Epstein-Barr Virus (EBV) Is Mostly Latent and Clonal in Angioimmunoblastic T Cell Lymphoma (AITL).

The Epstein-Barr virus (EBV) is associated with angioimmunoblastic T cell lymphoma (AITL), a peripheral T lymphoma of poor prognosis in at least 90% of cases. The role of EBV in this pathology is unknown. Using next-generation sequencing, we sequenced the entire EBV genome in biopsies from 18 patients with AITL, 16 patients with another EBV-associated lymphoma, and 2 controls. We chose an EBV target capture method, given the high specificity of this technique, followed by a second capture to increase sensitivity. We identified two main viral strains in AITL, one of them associated with the mutations BNRF1 S542N and BZLF1 A206S and with mutations in the EBNA-3 and LMP-2 genes. This strain was characterized in patients with short post-diagnosis survival. The main mutations found during AITL on the most mutated latency or tegument genes were identified and discussed. We showed that the virus was clonal in all the AITL samples, suggesting that it may be involved in this pathology. Additionally, EBV was latent in all the AITL samples; for one sample only, the virus was found to be latent and probably replicative, depending on the cells. These various elements support the role of EBV in AITL.

Comprehensive Epstein-Barr Virus Transcriptome by RNA-Sequencing in Angioimmunoblastic T Cell Lymphoma (AITL) and Other Lymphomas.

The Epstein-Barr virus (EBV) is associated with angioimmunoblastic T cell lymphoma (AITL) in more than 80% of cases. Few studies have focused on this association and it is not clear now what role the virus plays in this pathology. We used next-generation sequencing (NGS) to study EBV transcriptome in 14 AITLs compared to 21 other lymphoma samples and 11 cell lines including 4 lymphoblastoid cell lines (LCLs). Viral transcripts were recovered using capture probes and sequencing was performed on Illumina. Bam-HI A rightward transcripts (BARTs) were the most latency transcripts expressed in AITLs, suggesting they may play a role in this pathology. Thus, BARTs, already described as highly expressed in carcinoma cells, are also very present in AITLs and other lymphomas. They were poorly expressed in cell lines other than LCLs. AITLs showed a latency IIc, with BNLF2a gene expression. For most AITLs, BCRF1, which encodes a homologous protein of human interleukin 10, vIL-10, was in addition expressed. This co-expression can contribute to immune escape and survival of infected cells. Considering these results, it can be assumed that EBV plays a pathogenic role in AITLs.

Correction to: Relationship between Toxoplasma gondii seropositivity and schizophrenia in the Lebanese population: potential implication of genetic polymorphism of MMP-9.

An amendment to this paper has been published and can be accessed via the original article.

Relationship between Toxoplasma gondii seropositivity and schizophrenia in the Lebanese population: potential implication of genetic polymorphism of MMP-9.

BACKGROUND: Toxoplasma multiplication and its persistence into the brain cause a local neuroinflammatory reaction, resulting synthesis of neurotransmitters involved in neurological disorders, especially schizophrenia. The Matrix metallopeptidase 9 (MMP-9) protein can play a major role in this neuroinflammation. It can promote extravasation and migration of infected immune cells into the brain. The objectives of this study are to determine the possible association between schizophrenia and toxoplasmosis and highlight the existence of gene polymorphism encoding MMP-9 protein's in patients presented both schizophrenia and toxoplasmosis. METHODS: A case-control study was conducted on 150 patients with schizophrenia (case group), and 150 healthy persons (control group). Groups were matched with age, gender, and place of residence. The survey was conducted using a questionnaire and a serological profile assay for specific IgG and IgM antibodies against T. gondii. Reverse transcription-polymerase chain reaction (RT-PCR) of gene polymorphism encoding MMP-9 was performed on 83 cases selected randomly. RESULTS: Data show a significant association between toxoplasmosis (IgM+/IgG+ serological profile) and schizophrenia. Significant effects of raw meat consumption and contact with cats have been associated with the occurrence of schizophrenia. RT-PCR shows the presence of muted allele of MMP-9 gene in selected cases whose present T. gondii serological profile IgM+/IgG+ and IgM-/IgG+ respectively. CONCLUSION: Toxoplasmosis may be one of the etiological causes of schizophrenia, and MMP-9 gene polymorphism could be involved in the occurrence mechanism of this pathology following Toxoplasma infection.

Toxoplasma gondii Modulates the Host Cell Responses: An Overview of Apoptosis Pathways.

