Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0021345 (infectious mononucleosis)
 3,358 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The primary infection of Epstein-Barr virus (EBV) may result in fatal infectious mononucleosis or hemophagocytic syndrome (HPS) in 2 diseases; that is, X-linked lymphoproliferative disorder (XLP) and hemophagocytic lymphohistiocytosis (HLH). XLP is linked to mutations of the SAP/SH2D1A gene with dysregulated T-cell activation in response to EBV infection. Patients with sporadic HLH, however, usually have no mutation of the SAP/SH2D1A gene, and EBV latent membrane protein-1 (LMP1) can up-regulate Th1 cytokines in EBV-infected T cells. Since both diseases share common manifestations of HPS, it is important to clarify whether a cross-talk exists between signaling lymphocyte activation molecule (SLAM)-associated protein (SAP) and LMP1-mediated pathways to explain the common pathogenesis of HPS. In this study, no mutation of the SAP/SH2D1A gene at exon 2/3 was detected in 7 HLH cases. Interestingly, EBV LMP1 could transcriptionally inhibit the expression of SAP/SH2D1A and activate downstream molecules ERK and interferon-gamma (IFN-gamma). LMP1-mediated SAP/ERK/IFN-gamma signals appear to act via the TNF receptor-associated factor (TRAF)2,5/nuclear factor kappaB (NF-kappaB) pathway, since dominant-negative TRAF2/5 and NF-kappaB inhibitor could rescue SAP expression and downregulate IFN-gamma. Although HLH is genetically distinct from XLP, our data suggest that both diseases share a common signal pathway, through either the mutation or LMP1-mediated suppression of the SAP gene, leading to overt T-cell activation and enhanced Th1 cytokine secretion in response to EBV infection.
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PMID:Epstein-Barr virus LMP1 inhibits the expression of SAP gene and upregulates Th1 cytokines in the pathogenesis of hemophagocytic syndrome. 1600 23

In this report, the authors present a detailed immunological and virological assessment of an immunocompetent 17-year-old Caucasian male with a fatal Epstein-Barr virus (EBV) infectious mononucleosis presenting with meningoencephalitis and hemophagocytic syndrome. The patient with serologically confirmed EBV infectious mononucleosis was admitted to the hospital because of 3 weeks' fever. Fine-needle aspiration of lymph nodes showed reactive hyperplasia with prominent hemophagocytosis. Percentages of intracellular interferon-gamma (IFN-gamma) in CD4(+) and CD8(+) T cells in the peripheral blood progressively increased during the course of disease (10.2% and 8.5% on day 35; 30.1% and 53.2% on day 44; 42.2% and 75.2% on day 50; 36.1% and 50.6% on day 59, respectively). On day 50, the patient developed meningoencephalitis. Brain computed tomography (CT) was normal. Brain magnetic resonance imaging (MRI) showed multifocal inflammatory lesions in frontal and temporal cortex of the right hemisphere as well as severe perivascular inflammatory reaction. The patient was treated with steroids, cyclosporin A, and methotrexate intratecally. Following treatment, EBV viremia in the blood and cerebrospinal fluid (CSF) decreased from pretreatment values (54,490 copies of EBV DNA/ml and 39,500 copies/ml, respectively) to 8715 copies/ml in the blood and 14,690 in the CSF. Despite treatment, the patient remained unconscious and died of sepsis and pneumonia 3 months after initial symptoms. Immunohistochemical staining showed the presence of EBV in both perivascular infiltrates and grey matter. Enhanced Th1 response as shown by high levels of IFN-gamma in peripheral blood lymphocytes may be a predictor of severe complications during acute EBV infection. Early implementation of immunosuppressive therapy in these patients should be considered.
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PMID:Virological and immunological characteristics of fatal Epstein-Barr virus mononucleosis in a 17-year-old Caucasian male presenting with meningoencephalitis and hemophagocytic syndrome. 1784 23

We studied simultaneously Epstein-Barr virus (EBV)-specific CD4(+) and CD8(+) T cell responses during and after infectious mononucleosis (IM), using a previously described 12-day stimulation protocol with EBNA1 or BZLF1 peptide pools. Effector function of EBV-specific T cells was determined after restimulation by measuring intracellular interferon-gamma production. During IM, BZLF1-specifc CD4(+) T cell responses were dominant compared with CD8(+) T cell responses. EBNA1-specific CD4(+) and CD8(+) T cell responses were low and remained similar for 6 months. However, 6 months after IM, BZLF1-specific CD4(+) T cell responses had declined, but CD8(+) T cell responses had increased. At diagnosis, EBV-specific CD8(+) T cells as studied by human leucocyte antigen class I tetramer staining comprised a tetramer(bright)CD8(bright) population consisting mainly of CD27(+) memory T cells and a tetramer(dim)CD8(dim) population consisting primarily of CD27(-) effector T cells. The remaining EBV-specific CD8(+) T cell population 6 months after the diagnosis of IM consisted mainly of tetramer(bright)CD8(bright) CD27(+) T cells, suggesting preferential preservation of memory T cells after contraction of the EBV-specific T cell pool.
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PMID:Detailed analysis of Epstein-Barr virus-specific CD4+ and CD8+ T cell responses during infectious mononucleosis. 1854 39

Regulatory T cells (T(reg)) provide a balance to immune T cell activation thereby protecting the body from pathogen-induced immunopathology. Several persistent viruses induce T(reg) that subvert protective immune mechanisms and promote viral persistence. Epstein-Barr virus (EBV) generally infects children subclinically and persists thereafter, but primary infection in early adulthood may cause immunopathological damage manifest as infectious mononucleosis. In this study the role of T(reg) was investigated in acute infectious mononucleosis and healthy EBV seropositive donors. The proportion of CD4(+)CD25(high) T cells in blood from infectious mononucleosis patients was significantly lower than in seropositive donors (P = 0.05). Using the FOXP3 marker for T(reg) the same frequency and extra-follicular distribution of T(reg) was noted in infectious mononucleosis and control tonsils. Regulatory cytokines, interleukin (IL)-10 and transforming growth factor (TGF)-beta, were significantly raised in infectious mononucleosis compared to seropositive donor plasma (P = 0.0001, P = 0.0004 respectively) although levels of IL-10 peaked earlier in infectious mononucleosis than TGF-beta. Previous studies identified EBV latent membrane protein (LMP)-1-induced T(reg) activity [Marshall et al. (2003): J Immunol 170:6183-6189; Marshall et al. (2007): Brit J Haematol 139:81-89], and in this study a significant reduction in interferon-gamma production was found from infectious mononucleosis but not seropositive donor lymphocytes after stimulation with a recall antigen when LMP-1 peptide PRG was added (P = 0.03). It is possible that T(reg) are important in controlling primary EBV infection to a subclinical level in most cases and that infectious mononucleosis represents a failure of this protective mechanism.
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PMID:Regulatory T cell activity in primary and persistent Epstein-Barr virus infection. 1931 50


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