Viral infections and multiple sclerosis.

The etiology and pathogenesis of MS is likely to involve multiple factors interacting with each other, and the role of infectious and viral agents is still under debate, however a consistent amount of studies suggests that some viruses are associated with the disease. The strongest documentation has come from the detection of viral nucleic acid or antigen or of an anti-viral antibody response in MS patients. A further step for the study of the mechanism viruses might be involved in can be made using in vitro and in vivo models. While in vitro models, based on glial and neural cell lines from various sources are widely used, in vivo animal models present challenges. Indeed neurotropic animal viruses are currently used to study demyelination in well-established models, but animal models of demyelination by human virus infection have only recently been developed, using animal gammaherpesviruses closely related to Epstein Barr virus (EBV), or using marmosets expressing the specific viral receptor for Human Herpesvirus 6 (HHV-6). The present review will illustrate the main potential mechanisms of MS pathogenesis possibly associated with viral infections and viruses currently used to study demyelination in animal models. Then the viruses most strongly linked with MS will be discussed, in the perspective that more than one virus might have a role, with varying degrees of interaction, contributing to MS heterogeneity.

Retrospective analysis on safety and efficacy of everolimus in treatment of metastatic renal cancer patients receiving dialysis.

AIMS: This retrospective study aimed to investigate safety and efficacy of everolimus in patients with metastatic renal cell carcinoma (mRCC) and end-stage renal disease requiring dialysis. PATIENTS & METHODS: From November 2009 to December 2012, 11 mRCC patients undergoing dialysis were treated with everolimus after failure of anti-VEGF therapy at six Italian institutions. Patient characteristics, safety and outcomes were collected. RESULTS: Progression-free survival and overall survival were determined using the Kaplan-Meier method. Median progression-free survival and overall survival were 9.01 and 15.7 months, respectively. No unexpected adverse events were reported. CONCLUSION: Everolimus appears to be safe in mRCC patients with renal impairment or end-stage renal disease requiring dialysis. Larger prospective studies are required to confirm these findings.

Cerebral circulation time is prolonged and not correlated with EDSS in multiple sclerosis patients: a study using digital subtracted angiography.

Literature has suggested that changes in brain flow circulation occur in patients with multiple sclerosis. In this study, digital subtraction angiography (DSA) was used to measure the absolute CCT value in MS patients and to correlate its value to age at disease onset and duration, and to expand disability status scale (EDSS). DSA assessment was performed on eighty MS patients and on a control group of forty-four age-matched patients. CCT in MS and control groups was calculated by analyzing the angiographic images. Lesion and brain volumes were calculated in a representative group of MS patients. Statistical correlations among CCT and disease duration, age at disease onset, lesion load, brain volumes and EDSS were considered. A significant difference between CCT in MS patients (mean = 4.9s; sd = 1.27 s) and control group (mean = 2.8s; sd = 0.51 s) was demonstrated. No significant statistical correlation was found between CCT and the other parameters in all MS patients. Significantly increased CCT value in MS patients suggests the presence of microvascular dysfunctions, which do not depend on clinical and MRI findings. Hemodynamic changes may not be exclusively the result of a late chronic inflammatory process.

Rhabdomyolysis in an elderly multitreated patient: multiple drug interactions after statin withdrawal.

