-Hodgkin's lymphoma occurred at a rate 7.6 times that of the adult general population in England, whereas the rate for Hodgkin's lymphoma was 5.9 times. The incidence of PTLD was highest during the 10th to 14th posttransplantation years. Early-onset disease was associated with EBV-seronegative recipient status, EBV-positive histology, and the involvement of extranodal sites. PTLD occurring in EBV-seronegative recipients was associated with EBV nuclear antigen antibody deficiency, polymorphic disease, and the involvement of extranodal sites. EBV-negative histology occurred in 32% of cases at a median time to presentation of 109 months. PTLD involving the allograft, central nervous system, and skin was uncommon and occurred late.

CONCLUSION

The incidence of PTLD is highest in the late posttransplantation period. Close clinical surveillance and education for transplant recipients is required for the duration of time while immunosuppressed. Failure to detect EBV DNA in blood should not reassure, particularly in patients with symptoms such as abdominal pain, oropharyngeal complaints, neck lumps, and B-symptoms.

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

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

The effect of Epstein-Barr virus Latent Membrane Protein 2 expression on the kinetics of early B cell infection

Infection of human B cells with wild-type Epstein-Barr virus (EBV) in vitro leads to activation and proliferation that result in efficient production of lymphoblastoid cell lines (LCLs). Latent Membrane Protein 2 (LMP2) is expressed early after infection and previous research has suggested a possible role in this process. Therefore, we generated recombinant EBV with knockouts of either or both protein isoforms, LMP2A and LMP2B (Δ2A, Δ2B, Δ2A/Δ2B) to study the effect of LMP2 in early B cell infection. Infection of B cells with Δ2A and Δ2A/Δ2B viruses led to a marked decrease in activation and proliferation relative to wild-type (wt) viruses, and resulted in higher percentages of apoptotic B cells. Δ2B virus infection showed activation levels comparable to wt, but fewer numbers of proliferating B cells. Early B cell infection with wt, Δ2A and Δ2B viruses did not result in changes in latent gene expression, with the exception of elevated LMP2B transcript in Δ2A virus infection. Infection with Δ2A and Δ2B viruses did not affect viral latency, determined by changes in LMP1/Zebra expression following BCR stimulation. However, BCR stimulation of Δ2A/Δ2B cells resulted in decreased LMP1 expression, which suggests loss of stability in viral latency. Long-term outgrowth assays revealed that LMP2A, but not LMP2B, is critical for efficient long-term growth of B cells in vitro. The lowest levels of activation, proliferation, and LCL formation were observed when both isoforms were deleted. These results suggest that LMP2A appears to be critical for efficient activation, proliferation and survival of EBV-infected B cells at early times after infection, which impacts the efficient long-term growth of B cells in culture. In contrast, LMP2B did not appear to play a significant role in these processes, and long-term growth of infected B cells was not affected by the absence of this protein.

Intraocular lymphoma after cardiac transplantation: magnetic resonance imaging findings

We report a case of intraocular lymphoma in a 65-year-old man, 15 months after cardiac transplantation. On Magnetic Resonance (MR) images, the iris and the anterior chamber of the right eye were found to be involved with an enhancing soft-tissue lesion. To our knowledge, this is the first case of post-transplantation intraocular lymphoma evaluated with MR imaging.

Gastrointestinal B-cell lymphomas: From understanding B-cell physiology to classification and molecular pathology

The gut is the most common extranodal site where lymphomas arise. Although all histological lymphoma types may develop in the gut, small and large B-cell lymphomas predominate. The sometimes unexpected finding of a lymphoid lesion in an endoscopic biopsy of the gut may challenge both the clinician (who is not always familiar with lymphoma pathogenesis) and the pathologist (who will often be hampered in his/her diagnostic skill by the limited amount of available tissue). Moreover, the past 2 decades have spawned an avalanche of new data that encompasses both the function of the reactive B-cell as well as the pathogenic pathways that lead to its neoplastic counterpart, the B-cell lymphoma. Therefore, this review aims to offer clinicians an overview of B-cell lymphomas in the gut, and their pertinent molecular features that have led to new insights regarding lymphomagenesis. It addresses the question as how to incorporate all presently available information on normal and neoplastic B-cell differentiation, and how this knowledge can be applied in daily clinical practice (e.g., diagnostic tools, prognostic biomarkers or therapeutic targets) to optimalise the managment of this heterogeneous group of neoplasms.

