Previous studies have shown that activated T-Cells can successfully cross Endothelial barriers and will accumulate in tissue which contains their specific Antigen.

Myelin specific T-Cells (e.g. Myelin Basic Protein specific) are recognized to play an important role in the induction of Experimental AutoImmune DeMyelinating disease of the CNS and have been shown to induce Blood-Brain Barrier breakdown effectively.

In this study we injected T-Cells reactive to a Non-Neural Antigen (Ovalbumin) systemically into Lewis rats and caused them to accumulate in the Thoracic Dorsal Column by a prior injection of Ovalbumin.

Selected rats were given systemic DeMyelinating AntiBody, AntiMyelin Oligodendrocyte AntiBody (Anti-MOG AntiBody), to provide evidence of permeability changes to the Blood-Brain Barrier.

These animals were compared with control rats given systemic Anti-P0 MonoClonal AntiBody and to other rats given a direct micro-injection (3 mul) of Anti-MOG AntiBody into the Thoracic Dorsal Column.

All animals were monitored by serial NeuroPhysiological studies and by Histological examination.

Direct Anti-MOG AntiBody injection produced a focal Conduction Block at the injection site and a large circumscribed area of primary DeMyelination with Axonal preservation within the Dorsal Column.

An even more profound Conduction Block and more extensive plaque-like region of DeMyelination were seen in animals given Antigen, activated T-Cells and systemic AntiBody.

However, animals given Antigen and T-Cells without relevant AntiBody did not show Conduction impairment or DeMyelination, except when very large numbers of T-Cells were given; such rats developed severe irreversible Axonal damage.

This study demonstrates the Blood-Brain Barrier is disrupted by activated T-Cells of non-Neural specificity and allows large plaque-like regions of DeMyelination to form in the presence of circulating AntiMyelin AntiBody. The relevance of this finding to Multiple Sclerosis is discussed.

Tumor Necrosis Factor-alpha (TNF-) has been causally implicated in several DeMyelinating Disorders, including Multiple Sclerosis.

Because Insulin-like Growth Factor I (IGF-I) is a potent stimulator of Myelination, we investigated whether it can protect Oligodendrocytes and Myelination from TNF--induced damage using mouse Glial cultures as a model.

Compared with controls, TNF- decreased Oligodendrocyte number by approximately 40% and doubled the number of Apoptotic Oligodendrocytes and their precursors.

Addition of Boc-Aspartyl(Ome)-Fluoromethyl ketone (BAF), an inhibitor of InterLeukin-1ß Converting Enzyme (ICE)/caspase proteases, blocked TNF--induced reductions in Oligodendrocytes.

Indicating, the TNF--induced reduction in Oligodendrocytes is, at least in part, due to Apoptosis, and that ICE/caspases are one of TNF- action mediators.

Simultaneous addition of IGF-I to TNF--treated cultures negated these TNF- effects nearly completely.

Furthermore, IGF-I promoted Oligodendrocyte precursor proliferation and/or differentiation in TNF--treated cultures.

To analyze TNF- and IGF-I actions on Oligodendrocyte function, we measured the abundance of messenger RNAs (mRNAs) for two major Myelin-specific proteins, Myelin Basic Protein (MBP) and ProteoLipid Protein (PLP).

While TNF- decreased MBP and PLP mRNA abundance by 5- to 6-fold, IGF-I abrogated TNF--induced reductions in a dose- and time-dependent manner.

The changes in MBP and PLP mRNA abundance could not be completely explained by the changes in Oligodendrocyte number, indicating that Myelin protein Gene expression is regulated by both TNF- and IGF-I.

These data support the hypothesis that TNF- can mediate Oligodendrocyte and Myelin damage, and indicate that IGF-I protects Oligodendrocytes from TNF- insults by blocking TNF--induced Apoptosis.

And, by promoting Oligodendrocyte and Precursor proliferation/differentiation and Myelin protein Gene expression.