Rhabdomyolysis precipitated by multitherapy is most frequently described during statin treatment, due to impairment of statin clearance by drugs sharing cytochrome P450 biotransformation pathway. Modulation of membrane transporters for drug efflux, operated by substrates, can also affect drugs' tissue levels. We report rhabdomyolysis in an elderly patient, in multitreatment with different potentially myotoxic medications, taking place seven months after atorvastatin discontinuation. Affected by ischaemic heart disease, arterial hypertension and dementia-related behaviour disturbances, the patient was receiving angiotensin 2-receptor inhibitors, beta-blockers, vasodilators, diuretics, salycilates, allopurinol, proton pump inhibitors, antipsychotics and antidepressants. He had taken atorvastatin for 14 years, with constantly normal creatine-kinase plasma levels. Two months after addition of the antianginal drug ranolazine, creatine-kinase mildly increased and atorvastatin was withdrawn. Nonetheless, creatine-kinase progressively rose, with severe weakness and rhabdomyolysis developing seven months later. Muscle biopsy showed a necrotizing myopathy with no inflammation or autoimmune changes. After ranolazine withdrawal, creatine-kinase and myoglobin returned to normal levels and strength was restored. Several psychotropic and cardiovascular medications prescribed to the patient share either cytochrome P450 biotransformation and permeability-glycoprotein efflux transport. In the event of cardiovascular/neuropsychiatric polypharmacy in geriatric patients, the risk of muscle severe adverse effects from pharmacokinetic drug-drug interaction should be considered beyond the direct myotoxicity of statins.

Successful response of non-recovering Ramsay Hunt syndrome to intravenous high dose methylprednisolone.

Ramsay Hunt syndrome (RHS) is a frequent cause of facial palsy. It is a consequence of the infection of geniculate ganglion by herpes zoster or herpes simplex virus. In the lack of randomized controlled trials, RHS is empirically treated by a combination therapy of antiviral agents and steroids given orally. However, RHS has, per se, a poorer prognosis than idiopathic facial palsy (Bell's palsy). We describe a case series of two patients with RHS unsuccessfully treated with antiviral drugs and oral corticosteroids, showing an almost complete recovery after late administration of intravenous (i.v.) high dose methylprednisolone. Both patients had all recognized negative prognostic factors including age of onset, a high grade facial weakness, absence of R1 and R2 response at blink reflex test, and in the first case, the involvement of greater superficial petrosal nerve. We propose that i.v. high dose methylprednisolone should be considered, even as a late treatment option, in patients with RHS non recovering after standard antiviral and oral steroid therapy as well as presenting clinical features suggestive of a poor prognosis.

Association of human herpesvirus-6B with mesial temporal lobe epilepsy.

BACKGROUND: Human herpesvirus-6 (HHV-6) is a beta-herpesvirus with 90% seroprevalence that infects and establishes latency in the central nervous system. Two HHV-6 variants are known: HHV-6A and HHV-6B. Active infection or reactivation of HHV-6 in the brain is associated with neurological disorders, including epilepsy, encephalitis, and multiple sclerosis. In a preliminary study, we found HHV-6B DNA in resected brain tissue from patients with mesial temporal lobe epilepsy (MTLE) and have localized viral antigen to glial fibrillary acidic protein (GFAP)-positive glia in the same brain sections. We sought, first, to determine the extent of HHV-6 infection in brain material resected from MTLE and non-MTLE patients; and second, to establish in vitro primary astrocyte cultures from freshly resected brain material and determine expression of glutamate transporters. METHODS AND FINDINGS: HHV-6B infection in astrocytes and brain specimens was investigated in resected brain material from MTLE and non-MTLE patients using PCR and immunofluorescence. HHV-6B viral DNA was detected by TaqMan PCR in brain resections from 11 of 16 (69%) additional patients with MTLE and from zero of seven (0%) additional patients without MTLE. All brain regions that tested positive by HHV-6B variant-specific TaqMan PCR were positive for viral DNA by nested PCR. Primary astrocytes were isolated and cultured from seven epilepsy brain resections and astrocyte purity was defined by GFAP reactivity. HHV-6 gp116/54/64 antigen was detected in primary cultured GFAP-positive astrocytes from resected tissue that was HHV-6 DNA positive-the first demonstration of an ex vivo HHV-6-infected astrocyte culture isolated from HHV-6-positive brain material. Previous work has shown that MTLE is related to glutamate transporter dysfunction. We infected astrocyte cultures in vitro with HHV-6 and found a marked decrease in glutamate transporter EAAT-2 expression. CONCLUSIONS: Overall, we have now detected HHV-6B in 15 of 24 patients with mesial temporal sclerosis/MTLE, in contrast to zero of 14 with other syndromes. Our results suggest a potential etiology and pathogenic mechanism for MTLE.