Epidemiology and morbidity of Epstein-Barr virus infection in pediatric renal transplant recipients: a multicenter, prospective study

BACKGROUND

The epidemiology and morbidity of Epstein-Barr virus (EBV) infection in pediatric renal transplant recipients have been characterized insufficiently.

METHODS

In a prospective, multicenter study among 106 pediatric kidney allograft recipients aged 11.4 ± 5.9 years, we investigated the epidemiology of EBV infection and the relationship between EBV load, EBV serology, and EBV-related morbidity (posttransplant lymphoproliferative disease [PTLD] or symptomatic EBV infection, defined as flu-like symptoms or infectious mononucleosis).

RESULTS

EBV primary infection occurred in 27 of 43 (63%) seronegative patients and reactivation/reinfection in 28 of 63 (44%) seropositive patients. There was no association between the degree or duration of EBV load and EBV-related morbidity: The vast majority (17 of 18 [94%]) of patients with a high, persistent EBV load remained PTLD-free throughout a follow-up of 5.0 ± 1.3 years, while 2 of 3 (66%) patients with EBV-related PTLD exhibited only a low EBV load beforehand. Eight of 18 (44%) patients with a high, persistent EBV load remained asymptomatic during a follow-up of 5.3 ± 2.9 years. Multivariate analysis identified the EBV high-risk (D(+)/R(-)) serostatus (odds ratio [OR], 7.07; P < .05), the presence of human leukocyte antigen (HLA)-DR7 (OR, 5.65; P < .05), and the intensity of the immunosuppressive therapy (OR, 1.53; P < .01) as independent risk factors for the development of a symptomatic EBV infection.

CONCLUSIONS

Presence of EBV high-risk seroconstellation, HLA-DR7, and intensity of immunosuppressive therapy are significant risk factors for a symptomatic EBV infection, whereas there is no close association between the degree or duration of EBV load and EBV-related morbidity. Clinical Trials Registration. NCT00963248.

Epstein-Barr virus load and immune activation in human immunodeficiency virus type 1-infected patients

BACKGROUND

Patients infected with HIV-1 are at high risk of developing Epstein-Barr Virus (EBV)-related diseases. Chronic immune activation is a hallmark of HIV-1 pathogenesis and may play a role in B-cell stimulation and expansion of EBV-infected cells.

OBJECTIVES

The aim of the study was to define the relationship between parameters of immune activation and EBV load in HIV-1-infected subjects.

STUDY DESIGN

A total of 156 HIV-1-infected patients were studied. EBV types 1 and 2 were quantified on peripheral blood mononuclear cells by multiplex real-time PCR. Plasma levels of cytokines and lipopolysaccharide (LPS) were determined by immunoenzymatic assays. B-cell activation was analyzed by flow cytometry.

RESULTS

EBV-DNA was detected in 114 patients, and in all but 3 was EBV type 1. The median [interquartile] EBV-DNA load was 43[1-151] copies/10(5) PBMC. EBV-DNA load was higher in patients with detectable HIV-1 plasma viremia, despite good immunological status (CD4>500 cells/μl), than in patients with undetectable HIV-1 plasma viremia regardless of immunological status (46[5-136] copies/10(5) cells vs 17[1-56] copies/10(5) cells, p=0.008). Patients with high EBV-DNA load (>median value) had higher levels of LPS and proinflammatory cytokines (IL-6, IL-10 and TNF-α) than patients with low EBV load. Furthermore, percentages of activated B-cells correlated with EBV-DNA load (r(s)=0.754; p<0.001).

