Primary effusion lymphoma associated with Human Herpes Virus-8 and Epstein Barr virus in an HIV-infected woman from Kampala, Uganda: a case report

<p>Abstract</p> <p>Introduction</p> <p>Primary effusion lymphoma is a recently recognized entity of AIDS related non-Hodgkin lymphomas. Despite Africa being greatly affected by the HIV/AIDS pandemic, an extensive MEDLINE/PubMed search failed to find any report of primary effusion lymphoma in sub-Saharan Africa. To our knowledge this is the first report of primary effusion lymphoma in sub-Saharan Africa. We report the clinical, cytomorphologic and immunohistochemical findings of a patient with primary effusion lymphoma.</p> <p>Case presentation</p> <p>A 70-year-old newly diagnosed HIV-positive Ugandan African woman presented with a three-month history of cough, fever, weight loss and drenching night sweats. Three weeks prior to admission she developed right sided chest pain and difficulty in breathing. On examination she had bilateral pleural effusions.</p> <p>Haematoxylin and eosin stained cytologic sections of the formalin-fixed paraffin-embedded cell block made from the pleural fluid were processed in the Department of Pathology, Makerere University, College of Health Sciences, Kampala, Uganda. Immunohistochemistry was done at the Institute of Haematology and Oncology "L and A Seragnoli", Bologna University School of Medicine, Bologna, Italy, using alkaline phosphatase anti-alkaline phosphatase method. <it>In situ </it>hybridization was used for detection of Epstein-Barr virus.</p> <p>The tumor cells were CD45+, CD30+, CD38+, HHV-8 LANA-1+; but were negative for CD3-, CD20-, CD19-, and CD79a- and EBV RNA+ on <it>in situ </it>hybridization. CD138 and Ki-67 were not evaluable. Our patient tested HIV positive and her CD4 cell count was 127/μL.</p> <p>Conclusions</p> <p>A definitive diagnosis of primary effusion lymphoma rests on finding a proliferation of large immunoblastic, plasmacytoid and anaplastic cells; HHV-8 in the tumor cells, an immunophenotype that is CD45+, pan B-cell marker negative and lymphocyte activated marker positive. It is essential for clinicians and pathologists to have a high index of suspicion of primary effusion lymphoma when handling HIV positive patients who have effusions without palpable tumor masses. Basic immunohistochemistry is essential for definitive diagnosis.</p

Cancers associated with Kaposi's sarcoma (KS) in AIDS: a link between KS herpesvirus and immunoblastic lymphoma

Kaposi's sarcoma (KS), common among persons with acquired immunodeficiency syndrome (AIDS), is caused by KS herpesvirus (KSHV) but whether KSHV causes other malignancies is uncertain. Using linked United States AIDS and cancer registries, we measured the incidence of specific malignancies in persons with AIDS (4–27 months after AIDS onset). We identified associations with KSHV by calculating a relative risk: cancer incidence in persons with KS (all were KSHV-infected) divided by incidence in persons without KS. Using Poisson regression, relative risks were adjusted for human immunodeficiency virus risk group, gender, age, race, and calendar year. We included 189 159 subjects (26 972 with KS). Immunoblastic lymphoma was significantly associated with KS (506 cases; relative risks: unadjusted 2.44, 95%CI 2.00–2.96, adjusted 1.58, 95%CI 1.29–1.93). Only one immunoblastic lymphoma had pleura as primary site. None of 37 other specified malignancies (other non-Hodgkin lymphomas, haematological malignancies, solid tumours) was significantly associated with KS. In summary, the association of immunoblastic lymphoma with KS was specific among examined malignancies and remained significant after statistical adjustment. Our findings, and the previously demonstrated presence of KSHV in the histologically related primary effusion lymphoma, suggest that KSHV is involved in the pathogenesis of some immunoblastic lymphomas. © 2001 Cancer Research Campaig

Primary Effusion Lymphoma Cell Death Induced by Bortezomib and AG 490 Activates Dendritic Cells through CD91

