Viral lymphomagenesis: from pathophysiology to the rationale for novel therapies

Relapsed Plasmablastic Lymphoma in an HIV-Infected Patient—Experience of High-Dose Chemotherapy with Autologous Stem Cell Rescue: A Case Report with Review of Literature

Plasmablastic lymphoma (PBL) is a subtype of non-Hodgkin lymphoma with dismal outcome despite multidrug chemotherapy regimen leading to high rates of disease recurrence. High-dose chemotherapy with autologous stem cell rescue (HDCT/ASCR) is an effective salvage therapy in patients with chemo-sensitive human immunodeficiency virus (HIV)-associated non-Hodgkin lymphoma. We report a case of 38 years old male with relapsed PBL associated with underlying HIV infection, who underwent HDCT/ASCR. He presented with low-grade fever and abdominal discomfort. He was evaluated with fluorodeoxyglucose positron emission tomography scan followed by omental biopsy that confirmed disease relapse. He received second-line therapy containing bortezomib and daratumumab and achieved remission (CR2). Subsequently, he underwent HDCT/ASCR. He has been clinically asymptomatic in good general condition having disease-free survival of 18 months after HDCT/ASCR. Our objective of presenting this case report is its complexity from presentation, diagnosis, and treatment. We take this opportunity to review the epidemiology and clinicopathological characteristics of PBL, as well as discuss the advancements in therapeutic options of this challenging disease.

Composite Epstein-Barr Virus-associated T-lymphoblastic and Peripheral T-cell Lymphomas: A Clonal Study

A 30-year-old woman was diagnosed with T-lymphoblastic lymphoma (T-LBL) that harbored a clonal Epstein-Barr virus (EBV) genome. At relapse, axillary lymph node adenopathy, which was diagnosed as peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), was detected. Southern blot analyses of the T-cell receptor and EBV genome revealed that the T-LBL and PTCL-NOS were clonally identical. We previously showed that CD21 acted as an entry molecule that allowed EBV into the patient's T-LBL cells. Interestingly, the PTCL-NOS cells lacked CD21 expression. Our case suggests that EBV might infect immature CD21-positive T-cells, and CD21-negative PTCL-NOS might subsequently arise through phenotypic changes.

Characterization of hepatitis B virus infection and viral DNA integration in non-Hodgkin lymphoma

Hepatitis B virus (HBV) infection has been reported to be associated with non-Hodgkin lymphoma (NHL). However, the evidence is limited to the seroepidemiological study. There is a lack of evidence showing the HBV infection and integration in NHL cells. Here, we reported that in the Shanghai area, the positive rates of serum HBsAg (OR: 3.11; 95% CI: 2.20-4.41) and HBeAg (OR: 3.99; 95% CI: 1.73-9.91) were significantly higher in patients with NHL. HBsAg, HBcAg and HBV DNA were detected in 34.4%, 45.2% and 47.0% of the NHL tissues, respectively. Furthermore, by using a high-throughput viral integration detection approach (HIVID), integrated HBV DNA was identified from 50% (6/12) HBV-related NHL tissues. There were a total of 313 HBV integration sites isolated from the NHL tissues, among which four protein-coding genes (FAT2, SETX, ITGA10 and CD63) were interrupted by HBV DNA in their exons. Seven HBV preferential target genes (ANKS1B, HDAC4, EGFLAM, MAN1C1, XKR6, ZBTB38 and CCDC91) showed significantly altered expression levels in NHL, suggesting a potential role of these genes in NHL development. Taken together, HBV integration is a common phenomenon in NHL. This finding opens up a new direction of research into the mechanistic link between HBV infection and NHL.

Mechanistic Insights into Chemoresistance Mediated by Oncogenic Viruses in Lymphomas

Viral lymphomagenesis induced by infection with oncogenic viruses, such as Kaposi’s sarcoma associated herpesvirus (KSHV), Epstein–Barr virus (EBV) and human T-cell leukemia virus (HTLV-1), represents a group of aggressive malignancies with a diverse range of pathological features. Combined chemotherapy remains the standard of care for these virus-associated lymphomas; however, frequent chemoresistance is a barrier to achieving successful long-term disease-free survival. There is increasing evidence that indicates virus-associated lymphomas display more resistance to cytotoxic chemotherapeutic agents than that observed in solid tumors. Although the tumor microenvironment and genetic changes, such as key oncogene mutations, are closely related to chemoresistance, some studies demonstrate that the components of oncogenic viruses themselves play pivotal roles in the multidrug chemoresistance of lymphoma cells. In this review, we summarize recent advances in the understanding of the mechanisms through which oncogenic viruses mediate lymphoma cell chemoresistance, with a particular focus on KSHV and EBV, two major oncogenic viruses. We also discuss the current challenges to overcome these obstacles in the treatment of virus-associated lymphomas.