CONCLUSIONS

Overall, these findings indicate a strong association between HIV-1 viremia, markers of immune activation and EBV load and suggest that persistence of HIV-1 viremia and immune activation, regardless of peripheral CD4 cell depletion/repopulation, may favor expansion of EBV-infected cells and onset of EBV-related malignancies.

[Role of viral infections in immunosuppressed patients]

Ser receptor de un trasplante de órgano sólido, así como recibir tratamiento quimioterápico para una enfermedad hematólógica maligna, predispone claramente a padecer infecciones virales tanto comunes como oportunistas, de origen tanto comunitario como procedentes del donante de órganos y/o de una reactivación de un virus latente endógeno. Herpes virus y más especialmente citomegalovirus y virus de Epstein-Barr son los que con más frecuencia afectan a estos enfermos, así como los virus respiratorios. El tratamiento consiste en la combinación de reducir la inmunodepresión inducida junto con tratamiento antiviral. Se ha realizado una revisión de la literatura pormenorizada y actualizada de la epidemiología, la patogenia, las manifestaciones clínicas y la aproximación terapéutica de las infecciones virales en estos enfermos.

Role of viral infections in immunosuppressed patients

Being a solid organ and hematopoietic stem cell transplant recipient as well as receiving chemotherapy for a malignant hematological disease clearly predispose the subject to a variety of viral infections, both common and opportunistic diseases. The patient may have acquired these infections from the community as well as from the donor organ (donor-derived infections) and/or from reactivation of an endogenous latent virus. Herpes viruses and especially the cytomegalovirus and Epstein-Barr virus are among the most common of the opportunistic viral pathogens affecting these patients, in addition to respiratory viruses. Treatment consists in antiviral drug therapies combined with the reduction in the degree of the induced immunosuppression. A review of the literature has been performed in order to update the epidemiology, pathogenesis, clinical manifestations and therapeutic approach of the viral infections in these immunocompromised patients.

Lymphoproliferative disorders after solid organ transplantation-classification, incidence, risk factors, early detection and treatment options

Posttransplant lymphoproliferative disorder (PTLD) is a heterogeneous disease group of benign and malignant entities. The new World Health Organisation classification introduced in 2008 distinguishes early lesions, polymorphic, monomorphic and classical Hodgkin lymphoma-type PTLD. Based on the time of appearance, early and late forms can be identified.PTLDs are the second most frequent posttransplantation tumors in adulthood, and the most frequent ones in childhood. The incidence varies with the transplanted organ-from 1%-2% following kidney transplantation to as high as 10% following thoracic organ transplantation-due to different intensities in immunosuppression. Immunocompromised state and Epstein-Barr virus (EBV) infection are the two major risk factors.In Europe and the US approximately 85% of PTLDs are of B-cell origin, and the majority are EBV-associated. Symptoms are often unspecific; extranodal, organ manifestations and central nervous system involvement is common. Early lesions respond well to a decrease in immunosuppression. Malignant entities are treated with rituximab, chemotherapy, radiotherapy and surgical therapy. Adoptive T-cell transfer represents a promising therapeutic approach. The prognosis is favorable in early PTLD, and poor in late PTLD. Five-year survival is 30% for high-grade lymphomas. The prognosis of EBV-negative lymphomas is worse.Lowering the risk of PTLD may be achieved by low dose maintenance immunosuppression, immunosuppressive drugs inhibiting cell proliferation, and special immunotherapy (e.g. interleukin-2 inhibitors). Early detection is especially important for high risk-e.g. EBV-negative-patients, where the appearance of EBV-DNA and the increase in its titer may help.

Are antibody deficiency disorders associated with a narrower range of cancers than other forms of immunodeficiency?

