Giuseppe Mameli

Multiple sclerosis–associated retrovirus (MSRV) in Sardinian MS patients

Abstract—Blood and CSF of Sardinian patients with MS and neurologic control subjects were tested for MS-associated retrovirus (MSRV). CSF detection in MS was 50% at clinical onset, increasing with temporal disease progression, and 40% in control subjects. In blood, MSRV was detected in all MS patients, in most patients with inflammatory neurologic diseases, and rarely in healthy blood donors. MSRV may represent a marker of neurologic diseases of inflammatory origin.

Expression and activation by Epstein Barr virus of human endogenous retroviruses-W in blood cells and astrocytes: inference for multiple sclerosis.

Background Proposed co-factors triggering the pathogenesis of multiple sclerosis (MS) are the Epstein Barr virus (EBV), and the potentially neuropathogenic MSRV (MS-associated retrovirus) and syncytin-1, of the W family of human endogenous retroviruses. Methodology/Principal Findings In search of links, the expression of HERV-W/MSRV/syncytin-1, with/without exposure to EBV or to EBV glycoprotein350 (EBVgp350), was studied on peripheral blood mononuclear cells (PBMC) from healthy volunteers and MS patients, and on astrocytes, by discriminatory env-specific RT-PCR assays, and by flow cytometry. Basal expression of HERV-W/MSRV/syncytin-1 occurs in astrocytes and in monocytes, NK, and B, but not in T cells. This uneven expression is amplified in untreated MS patients, and dramatically reduced during therapy. In astrocytes, EBVgp350 stimulates the expression of HERV-W/MSRV/syncytin-1, with requirement of the NF-κB pathway. In EBVgp350-treated PBMC, MSRVenv and syncytin-1 transcription is activated in B cells and monocytes, but not in T cells, nor in the highly expressing NK cells. The latter cells, but not the T cells, are activated by proinflammatory cytokines. Conclusions/Significance In vitro EBV activates the potentially immunopathogenic and neuropathogenic HERV-W/MSRV/syncytin-1, in cells deriving from blood and brain. In vivo, pathogenic outcomes would depend on abnormal situations, as in late EBV primary infection, that is often symptomatic, or/and in the presence of particular host genetic backgrounds. In the blood, HERV-Wenv activation might induce immunopathogenic phenomena linked to its superantigenic properties. In the brain, toxic mechanisms against oligodendrocytes could be established, inducing inflammation, demyelination and axonal damage. Local stimulation by proinflammatory cytokines and other factors might activate further HERV-Ws, contributing to the neuropathogenity. In MS pathogenesis, a possible model could include EBV as initial trigger of future MS, years later, and HERV-W/MSRV/syncytin-1 as actual contributor to MS pathogenicity, in striking parallelism with disease behaviour.

In vitro modulation of the multiple sclerosis (MS)-associated retrovirus by cytokines: Implications for MS pathogenesis

Multiple sclerosis (MS)-associated retrovirus (MSRV) is a component of the human endogenous retrovirus (HERV)-W family, with gliotoxic and superantigenic properties, related to MS clinical progression, and transactivated by viral agents. The authors studied MSRV modulation by cytokines involved in vivo in MS course, utilizing peripheral blood mononuclear cells from MSRV-positive and MRSV-negative individuals. Cultured cells from MSRV-negative subjects did not produce virus, whereas spontaneous MSRV release was detected in cultures from MSRV-positive donors; virus release was increased by interleukin (IL)-4 and IL-6 and, to a greater extent, by the detrimental cytokines interferonγ and tumor necrosis factor (TNF)α. Interferonβ, used in MS therapy, inhibits MSRV release. A parallel between the effects of these cytokines on MSRV production in vitro and on MS disease in vivo is observed, which deserves further elucidations.

Multiple sclerosis–associated retrovirus and MS prognosis An observational study

Abstract—MS-associated retrovirus (MSRV) in the CSF may have gliotoxic properties and could be associated with a more disabling MS. The authors tested this hypothesis in 15 untreated patients with MS: 6 MSRV− and 9 MSRV+ at the time of CSF withdrawal. After a 3-year mean follow-up, MSRV− patients showed a stable MS course, whereas MSRV+ patients had a progressive course (p = 0.01).

Multiple sclerosis and multiple sclerosis-associated retrovirus in Sardinia.

Abstract. The island of Sardinia has a high and increasing incidence of multiple sclerosis (MS). In a search for environmental factors that may account for this anomalously high incidence, we looked for evidence of multiple sclerosis-associated retrovirus (MSRV) that has previously been found in the plasma and cerebrospinal fluid of MS patients. We studied 25 MS patients and 25 matched healthy controls of ascertained Sardinian lineage. Blood samples were processed for extracellular RNA extraction. RNAs underwent reverse transcription/nested polymerase chain reaction (RT-PCR) with primers specific for MRSV-pol gene. We found a striking correlation between MSRV positivity and MS disease, but the virus was found also only in controls (100% and 12% respectively; Fishers exact test, p<0.00001). It is unclear whether MSRV exerts any pathogenic role in MS. It is possible that this is simply an epiphenomenon, but even then, it may constitute a diagnostic marker.

