MS Abstracts: 3e-2g

Hybridoma Cells, which secrete an IgM AntiGalactoCerebroside, were implanted into the Spinal Cord of Cyclosporine-treated juvenile or adult rats, and the animals were sacrificed approximately 2-3 wk later.

About half the recipient animals developed Myelin lesions. In some, sharply circumscribed foci of DeMyelination formed within the Dorsal Columns.

Cellular reaction consisted of Macrophages containing refractile globules in the Parenchyma and within enlarged PeriVascular spaces as well as thickened Endothelial Cells.

"Shadow plaques" also developed, i.e. regions in which Axons were surrounded by thin Myelin Sheaths, compatible with ReMyelination.

In addition, we found damaged Axons, some of which were swollen with Organelles, comparable to the enlarged Axon profiles seen at sites of constriction or interruption.

Compromize of the Blood-Brain Barrier at sites of Hybridoma growth was demonstrated by extravasation of Evans blue dye. Discontinuation of Cyclosporine was followed by an Anti-Hybridoma, Complement-fixing AntiBody response within 2-3 d.

This model of focal CNS DeMyelination and ReMyelination, with evidence of some Axon damage, is mediated by a defined IgM AntiGlycoLipid MonoClonal AntiBody secreted within the Spinal Cord Parenchyma.

The lesions, which are similar to those of Multiple Sclerosis, probably result from the interaction between the Intrathecally secreted IgM AntiBody and Complement entering from the circulation at foci of compromized Blood-Brain Barrier plus activation of endogenous or Hematogenous Macrophages via their Complement receptors.

Myelination provides extrinsic Trophic signals that influence normal maturation and long-term survival of Axons. The extent of Axonal involvement in diseases affecting Myelin or Myelin forming cells has traditionally been underestimated.

There are, however, many examples of Axon damage as a consequence of DysMyelinating or DeMyelinating Disorders. More than a century ago, Charcot described the Pathology of Multiple Sclerosis (MS) in terms of DeMyelination and relative sparing of Axons.

Recent reports demonstrate a strong correlation between inflammatory DeMyelination in MS lesions and Axonal transection, indicating Axonal loss at disease onset.

Disruption of Axons is also observed in Experimental Allergic EncephaloMyelitis and in Theiler's murine EncephaloMyelitis Virus Disease, two animal models of inflammatory DeMyelinating CNS disease.

A number of DysMyelinating mouse mutants with Axonal pathology have provided insights regarding cellular and molecular mechanisms of Axon degeneration.

For example, the Myelin-Associated GlycoProtein and ProteoLipid Protein have been shown to be essential for mediating Myelin-derived Trophic signals to Axons.

Patients with the Inherited Peripheral Neuropathy Charcot-Marie Tooth Disease type 1 develop symptomatic progressive Axonal loss due to abnormal Schwann Cell expression of peripheral Myelin protein 22.

The data summarized in this review indicate that Axonal Damage is an integral part of Myelin Disease, and that loss of Axons contributes to the irreversible functional impairment observed in affected individuals.

Early NeuroProtection should be considered as an additional therapeutic option for these patients.

ReMyelination is an extremely efficient process in the adult rodent Central Nervous System yet the source of new Oligodendroglia that appear following primary DeMyelination is still subject to much debate.

Using a reliable marker for Oligodendroglial Progenitor Cells in vivo, the NG2 Chondroitin Sulphate ProteoGlycan, we have evaluated the response of endogenous NG2⁺ Cells in the adult rat BrainStem and Cerebellum to inflammatory DeMyelinating lesions.

In an experimentally induced animal model of Multiple Sclerosis (MS), AntiBody augmented Experimental Allergic EncephaloMyelitis (ADEAE).

We have manipulated T-Cell mediated EAE in Lewis rats by injecting either:
1. Anti-Myelin/Oligodendroglial Glycoprotein (MOG) AntiBodies to induce Inflammatory DeMyelination
2. Non-specific mouse ImmunoGlobulins to induce an Inflammatory Response without DeMyelination.

We have examined the relationship of NG2⁺ Progenitor Cells to Microglia (OX-42⁺), Astrocytes (GFAP⁺) and mature Oligodendroglia (CNP⁺), in the normal and DeMyelinated CNS.

In the normal CNS NG2-expressing cells are closely intermingled with other Glia but represent a distinct cell population.

A prominent inflammatory response, identified by the presence of large PeriVascular and PeriVentricular accumulations of reactive OX42⁺ Macrophages/Microglia, occurred in animals with ADEAE at 7-9 days post injection (DPI), coinciding with severe clinical symptoms.

