MS Abstracts 01b-2g1

A series of recently published articles by a group of Austrian, German and American NeuroPathologists have proposed the existence of several different PathoGenetic pathways in Multiple Sclerosis (MS). These studies were based on both biopsy and autopsy material.

A review of the available published Clinical, Imaging and CerebroSpinal Fluid data suggest that some the cases used in those studies were more probably instances of Disseminated EncephaloMyelitis rather than MS.

This has serious implications regarding the specificity and significance of the findings in regard to MS PathoGenesis.

The specific MyelinoClastic sequence and the variable clinical course of MS are determined by the individual's Genetic endowment and Immunologic history.

Regardless of PathoGenetic pathway and clinical course, the final pathologic picture of MS is always the same. The MS Brain is Genetically programmed to produce a unique, pathoGnomonic change, the plaque with sharply demarcated borders.

Until recently, the Central Nervous System (CNS) has been considered to be an Immunologically privileged site, where the highly specialized Endothelial Blood-Brain Barrier (BBB) allows no entry of circulating Lymphocytes.

However, during inflammation in the CNS, MonoNuclear Cells readily gain access to the CNS Parenchyma.

The molecular mechanisms involved in Lymphocyte recruitment across the BBB have been mostly studied in Experimental AutoImmune EncephaloMyelitis (EAE), the prototype model for human Inflammatory DeMyelinating Diseases of the CNS such as Multiple Sclerosis (MS).

As Endothelial Cells actively participate in the regulation of Lymphocyte entry into various tissues, it is likely that the specialization of the BBB Endothelium extends to CNS-specific traffic signals involved in Lymphocyte recruitment.

Identification of the traffic signals mediating entry of Lymphocytes into the CNS is likely to be of great clinical importance, as blocking the responsible molecules possibly offers new specific routes of treatment of CNS Inflammatory Diseases.

Such a therapeutic regime, however, is not yet available. Rather, acute MS is often treated with high dose GlucoCorticoids.

Current evidence for a possible role of GlucoCorticoids in regulating the expression of Adhesion Molecules and thus inhibiting T-Cell recruitment across the BBB is discussed.

Objectives
To quantify, using Diffusion Tensor Imaging (DTI), the tissue damage in lesions and Normal-Appearing White Matter (NAWM) from a large cohort of patients with MS.

And, to investigate the magnitude of the correlation between DTI-derived metrics and clinical disability.

Methods
Dual-Echo and DTI scans were obtained from 78 patients with Relapsing/Remitting, Secondary/Progressive, or Primary/Progressive MS and from 20 normal control participants. Post-contrast T₁-weighted images were also obtained from the patients.

After creating Mean Diffusivity () and Fractional Anisotropy (FA) images and image coregistration.

FA values were measured for 4,846 Lesions:
• 3,207 NonEnhancing T₁-IsoIntense
• 1,511 NonEnhancing T₁-HypoIntense
•   128 Enhancing
•   497 NAWM areas from patients
•   160 White Matter areas from controls

Results
The average lesion was higher and the average lesion FA was lower than the corresponding quantities of the NAWM (p < 0.001).

The values of Enhancing and NonEnhancing Lesions were not different, whereas Enhancing lesions had lower FA (p < 0.001).

T₁-HypoIntense lesions had higher and lower FA than T₁-IsoIntense lesions (p < 0.001). NAWM of patients had higher and lower FA than White Matter of controls (p = 0.01).

Significant correlations were found between T₁ and T₂ lesion volume and and FA of lesions and NAWM.

In the overall patient sample, a moderate correlation was also found between lesion and the Expanded Disability Status Scale score (r = 0.28, p = 0.01).

However, the r value of this correlation was 0.48 in patients with Secondary/Progressive MS, whose Disability was also correlated with average lesion FA (r = -0.50).

Conclusions
The results of this study show that DTI is able to identify MS lesions with severe tissue damage and to detect changes in the NAWM.

They also indicate that DTI-derived measures are correlated with clinical disability, especially in patients with Secondary/Progressive MS, thus suggesting a role for DTI in monitoring advanced phases of the disease.

Background
MS is common in people of Northern European ethnicity who live in Northern geographic areas; however, MS is rarely identified among Aboriginal peoples living in the same areas.