Detection of active human herpesvirus-6 infection in the brain: correlation with polymerase chain reaction detection in cerebrospinal fluid.

One-half of bone-marrow transplant (BMT) and stem-cell transplant recipients have reactivation of latent human herpesvirus (HHV)-6 2-4 weeks after transplant. Although the detection of viral DNA, RNA, and antigen in brain material confirmed active HHV-6 variant B infection, peak viral loads in cerebrospinal fluid (CSF) and serum occurred 2-4 weeks before death and decreased to low levels before or at autopsy. All autopsy samples consistently demonstrated HHV-6 active infection in the hippocampus. Astrocytic cells positive for viral antigen provided support for an HHV-6-specific tropism for hippocampal astrocytes. HHV-6 DNA in CSF and serum may not reflect the level of active viral infection in the brain after BMT.

Encephaloradiculomyelitis associated to HHV-7 and CMV co-infection in immunocompetent host.

An active co-infection with CMV and HHV-7 has been never described in immunocompetent patients. The authors describe a case of encephaloradiculomyelitis in an immunocompetent man. Polymerase chain reaction (PCR) performed on cerebrospinal fluid (CSF) showed positivity for DNA of Cytomegalovirus (CMV) and Herpes-virus type 7 (HHV-7), whereas the same test applied on peripheral blood mononuclear cells gave negative result. These results are highly supportive of an infection of the central and peripheral nervous systems, caused by CMV and HHV7. Such viral co-infection has only been described in immune-depressed patients with CMV disease, in which HHV-7 was supposed to act as a cofactor, enhancing clinical manifestations. The same mechanism is presumably responsible for the development of encephaloradiculomyelitis clinical signs in the present case. This is the second case in which DNA of HHV-7 has been found in the CSF of an adult immunocompetent patient. This novel observation suggests that the search for viral DNA in the CSF should be performed also in immunocompetent patients.

Complete replication cycle and acquisition of tegument in nucleus of human herpesvirus 6A in astrocytes and in T-cells.

The ultrastructural replication cycle of human herpesvirus 6A and 6B, both T-lymphotropic viruses, with tropism for the central nervous system, was compared by electron microscopy in the same cells, that is, in the T-lymphoblastoid cell line SupT-1 and in human astrocytes. Both HHV-6A and HHV-6B replicated efficiently in SupT-1 and formed viral particles. The tegument is the least characterized structure of the herpesviral particle and both variants were able to form intranuclear membrane compartments called tegusomes in SupT-1 where tegumentation occurred. Also, tegumentation occurred in HHV-6A infected cells in the nucleoplasm without the presence of a tegusome. This suggests that there is more than one possible route of tegumentation. Differences in the replication cycles between HHV-6A and HHV-6B were also observed in the cytoplasm. One such difference was that prominent annulate lamellae were only found in the cytoplasm of HHV-6A infected cells. In astrocytes a successful formation of viral particles was only seen with the HHV-6A variant. The HHV-6A virus life cycle in astrocytes resembled the life cycle in the T-cell line SupT-1, except that no annulate lamellae were found. Complete viral particles were found extracellularly around the astrocytes and the supernatant of infected astrocytes were able to re-infect SupT-1 cells. This suggests that HHV-6A infection in astrocytes can generate complete, viable, and infectious viral particles. The HHV-6 variants behave differently in the same type of cells and have different tropisms for astrocytes, supporting the notion that the variants might induce different diseases.

Detection of HHV-6B in post-mortem central nervous system tissue of a post-bone marrow transplant recipient: a multi-virus array analysis.