In animals injected with anti-MOG AntiBodies inflammation was followed by the appearance of large areas of DeMyelination at 11-14 DPI, at which point the animals had recovered clinically.

The response of NG2⁺ cells was different depending on whether the inflammation was accompanied by DeMyelination.

In the presence of inflammation, NG2⁺ Cells responded by an increase in ImmunoReactivity and an alteration in their morphology, exhibiting enlarged cell bodies and an increased number of intensely stained processes.

In areas of DeMyelination NG2⁺ Cells had fewer intensely stained processes reminiscent of progenitor cells seen during development.

Quantitative analysis revealed a 3-fold increase in the number of NG2⁺ Cells in DeMyelinated lesions at 11 DPI, whereas no change was observed in areas of inflammation in the absence of DeMyelination.

Mitotic figures were only seen in NG2⁺ Cells in areas of DeMyelination. NG2⁺ Cell numbers appeared to return to control levels following ReMyelination.

These results suggest that endogenous Oligodendroglial progenitors divide and/or migrate, in response to signals triggered by DeMyelinating rather than inflammatory events, to generate a large progenitor population sufficient to promote the rapid and successful ReMyelination observed in this model.

Multiple Sclerosis (MS) is an Inflammatory DeMyelinating disease of the Central Nervous System and one of the earliest changes in inflammatory focus involves the activation of Vascular CerebroVascular Endothelial Cells.

We determined the Plasma level of PlasMinogen Activator Inhibitor-1 (PAI-1), a key regulator of FibrinoLysis and Cell Migration, in patients with MS.

The level of Plasma PAI-1 was significantly higher in active MS cases when compared to stable MS and controls.

Plasma concentrations of tissue PlasMinogen Activator, Transforming Growth Factor beta-1, and LipoProtein-a remained normal in spite of disease activity.

These results suggested that PAI-1 Plasma levels are associated with MS disease activity and is a good marker for MS relapse.

In children, Multiple Sclerosis is rare and has some clinical and paraclinical differences compared with adults. The assessment of CorticoSpinal Motor Tracts is expected to be relevant because of their frequent early involvement in this disease.

Reported are the results of TransCranial Magnetic Stimulation in two children who presented at 12 and 9 years of age with Clinically Probable and Definite Multiple Sclerosis, respectively.

In Patient 1 the excitatory Cortical threshold for the upper limbs was abnormally raised.

In Patient 2 the latency of the Motor-Evoked Potentials was considerably increased for the right Tibialis Anterior Muscle, with a slowing of the Central Conduction Time.

Although these abnormalities may be consistent with Central Conduction Impairment, they may alternatively suggest early Axonal Damage, because irreversible Axonal lesions occurring at the onset of the disease have recently been reported.

Testing of Central Motor Tracts, in addition to Visual, Auditory, and SomatoSensory Pathways, therefore appears appropriate in the multimodal assessment of pediatric patients with suspected Multiple Sclerosis.

Background
Neutrailzing AntiBodies (NABs) against Interferon-ß have been described in one third of patients with Multiple Sclerosis treated with Interferon-ß. We have analyzed the frequency of NABs and their clinical consequences.

Patients And Methods
We have studied 68 patients. NABs were determined by protein A MyxoVirus assay.

Results
Positive NABs were detected in 13% of the patients after 2 years of treatment.

Conclusions
It does not seem to exist a relationship between presence of NABs and a poor evolution of the disease in our patients with Multiple Sclerosis treated with Interferon-ß.

Theiler's Murine EncephaloMyelitis Virus (TMEV) belongs to the genus CardioVirus of the family PicornaViridae and is divided into two subgroups on the basis of different biological activities.

GDVII subgroup strains produce acute and fatal PolioEncephaloMyelitis in mice with no Virus persistence. In contrast, DA or TO subgroup strains cause an early nonfatal PolioEncephaloMyelitis.

TMEV is thought to be an excellent animal model for the human DeMyelinating Disease, Multiple Sclerosis.

Data suggest that Macrophages are a major reservoir harboring the Virus. A small out-of-frame protein designated L* is synthesized in DA subgroup strains from an alternative, out-of-frame, initiation site.

Studies of a DA mutant virus, having an ACG rather than an AUG and therefore does not synthesize L* protein, demonstrate that this protein is important for Virus growth in particular cell types and is critical for DA-induced DeMyelinating disease and Virus persistence.