Objectives
To determine the prevalence, clinical features, HLA type, and Viral infections associated with MS among Aboriginals in Manitoba, Canada.

Methods
A retrospective study was performed in which the clinical features of all Aboriginal patients with MS together with HLA type and Human HerpesVirus-6, HIV-1, human T-Cell LymphoTropic Virus-1.

And, endogenous RetroVirus associated with MS (MSRV) infections were analyzed and compared with results from NonAboriginal patients with MS.

Results
Seven Aboriginals with MS were identified with a period prevalence among Aboriginals of 40:100,000.

Clinical features included Relapsing/Remitting (n = 6) or Primary/Progressive (n = 1) phenotypes with aggressive disease courses and frequent involvement of Optic Nerves and Spinal Cord (n = 5) compared with NonAboriginal patients.

Autopsy of one patient showed Necrosis and Eosinophil infiltrates in a Cervical Spinal Cord lesion and a DeMyelinated Optic Nerve.

Analysis of HLA alleles at the DRB1 and DQB1 loci indicated that the HLA types detected were common in Aboriginals, but there were no HLA alleles previously associated with the development of MS.

Analysis of the copy number of MRSV did not show differences among Aboriginals and NonAboriginals with or without MS.

Conclusions
Aboriginals of Algonkian background are at increased risk for an aggressive type of MS, resembling NeuroMyelitis Optica.

Which, is resistant to conventional MS treatments and occurs independently of HLA alleles previously associated with MS.

Multiple Sclerosis (MS) is a Chronic Inflammatory DeMyelinating disease of unknown cause that afflicts the Central Nervous System.

MS is typified by a highly clonally restricted Antigen-driven AntiBody response that is confined largely to the Central Nervous System.

The major Antigenic targets of this response and the role of AntiBody in disease PathoGenesis remain unclear.

To help resolve these issues, we cloned the Ig G repertoire directly from active plaque and PeriPlaque regions in MS Brain and from B-Cells recovered from the CerebroSpinal Fluid of a patient with MS with subacute disease.

We found that high-affinity Anti-DNA AntiBodies are a major component of the Intrathecal IgG response in the patients with MS that we studied.

Furthermore, we show DNA-specific MonoClonal AntiBodies rescued from two subjects with MS as well as a DNA-specific AntiBody.

Rescued from an individual suffering from Systemic Lupus Erythematosus bound efficiently to the surface of Neuronal Cells and Oligodendrocytes.

For two of these AntiBodies, cell-surface recognition was DNA dependent.

Our findings indicate that Anti-DNA AntiBodies may promote important NeuroPathologic mechanisms in Chronic Inflammatory Disorders, such as MS and Systemic Lupus Erythematosus.

Background
There has been some concern that vaccination may precipitate the onset of Multiple Sclerosis or lead to relapses.

Since the recent Hepatitis B vaccination program in France, there have been new reports of an increased risk of active Multiple Sclerosis after vaccination.

Methods
We conducted a case-crossover study to assess whether vaccinations increase the risk of relapse in Multiple Sclerosis.

The subjects were patients included in the European Database for Multiple Sclerosis who had a relapse between 1993 and 1997.

The index relapse was the first relapse confirmed by a visit to a Neurologist and preceded by a relapse-free period of at least 12 months.

Information on vaccinations was obtained in a standardized telephone interview and confirmed by means of medical records.

Exposure to vaccination in the two-month risk period immediately preceding the relapse was compared with that in the four previous two-month control periods for the calculation of relative risks, which were estimated with the use of conditional logistic regression.

Results
Of 643 patients with relapses of Multiple Sclerosis, 15 percent reported having been vaccinated during the preceding 12 months.

The reports of 94 percent of these vaccinations were confirmed.

Of all the patients, 2.3 percent had been vaccinated during the preceding two-month risk period as compared with 2.8 to 4.0 percent who were vaccinated during one or more of the four control periods.

The relative risk of relapse associated with exposure to any vaccination during the previous two months was 0.71 (95 percent confidence interval, 0.40 to 1.26).

There was no increase in the specific risk of relapse associated with Tetanus, Hepatitis B, or Influenza vaccination (range of relative risks, 0.22 to 1.08).

Analyzes based on risk periods of one and three months yielded similar results.

Conclusions
Vaccination does not appear to increase the short-term risk of relapse in Multiple Sclerosis.