The opportunistic effect of exosomes on Non-Hodgkin Lymphoma microenvironment modulation

There has been a shift in the paradigm of Non-Hodgkin lymphomas, changing from the classical genetic aberration-based model to a more complex and dynamic model involving tumor microenvironment interactions. In this instance, exosomes have emerged as important mediators in intercellular communication by providing survival and proliferation signals, licensing immune evasion and acquisition of drug resistance. The capability to transfer molecular cargo made exosomes a focus of research to understand cancer pathogenesis and its progression pathways. Several studies identified exosomes transporting tumor-released components in peripheral blood and focused on understanding their clinical relevance in the diagnosis, prognostic and in monitoring cancer progression. Moreover, due to their biophysical properties and physiological function, exosomes have drawn attention as potential therapeutic target and drug delivery vehicles. This review will discuss the function of exosomes in Non-Hodgkin lymphomagenesis, highlight their potential as diagnosis and prognosis biomarkers, and as new therapeutic opportunities in lymphoma management.

Aggressive large B-cell lymphoma triggered by a parvovirus B19 infection in a previously healthy child

In absence of red blood cells disease or immune defect, parvovirus B19 (PVB-19) is usually considered as a benign condition. Here, we report the case of a 10-year-old boy, previously healthy, presenting with a PVB-19 infection revealed by a bicytopenia and a voluminous axillary adenopathy. Pathophysiology examination showed reactional lymphoid population. Nine months later and in the absence of remission, a new biopsy of the same adenopathy revealed a Hodgkin lymphoma with area of T-cell rich aggressive large B-cell lymphoma. This case suggests PVB-19 as potential trigger of this malignant childhood hemopathy. Although no definitive conclusion can be drawn, our clinical case questions the role of PVB-19 in lymphomagenesis.

Plasmablastic lymphoma: current perspectives

Plasmablastic lymphoma (PbL) is a rare and aggressive B-cell malignancy with large neoplastic cells, most of them resembling plasmablasts that have a CD20-negative phenotype. Although initially described as being associated with HIV, over the years it has also been identified in patients with solid organ transplant and immunocompetent patients. Little is known about molecular basis that drives PbL, and still its diagnosis remains challenging given its rarity. However, proper recognition of its clinical characteristics, localization, and morphological features can establish a correct diagnosis of PbL within the spectrum of CD20-negative large B-cell lymphomas (LBCLs). PbL is characterized by CD20 and PAX5 negativity together with the expression of CD38, CD138, MUM1/IRF4, Blimp1, and XBP1 plasmacytic differentiation markers. It is usually associated with Epstein–Barr virus infections, and MYC gene rearrangements. PbL should be carefully differentiated from other CD20-negative B-cell neoplasms, ie, primary effusion lymphoma, anaplastic lymphoma kinase-positive (ALK) large B-cell lymphoma, and LBCL in human herpesvirus 8-associated multicentric Castleman disease. Despite our improved understanding of this disease, its prognosis remains dismal with short overall survival. There is no standard of care for this entity. Several chemotherapy combinations have been used with hardly any differences on its outcome. Thus, new approaches with the addition of novel molecules are needed to overcome its poor prognosis. Our current understanding and knowledge of PbL relies primarily on case reports and small case series. In this review, we revise through an extensive literature search, the clinical and biological characteristics of this entity, and the potential therapeutic options.

Loss of T-Cell Multifunctionality and TCR-Vβ Repertoire Against Epstein-Barr Virus Is Associated With Worse Prognosis and Clinical Parameters in HIV+ Patients

Epstein-Barr virus (EBV) is an oncogenic virus associated with the development of aggressive and poor-prognosis B-cell lymphomas in patients infected with human immunodeficiency virus (HIV⁺ patients). The most important risk factors for these malignancies include immune dysfunction, chronic immune activation, and loss of T-cell receptor (TCR) repertoire. The combination of all these factors can favor the reactivation of EBV, malignant cell transformation, and clinical progression toward B-cell lymphomas. The overarching aim of this study was to evaluate the frequency, phenotype, functionality, and distribution of TCR clonotypes for EBV-specific T-cell subpopulations in HIV⁺ patients at different clinical stages and for HIV⁺ patients with B-cell lymphoma, as well as to establish their association with clinical variables of prognostic value. Factors were studied in 56 HIV⁺ patients at different clinical stages and in six HIV+ subjects with diagnosed B-cell lymphoma. We found a significant decrease in all subpopulations of EBV-specific CD4⁺ T cells from HIV⁺ patients at stage 3 and with B-cell lymphoma. EBV-specific effector CD8⁺ T cells, particularly effector memory cells, were also reduced in HIV⁺ patients with B-cell lymphoma. Interestingly, these cells were unable to produce IFN-γ and lacked multifunctionality in HIV+ patients. The TCR-Vβ repertoire, which is key for protection against EBV in healthy individuals, was less diverse in HIV⁺ patients due to a lower frequency of TCR-Vβ2⁺, Vβ4⁺, Vβ7.1⁺, Vβ9⁺, Vβ13.6⁺, Vβ14⁺, Vβ17⁺, Vβ22⁺ CD4⁺, Vβ14⁺, and Vβ17⁺ CD8⁺ T cells. HIV⁺ patients with positive plasma EBV loads (EBV⁺HIV⁺) had a noteworthy decrease in the levels of both TNF-α⁺ and multifunctional TNF-α⁺/IL-2⁺ and TNF-α⁺/IFN-γ⁺ CD8⁺ T cells. Altogether, our findings demonstrate that HIV⁺ patients have significant alterations in the immune response to EBV (poor-quality immunity) that can favor viral reactivation, escalating the risk for developing EBV-associated B-cell lymphomas.

