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 and optic neuritis.

One prognostic factor for early multiple sclerosis (MS) patients to develop a definite MS may be the presence of the MS-associated retrovirus (MSRV) in the cerebrospinal fluid (CSF). We designed a specific study on a cohort of optic neuritis (ON) patients to evaluate the MSRV-dependent conversion to MS relative to the prediction conferred by magnetic resonance imaging (MRI) and CSF abnormalities. At follow-up, 33.3% MSRV+ and 0% MSRV- ON patients developed MS (P = 0.03). The prediction value is lower than that given by CSF and MRI abnormalities (42.3%). This intriguing finding is discussed in the light of the abundant discrepancies observed in the MSRV literature. Multiple Sclerosis 2006; 12: 357-359. www.multiplesclerosisjournal.com

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.

Multiple sclerosis-associated retrovirus and MS prognosis: an observational study.

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 complexity in selected populations: the challenge of Sardinia, insular Italy.

Several lines of evidence indicate a genetic contribution to multiple sclerosis (MS) both in terms of predisposition to the disease and of immunological mechanisms which are known to play crucial roles in MS pathogenesis. The presence of high- and low-risk areas for MS in neighbouring regions supports the theory that MS predisposition is influenced by a complex interaction of genetic and environmental factors. Therefore, the use of genetically homogeneous and geographically isolated populations becomes an increasing requirement to reduce biasing biological variables. Sardinians fulfil these conditions well because of their different phylogeny from Europeans and the unique selective pressures which shaped their genome. Sardinians display amongst the highest MS prevalence rates world-wide and increasing MS incidence rates over time. Also, MS in Sardinia is linked to distinct human leucocyte antigen (HLA) alleles and associated to different patterns of cytokine production from lymphoid cells of different HLA subtypes. In this context, recent findings and future perspectives on the peculiarities of Sardinian MS concerning genetic, immunological and epidemiological aspects are presented. So far, our results indicate that variations at the level of territorial distribution and HLA-association are present which render MS heterogeneous even in this ethnically homogeneous population.

Multiple sclerosis-associated retrovirus (MSRV) in Sardinian MS patients.

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.

Multiple sclerosis and multiple sclerosis-associated retrovirus in Sardinia.

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; Fisher's 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.

Genetic susceptibility to multiple sclerosis in Sardinians: an immunological study.

OBJECTIVES: We studied the in vitro production of variably MS-related cytokines from Sardinian MS and healthy donors bearing the two "Sardinian" MS-associated HLA-DR alleles: DR3 and DR4, with the purpose to evidentiate possible differences in their immune response. MATERIALS AND METHODS: ELISA were used for detection of cellular products by mitogen-activated peripheral blood mononuclear cells. RESULTS: PHA-activated HLA-DR4+/DR3- mononuclear cells produce significantly higher amounts of TNF-alpha compared with the DR3+/DR4-. In addition, homozygous HLA-DR3+ mononuclear cells from MS patients produce significantly lower amounts of IL-10 than those from homozygous HLA-DR3+ healthy donors. CONCLUSION: The abnormal production of detrimental or regulatory cytokines may account for the genetic susceptibility to MS in different HLA-subgroups of Sardinian MS patients.

Inhibition of HIV type 1 BaL replication by MIP-1alpha, MIP-1beta, and RANTES in macrophages.

The beta-chemokines RANTES, MIP-1alpha, and MIP-1beta have been shown to inhibit the infection of T cells by macrophage-tropic HIV-1 strains by blocking env-driven HIV-1 fusion through competition for the chemokine receptors or receptor downregulation. This study was aimed at testing whether beta-chemokines also inhibit the productive infection of monocyte-derived macrophages (MDMs) by a monocytotropic HIV-1 strain, by using virus yield assays. The action of the beta-chemokines MIP-1alpha, MIP-1beta, and RANTES was captured with that of the alpha-chemokine interleukin 8 (IL-8) and of interferon alpha (IFN-alpha), which is a well-known broad-range inhibitor of viral replication. While IL-8 did not inhibit HIV-1 BaL replication in MDMs, the beta-chemokines were dose-dependently inhibitory. RANTES was the most effective, reaching at 300 ng/ml a protection similar to that obtained with IFN-alpha at 1000 IU/ml, and was even more inhibitory when added to MDMs after virus attachment. In contrast to IFN-alpha, the antiviral activity of beta-chemokines was restricted to HIV, because another virus was not inhibited. As compared with untreated MDMs, full-length proviral DNA at day 1 postinfection was inhibited in MDMs treated with RANTES either before or after the absorption phase, and even more so in IFN-treated MDMs, whereas in IL-8-treated MDMs no inhibition was observed. Our results indicate that in MDMs both RANTES and IFN affect early steps of HIV-1 BaL replication, preceding the completion of viral DNA synthesis.