To understand how cytotoxic agent-induced cancer cell death affects the immune system is of fundamental importance to stimulate immune response to counteract the high mortality due to cancer. Here we compared the immunogenicity of Primary Effusion Lymphoma (PEL) cell death induced by anticancer drug Bortezomib (Velcade) and Tyrphostin AG 490, a Janus Activated Kinase 2/signal trasducer and activator of transcription-3 (JAK2/STAT3) inhibitor. We show that both treatments were able to induce PEL apoptosis with similar kinetics and promote dendritic cells (DC) maturation. The surface expression of molecules involved in immune activation, namely calreticulin (CRT), heat shock proteins (HSP) 90 and 70 increased in dying cells. This was correlated with DC activation. We found that PEL cell death induced by Bortezomib was more effective in inducing uptake by DC compared to AG 490 or combination of both drugs. However the DC activation induced by all treatments was completely inhibited when these cells were pretreated with a neutralizing antiboby directed against the HSP90/70 and CRT common receptor, CD91. The activation of DC by Bortezomib and AG 490 treated PEL cells, as seen in the present study, might have important implications for a combined chemo and immunotherapy in such patients

Viral FLICE Inhibitory Protein of Rhesus Monkey Rhadinovirus Inhibits Apoptosis by Enhancing Autophagosome Formation

Rhesus monkey rhadinovirus (RRV) is a gamma-2 herpesvirus closely related to human herpesvirus 8 (HHV8). RRV encodes viral FLICE inhibitory protein (vFLIP), which has death effector domains. Little is known about RRV vFLIP. This study intended to examine its function in apoptosis. Here we found that RRV vFLIP inhibits apoptosis induced by tumor necrosis factor-α (TNF-α) and cycloheximide. In HeLa cells with vFLIP expression, the cleavage of poly [ADP-ribose] polymerase 1 (PARP-1) and activities of caspase 3, 7, and 9 were much lower than those in controls. Cell viability of HeLa cells with vFLIP expression was significantly higher than control cells after apoptosis induction. However, RRV vFLIP appears unable to induce NF-κB signaling when tested in NF-κB reporter assay. RRV vFLIP was able to enhance cell survival under starved conditions or apoptosis induction. At early time points after apoptosis induction, autophagosome formation was enhanced and LC3-II level was elevated in cells with vFLIP and, when autophagy was blocked with chemical inhibitors, these cells underwent apoptosis. Moreover, RRV latent infection of BJAB B-lymphoblastoid cells protects the cells against apoptosis by enhancing autophagy to maintain cell survival. Knockdown of vFLIP expression in the RRV-infected BJAB cells with siRNA abolished the protection against apoptosis. These results indicate that vFLIP protects cells against apoptosis by enhancing autophagosome formation to extend cell survival. The finding of vFLIP’s inhibition of apoptosis via the autophagy pathway provides insights of vFLIP in RRV pathogenesis

Activation of Host Translational Control Pathways by a Viral Developmental Switch

In response to numerous signals, latent herpesvirus genomes abruptly switch their developmental program, aborting stable host–cell colonization in favor of productive viral replication that ultimately destroys the cell. To achieve a rapid gene expression transition, newly minted capped, polyadenylated viral mRNAs must engage and reprogram the cellular translational apparatus. While transcriptional responses of viral genomes undergoing lytic reactivation have been amply documented, roles for cellular translational control pathways in enabling the latent-lytic switch have not been described. Using PEL-derived B-cells naturally infected with KSHV as a model, we define efficient reactivation conditions and demonstrate that reactivation substantially changes the protein synthesis profile. New polypeptide synthesis correlates with 4E-BP1 translational repressor inactivation, nuclear PABP accumulation, eIF4F assembly, and phosphorylation of the cap-binding protein eIF4E by Mnk1. Significantly, inhibiting Mnk1 reduces accumulation of the critical viral transactivator RTA through a post-transcriptional mechanism, limiting downstream lytic protein production, and impairs reactivation efficiency. Thus, herpesvirus reactivation from latency activates the host cap-dependent translation machinery, illustrating the importance of translational regulation in implementing new developmental instructions that drastically alter cell fate

The Interaction between Regulatory T Cells and NKT Cells in the Liver: A CD1d Bridge Links Innate and Adaptive Immunity

Regulatory T cells (Tregs) and natural killer T (NKT) cells are two distinct lymphocyte subsets that independently regulate hepatic adaptive and innate immunity, respectively. In the current study, we examine the interaction between Tregs and NKT cells to understand the mechanisms of cross immune regulation by these cells.The frequency and function of Tregs were evaluated in wild type and NKT cell deficient (CD1dko) mice. In vitro lymphocyte proliferation and apoptosis assays were performed with NKT cells co-cultured with Tregs. The ability of Tregs to inhibit NKT cells in vivo was examined by adoptive transfer of Tregs in a model of NKT cell mediated hepatitis.CD1dko mice have a significant reduction in hepatic Tregs. Although, the Tregs from CD1dko mice remain functional and can suppress conventional T cells, their ability to suppress activation induced NKT cell proliferation and to promote NKT cell apoptosis is greatly diminished. These effects are CD1d dependent and require cell to cell contact. Adoptive transfer of Tregs inhibits NKT cell-mediated liver injury.NKT cells promote Tregs, and Tregs inhibit NKT cells in a CD1d dependent manner requiring cell to cell contact. These cross-talk immune regulations provide a linkage between innate and adaptive immunity