Infection with Toxoplasma gondii has a major implication in public health. Toxoplasma gondii is an obligate intracellular protozoan parasite that can infect all nucleated cells belonging to a wide range of host species. One of the particularities of this parasite is its invasion and persistence in host cells of immunocompetent people. This infection is usually asymptomatic. In immunocompromised patients, the infection is severe and symptomatic. The mechanisms by which T. gondii persists are poorly studied in humans. In mouse models, many aspects of the interaction between the parasite and the host cells are being studied. Apoptosis is one of these mechanisms that could be modulated by Toxoplasma to persist in host cells. Indeed, Toxoplasma has often been implicated in the regulation of apoptosis and viability mechanisms in both human and murine infection models. Several of these studies centered on the regulation of apoptosis pathways have revealed interference of this parasite with host cell immunity, cell signalling, and invasion mechanisms. This review provides an overview of recent studies concerning the effect of Toxoplasma on different apoptotic pathways in infected host cells.

Clonal deleted latent membrane protein 1 variants of Epstein-Barr virus are predominant in European extranodal NK/T lymphomas and disappear during successful treatment.

Extranodal natural killer/T-cell lymphomas (NK/TL), rare in Europe, are Epstein-Barr virus (EBV) associated lymphomas with poor outcomes. Here, we determined the virus type and analyzed the EBV latent membrane protein-1 (LMP1) gene sequence in NK/TL from French patients. Six clones of viral LMP1 were sequenced by Sanger technology in blood from 13 patients before treatment with an l-asparaginase based regimen and, for 8 of them, throughout the treatment. Blood LMP1 sequences from 21 patients without any known malignancy were tested as controls. EBV Type A was identified for 11/13 patients and for all controls. Before treatment, a clonal LMP1 gene containing a 30 bp deletion (del30) was found in 46.1% of NK/TL and only in 4.8% of controls. Treatment was less effective in these patients who died more rapidly than the others. Patients with a deleted strain evolving toward a wild-type strain during treatment reached complete remission. The LMP1 gene was sequenced by highly sensitive next-generation sequencing technology in five NK/TL nasopharyngeal biopsies, two of them originating from the previous patients. Del30 was present in 100% of the biopsies; two viruses at least coexisted in three biopsies. These results suggest that del30 may be associated with poor prognosis NK/TL and that strain evolution could be used as a potential marker to monitor treatment.

Interferon gamma effect on immune mediator production in human nerve cells infected by two strains of Toxoplasma gondii.

Interferon gamma (IFN-γ) is the major immune mediator that prevents toxoplasmic encephalitis in murine models. The lack of IFN-γ secretion causes reactivation of latent T. gondii infection that may confer a risk for severe toxoplasmic encephalitis. We analyse the effect of IFN-γ on immune mediator production and parasite multiplication in human nerve cells infected by tachyzoites of two T. gondii strains (RH and PRU). IFN-γ decreased the synthesis of MCP-1, G-CSF, GM-CSF and Serpin E1 in all cell types. It decreased IL-6, migration inhibitory factor (MIF) and GROα synthesis only in endothelial cells, while it increased sICAM and Serpin E1 synthesis only in neurons. The PRU strain burden increased in all nerve cells and in contrast, RH strain replication was controlled in IFN-γ-stimulated microglial and endothelial cells but not in IFN-γ-stimulated neurons. The proliferation of the PRU strain in all stimulated cells could be a specific effect of this strain on the host cell.

In vitro infection of human nervous cells by two strains of Toxoplasma gondii: a kinetic analysis of immune mediators and parasite multiplication.

The severity of toxoplasmic infection depends mainly on the immune status of the host, but also on the Toxoplasma gondii strains, which differ by their virulence profile. The relationship between the human host and T. gondii has not yet been elucidated because few studies have been conducted on human models. The immune mechanisms involved in the persistence of T. gondii in the brains of immunocompetent subjects and during the reactivation of latent infections are still unclear. In this study, we analyzed the kinetics of immune mediators in human nervous cells in vitro, infected with two strains of T. gondii. Human neuroblast cell line (SH SY5Y), microglial (CMH5) and endothelial cells (Hbmec) were infected separately by RH (type I) or PRU (type II) strains for 8 h, 14 h, 24 h and 48 h (ratio 1 cell: 2 tachyzoites). Pro-inflammatory protein expression was different between the two strains and among different human nervous cells. The cytokines IL-6, IL-8 and the chemokines MCP-1 and GROα, and SERPIN E1 were significantly increased in CMH5 and SH SY5Y at 24 h pi. At this point of infection, the parasite burden declined in microglial cells and neurons, but remained high in endothelial cells. This differential effect on the early parasite multiplication may be correlated with a higher production of immune mediators by neurons and microglial cells compared to endothelial cells. Regarding strain differences, PRU strain, but not RH strain, stimulates all cells to produce pro-inflammatory growth factors, G-CSF and GM-CSF. These proteins could increase the inflammatory effect of this type II strain. These results suggest that the different protein expression profiles depend on the parasitic strain and on the human nervous cell type, and that this could be at the origin of diverse brain lesions caused by T. gondii.