Role of Feline Immunodeficiency Virus in Lymphomagenesis--Going Alone or Colluding?

Feline immunodeficiency virus (FIV) is a naturally occurring lentivirus of domestic and nondomestic feline species. Infection in domestic cats leads to immune dysfunction via mechanisms similar to those caused by human immunodeficiency virus (HIV) and, as such, is a valuable natural animal model for acquired immunodeficiency syndrome (AIDS) in humans. An association between FIV and an increased incidence of neoplasia has long been recognized, with frequencies of up to 20% in FIV-positive cats recorded in some studies. This is similar to the rate of neoplasia seen in HIV-positive individuals, and in both species neoplasia typically requires several years to arise. The most frequently reported type of neoplasia associated with FIV infection is lymphoma. Here we review the possible mechanisms involved in FIV lymphomagenesis, including the possible involvement of coinfections, notably those with gamma-herpesviruses.

An Epstein-Barr virus susceptible immature T-cell line, WILL4, established from a patient with T-lymphoblastic lymphoma bearing CD21 and a clonal EBV genome

We managed a patient with an Epstein-Barr virus-associated T-cell lymphoblastic lymphoma. Mediastinal tumor cells at initial admission were positive for CD4, CD8, and TdT. Interestingly, a lymph node at necropsy was compatible for a CD4-positive peripheral T-cell lymphoma without CD8 and TdT expression, suggesting a different phenotype from the mediastinal tumor. Tumor cells in pleural effusion continued to proliferate in in vitro and were designated as WILL4. WILL4 cells were positive for CD3, CD4, CD8, CD21, T-cell receptor (TcR) αβ, and TdT, indicating a similar phenotype to thymocytes. Southern blot analyses showed that the pleural tumor and WILL4 cells shared a TcR gene rearrangement, and that both contained a clonal EBV genome in an episomal form. RT-PCR showed that EBNA1 and LMP1 were expressed in the fresh tumor and WILL4 cells. Southern blot analyses revealed that WILL4 cells were susceptible to EBV infection in vitro using B95-8 supernatant. Anti-CD21 antibody inhibited in vitro infection of EBV, suggesting that CD21 plays a role in EBV infection into WILL4 cells. In vitro infection of EBV did not affect latent gene expression in WILL4 cells. WILL4 is a useful tool for analyzing the roles of EBV in onocogenesis in immature T-lymphoid malignancies.

The biology and treatment of plasmablastic lymphoma

Plasmablastic lymphoma (PBL) is an aggressive lymphoma commonly associated with HIV infection. However, PBL can also be seen in patients with other immunodeficiencies as well as in immunocompetent individuals. Because of its distinct clinical and pathological features, such as lack of expression of CD20, plasmablastic morphology, and clinical course characterized by early relapses and subsequent chemotherapy resistance, PBL can represent a diagnostic and therapeutic challenge for pathologists and clinicians alike. Despite the recent advances in the therapy of HIV-associated and aggressive lymphomas, patients with PBL for the most part have poor outcomes. The objectives of this review are to summarize the current knowledge on the epidemiology, biology, clinical and pathological characteristics, differential diagnosis, therapy, prognostic factors, outcomes, and potential novel therapeutic approaches in patients with PBL and also to increase the awareness toward PBL in the medical community.

EBV-driven B-cell lymphoproliferative disorders: from biology, classification and differential diagnosis to clinical management

Epstein–Barr virus (EBV) is a ubiquitous herpesvirus, affecting >90% of the adult population. EBV targets B-lymphocytes and achieves latent infection in a circular episomal form. Different latency patterns are recognized based on latent gene expression pattern. Latent membrane protein-1 (LMP-1) mimics CD40 and, when self-aggregated, provides a proliferation signal via activating the nuclear factor-kappa B, Janus kinase/signal transducer and activator of transcription, phosphoinositide 3-kinase/Akt (PI3K/Akt) and mitogen-activated protein kinase pathways to promote cellular proliferation. LMP-1 also induces BCL-2 to escape from apoptosis and gives a signal for cell cycle progression by enhancing cyclin-dependent kinase 2 and phosphorylation of retinoblastoma (Rb) protein and by inhibiting p16 and p27. LMP-2A blocks the surface immunoglobulin-mediated lytic cycle reactivation. It also activates the Ras/PI3K/Akt pathway and induces Bcl-xL expression to promote B-cell survival. Recent studies have shown that ebv-microRNAs can provide extra signals for cellular proliferation, cell cycle progression and anti-apoptosis. EBV is well known for association with various types of B-lymphocyte, T-lymphocyte, epithelial cell and mesenchymal cell neoplasms. B-cell lymphoproliferative disorders encompass a broad spectrum of diseases, from benign to malignant. Here we review our current understanding of EBV-induced lymphomagenesis and focus on biology, diagnosis and management of EBV-associated B-cell lymphoproliferative disorders.