Kaposi's Sarcoma-Associated Herpesvirus K7 Induces Viral G Protein-Coupled Receptor Degradation and Reduces Its Tumorigenicity

The Kaposi's sarcoma-associated herpesvirus (KSHV) genome encodes a G protein-coupled receptor (vGPCR). vGPCR is a ligand-independent, constitutively active signaling molecule that promotes cell growth and proliferation; however, it is not clear how vGPCR is negatively regulated. We report here that the KSHV K7 small membrane protein interacts with vGPCR and induces its degradation, thereby dampening vGPCR signaling. K7 interaction with vGPCR is readily detected in transiently transfected human cells. Mutational analyses reveal that the K7 transmembrane domain is necessary and sufficient for this interaction. Biochemical and confocal microscopy studies indicate that K7 retains vGPCR in the endoplasmic reticulum (ER) and induces vGPCR proteasomeal degradation. Indeed, the knockdown of K7 by shRNA-mediated silencing increases vGPCR protein expression in BCBL-1 cells that are induced for KSHV lytic replication. Interestingly, K7 expression significantly reduces vGPCR tumorigenicity in nude mice. These findings define a viral factor that negatively regulates vGPCR protein expression and reveal a post-translational event that modulates GPCR-dependent transformation and tumorigenicity

Mutual Inhibition between Kaposi's Sarcoma-Associated Herpesvirus and Epstein-Barr Virus Lytic Replication Initiators in Dually-Infected Primary Effusion Lymphoma

Background: Both Kaposi’s sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV) are members of the human gamma herpesvirus family: each is associated with various human cancers. The majority of AIDS-associated primary effusion lymphoma (PEL) are co-infected with both KSHV and EBV. Dually-infected PELs selectively switch from latency to lytic replication of either KSHV or EBV in response to chemical stimuli. KSHV replication and transcription activator (K-RTA) is necessary and sufficient for the switch from KSHV latency to lytic replication, while EBV BZLF1 gene product (EBV-Z) is a critical initiator for induction of EBV lytic replication. Methodology/Principal Findings: We show K-RTA and EBV-Z are co-localized and physically interact with each other in dually-infected PELs. K-RTA inhibits the EBV lytic replication by nullifying EBV-Z-mediated EBV lytic gene activation. EBV-Z inhibits KSHV lytic gene expression by blocking K-RTA-mediated transactivations. The physical interaction between K-RTA and EBV-Z are required for the mutual inhibition of the two molecules. The leucine heptapeptide repeat (LR) region in K-RTA and leucine zipper region in EBV-Z are involved in the physical interactions of the two molecules. Finally, initiation of KSHV lytic gene expression is correlated with the reduction of EBV lytic gene expression in the same PEL cells. Conclusions/Significance: In this report, how the two viruses interact with each other in dually infected PELs is addressed. Our data may provide a possible mechanism for maintaining viral latency and for selective lytic replication in dually infected PELs, i.e., through mutual inhibition of two critical lytic replication initiators. Our data about putative interactions between EBV and KSHV would be applicable to the majority of AIDS-associated PELs and may be relevant to the pathogenesis of PELs

Pre-Micro RNA Signatures Delineate Stages of Endothelial Cell Transformation in Kaposi Sarcoma

MicroRNAs (miRNA) have emerged as key regulators of cell lineage differentiation and cancer. We used precursor miRNA profiling by a novel real-time QPCR method (i) to define progressive stages of endothelial cell transformation cumulating in Kaposi sarcoma (KS) and (ii) to identify specific miRNAs that serve as biomarkers for tumor progression. We were able to compare primary patient biopsies to well-established culture and mouse tumor models. Loss of mir-221 and gain of mir-15 expression demarked the transition from merely immortalized to fully tumorigenic endothelial cells. Mir-140 and Kaposi sarcoma–associated herpesvirus viral miRNAs increased linearly with the degree of transformation. Mir-24 emerged as a biomarker specific for KS