Increased replication of T-cell-tropic HIV strains and CXC-chemokine receptor-4 induction in T cells treated with macrophage inflammatory protein (MIP)-1alpha, MIP-1beta and RANTES beta-chemokines.

OBJECTIVE AND DESIGN: To study, in T-lymphoid cells, the effects of macrophage inflammatory protein (MIP)-1alpha, MIP-1beta and RANTES beta-chemokines on the replication of T-cell-tropic HIV-1 strains, since it has been reported that beta-chemokines interfere with the replication of macrophage-tropic HIV-1 strains, but not T-cell-tropic strains. METHODS: Freshly phytohaemagglutinin (PHA)-activated peripheral blood lymphocytes (PBL) and cultured PHA-activated T cells from healthy volunteers, as well as the C8166 T-cell line, were treated overnight with beta-chemokines before infection with T-cell-tropic HIV-1 isolates, or human T-lymphotropic virus type IIIB. HIV replication was followed by detecting the production of infectious particles, p24 antigen, and viral sequences. CXC-chemokine receptor (CXCR)-4 expression was followed by detection and quantification of specific transcripts. RESULTS: Pretreatment of T cells with MIP-1alpha, MIP-1beta and RANTES affected T-cell-tropic strains, increased the replication of HIV-1beta and HIV-1RPdT strains dose-dependently, as well as virus absorption and provirus DNA accumulation. These findings were associated with increased accumulation of CXCR-4 transcripts, and mediated by the protein tyrosine kinase signalling. Moreover, beta-chemokines stimulated PBL proliferation. CONCLUSIONS: Beta-chemokines increase the adsorption and replication of at least some T-cell-tropic HIV-1 strains, and this is related to stimulated expression of the CXCR-4 coreceptor.

Heparin-binding domain of human fibronectin binds HIV-1 gp120/160 and reduces virus infectivity.

In vitro experiments indicate that components of the host present in body fluids may prevent the attachment of human immunodeficiency virus type 1 (HIV-1) to target cells. Fibronectin (Fn), a dimeric 440-kDa extracellular matrix adhesion protein, is secreted by mesenchymal cells and assembled into insoluble matrices. Fn exerts important effects on cell growth and differentiation through a number of discrete functional domains. Several microorganisms are known to bind Fn. We show that, under physiological conditions, HIV-1 gp120 and gp160 are capable of binding plasma and cellular Fn as well as laminin and vitronectin. Experiments were set up to analyze in detail the binding of HIV gp120 and gp160 to Fn. The gp120 and gp160 specifically recognize the C-terminal heparin-binding domain of Fn (Fn-CTHBD) with a calculated KD of 2.8 x 10(-7) M for gp160. Binding of gp160 to Fn-CTHBD is a saturable and specific process that is blocked by antibodies to Fn-CTHBD and by heparin and is inhibited to a minor extent by heparan sulfate and dextran sulfate. These observations suggest that gp120/160 specifically recognize the III15 repeat within Fn-CTHBD. Intact Fn and Fn-CTHBD strongly inhibit the interaction of gp120/160 with soluble CD4 and, under low serum conditions, are capable of neutralizing the infectivity of HIV-1 for CD4-positive T cells. Thus, Fn that is present in plasma and mucinous secretions may well affect HIV infectivity and virus distribution in vivo.

Persistent infection of human vascular endothelial cells by group B coxsackieviruses.