In addition, TMEV can be used as a vector for delivering foreign sequences into the Central Nervous System.

Background
HHV-6 is a ubiquitous Virus and its infection usually occurs in childhood and then becomes a latent infection. HHV-6 reactivation has been shown to play a role in the PathoGenesis of AIDS and several other diseases.

Objectives
To determine what role HHV6 infection or reactivation plays in the PathoGenesis of Multiple Sclerosis (MS) and Chronic Fatigue Syndrome (CFS).

Results
Twenty-one MS and 35 CFS patients were studied and followed clinically. In these patients, we measured HHV-6 IgG and IgM AntiBody levels and also analyzed their Peripheral Blood MonoNuclear Cells (PBMCs) for the presence of HHV-6, using a short term culture assay.

In both MS and CFS patients, we found higher levels of HHV-6 IgM AntiBody and elevated levels of IgG AntiBody when compared to healthy controls.

Seventy percent of the MS patients studied contained IgM AntiBodies for HHV-6 late Antigens (capsid), while only 15% of the Healthy Donors (HD) and 20% of the patients with Other Neurological Disorders (OND) had HHV-6 IgM AntiBodies.

Higher frequency of IgM AntiBody was also detected in CFS patients (57.1%) compared to HD (16%).

Moreover, 54% of CFS patients exhibited AntiBody to HHV-6 early protein (p41/38) compared to only 8.0% of the HD. Elevated IgG AntiBody titers were detected in both the MS and the CFS patients.

PBMCs from MS, CFS and HD were analyzed in a short term culture assay in order to detect HHV-6 Antigen expressing cells and to characterize the Viral isolates obtained as either Variant A or B.

Fifty-four percent of MS patients contained HHV-6 early and late Antigen producing cells and 87% of HHV-6 isolates were Variant B.

Isolates from CFS, patients were predominately Variant A (70%) and isolates from HD were predominately Variant B (67%).

Moreover, one isolate from OND was also Variant B. Persistent HHV-6 infection was found in two CFS patients over a period of 2.5 years and HHV-6 specific Cellular Immune Responses were detected in PBMCs from ten CFS patients.

Conclusions
In both MS and CFS patients, we found increased levels of HHV-6 AntiBody and HHV-6 DNA. A decrease in Cellular Immune Responses was also detected in CFS patients. These data suggest that HHV-6 reactivation plays a role in the PathoGenesis of these disorders.

Background
Progressive Multifocal Leukoencephalopathy (PML) and Multiple Sclerosis (MS) are DeMyelinative Diseases of the Central Nervous System (CNS).

PML occurs mostly in individuals with AIDS-impaired immunity and is thought to be caused by JC polyoma virus (JCV). In MS a NeuroTrophic Virus trigger is suspected, but the precise etiology remains unknown.

Human HerpesVirus 6 (HHV6) is a ubiquitous, commensal and usually benign beta-HerpesVirus. Some researchers have found evidence for HHV6 infection in MS plaques and sera.

We recently demonstrated a high frequency of cells containing HHV6 Genome in PML lesions, as well as co-infection of Oligodendrocytes by JCV and HHV6.

This suggests that HHV6 may be a co-factor in the etiology of PML, and raises questions about its role in other DeMyelinative Diseases.

Objectives
To determine the prevalence and cellular localization of HHV6, JCV and HIV-1 infected cells in PML, MS, AIDS and control CNS tissues, and their potential relationship with disease.

Study Design
An unconventional, sensitive two-step In Situ Polymerase Chain Reaction (ISPCR) procedure was used to amplify and detect HHV6, JCV and HIV-1 genomic DNAs in formalin fixed, paraffin-embedded archival CNS tissues.

HHV6, JCV and HIV-1 Gene expression was detected by ICC for HHV6 p41 and gp101, JCV large T, and HIV-1 p24 gag and NEF proteins.

Results
A high frequency of HHV6 genome was consistently detected in both PML and MS White Matter lesional cells; a Peri-Lesional concentration was notable.

HHV6 was found mainly in Oligodendrocytes, but Neurons were also infected. HHV6 was present in larger amounts than JCV in PML lesions, while more HIV-1 than HHV6 was present in AIDS.

Variable amounts of HHV6 genome were detected in normal, AIDS and other control brains; the frequency of infected cells tended to increase with patient age.

Conclusions
High concentrations of HHV6 genome in association with PML and MS lesions, open the possibility that HHV6 activation may play a role in the PathoGenesis of these DeMyelinative diseases.