Analysis of cancer risk in primary immune deficiency (PID) offers insight into the relationship between immune function and cancer. Data on Australian patients (n = 1132) notified voluntarily to the Australasian Society of Clinical Immunology and Allergy PID Registry (1990-2008) were linked with national death and cancer registries. Person-years of follow-up commenced from up to 15 years before registration on the PID Registry or January 1982, the inception of national cancer registration. Site-specific, 5-year age-, sex-, calendar year-, and state-standardized incidence ratios (SIRs) with 95% confidence intervals (95% CIs) were calculated for all cancers except nonmelanocytic skin cancer. During an average of 16 person-years follow-up, a 1.6-fold excess relative risk of cancer was observed (n = 58; SIR 1.60, 95% CI 1.22-2.07) for all PID combined. Relative risk was increased for non-Hodgkin lymphoma (n = 16; SIR 8.82, 95% CI 5.04-14.30), leukemia (n = 4; SIR 5.36, 95% CI 1.46-13.73), and stomach cancer (n = 3; SIR 6.10, 95% CI 1.26-17.84). Excess cancer risk was observed for predominantly antibody deficiencies and other well-defined immunodeficiency syndromes. Results suggest that predominantly antibody deficiencies may be associated with a narrower range of solid cancers than immunodeficiency characterized by predominantly T-cell deficiency, such as iatrogenic and HIV-related immunodeficiency, although this requires confirmation in larger cohorts.

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.

Cellular factors associated with latency and spontaneous Epstein-Barr virus reactivation in B-lymphoblastoid cell lines

EBV-immortalized B-lymphoblastoid cell lines are used as models for cellular transformation and as antigen-presenting cells in immunological assays. LCLs vary in surface markers and other phenotypic properties, but it is not known how this heterogeneity relates to the EBV life cycle. To explore correlations, we examined 62 LCLs for cellular and viral phenotypes. LCLs generated from pediatric and adult donors could similarly be categorized as either low in EBV copy number or fluctuating within a high range. High-copy status accompanied higher lytic viral gene expression and lower latent gene expression. Inhibiting lytic EBV replication did not affect cellular phenotype or lytic switch protein expression, indicating that an LCL's lytic permissivity was a stable property. Among the cellular genes overexpressed in permissive LCLs were unfolded protein response genes and plasma cell markers. Among genes overexpressed in non-permissive LCLs were transcription factors involved in maintaining B cell lineage, in particular EBF1. This study suggests previously undetected mechanisms by which cellular pathways influence the lytic reactivation of EBV.

Epidemiology of pretransplant EBV and CMV serostatus in relation to posttransplant non-Hodgkin lymphoma

BACKGROUND.: Despite the importance of non-Hodgkin lymphoma (NHL) as a posttransplant complication, the relationship between NHL and recipient seropositivity for Epstein-Barr virus (EBV) or cytomegalovirus (CMV) is incompletely understood. METHODS.: Kidney, heart, and liver transplant recipients reported to the Collaborative Transplant Study with known pretransplant EBV and CMV serostatus were analyzed in terms of clinically manifest NHL. Cox multivariate regression analysis was performed to account for a wide range of possible confounders. RESULTS.: In total, 18,682 kidney, 2042 heart, and 2616 liver transplant recipients were analyzed. Regardless of age, pretransplant EBV serostatus was significantly associated with risk of NHL in kidney transplant recipients (P<0.001). There was no significant difference in lymphoma rates according to CMV and CMV serostatus among EBV and EBV recipients (log-rank P=0.55 and P=0.57, respectively), but hospitalization for CMV disease during year 1 posttransplant was associated with subsequent NHL (hazard ratio [HR] 6.1; 95% confidence interval [CI] 2.0-18.4; P=0.001). EBV serostatus was also associated with increased risk of NHL in heart transplant patients (HR 3.6; 95% CI 1.1-11.3; P=0.031) but, contrary to expectation, not in liver recipients (HR 0.6; 95% CI 0.1-1.7; P=0.32). CONCLUSIONS.: In view of the striking increase in risk of NHL in EBV kidney transplant recipients of all ages, EBV serostatus should be determined pretransplant in all age groups. CMV serostatus was not independently associated with risk of NHL after kidney transplantation. Surprisingly, in liver transplantation, the risk of NHL was virtually unaffected by EBV serostatus.