Background
Reports of Multiple Sclerosis developing after Hepatitis B vaccination have led to the concern that this vaccine might be a cause of Multiple Sclerosis in previously healthy subjects.

Methods
We conducted a nested case-control study in two large cohorts of Nurses in the United States, those in the Nurses' Health Study.

Which has followed 121,700 women since 1976 and those in the Nurses' Health Study II, which has followed 116,671 women since 1989).

For each woman with Multiple Sclerosis, we selected as controls five healthy women and one woman with breast Cancer.

Information about Hepatitis B vaccination was obtained by means of a mailed questionnaire and was confirmed by means of vaccination certificates.

The analyzes included 192 women with Multiple Sclerosis and 645 matched controls and were conducted with the use of conditional logistic regression.

Results
The multivariate relative risk of Multiple Sclerosis associated with exposure to the Hepatitis B vaccine at any time before the onset of the disease was 0.9 (95 percent confidence interval, 0.5 to 1.6).

The relative risk associated with Hepatitis B vaccination within two years before the onset of the disease was 0.7 (95 percent confidence interval, 0.3 to 1.8).

The results were similar in analyzes restricted to women with Multiple Sclerosis that began after the introduction of the recombinant Hepatitis B vaccine.

There was also no association between the number of doses of vaccine received and the risk of Multiple Sclerosis.

Conclusions
These results indicate no association between Hepatitis B vaccination and the development of Multiple Sclerosis.

RANTES is a ß-family Chemokine with potent ChemoAttractant activity for Lymphocytes and Monocytes that are implicated in the PathoGenesis of Multiple Sclerosis (MS) lesions.

Glial Cells have been shown to produce RANTES in response to stimulation with Th1 Cytokines (IFN-gamma, TNF-, and IL-1ß) in vitro, and they may be a major source of RANTES production within diseased Brain.

This study was undertaken to investigate the mechanism underlying the effect of the Th1 Cytokines on the induction of RANTES in a model system for human Astroglia.

We show that IFN- has a synergistic effect with TNF- or IL-1ß on RANTES mRNA and Chemokine production in this system.

We further show that the combination treatment of IFN- and TNF-, or IFN- and IL-1ß induced 3-fold higher levels of RANTES Gene transcription than seen with either TNF- or IL-1ß alone, as measured by in vitro nuclear transcript elongation assays.

In addition, we found that IFN- decreased the rate of degradation of RANTES mRNA, caused by TNF- or IL-1ß.

The t(1/2) of RANTES mRNA was 25+/-1 h in the presence of both IFN- and TNF-, as compared to a t(1/2) of 15+/-1 h in the presence of TNF- alone. This 10 h difference represents an approximate 70% increment in RANTES mRNA half-life.

Thus, these results suggest that both increased RANTES Gene transcription and increased RANTES mRNA stability may account for the synergistic effect of Th1 Cytokines on the up-regulation of RANTES expression in human Astroglial Cells.

Identification of the causative agent of Multiple Sclerosis (MS) has long eluded investigators and has become the "Holy Grail" of researchers in the field.

The Immune Response in CerebroSpinal Fluid of patients with MS, indicated by an increased IgG level and the presence of specific OligoClonal Bands after Electrophoresis.

Strongly parallels that found in various infectious diseases of the Central Nervous System.

To understand the nature of B-Lymphocyte activation in MS, 4 laboratories studied the Antigen-binding regions of AntiBodies found in MS Brain DeMyelinative Plaques and CerebroSpinal Fluid. Each analysis revealed:

1. Limited germline expression, results not expected for a random bystander response
2. Features consistent with a specific Antigen-targeted process
3. The clonal expansion of populations of B-Lymphocytes in MS

The screening of libraries expressing protein products derived from chronic MS plaque messenger RNA with AntiBodies purified from Plaques, CerebroSpinal Fluid, or Serum of patients with MS has thus far not revealed the Antigenic target(s) of the MS AntiBody response.

Because putative MS Antigens could be in low abundance, the screening of large libraries of random Peptides expressed on phage surfaces might offer an alternative approach to identify Peptide sequences recognized by MS AntiBodies.

New sophisticated molecular Immunologic techniques described herein should enhance our ability to identify putative Antigen(s) targets in MS.