Novel reliable real-time PCR for differential detection of MSRVenv and syncytin-1 in RNA and DNA from patients with multiple sclerosis

Two components of the HERV-W family of human endogenous retroviruses are activated during multiple sclerosis (MS) and proposed immunopathogenic co-factors: MSRV (MS-associated retrovirus), and ERVWE1 (whose env protein, syncytin-1, reaches the plasma membrane). MSRVenv and syncytin-1 are closely related, and difficult to distinguish each other. The sequences of extracellular MSRVenv and of syncytin-1 available in GenBank were compared with those found in MS patients and controls of the cohort under study. With respect to syncytin-1, MSRVenv sequences have a 12-nucleotide insertion in the trans-membrane moiety. Based on this insertion, discriminatory real-time PCR assays were developed, that can amplify selectively either MSRVenv or syncytin-1. The data of MS patients and controls indicated that MSRV and ERVWE1 are both expressed in the brain of MS patients, while only MSRV is present in the blood; MSRV was released in culture by PBMCs of MSRV-producer individuals. These cells expressed the complete MSRVenv gene in the absence of syncytin-1 expression, up to the final, fully glycosylated envelope protein product, since western blot staining with anti-HERV-Wenv antibody detected two bands of the same molecular weight (73 and 61kDa) of the fully glycosylated and partially glycosylated HERV-Wenv uncleaved proteins. Beyond MSRVenv DNA copy numbers were more abundant in MS patients than in healthy humans, while syncytin-1 were unchanged. These findings reinforce the link between MSRV and MS.

Inhibition of multiple sclerosis-associated retrovirus as biomarker of interferon therapy

The authors performed a longitudinal evaluation of multiple sclerosis (MS) patients, during 1 year of therapy with interferon-β (IFN-β), by clinical examination and detection of presence in the blood and viral load of MS-associated retrovirus (MSRV), by MSRVenv-specific, fully quantitative, real time reverse transcriptase-polymerase chain reaction (RT-PCR). MSRV load in the blood was directly related to MS duration and fell below detection limits within 3 months of IFN therapy; one patient had strong progression, accompanied by total MSRV rescue. These findings suggest that evaluation of plasmatic MSRV could be considered the first prognostic marker for the individual patient, to monitor disease progression and therapy outcome.

Multiple sclerosis-associated retrovirus and progressive disability of multiple sclerosis

Retrovirus-like particles containing the multiple sclerosis-associated retrovirus RNA, significantly found in the cerebrospinal fluid of patients with multiple sclerosis, have been preliminarily associated with a short-term poor clinical and radiological prognosis of the disease. We asked whether these prognostic indications are still measurable after a long-term clinical evaluation (10 years). Our 10-year blind observational study confirms that the presence of multiple sclerosis-associated retrovirus in the cerebrospinal fluid of early multiple sclerosis patients is associated with a significantly greater rate of relapse-unrelated unremitting disability and secondary progression of the disease.

Multiple sclerosis-associated retrovirus in early multiple sclerosis: a six-year follow-up of a Sardinian cohort.

The human endogenous retroviruses (HERV)-W family contains an extracellular particle detected in multiple sclerosis (MS) patients and designated as MS-associated retrovirus (MSRV). Through nested RT-PCR assays specific for pol MSRV gene, we preliminary reported that its presence in the cerebrospinal fluid (CSF) of early MS patients could be indicative of a poor prognosis upon a three-year follow-up. In the present clinical study, we enlarged our blind observation up to six years. At study entry, 10 MS patients were MSRV- and eight were MSRV+ in the CSF, both groups having a similar mean age and Expanded Disability Status Scale (EDSS) score. After six year follow-up, the mean EDSS significantly differed between the MSRV- and MSRV+ cohorts (4.3 versus 2.2; P = 0.004), as did the annual relapse rate (0.5 in the MSRV- versus 0.3 in the MSRV+; P = 0.01). Finally, two MSRV- patients entered the progressive phase, whilst none of the MSRV+ group entered this phase, and 9/10 MSRV- versus 2/8 MSRV+ patients were treated with immunomodulatory or immunosuppressive drugs (P = 0.009). In conclusion, we found that the presence of MSRV virions in the CSF at the onset of MS is associated, not only with disability accumulation, but also with a higher rate of clinical re-exacerbations. With the known potential pathogenic effects of MSRV given in the literature, further investigations on MSRV are warranted.

Epstein–Barr virus and Mycobacterium avium subsp. paratuberculosis peptides are cross recognized by anti-myelin basic protein antibodies in multiple sclerosis patients

Epstein-Barr virus and Mycobacterium avium subsp. paratuberculosis (MAP) have been associated to multiple sclerosis (MS). We searched for antibodies against the homologous peptides Epstein-Barr virus nuclear antigen 1 (EBNA1)400-413, MAP_0106c protein (MAP)121-132, and myelin basic protein (MBP)85-98 on a MS Sardinian cohort, showing that these antibodies are highly prevalent among MS patients compared to healthy controls. Competitive assay demonstrated that antibodies recognizing EBNA1400-413 and MAP121-132 cross-react with MBP85-98, possibly through a molecular mimicry mechanism. Indeed, the fact that peptides from different pathogens can be cross-recognized by antibodies targeting self-epitopes supports the hypothesis that EBV and MAP might trigger autoimmunity through a common target.