BACKGROUND: HHV-6 has been implicated in a number of neurological disorders. Recent evidence has suggested high incidence of HHV-6 infection in patients (46%) undergoing allogeneic bone marrow transplant (BMT). OBJECTIVE: To investigate whether HHV-6 plays a role in the development of fatal encephalopathy in an allogeneic post-BMT patient using an unbiased approach. RESULTS: Detection of HHV-6 viral DNA sequence and RNA expression were demonstrated in fresh frozen post-mortem autopsy material derived from the insular cortex using a multi-virus array platform. In addition, PCR analysis by real-time quantitative TaqMan demonstrated high viral burden in multiple brain regions tested. Sequencing analysis of PCR product confirmed the virus to be HHV-6 variant B. CONCLUSIONS: Active infection as demonstrated by expression of viral RNA and high viral load in the CNS suggest a possible pathogenic role of HHV-6 in development neurologic complications post-BMT.

Variant-specific tropism of human herpesvirus 6 in human astrocytes.

Though first described as a lymphotropic virus, human herpesvirus 6 (HHV-6) is highly neuropathogenic. Two viral variants are known: HHV-6A and HHV-6B. Both variants can infect glial cells and have been differentially associated with central nervous system diseases, suggesting an HHV-6 variant-specific tropism for glial cell subtypes. We have performed infections with both viral variants in human progenitor-derived astrocytes (HPDA) and monitored infected cell cultures for cytopathic effect (CPE), intra- and extracellular viral DNA load, the presence of viral particles by electronic microscopy, mRNA transcription, and viral protein expression. HHV-6A established a productive infection with CPE, visible intracellular virions, and high virus DNA loads. HHV-6B-infected HPDA showed no morphological changes, intracellular viral particles, and decreasing intra- and extracellular viral DNA over time. After long-term passage, HHV-6B-infected HPDA had stable but low levels of intracellular viral DNA load with no detectable viral mRNA. Our results demonstrate that HHV-6A and HHV-6B have differential tropisms and patterns of infection for HPDA in vitro, where HHV-6A results in a productive lytic infection. In contrast, HHV-6B was associated with a nonproductive infection. These findings suggest that HHV-6 variants might be responsible for specific infection patterns in glial cells in vivo. Astrocytes may be an important reservoir for this virus in which differential tropism of HHV-6A and HHV-6B may be associated with different disease outcomes.

CD46 on glial cells can function as a receptor for viral glycoprotein-mediated cell-cell fusion.

Membrane cofactor protein (CD46) is a regulator of complement activation that also serves as the entry receptor for human herpes virus 6 (HHV-6) and measles virus (MV) into human cells. While it is clear that oligodendrocytes and astrocytes are cell types commonly infected by these viruses, it is unclear whether oligodendrocytes express CD46, or which are the cellular mechanisms underlying the infection. We show that adult oligodendrocytes, as well as astrocytes and microglial cells, express CD46 on the cellular surface. Moreover, we employed a quantitative fusion assay to demonstrate that HHV-6A infection of T lymphocytes enables cell-cell fusion of these cells to astrocytes or to oligodendroglial cells. This fusion is mediated by the interaction between viral glycoproteins expressed on the membrane of the infected cells and CD46 on the glial targets, and is also observed using cells expressing recombinant MV glycoproteins. These data suggest a mechanism that involves cell-cell fusion by which certain viruses could spread the infection from the periphery to the cells in the nervous system.

Delayed emesis: incidence, pattern, prognostic factors and optimal treatment.

Delayed emesis has been arbitrarily defined as vomiting and/or nausea beginning, or persisting for, more than 24 h after chemotherapy administration. Acute emesis is the most important prognostic factor for delayed emesis. Owing to the relatively high incidence and severity all patients treated with cisplatin > or = 50 mg/m(2) should receive antiemetic prophylaxis. In these patients a combination of dexamethasone plus metoclopramide or a 5-HT3 antagonist is the most efficacious regimen. All patients submitted to moderately emetogenic chemotherapy, such as cyclophosphamide, carboplatin, doxorubicin and epirubicin, should also receive antiemetic prophylaxis with oral dexamethasone to prevent delayed emesis.