Epstein-Barr virus-positive diffuse large B-cell lymphoma in elderly patients is rare in Western populations

In the currently published World Health Organization-Classification, the new entity of Epstein-Barr virus-positive diffuse large B-cell lymphoma of the elderly was introduced largely based on findings from East-Asian populations. Little is known about its frequency or characteristics in the West, especially in European populations. Using a tissue microarray approach, we identified 8 out of 258 diffuse large B-cell lymphoma cases fulfilling the World Health Organization criteria of an Epstein-Barr virus-positive diffuse large B-cell lymphoma of the elderly, suggesting an incidence of 3.1% in a European population. The median patient age was 65 years. The highest diagnostic sensitivity was only achieved by EBER in situ hybridization. No correlation between Epstein-Barr virus status and outcome was noted except in latency type 3 lymphomas, which had a very poor survival. Sixty-seven percent of Epstein-Barr virus-positive cases showed the presence of necrosis and 50% expressed the activation marker CD30. However, no morphological or immunohistochemical features reliably distinguished all Epstein-Barr virus-positive diffuse large B-cell lymphoma cases. Thus, to identify these Epstein-Barr virus-positive diffuse large B-cell lymphoma in the elderly, EBER in situ hybridization of all de novo diffuse large B-cell lymphoma cases of patients older than 50 years should be considered. In summary, Epstein-Barr virus-positive diffuse large B-cell lymphoma of the elderly is rare in Europeans older than 50 years. It can only be diagnosed by EBER-ISH, and its precise prognostic role is unclear. Whether routine testing of all diffuse large B-cell lymphoma patients older than 50 years can be recommended depends essentially on its clinical relevance. Future studies are needed to address this question.

Epithelial raft cultures for investigations of virus growth, pathogenesis and efficacy of antiviral agents

The organotypic epithelial raft cultures, originally developed to study keratinocytes differentiation, represent a novel approach to the study of viruses able to infect epithelial cells. Organotypic epithelial raft cultures accurately reproduce the process of epithelial differentiation in vitro and can be prepared from normal keratinocytes, explanted epithelial tissue, or established cell lines. This culture system permits cells to proliferate and fully differentiate at the air-liquid interface on a dermal-equivalent support. Normal primary human keratinocytes (PHKs) stratify and fully differentiate in a manner similar to the normal squamous epithelial tissues, while transformed cell lines exhibit dysplastic morphologies similar to the (pre)neoplastic lesions seen in vivo. This three-dimensional (3D) culture system provides an essential tool for investigations of virus growth, virus-host cell interactions, for the genetic analysis of viral proteins and regulatory sequences, and for the evaluation of antiviral agents. The 3D epithelial cultures have proven a breakthrough in the research on papillomaviruses, since their life cycle is strictly linked to the differentiation of the host epithelium. In the last years, several reports have shown the usefulness of the 3D epithelial cultures for the study of other viruses that target at least during a part of their life cycles epithelial cells. The 3D epithelial cultures allow the analysis of virus-host cell interactions in stratified epithelia that more closely resemble the in vivo situation. In this review we describe the advances on research on 3D epithelial cultures for the study of virus growth and pathogenesis of different families of viruses, including papilloma-, herpes-, pox-, adeno-, and parvoviruses.