Group B coxsackieviruses (CVBs) cause >20% of the cases of myocarditis and dilated cardiomyopathy. Information on the permissiveness of vascular cells to CVBs is scant. Interactions of CVBs with human vascular endothelial cells (ECs) were investigated in vitro. All 6 CVBs (CVB-1 to -6) consistently infected primary EC cultures and an immortalized EC line without producing cytopathology. Whereas replication of types 1, 2, 4, and 6 ceased within 30-60 days after infection, CVB-3 and -5 caused a persistent infection. Replication of CVB-3 and -5 continued for >260 days. In ECs, the constitutive production of interferon-beta, but not of other cytokines, appeared to confer resistance to CVBs. Persistence of CVB-3 and -5 was associated with the chronic release of tumor necrosis factor-alpha, a cytotoxic cytokine that also has a negative inotropic effect on myocardial cells. The results suggest that chronic endothelial CVB infections may play a role in vascular disease.

Productive HIV-1 infection of human vascular endothelial cells requires cell proliferation and is stimulated by combined treatment with interleukin-1 beta plus tumor necrosis factor-alpha.

Vascular endothelial cells (EC) play a key role in viral tropism in vivo. Since conflicting reports have been published on the capability of HIV to infect EC in vitro, we analyzed some factors potentially capable of influencing the susceptibility of human umbilical vein endothelial cells (HUVEC) to HIV-1. Both primary cultures and differentiated immortalized HUVEC lines were used. HUVEC were negative for the expression of CD4, but weakly CD26- and galactosylceramide-positive. Although binding of HIV to EC was substantial, the virus was apparently incapable of replicating in nonproliferating cultures. In resting cultures, the content of cell-associated HIV disappeared 4-6 days after infection without production of p24 and infectious progency. In contrast, infection of proliferating EC cultures led to the transient release of p24 and infectious virus (10(2.5)-10(3.5) SFU/ml) peaking 2-6 days postinfection. Antibody neutralization of cytokines that may be produced by EC (IL1, IL6, IL8, TNF, IFN-beta) failed to modify virus adsorption and replication, whereas treatment with IL1-beta plus TNF-alpha stimulated both virus binding and virus release. As seen by gag polymerase chain reaction (PCR), the viral genome persisted up to 15 days in untreated EC cultures, but over 20 days in cultures exposed to IL1-beta plus TNF-alpha. This study shows that: (a) CD4-negative HUVEC are capable of binding substantial amounts of HIV-1; (b) binding is enhanced by proinflammatory cytokines; (c) the establishment of productive infection is favored by cell proliferation; and (d) exposure to IL1-beta plus TNF-alpha enhances virus replication.

Productive HIV-1 infection of normal human mammary epithelial cells.

OBJECTIVE AND DESIGN: To determine the susceptibility of mammary epithelial cells (MEC) to HIV-1 as breastfeeding is an established route of HIV transmission, although the origin of virus in breastmilk is unclear. METHODS: Primary epithelial cell cultures were derived from the mammary glands of healthy donors; immortalized MEC lines were also used. HIV infection was followed by detection of infectious particle production, p24 antigen and viral sequences. RESULTS: Seven out of 11 primary MEC cultures and two out of three MEC lines were productively infected by HIV-1. Virus replication significantly reduced cell proliferation, although cell viability was only slightly affected. Cytopathic changes were not observed. MEC cultures expressed low levels of surface CD4, galactosylceramide and CD26, but essentially no human leukocyte antigen (HLA)-DR. Infection of HIV-permissive MEC cells was associated with the upregulation of surface HLA-DR and CD26. In contrast, the expression of CD4, tissue-specific markers, adhesion molecules and growth-factor receptors was downregulated. To a lesser extent, similar effects were also observed in non-permissive cells. Hormones (triiodothyronine plus beta-estradiol and prolactin) enhanced HIV replication, possibly through the stimulation of cellular DNA synthesis. CONCLUSIONS: We concluded that HIV-1 replication in ductal/alveolar MEC may be, in part, responsible for the presence of HIV-1 in milk; that hormones may stimulate virus replication; and that infection reduces the growth of epithelial cells. Although in vitro HIV is produced by MEC to a lesser extent than lymphoid cells, MEC-derived HIV might have selective advantages for the infection of mucosal epithelial cells during breastfeeding.