Experimental AutoImmune EncephaloMyelitis (EAE) induced by active immunization with the Myelin Oligodendrocyte Glycoprotein (MOG) is an Ab-mediated, T-Cell-dependent AutoImmune Disease that replicates the inflammatory DeMyelinating pathology of Multiple Sclerosis.

We report that disease susceptibility and severity are determined by MHC and MHC-linked effects on the MOG-specific B-Cell response that mediate severe clinical EAE in the EAE-resistant Brown Norway (BN) rat.

Immunization with the ExtraCellular domain of MOG in CFA induced fulminant clinical disease associated with widespread DeMyelination and with an inflammatory infiltrate containing large numbers of PolyMorphonuclear Cells and Eosinophils within 10 days of immunization.

To analyze the effects of the MHC (RT1 system) we compared BN (RT1 n) rats with Lewis (LEW) (RT1 l) and two reciprocal MHC congenic strains, LEW.1N (RT1n) and BN.1L (RT1 l).

This comparison revealed that disease severity and clinical course were strongly influenced by the MHC haplotype that modulated the Pathogenic MOG-specific AutoAntibody response.

The intra-MHC recombinant congenic strain LEW.1R38 demonstrated that Gene loci located both within the centromeric segment of the MHC containing classical Class I and Class II Genes and within the telomeric RT1.M region containing the MOG Gene are involved in determining Ab production and disease susceptibility.

This study indicates that the current T-Cell-centered interpretation of MHC-mediated effects on disease susceptibility must be re-assessed in Multiple Sclerosis and other AutoImmune Diseases in which AutoAntibody is involved in disease PathoGenesis.

Background
Interferon-beta (IFN-ß) lessens the overall frequency of acute attacks in patients with the Relapsing/Remitting form of Multiple Sclerosis (RRMS). IFN-ß may act by decreasing the synthesis of inflammatory Cytokines.

Objectives
To determine whether IFN-ß-1b treatment had an initial and sustained effect on the in vivo synthesis and secretion of Tumor Necrosis Factor alpha (TNF) and IFN.

Methods
A highly sensitive reverse-transcriptase PCR technique was used to measure baseline levels of mRNA in freshly isolated cells from patients before therapy and at 3, 6, and 12 months of treatment.

Also, protein concentration was measured in Serum and in culture supernatants from Mitogen-Stimulated Cells. The authors studied 16 patients, of whom 11 did not have clinical exacerbations, whereas 5 had one clinical relapse each during the study.

Results
Mean values of TNF mRNA levels in the 11 stable patients decreased significantly at 3 and 6 months of treatment in comparison with initial data.

After 6 months of therapy, IFN-ß-1b down modulated TNF transcripts in the 5 patients who experienced relapse.

In this group of patients, TNF levels rose sharply to reach pretreated values at 1 year of IFN-ß-1b treatment.

At the beginning of therapy, 6 patients had high concentrations of Serum TNF, which decreased to normal values following IFN-ß-1b therapy.

IFN mRNA expression also diminished after 6 and 12 months of IFN-ß-1b therapy in the group of stable patients, whereas nonrelevant variations were observed in patients who had one relapse.

Initially, patients' Peripheral MonoNuclear Cells secreted diminished amounts of TNF and IFN on PHA + PMA mitogen stimulation in comparison with normal control subjects.

After 1 year of therapy, IFN-ß-1b restored the normal production of TNF, whereas therapy did not restore IFN secretion to control values.

Conclusion
IFN-ß-1b decreases the spontaneous expression of two proinflammatory Cytokines.

Susceptibility to several disorders, including Insulin-dependent Diabetes Mellitus and Multiple Sclerosis, has been associated with alleles of HLA Class II Genes and loci in the TNF cluster in the central Major Histocompatibility Complex (MHC) region.

As recombination within this region is rare, it is difficult to determine which Genes are important. This will be facilitated by the identification of functional polymorphisms.