Cancer incidence and risk factors after solid organ transplantation

Iatrogenic immunosuppression is a unique setting for investigating immune-related mechanisms of carcinogenesis. Solid organ transplant recipients have a 3-fold excess risk of cancer relative to the age- and sex-matched general population. Population-based studies utilizing cancer registry records indicate that a wide range of cancers, mostly those with a viral etiology, occur at excess rates. To date, cancer risk has predominantly been examined in adult kidney transplant recipients in Western countries. It is yet to be established whether a similar incidence profile exists in the long-term for other solid organ, pediatric and non-Western transplant recipients. The cancer incidence profile before and after kidney transplantation strongly suggests a relatively minor contribution by both preexisting cancer risk factors and the conditions underlying end-stage kidney disease, and points to a causal role for immunosuppression. Within-cohort risk factor analyses have largely been performed on cohorts with voluntary cancer notification, and very few have incorporated biomarkers of the level of immunosuppression, the current receipt of immunosuppressive agents, or genetic risk factors. Because of their markedly high risk of certain cancers, findings from comprehensive studies in transplant recipients have the potential to raise new avenues for investigation into causal mechanisms and preventive measures against immune-related and infectious causes of cancer.

Introducing mediterranean journal of hematology and infectious diseases

Mediterranean Journal of Hematology and Infectious Diseases (MJHID) is a new open access, peer-reviewed, online journal, which encompasses different aspects of clinical and translational research providing an insight into the relationship between acute and chronic infections and hematological diseases. MJHID will be a topical journal on subjects of current importance in clinical haematology and infectious diseases. Every issue should have, beside the editor in chief, a guest editor. Both editor in chief and guest editor provide to invite experts in the selected topic to performe a complete update of the arguments readily available for practising phisicians. The journal will have also a section devoted to original papers, case reports and letters to editor and Editorial comment mostly focusing on the arguments treated in the previous topical issues.

Targeted monitoring of patients at high risk of post-transplant lymphoproliferative disease by quantitative Epstein-Barr virus polymerase chain reaction

BACKGROUND

Epstein-Barr virus (EBV)-associated post-transplantation lymphoproliferative disease (PTLD) is a serious complication after allogeneic stem cell transplantation (SCT). The likelihood of PTLD is increased in the presence of specific risk factors. Monitoring of EBV DNA load and early administration of rituximab in patients with high EBV loads is recommended for high-risk patients.

METHODS

Patients at high risk of EBV-associated PTLD were defined as those showing an EBV serological mismatch between donor and recipient, those with lymphoma, those given cord blood grafts, and those with primary EBV disease before SCT. High-risk patients were prospectively monitored by weekly measurement of EBV DNA by quantitative polymerase chain reaction assay, and rituximab was given when the EBV load reached 10,000 copies/mL or symptoms were suggestive of EBV disease. During the study period (July 2005 to the end of June 2007) 131 patients underwent SCT, of whom 53 had high risk factors. A historical control group transplanted between January 2003 to the end of June 2005 was retrospectively used to evaluate the effect of the prospective monitoring strategy.

RESULTS

Of the patients, 30% were positive for EBV DNA at least once; 10% of patients with EBV DNAemia developed PTLD. Risk factors of EBV DNAemia were younger age (P=0.04), receiving transplants from mismatched family or unrelated donors (P=0.01), and acute graft-versus-host disease grades II-IV (P=0.001). The overall frequency of PTLD was 3%; 5.7% in the high-risk group and 1.3% in the standard-risk group. Previous splenectomy (P=0.046) was the only significant risk factor associated with PTLD. In the control group, 6 of 150 patients (4%) developed PTLD; 5/53 (9.4%) in the high-risk group and 1/97 (1%) in the standard-risk group. Human leukocyte antigen-mismatched donors (P<0.01) and EBV-positive donors/EBV-negative recipients (P=0.01) had a significant impact on the risk of PTLD.

CONCLUSION

A targeted monitoring strategy among patients at a high risk of EBV-associated PTLD might be helpful to decrease the risk of development of PTLD. However, larger prospective studies are needed to verify this hypothesis.

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.