Hence we are sequencing reverse transcription-polymerase chain reaction products derived from central MHC Genes in well characterized and conserved ancestral haplotypes.

Here we address the IKBL gene, which lies near the TNF cluster at the telomeric end of the central MHC.

Although the IKBL cDNA sequence was conserved between most ancestral haplotypes, a synonymous nucleotide substitution, a 3' untranslated region substitution, and a single nonsynonymous substitution were identified.

The latter (IKBL+738) was present in multiple examples of the 7.1 haplotype [HLA-A3, B7, DR2 (DR15)] and resulted in a Cysteine to Arginine substitution in a predicted protein kinase C phosphorylation site.

This polymorphism did not occur in 18 other common haplotypes from the 10th International HistoCompatibility Workshop and thus appears haplospecific.

A role for IKBL+738 in the association between HLA-A3,B7,DR2(DR15) and susceptibility to Multiple Sclerosis is discussed.

Adhesion molecules on the Endothelial surface of the Blood-Brain Barrier (BBB) play an important role in the PathoGenesis of many Encephalopathies, including Multiple Sclerosis (MS) and Cerebral Malaria (CM).

The expression of four surface molecules of relevance to MS and CM on the immortalized human umbilical vein Endothelial Cell Line, ECV304, was investigated using Immunofluorescence flow cytometry.

We found that ECV304 cells express InterCellular Adhesion Molecule-1 (ICAM-1) and low levels of CD36, but not Vascular Cell Adhesion Molecule-1 (VCAM-1) or E-Selectin.

This expression pattern was unaltered on ECV304 cells which were co-cultured with C6 Glioma Cells; conditions under which the Endothelial Cells

Tumor Necrosis Factor-alpha (TNF-), which is elevated in MS and CM, decreased the integrity of the barrier in co-cultured Endothelial Cells and upregulated the expression of ICAM-1 nine-fold.

The significance of elevated ICAM-1 expression in relation to the binding of parasitised Erythrocytes at the BBB in CM is discussed.

Copyright 1999 Elsevier Science B.V.

There are occasional reports about the low prevalence of Multiple Sclerosis among Gypsies.

To verify these reports of low prevalence of Multiple Sclerosis among Gypsies compared to the white population in Bulgaria, an Epidemiological study was conducted in two small regions of Bulgaria.

All patients with clinically or laboratory-supported, definite Multiple Sclerosis according to Poser's criteria were personally interviewed and examined. The study was begun on January 1, 1997 and March 31, 1998 was selected as prevalence day.

For the white population, the prevalence ratio of Multiple Sclerosis per 100,000 population was 44.9 in the first region and 44.4 in the second.

The prevalence of Multiple Sclerosis in Gypsies was found to be 19.1/100,000 in the first region and 18.4 in the second.

It is concluded that Multiple Sclerosis is less common in Gypsies than in whites living in the same areas.

The relationship between Multiple Sclerosis (MS) and the HLA Antigens DR2 and DQ1 is well recognized, but, in Spain, it has not been clearly defined.

The aim of our study was to investigate the relationship between MS and HLA Antigens in the sanitary district of Calatayud, northern Spain, and to correlate these Antigens with the progression of the disease.

Thirty-four patients were selected from a long-term (October 1990 to July 1996) prospective survey in the region where there was a prevalence rate of 58 per 100,000 population.

The HLA Antigens were determined in 31 patients. A control group of 895 people of Caucasian race was recruited from the same population.

We performed serologic tests on all participants. Nucleotide typing was carried out in DR2-positive patients.

The most frequent Antigens in excess in MS were: A19 (odds ratio, OR: 2.29, p = 0.04), B5 (OR: 2.85, p = 0.02), B41 (OR: 7.65, p = 0.04), CW7 (OR: 3.4, p = 0.004), DR6 (OR: 6.18, p = 0.0001) and DR10 (OR: 3.4, p = 0.004).

The DR2 Antigen was also more frequent in MS patients (39%) than in controls (19%; OR: 2.69, p = 0.01). All positive DR2 patients showed the DR15(2) split but not the DR16(2) split. The frequency of Antigens CW4 and DR1 was lower in MS patients than in controls.

The CW4 Antigen was detected in 12% of the patients and in 33% of the controls (OR: 0.28, p = 0.04). The DR1 Antigen was found in 20% of the controls and in none of the MS patients (OR: undefined, p = 0.01).

The DQ1 Antigen was observed in 68% of the patients and in 50% of the controls (OR: 2.1, p = 0.07). We did not find any relationship between HLA Antigens and progression of the disease.

Although we found that DR2 Antigen is linked to MS, we also found other Antigens related to the disease. This suggests a Genetic Heterogeneity in our geographic area.

We also concluded that the DR1 Antigen may play a protective role, as it was detected in 20% of the controls and in none of the MS cases.

Ischemic Stroke is associated with altered Systemic Immune Responses both early after the onset and in the recovery phase.

InterLeukin-10 (IL-10), a Th1 related Cytokine, has multiple effects on different cell types, including T and B-Lymphocytes, Monocytes, Neutrophils and Mast Cells. IL-4 is another Th1 Cytokine that inhibits the synthesis of ProInflammatory Cytokines by Th1 clones.

We used enzyme-linked Immunospot assays to detect and enumerate blood MonoNuclear Cells (MNC) secreting IL-10 and IL-4 spontaneously as well as after stimulation with Myelin Basic Protein (MBP).

Considered to be an AutoAntigen of possible Pathogenic importance in, for example, Multiple Sclerosis, to evaluate the involvement of anti-inflammatory Cytokines in Ischemic Stroke.

All patients with Ischemic Stroke and Cerebral Hemorrhage had strongly elevated numbers of IL-10 secreting blood MNC compared with healthy individuals.

Numbers of MBP-reactive IL-10 secreting blood MNC were also elevated in a proportion of the patients with Stroke and Hemorrhage.

Levels of IL-4 secreting blood MNC did not differ in Ischemic Stroke versus healthy individuals. The anti-inflammatory IL-10 could play a pivotal role in Ischemic Stroke as well as Cerebral Hemorrhage.

Copyright 1999 Lippincott Williams & Wilkins

Multiple Sclerosis (MS) is a T-Cell-dependent chronic inflammatory disease of the Central Nervous System.

The role of Chemokines (Cytokines) in MS and its different stages is uncertain. Recent data suggest a bias in expression of Chemokine receptors by Th1 vs. Th2 Cells; human Th1 clones express CXCR3 and CCR5 and Th2 clones express CCR3 and CCR4.

Chemokine Receptors expressed by Th1 cells may be important in MS, as increased Interferon-gamma (IFN-) precedes clinical attacks, and IFN- injection induces disease exacerbations.

We found CXCR3⁺ T-Cells increased in blood of Relapsing/Remitting MS, and both CCR5⁺ and CXCR3⁺ T-Cells increased in Progressive MS compared with controls. Furthermore, peripheral blood CCR5⁺ T-Cells secreted high levels of IFN-.

In the Brain, the CCR5 Ligand, MIP-1, was strongly associated with Microglia/Macrophages, and the CXCR3 Ligand, IP-10, was expressed by Astrocytes in MS lesions but not unaffected White Matter of control or MS subjects.

Areas of plaque formation were infiltrated by CCR5-expressing and, to a lesser extent, CXCR3-expressing cells; InterLeukin-18 (IL-18) and IFN- were expressed in DeMyelinating lesions.

No Leukocyte expression of CCR3, CCR4, or six other Chemokines, or anti-inflammatory Cytokines IL-5, IL-10, IL-13, and Transforming Growth Factor-ß was observed.

Thus, Chemokine Receptor expression may be used for Immunologic staging of MS and potentially for other Chronic AutoImmune/inflammatory processes such as Rheumatoid Arthritis, AutoImmune Diabetes, or Chronic transplant rejection.